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        Permian basinal ammonoid sequence in Nanpanjiang area of South China—possible overlap between basinal Guadalupian and platform-based Lopingian
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        Permian basinal ammonoid sequence in Nanpanjiang area of South China—possible overlap between basinal Guadalupian and platform-based Lopingian
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Abstract

The Permian pandemic ammonoids in Nanpanjiang Basin (41 genera, including two new genera Glenisteroceras and Fusicrimites, and 56 species, including 21 new species) are systematically described and/or discussed. New species described in this paper are Agathiceras sequaxilirae n. sp., Akmilleria parahuecoensis n. sp., Aristoceras liuzhaiense n. sp., Bamyaniceras nandanense n. sp., Bamyaniceras yangchangense n. sp., Bransonoceras longyinense n. sp., Difuntites furnishi n. sp., Emilites globosus n. sp., Eoaraxoceras spinosai n. sp., Eumedlicottia kabiensis n. sp., Fusicrimites nanpanjiangensis n. gen. n. sp., Glenisteroceras sidazhaiense n. gen. n. sp., Metaperrinites shaiwaensis n. sp., Miklukhoceras guizhouense n. sp., Neocrimites guizhouensis n. sp., Neopronorites leonovae n. sp., Popanoceras ziyunense n. sp., Properrinites gigantus n. sp., Stacheoceras shaiwaense n. sp., Svetlanoceras uraloceraformis n. sp., and Synartinskia meyaoense n. sp. A relatively complete Permian basinal ammonoid sequence with six zones has been newly recognized in South China, in ascending order, Properrinites gigantus-Svetlanoceras serpentinum, Svetlanoceras uraloceraformis-Prothalassoceras biforme, Popanoceras kueichowense-Medlicottia orbignyanus, Metaperrinites shaiwaensis-Popanoceras ziyunense, Waagenoceras sp.-Propinacoceras beyrichi, and Eoaraxoceras spinosai-Difuntites furnishi. The upper three zones are close to being duplicated from the Permian of Las Delicias, Coahuila, Mexico and west Texas, USA; while the lower three zones compare well to those of the Lower Permian in South Urals. The Eoaraxoceras-Difuntites assemblage, as an index fauna of the upper Capitanian in Coahuila, has been found from the Claystone (3rd) Member of the Shaiwa Formation with the commonly accepted Lopingian stratigraphic age. The updated Permian ammonoid biostratigraphy in South China reveals a possible overlap between the basinal Guadalupian from North America and the platform-based Lopingian from South China.

Introduction

It has been well known since the 1920s that the Permian ammonoids found in South China display a glaringly endemic character and are difficult to compare with those found from the classic areas in the world (e.g., west Texas in USA, Urals in Russia and Kazakhstan, Timor in Indonesia, etc.) (Yabe, Reference Yabe1920, Reference Yabe1928; Chao, Reference Chao1940, Reference Chao1954, Reference Chao1955, Reference Chao1965; Zhao [formerly Chao] and Zheng, Reference Zhao and Zheng1977; Zhao et al., Reference Zhao, Liang and Zheng1978; Zhou et al., Reference Zhou, Glenister and Furnish2002; Zhou, Reference Zhou2007a, Reference Zhoub). However, comparable pandemic ammonoid assemblages were successively discovered from the Nanpanjiang Basin in southwest Guizhou and northwest Guangxi in 1980s (Zhou, 1985–Reference Zhou1986, Reference Zhou1987, Reference Zhou1988Reference Zhou1989) (Fig. 1.3.A–1.3.H). These discoveries demonstrated that the basinal solitary specimens of Popanoceras kueichowense (Zhao in Zhao and Liang, Reference Zhao and Liang1974) and Neocrimites kuangsiensis, Zhao and Liang, Reference Zhao and Liang1974 were not incidental, and verified the ecological control on the distribution of those so-called ‘pelagic’ organisms. Concomitant inspection of the geological background on the above-mentioned ‘unusual’ ammonoids resulted in the proposal of the concept of “ecological patterns” of the Permian ammonoids (Zhou, 1985–Reference Zhou1986, Zhou et al., Reference Zhou, Glenister, Furnish and Spinosa1999, figs. 3, 4).

Figure 1 Permian tectonic subdivisions, platform, and basin in South China, and the open-sea pandemic ammonoid faunas in Nanpanjiang Basin (tectonics modified from Lehrmann et al., Reference Lehrmann, Enos, Payne, Montgomery, Wei, Yu, Xiao and Orchard2005, and partially referred to Zhou, 1985–Reference Zhou1986).

An analysis of the spatial distribution of Permian ammonoids in South China confirmed that the endemic ammonoid assemblages reported in previous studies consistantly occurred within the South China Platform, mainly in the marginal region of the epicontinental sea, and exclusively in relation to the coal-bearing detrital zone. Such ammonoids and their living environment were shielded from the open ocean, and migrated in the platform interior through the paralic areas (Figs. 1.1, 1.2, 2) with eustacy, and hence named the “restricted-sea ecological pattern.”

Figure 2 Permian stratigraphic standards, and the subdivisions on background of depositional environments in South China Block—The ICS and regional standards in the left columns, the depositional environments on the top rows. The stratigraphical units are not in proportion with the real thickness, and the boundaries between environments are irregularly zigzag-like, in accordance with migration of the sedimentation. The major environmental framework is modified from Lehrmann et al. (Reference Lehrmann, Enos, Payne, Montgomery, Wei, Yu, Xiao and Orchard2005). Shadow showing the possible overlap between the Lopingian in South China and the Guadalupian in North America. The regional stages of South China are principally in accord with the Permian biostratigraphical subdivisions in the Chinese Stratigraphic Lexicon (Jin et al., Reference Jin, Shang, Hou, Li, Wang, Zhu and Fei2000, table 2). Zones 1–6 are the comparable open-sea pandemics found from the Nanpanjiang Basin and documented in the present work.

On the other hand, the pandemics in South China, systematically described herein for the first time, were basically affected by the various turbidity sequences, from the talus to various clastic limestones and siliciclastics in the open-marine basinal environment. This kind of ammonoids and deposits were chiefly distributed in front of the reef-/beach-characterized platform margin around the Nanpanjiang Basin, which was attached to the southwest margin of the South China Platform, therefore they are named with the “open-sea ecological pattern” (Figs. 1.3, 2, 3).

Figure 3 Occurrence of the Permian open-sea pandemic ammonoid faunas in Guizhou, including the northern Nanpanjiang Basin and the Early Permian Pu’an-Qinglong Beipanjiang Fault-Depression in platform interior. Enlarged on the framed part of the basin area in Figure 1.3.

Taxonomically, the former from the restricted-sea is mainly featured by the tornoceratins (Paleozoic ammonoids with siphuncle-heterotopia ontogenetically), the Paleozoic primitive ceratitids, and some eurytopic or specialized goniatitids; whereas the latter, from the open sea, is normally characterized by the representatives with the ventral-located siphuncle, namely, the order Prolecanititida, and the great majority of the order Goniatitida (Zhou, 1985–Reference Zhou1986).

The regional geological survey carried out by the Geological Bureaus of Guizhou and Guangxi Provinces since the late 1970s has confirmed that the Nanpanjiang area is a reliable basin with some micro-intra-basinal carbonate platforms, characterized by almost complete marine depositional history from the late Proterozoic through the Late Triassic. In Permian, the Nanpanjiang Basin formed a relatively deep-marine embayment by the southwest margin of the South China Platform. A successive facies series from basin, through platform-margin, platform-interior, paralic, finally to the terrestrial could be traced in the northwest profiles in both southwest Guizhou and northwest Guangxi up to west Yunnan (Figs. 1, 2).

All the geological knowledge, known so far, indicates that the Nanpanjiang Basin is certainly not a Triassic allochthonous terrane as first thought by Hsü et al. (Reference Hsü, Li, Chen, Wang, Sun and Sengör1990).

Investigation of the Permian pandemic ammonoids within Nanpanjiang area has discovered 41 genera and 56 species in total; besides the monotypic Popanoceras kueichowense (Zhao in Zhao and Liang, Reference Zhao and Liang1974) and Neocrimites kuangsiensis Zhao and Liang, Reference Zhao and Liang1974, the additional taxa were sampled by the present author in a series of field works during 1982–1996. All these open-sea materials (including two new genera, Glenisteroceras and Fusicrimites, and 21 new species) are formally described and/or discussed. They might be grouped into six ammonoid zones with fairly good comparability to those in the major classic areas, North America, Pamirs, and South-Urals.

Discovery of the pandemic ammonoid sequence in the Nanpanjiang Basin, especially, the Eoaraxoceras spinosai n. sp.-Difuntites furnishi n. sp. Zone, the Waagenoceras sp.-Propinacoceras beyrichi Zone, and the Metaperrinites shaiwaensis n. sp.-Popanoceras ziyunense n. sp. Zone, from the basinal Shaiwa-Sidazhai general section (Sec. IV-IV”) (Figs. 4 6, 9) indicates identity with equivalents from the Permian section of Las Delicias, Coahuila, Mexico (Miller, Reference Miller1944; Wardlaw et al., Reference Wardlaw, Rudine and Nestell2000). Direct correlation through the zonation of the ‘top index fossils’ leads to the conclusion that one or more stage inaccuracies may exist in the traditional correlation scheme between the South China (even the entire Tethys) and North America. Most noticeably, the platform-based Lopingian Series partially overlaps with the basinal Guadalupian (Capitanian and probably the upper Wordian Stage) (Figs. 2, 6, 9). This work confirms the previous conclusion that the Dzhulfian in Transcaucasia represents the overlap of at least part of the Capitanian of North America based on the material from Abadeh, central Iran (Zhou et al., Reference Zhou, Glenister and Furnish1989, p. 282).

Figure 4 Sidazhai Formation of Shaiwa section (Sec. IV-IV’), started near Gaijiao and ended near Chongtou Villages, Shaiwa, Sidazhai, Ziyun County, Guizhou; coordinates based on Google Maps: origin ~25.6065°N, 106.1577°E, ending ~25.6090°N, 106.1506°E. The section mainly consists of turbid calcareous deposits, overlain by the Shaiwa Formation and overlying the Nandan Formation, both conformably (Modified from Xiao et al., Reference Xiao, Wang, Zhang and Dong1986; the present author joined in measurement of the section in 1982).

Figure 5 Shaiwa Formation of Sidazhai section (Sec. IV’-IV”) starting near the town of Sidazhai, north-west ward, consisting of four segments with a total parallel shift in strike of the strata of 500m. Measured by Wang C.-W. and Liu A.-M. of the Regional Geological Surveying Academy in 1996; the present author partially joined in the field work; coordinates based on Google Maps; origin ~25.5864°N, 106.1651°E, ending ~25.5990°N, 106.1459°E.

Figure 6 Columnar stratigraphic section of the Sidazhai and Shaiwa formations based upon the Shaiwa-Sidazhai general section (Sec. IV-IV”), Ziyun County, Guizhou, showing the biostratigraphic relationship between the basinal deposits with the open-sea ammonoid zonation (Zones 6 to 4 and the equivalent Zone 3) and the Time Scales (both ICS and Regional) through the control of the T/P boundary and the fusulinid faunas of the Yanghsingian and Chuanshanian Series. The whole sequence contains the Longlinian through the Changhsingian Stages. The shadow represents the possible overlap between the basinal Capitanian with partial Wordian, and the platform-based Wuchiapingian. Legends see Figures 4 and 5.

The present memoir is the first to summarize the systematics, occurrences, and zonation of the pandemic ammonoids in Nanpanjiang Basin of South China, and clarifies the biostratigraphical significance upon the new collections. There are two sections, Shaiwa-Sidazhai general (Sec. IV-IV”) (Figs. 46, 9) and Meyao (Sec. V) (Figs. 7 9), representing the total basinal Permian in South China (Appendices 1 and 2, respectively).

Figure 7 (1) Meyao section (Sec. V), showing the Nandan Formation and Longma Member of the Sidazhai Formation (Measured by Huang Z.-X. et al., 1986, the Regional Geological Surveying Academia of Guangxi; published by Kuang et al., Reference Kuang, Li, Zhong, Su and Tao1999); coordinates based on Google Maps; origin ~25.2781°N, 107.3887°E, ending ~25.2755°N, 107.3931°E. (2) Geological map of Liuzhai District, Nandan County, Guangxi, with position of sections and ammonoid localities studied herein (Modified from the draft of Huang Z.-X., Regional Geological Surveying Academy of Guangxi Geological Bureau, 1986).

Figure 8 Columnar stratigraphic section of the bottom Sidazhai and the Nandan formations upon Meyao section (Sec. V), showing positions of the Zones 1 to 3, Liuzhai, Nandan County, Guangxi.

Figure 9 The Permian ammonoid zones 16 in Nanpanjiang Basin and the Permian intercontinental correlation between the Coahuila, Mexico in the Western Hemisphere, and the Nanpanjiang Basin, South China in the Eastern Hemisphere based on the ammonoid zones 4, 5, and 6.

Permian deposits in Nanpanjiang Basin and adjacent areas

The South China Block consisted of three components: Yangtze Craton (Fig. 1.1), South China Fold-Belt (Fig. 1.2), and Nanpanjiang Basin (Fig. 1.3). The first two combined to form the South China Platform (Fig. 1.1, 1.2) before the Late Paleozoic.

Comparative study of the environments and sedimentation between the basin and platform helps clarify the ecological differentiation and biostratigraphical sequences of the Permian ammonoids in the areas. A primary comparison had been made in 1980s by the present author (Zhou, 1985–Reference Zhou1986), and a visual comparison of the environments vis-à-vis the depositional units in the Permian of southwest Guizhou was made by Lehrmann et al. (Reference Lehrmann, Enos, Payne, Montgomery, Wei, Yu, Xiao and Orchard2005).

The present memoir, in accordance with Lehrmann and others, catagorizes the stratigraphic units of the Permian in southwest Guizhou and northwest Guangxi into five depositional environments: the basin, platform margin, platform interior, paralic, and terrestrial. The present memoir also follows the Chinese Stratigraphic Lexicon, which subdivides the Permian System into six local Stages, in descending order: Changhsingian and Wuchiapingian in the Upper (Lopingian) Series, Maokouan and Chihsian in the Middle (Yanghsingian) Series, and Longlinian and Zisongian in the Lower (Chuanshanian) Series (Jin et al., Reference Jin, Shang, Hou, Li, Wang, Zhu and Fei2000). The entire range of five depositional facies is represented in these Permian stratigraphical units (Fig. 2).

The Nanpanjiang Basin

Lehrmann et al. (Reference Lehrmann, Enos, Payne, Montgomery, Wei, Yu, Xiao and Orchard2005, p. 153) briefly summarized the basic characters of the basin (Fig. 1.3): “The Nanpanjiang Basin was broad, although rather shallow, but in southern Guizhou it was confined to a narrow gulf. The Early Permian deposits in the basin were dark-gray to black thin-bedded limestone, and mudstone, intercalated with debris-flow breccia” (e.g., Nandan Formation and lower Sidazhai Formation, 300–500 m thick). “The Middle Permian deposits in the basin were claystone and marl with subordinate limestone and shale” (e.g., upper Sidazhai Formation, 350–650 m thick). “In the Late Permian, the Nanpanjiang Basin in Guizhou became even narrower, presumably because of gradual progradation of the platform rimmed by reefs and bioclastics. Basinal deposits are claystone and bedded chert that enclose carbonate breccia and bioclastic limestone, probably turbidities” (e.g., Shaiwa Formation, about 860 m thick in Sidazhai section, VI’-VI”). Generally, deposits in the east basin were not destroyed during the Permian, although there was an obvious “Dongwu Movement” with numerous basalt eruptions around the boundary, between the Maokou Limestone and the Lungtan Coal Measure in the western part of South China (Huang and Chen, Reference Huang and Chen1987; Guizhou Bureau of Geology and Mineral Resources, 1987).

The South China Platform

There are four primary geographical units within the platform: margin of platform, platform interior, paralic, and terrestrial, respectively (Fig. 2). Facies migration in the platform frequently proceeded along the south-north direction in the Early Permian, altering to the east-west direction in the Late Permian. The major change in the direction of the depositional migration with time probably resulted from the ‘Dongwu Movement’ with extensive faults and large amounts of basalt. In the Late Permian, the material source at the Khamdian Massif was west of the epicontinental restricted sea of South China (Zhou, 1985–Reference Zhou1986, fig. 3; Figs. 1, 2).

Platform margin

The platform margin is a rather narrow belt, in most cases only several kilometers in width, and clearly marked by the reef and/or beach belt approximately westward along the line of county-towns (e.g., Luodian, Wangmo, Ziyun, Ceheng, and Xingning) in southwest Guizhou (Fig. 3). Deposits of the platform margin, which are represented by the Houziguan Formation, below, and the Wuchiaping Formation, above (Figs. 2, 3), mainly consisted of bioclastic limestone and sponge and/or coral boundstone. Although the pandemic Eumedlicottia kabiensis n. sp. and Propinacoceras beyrichi Gemmellaro, Reference Gemmellaro1887 combination is present in the intercalated claystone of Member XII, Houziguan Formation at Kabi within the marginal zone, it actually represents the progradation of the basinal deposit nearby.

Platform interior

The platform interior is present in the backreef area, which is characterized by deposits of bioclastic micrite, argillaceous limestone, chert, calcareous siltstone, and claystone, with all shallow-water indicators, and interfingered with the landward paralic deposits during eustacy. As a special case, the transient “Beipanjiang Fault-Depression” in west Guizhou, which is deeply embedded in the platform, probably represents the extension of the basin gulf, or a local faulted diminutive basin in the Early Artinskian, including the Longyin (Pu’an County)-Huagong (Qinglong County)-Langdai (Liuzhi County) area along the northwest tectonic strike, with tens to a thousand or more meters of detrital rocks and limestone containing the open-sea pandemic ammonoid fauna (Figs. 1.A, 3.A). However, rapid filling eliminated the depression by the later Cisuralian. In contrast to the Nanpanjiang Basin, the restricted-sea ammonoid assemblages occur in some marine-mudstone and/or in the platform-interior deposits (e.g., the Shengoceras [i.e., ‘Kufengoceras’] Fauna in the Kuhfeng Formation, the Araxoceras Fauna in the Heshan Formation, and the Pseudotirolites Fauna in the Talung Formation) (Fig. 2). They represent transitional facies (biotopes) between the carbonate and coal-bearing facies in the Middle to Late Permian in South China (Zhou et al., Reference Zhou, Zhu, Li and Hu1995).

Paralic area

The paralic area is present in a wider belt between the terrestrial and the marine-fossiliferous carbonate areas, which is along the lines between Weining and Fuyuan in the west, and Bijie and Pu’an in the east (Figs. 1, 2). There are still a few marine layers in the Lungtan and Wangjiazhai coal-bearing formations in the area, even preserving the restricted-sea ammonoid fauna at the top Lungtan Formation (Xiao, Reference Xiao1996, p. 289).

Terrestrial area

The terrestrial area represents the major siliciclastic source area distributed along the east wing of the Khamdian Oldland, or west of the epicontinental restricted sea of South China (Zhou, 1985–Reference Zhou1986, fig. 3; Figs. 1, 2).

Generally, regional deposition with consistent facies distribution indicates the Nanpanjiang area was an autochthonous part of South China in the Permian, tectonically, while the sum of the Shaiwa, Sidazhai, and upper Nandan formations (as basinal Permian units) is equal to or exceeds the total simultaneous deposits within the platform, stratigraphically.

Occurences of Permian open-marine pandemic ammonoids in Nanpanjiang Basin

Although unusual, it is important, that successive marine deposits with Permian comparably pandemic ammonoid zones occurred extensively in the Nanpanjiang Basin of South China. This occurrence provides the ability to correlate the platform-based Permian, Upper (Lopingian), Middle (Yanghsingian), and Lower (Chuanshanian) Series of South China to the basinal Guadalupian Series of North America and the Cisuralian Series of the Urals through the traditional index ammonoid zonation.

Six sections and at least 11 localities in the basin have yielded Permian pandemic ammonoids. These 17 sites are principally distributed in basin-slope or ‘micro-intra-basinal platforms’, and grouped into A to H districts geographically (Fig. 1.3.A–1.3.H).

Area A: the Longyin-Langdai district in western Guizhou

Two sections and one locality (Figs. 1.3.A, 3.A). As an exception, the area is near the Beipanjiang River, rather than in the Nanpanjiang Basin, where it probably is integrated as a faulted-depression stretched into the platform, while preserving normal connection with open sea of the Nanpanjiang Basin during Artinskian.

Longyin section (sec. I)

About 27 km linear distance north of the county-town of Pu’an, Guizhou, beginning near Longyin Village and ending near Baomoshan (Zhang et al., Reference Zhang, Rui, Zhao, Zhou, Wang, Li, Li and Kang1988, p. 18, fig. 10). Two local stages are included in the Longyin section: the Zisongian below, which is equal to 2nd and 3rd members of the Nandan Formation; and the Yangchangian above, which is approximately equal to the sum of the Baomoshan and Longyin formations. The Longyin (sensu lato) as a stage was replaced by the Longlinian Stage in the Chinese Stratigraphic Lexicon (Jin et al., Reference Jin, Shang, Hou, Li, Wang, Zhu and Fei2000) (Fig. 2). According to ammonoids collected from the Longyin Formation, the lower part of Longlinian Stage indicates an early Artinskian age (Zhou, Reference Zhou1988Reference Zhou1989), not Sakmarian (Wu et al., Reference Wu, Dong, Wang, Liao, Long and Zhang1979), nor Asselian through Sakmarian (Zhang et al., Reference Zhang, Rui, Zhao, Zhou, Wang, Li, Li and Kang1988). There are two major ammonoid-bearing claystone beds in the Longyin Formation (early Longlinian Stage), in descending order:

Bed 12:

Bamyaniceras nandanense n. sp. (NIGP 88973)

Eothinites cf. E. kargalensis Ruzhentsev, Reference Ruzhentsev1933 (NIGP 93752)

Bransonoceras longyinense n. sp. (NIGP 93674, 93662)

Bed 3:

Bamyaniceras nandanense n. sp. (NIGP 88974, 93747–93749, 93751)

Miklukhoceras guizhouense n. sp. (NIGP 154102, 154103)

Sicanites notabilis (Ruzhentsev, Reference Ruzhentsev1940c) (NIGP 154109)

Daraelites elegans Chernov, Reference Chernov1907 (NIGP 88980, 88981)

Almites sp. (NIGP 89015)

Bransonoceras longyinense n. sp. (NIGP 93660, 93661, 93685, 93739, 93740, 93743)

Popanoceras kueichowense (Zhao in Zhao and Liang, Reference Zhao and Liang1974) (NIGP 154091, 154093)

Eothinites cf. E. kargalensis (NIGP 93753)

Huagong section (sec. II)

About 25 km linear distance northwest of the county-town of Qinglong, and 10 km southeast to the Longyin section, beginning near the Huagong Tea-Plantation and measured northward (Xiao et al., Reference Xiao, Wang, Zhang and Dong1986; Zhou, Reference Zhou1988Reference Zhou1989). Ammonoids were collected mostly from beds 19–17 of the Longyin Formation, which consists of claystone, silty claystone, intercalating thin quartz sandstone, and lenses of marlstone. This section is approximately equivalent to Bed 3 of the Longyin section (sec. I), also early Artinskian age.

Beds 19–17 (total 14 m thick):

Neopronorites darvasicus Leonova, Reference Leonova1988 (NIGP 93663)

Miklukhoceras guizhouense n. sp. (NIGP 93678–93681)

Akmilleria parahuecoensis n. sp. (NIGP 93686)

Medlicottia orbignyanus (Verneuil, Reference Verneuil1845) (NIGP 93691, 93692)

Agathiceras sp. (NIGP 93708)

Almites sp. (NIGP 93718, 93719)

Pseudoschistoceras sp. (NIGP 93723)

Bransonoceras longyinense n. sp. (NIGP 93724–93727)

Ladang locality (loc. 1)

A well-preserved ammonoid individual collected from the ‘Tongkuangxi’ Formation (e.g., the Longyin Formation in current usage), at Village Ladang (about 26.0455°N, 105.2276°E), 13 km southwest of Langdai, Liuzhi County, Guizhou, near the Beipanjiang River, but now submerged under a huge reservoir, dammed on the river. The solitary specimen originally was identified as Propopanoceras kueichowense Chao, Reference Chao1965 (nom. nud.), with an assigned age of Sakmarian, although the formal description was not published until 1974. Finally, it was recombined into the genus Popanoceras (Zhou, Reference Zhou1989–1999), with an early Artinskian age. The monotypic Popanoceras kueichowense (Zhao in Zhao and Liang, Reference Zhao and Liang1974) (NIGP 22029) is the only, but important, representative at the locality.

Area B: the Sidazhai-Yangchang district in southwestern Guizhou

Area B encompases two sections and two localities in Ziyun County (Figs. 1.3.B, 3.B), including the Shaiwa-Sidazhai general section (sec. IV-IV”), which provides the major references of the Permian ammonoid zonation in the Nanpanjiang Basin.

Yangchang section (sec. III)

This section is 13km southeast of Ziyun, in ammonoid-bearing claystone within beds 35–32 of the Yangchang Formation (Zhang et al., Reference Zhang, Rui, Zhao, Zhou, Wang, Li, Li and Kang1988, p. 5). Ammonoids, which are close to forms from the lower Longyin Formation of the Longyin section (sec. I), also have an early Artinskian age:

Parapronorites cf. P. rectus Leonova, Reference Leonova1989 (NIGP 88971, 88972)

Bamyaniceras knighti (Miller and Furnish, Reference Miller and Furnish1940a) (NIGP 154106, 154107)

Bamyaniceras nandanense n. sp. (NIGP 93745, 93746)

Bamyaniceras yangchangense n. sp. (NIGP 154098–154101)

Sicanites notabilis (Ruzhentsev, Reference Ruzhentsev1940c) (NIGP 88982)

Eothinites cf. E. kargalensis Ruzhentsev, Reference Ruzhentsev1933 (NIGP 154079, 154080)

Miklukhoceras guizhouense n. sp. (NIGP 154105)

Shaiwa-Sidazhai general section (sec. IV-IV”)

The Shaiwa-Sidazhai general section was measured as two independent, but connected sections by the Regional Geological Survey Academy of Guizhou in 1982 and 1996, respectively (Figs. 2, 4--6, 9; Appendix 1). The author was invited to join in both programs for field investigation and ammonoid study.

The upper section, Sidazhai section (Sec. IV’-IV”), in the Shaiwa Formation, started from north Sidazhai, about 20 km southeast of Ziyun (Figs. 2, 5, 6) (coordinates based on Google Maps: origin about 25.5864°N, 106.1651°E, end about 25.5990°N, 106.1459°E). The section is along the footpath toward the northwest, consisting of four segments, totalling ~500 m, with parallel shifts along the stratum strike.

The Shaiwa Formation, which is ~800 m thick, mainly consists of turbid debris deposits, claystone, and bedded chert. It is subdivided into four members based on the major rock properties: the Calcirudite (4th), the Claystone (3rd), the Sandstone (2nd), and the Siliceous Rocks (1st) members, in descending order. The formation conformably overlies the upper Chongtou Member of the Sidazhai Formation, which preserves a fusulinid-bearing bioclastic calcarenite with Metadoliolina lepida (Schwager), Neoschwagerina sp., Reichelina sp., Kahlerina sinensis Sheng, Codonofusiella sp., Verbeekina sp. (Xiao et al., Reference Xiao, Wang, Zhang and Dong1986, identified by Zhang, L.-X. and Dong, W.-L.). This part of the section is equivalent to the upper Maokou Limestone in the platform interior.

The Shaiwa Formation is conformably overlaid by gray, thin-bedded calcareous mudstone with the ammonoid Ophiceras sp. and the bivalve Claraia sp. of the Lower Triassic Luolou Formation. The formation represents the basinal deposits of Lopingian age in Nanpanjiang area. Ammonoids are present in almost all of the beds of the section, but they are especially abundant in two guide horizons: the Eoaraxoceras fauna from the Claystone (3rd) Member, and the Waagenoceras fauna from the bottom Siliceous Rocks (1st) Member.

The lower section, Shaiwa section (Sec. IV-IV’), in the Sidazhai Formation, starts near Gaijiao Village and ends near Chongtou Village (Figs. 2, 4, 6) (coordinates based on Google Maps: origin about 25.6065°N, 106.1577°E, and ending about 25.6090°N, 106.1506°E). It was measured in the program “Early Permian Stratigraphy and Faunas in southern Guizhou” in 1982 (Xiao et al., Reference Xiao, Wang, Zhang and Dong1986). The section mainly consists of turbid calcareous deposits, conformably underlying the Shaiwa Formation and overlying the Nandan Formation, equal to the sum of the Maokouan with advanced fusulinid neoschwageinids, the Chihsian (sensu lato) with typical Misellina fusulinids, and the Longlinian with Pamirina-Robustoschwagerina fusulinids from the platform interior. The perrinitid ammonoid fauna is found in siliceous limestone lenses of the Chihsian Misellina claudiae horizon.

The Shaiwa-Sidazhai general section presumably represents the most complete Artinskian through the Lopingian sequence of the open-sea facies in South China, and contains the major ammonoid faunas occurring in the American equivalents biostratigraphically. Although there are no ammonoids reported from the underlying Nandan (or Maping) Formation in the Shaiwa section (Sec. IV-IV’) so far, the Asselian through the Artinskian pandemics could be supplied by the Meyao section (Sec. V) in the adjacent Liuzhai area, Nandan County, northwest Guangxi (Fig. 2, 7, 8).

Ammonoids collected from the Sidazhai-Shaiwa general section (IV-IV”) are listing in descending order as following:

Shaiwa Formation: Calcirudite (4th) Member:

KTP5-35:

Ammonoid fragments with regular longitudinal lirae probably represent individuals of the genus Pseudogastrioceras, and some fragments with two well-preserved rows of rib-like nodes may represent some medlicottids, as well as some remains of trilobites.

Claystone (3rd) Member:

KTP5-31:

Stacheoceras shaiwaense n. sp. (NIGP 139934 and 139940)

Difuntites furnishi n. sp. (NIGP 139933)

KTP5-26:

Difuntites furnishi n. sp. (NIGP 139932)

KTP5-23:

Epadrianites involutus (Haniel, Reference Haniel1915) (NIGP 139941–139944)

Stacheoceras shaiwaense n. sp. (NIGP 139935–139939)

?Timorites sp. (NIGP 154112)

Difuntites furnishi n. sp. (NIGP 139931)

?Xenodiscus sp. (NIGP 139955)

Eoaraxoceras spinosai n. sp. (NIGP 139945–139954)

Sandstone (2nd) Member:

KTP5-17:

Ammonoid fragments with regular, longitudinal lirae probably represent individuals of the genus Pseudogastrioceras.

Siliceous Rocks (1st) Member:

KTP5-12:

Ammonoid fragments with paraceltitin-shape and ridged venter

?Cibolites

KTP5-1 (equal to Bed 29), as the top of the Shaiwa section (Sec. IV-IV’), measured in 1982:

Ammonoid fragments with sculpture of adrianitids and paraceltitins

Waagenoceras sp. (NIGP 93715)

?Adrianites sp.

?Paraceltites sp.

Sidazhai Formation:

Chongtou Member: Mainly bioclastic calcarenite with turbid characters; the upper part is characterized by Metadoliolina lepida (Schwager), Yabeina gubleri Kanmera, Neoschwagerina kueichowensis Sheng, and many other Maokouan fusulinids (Sheng, Reference Sheng1963).

Lower part, Bed 12, is characterized by Misellina claudiae (Deprat) fusulinid fauna and the following ammonoids:

Parapronorites timorensis Haniel, Reference Haniel1915 (NIGP 93654–93656)

Prostacheoceras sp. (NIGP 93717)

Glenisteroceras sidazhaiense n. gen. n. sp. (NIGP 93728–93729)

Neocrimites guizhouensis n. sp. (NIGP 93711–93712)

Fusicrimites nanpanjiangensis n. gen. n. sp. (NIGP 93713)

Agathiceras mediterraneum Toumanskaya, Reference Toumanskaya1949 (NIGP 93704–93707)

Metaperrinites shaiwaensis n. sp. (NIGP 93714)

Popanoceras ziyunense n. sp. (93734–93738)

Gaijiao Member: Abundant ammonoid fragments are found in almost all the mudstone beds of the member, however the better specimens mainly are concentrated in Bed 6.

Bed 6:

Parapronorites cf. P. rectus Leonova, Reference Leonova1989 (NIGP 93658, 93659)

Propinacoceras toumanskayae Leonova, Reference Leonova1989 (NIGP 93672, 93673)

Bamyaniceras knighti (Miller and Furnish, Reference Miller and Furnish1940a) (NIGP 93668, 93670, 93671, 154104)

Bamyaniceras cf. B. spatiosum Leonova, Reference Leonova1992 (NIGP 93669)

Agathiceras sp.

Beds 2–1: Many fusulinids occur in the carbonate intercalations in these beds, including Robustoschwagerina sp., Pamirina sp., and schwagerinids. The underlying Nandan Formation contains gray fusulinid-bearing micrite with Sphaeroschwagerina sp. and Pseudoschwagerina sp.

Huohongchong locality (Loc. 2)

(Fig. 3.B). There is only a solitary, well-preserved specimen of Bamyaniceras yangchangense n. sp. (NIGP 154095, holotype), collected from the mudstone, ~400 m southeast of the Yangchang section (Sec. III), which supposedly is Artinskian in age.

Kabi locality (Loc.3)

(Fig. 3.B). Ammonoid-bearing claystone, representing the basinal progradation, is intercalated in the limestone of Member XII, at the top of the Houziguan Formation, which is stratigraphically equal to the top of the Maokou Formation in the platform interior. The Kabi locality is an outcrop 5 km northwest of Houchang, ~300 m west of the Village of Kabi, Ziyun County, Guizhou (coordinates on Google Maps about 25.6469°N, 106.2168°E).

The ammonoid collection presumably comes from a little below Bed 29 in the Shaiwa section (Sec. IV-IV’), but still correlates with the Waagenoceras sp. representatives of the Waagenoceras sp.-Propinacoceras beyrichi Zone, which is Wordian in age biostratigraphically. The ammonoids are listed below:

Eumedlicottia kabiensis n. sp. (NIGP 93693–93698)

Propinacoceras beyrichi Gemmellaro, Reference Gemmellaro1887 (NIGP 93664–93667)

Agathiceras suessi Gemmellaro, Reference Gemmellaro1887 (NIGP 93702–93703)

Area C: the Luodian district in south Guizhou

There is only one locality in the district (Figs. 1.3.C, 3.C).

Luodian locality (Loc. 4)

The Luodian locality is 5 km east of the county-town of Luodian in south Guizhou. There are many fragments of ammonoids, probably Agathiceras and unidentified medlicottids, found in the siliceous limestone of the bottom ‘Chihsia’ Formation.

Area D: the Liuzhai-Meyao district in northwest Guangxi

Area D includes two sections and two independent localities around Liuzhai in Nandan County, Guangxi (Figs. 1.3.D, 7.2). The major section at Meyao (Sec. V) exposes a successive lower Cisuralian ammonoid sequence. It is desirable to connect the Meyao Sction with the Shawa-Sidazhai general section (Sec. IV-IV”) to compose a successively Permian pandemic ammonoid sequence in the Nanpanjiang Basin (Figs. 2, 9)

Meyao section (Sec. V)

(Figs. 7, 8; Appendix 2). The Meyao section is 2.6 km southwest of Liuzhai town-center (coordinates using Google Maps: origin about 25.2781°N, 107.3887°E, ending about 25.2755°N, 107.3931°E), measured by Huang Z.-X., Regional Geological Survey Academy of Guangxi and the present author in 1986 (Kuang et al., Reference Kuang, Li, Zhong, Su and Tao1999). Ammonoid collections, in ascending order, labeled as 7082, 7084, and 7085, represent the Lower Permian basinal ammonoid sequence of the Asselian through the lower Artinskian. The former two collections (7082 and 7084) were sampled from the white-gray calcarenite of the 2nd and the 3rd members of the Nandan Formation, respectively. The last collection (7085) was sampled from claystone of the Longma Member, which represents the interlayer of the bottom Sidazhai Formation, approximately equal to the Longyin Formation of southwest Guizhou (Fig. 2). Ammonoids from collection 7085 are poorly preserved, but the equivalents sampled from the same member at Mading (Loc. 6), ~8 km west of the Meyao section, are adequately available. The ammonoid assemblages of the Meyao section (Sec. V) are listed in descending order as following:

Coll. 7085 (Bed 31), Artinskian in age, including:

Popanoceras kueichowense (Zhao in Zhao and Liang, Reference Zhao and Liang1974) (NIGP 154092, 154094, 154094-1) and numerous ammonoid fragments; correlates with the equivalent collection from Mading (Loc. 6).

Coll. 7084 (Bed 26), Asselian to Sakmarian in age, including:

Neopronorites leonovae n. sp. (NIGP 88969)

Metapronorites timorensis (Haniel, Reference Haniel1915) (NIGP 88663, 88664, 88966)

Agathiceras sequaxilirae n. sp. (NIGP 88987, 88988)

Svetlanoceras uraloceraformis n. sp. (NIGP 154088–1540090)

Prothalassoceras biforme (Gerasimov, Reference Gerasimov1937) (NIGP 93741, 93742)

Coll. 7082 (Bed 19), Asselian age, including:

Metapronorites timorensis (Haniel, Reference Haniel1915) (NIGP 88965)

Artinskia nalivkini Ruzhentsev, Reference Ruzhentsev1938 (NIGP 88975–88977)

Synartinskia meyaoense n. sp. (NIGP 88978, 88979)

Agathiceras sequaxilirae n. sp. (NIGP 88983, 88985, 88986)

Neopronorites leonovae n. sp. (NIGP 88967, 88968, 88970)

Emilites globosus n. sp. (NIGP 88989–88996, 88998)

Properrinites gigantus n. sp. (NIGP 89002–89004)

Eoasianites subhanieli Ruzhentsev, Reference Ruzhentsev1933 (NIGP 88999–89001)

Almites multisulcatus Bogoslovskaia, Reference Bogoslovskaia1978 (NIGP 89009–89011, 89014)

Svetlanoceras serpentinum (Maximova, Reference Maximova1948) (NIGP 150081–154087)

Prostacheoceras juresanense (Maximova, Reference Maximova1935) (NIGP 89006, 89007)

Zhuangli section (Sec. VI) (Fig. 7.2)

As a supplement, the Zhuangli section, which is 0.9 km northwest of Liuzhai (about 25.3097°N; 107.3911°E), measured by Huang Z.-X., Regional Survey Academy of Guangxi in 1986. Ammonoids with Asselian age are sampled as coll. 7095 (Bed 11), equivalent to coll. 7082 (Bed 19) of the Meyao section (Sec. V).

Coll. 7095:

Agathiceras sequaxilirae n. sp. (NIGP 88984)

Emilites globosus n. sp. (NIGP 88997)

Almites multisulcatus Bogoslovskaia, Reference Bogoslovskaia1978 (NIGP 89012, 89013)

Aristoceras liuzhaiense n. sp. (NIGP 89008)

Liuzhai Quarry (Loc. 5) (Fig. 7.2)

An abandoned quarry (about 25.3823°N; 107.3928°E), 1 km southwest of Liuzhai, by the road to Bading. The Asselian ammonoid assemblage there had already been described (Zhou, Reference Zhou1987), and is identical with collections 7082 and 7095 from the above-mentioned sections in both taxonomy and chronology. Ammonoids of the Liuzhai Quarry are revised herein, as follows:

Metapronorites timorensis (Haniel, Reference Haniel1915) (NIGP 94446–94451)

?Artinskia sp. (NIGP 94452)

Boesites intercalaris Ruzhentsev, Reference Ruzhentsev1978 (NIGP 94453–94458)

Agathiceras sequaxilirae n. sp. (formerly A. vulgatum Ruzhentsev, Reference Ruzhentsev1978) (NIGP 94459–94463)

Emilites globosus n. sp. (NIGP 94471) (formerly Emilites cf. E. prosperus Ruzhentsev, Reference Ruzhentsev1978)

Properrinites gigantus n. sp. (formerly P. plummeri Elias, Reference Elias1938; Zhou, Reference Zhou1987) (NIGP 94472)

Subkargalites liuzhaiensis (Zhou, Reference Zhou1987) (formerly Kargalites liuzhaiensis Zhou, Reference Zhou1987) (NIGP 94473)

Kargalites nandanensis Zhou, Reference Zhou1987 (NIGP 94474–94476)

Almites multisulcatus Bogoslovskaia, Reference Bogoslovskaia1978 (formerly Marathonites sp. Zhou, 1978) (NIGP 94477)

Eoasianites subhanieli Ruzhentsev, Reference Ruzhentsev1933 (NIGP 94478)

Mading locality (Loc. 6.) (Fig. 7.2)

Abundant ammonoids occur at locality about 25.3558°N, 107.2997°E; 10 km SW250° from Liuzhai, in claystones of the Longma Member, in the lower Sidazhai Formation. It is stratigraphically equivalent to the Artinskian Longyin Formation in Pu’an and Qinglong, Guizhou.

The ammonoid fauna from Mading, which corresponds to collection 7085 of Bed 31, Meyao section (Sec. V), includes:

Parapronorites cf. P. rectus Leonova, Reference Leonova1989 (NIGP 93657)

Bamyaniceras nandanense n. sp. (NIGP 93675–93677)

Miklukhoceras guizhouense n. sp. (NIGP 93682–93684)

Sicanites notabilis (Ruzhentsev, Reference Ruzhentsev1940c) (NIGP 93689)

Akmilleria parahuecoensis n. sp. (NIGP 93687, 93688)

Daraelites elegans Chernov, Reference Chernov1907 (NIGP 93699–93701)

Agathiceras sp. (NIGP 93709, 93710)

Almites sp. (NIGP 93720, 93721)

Eothinites cf. E. kargalensis Ruzhentsev, Reference Ruzhentsev1933 (NIGP 93730–93733)

Kargalites sp. (NIGP 93722)

Area E: the Tian’e district in northwest Guangxi

Two localities are included in Area E (Fig. 1.3.E): Tian’e locality (Loc. 7) and Shiangyang Village (e.g., Xiangyang Cun) locality (Loc. 8).

Tian’e locality (Loc. 7)

The Tian’e locality is an important occurrence of Metaperrinites from the ‘Chihsia’ Limestone with the fusulinid Parafusulina, from the north bank of the Hongshuihe River, suburb of the county-town Tian’e, Guangxi (about 25.0002°N, 107.1619°E). The ammonoid assemblage is dominated by the genera Metaperrinites and Cardiella. Specially, the relatively high abundance of Cardiella specimens show an excellent dimorphism of Paleozoic ammonoids. The whole assemblage is interpreted to be Kungurian in age, and includes:

Parapronorites timorensis Haniel, Reference Haniel1915 (NIGP 88961, 88962, 154096, 154097)

Metaperrinites shaiwaensis n. sp. (NIGP 89005)

Cardiella gracia Pavlov, Reference Pavlov1967 (NIGP 89016–89030)

Agathiceras sp.

Medlicottids genera and species indet.

Shiangyang Village (e.g., Xiangyang Cun) locality (Loc. 8)

This locality is within Tian’e County, about 25.04°N, 106.96°E, northwest of Tian’e (Loc. 7). Only Neocrimites guangsiensis Zhao and Liang, Reference Zhao and Liang1974 (NIGP 22028) is present in the ammonoid-bearing bed, which is thought to be ‘Chihsia’ limestone, also with a Kungulian age, just as in the Tian’e locality.

Area F: the Linyun district in northwest Guangxi

There is only one locality in the Linyuan district (Fig. 1.3.F).

Lingyun locality (Loc. 9)

The Lingyun locality is 1 km south of the Lingyun city center, northwestern Guangxi (around 24.33°N, 106.55°E), in the cliff debris accumulated on the southwest side of the road. Only a piece of phragmoconch of Metaperrinites was found in the talus in front of the reef zone. It is a potential locality for additional examination for the Artinskian-Wordian basinal ammonoid assemblage.

Area G: the Cehong district in south Guizhou

Only one locality, the Banqi locality, was found in the Cehong district (Fig. 1.3.G).

Banqi locality (Loc. 5)

This is another Metaperrinites locality, about 25 km southwest of the county-town of Ceheng, south Guizhou. The exact occurrence is unknown.

Area H: the Longlin district in northwest Guangxi

Only one locality, the Longlin locality, occurs in Longlin district (Fig. 1.3.H).

Longlin locality (Loc. 11)

The Longlin locality is 20 km southwest of the county-town of Longlin, northwest Guangxi. Some specimens that look like Agathiceras had been found in the light gray limestone of the Longlin Formation, which is equal to the topmost Nandan Formation, and might be of an Asselian through Artinskian age.

Permian open-marine pandemic ammonoid zonation of Nanpanjiang Basin

The Permian ammonoid assemblages found in the Nanpanjiang Basin in the recent decades are exclusively open-sea pandemics, with fairly good comparability to those of the classic areas globally. They can be grouped into six zones, in ascending order as follows:

Zone 1. Properrinites gigantus-Svetlanoceras serpentinum

Zhou’s (Reference Zhou1987) “First discovery of Asselian ammonoid fauna in China” is the earliest report about the comparable pandemic ammonoids from South China. Collections discussed in the paper were sampled from the Liuzhai Quarry (Loc. 5), which is in the same district as the Meyao (Sec. V) and Zhuangli (Sec. VI) sections in Area D, Liuzhai, Nandan County, northwestern Guangxi (Figs. 1.3.D, 7, 8).

The basinal Asselian ammonoids in Nanpanjiang comprise three collections, respectively labeled as collection 7082 of Bed 19, Meyao section (Sec. V); collection 7095 of Bed 11, Zhuangli section (Sec. VI); and the carbonate talus of the preceding Liuzhai Quarry (Loc. 5; Zhou, Reference Zhou1987, fig. 1). All of them are collected from the Second (2nd) Member, Nandan Formation. Although ammonoids were found from the turbidity-current deposits of the upper slope around the basin, they are still recognized as autochthonous because of the well-preserved body chambers in most cases (Jiang et al., Reference Jiang, Zhou and Huang1987).

The Asselian ammonoid assemblage comprises 15 species (including six new species) of 15 genera: Boesites intercalaris Ruzhentsev, Reference Ruzhentsev1978, Metapronorites timorensis (Haniel, Reference Haniel1915), Neopronorites leonovae n. sp., Artinskia nalivkini Ruzhentsev, Reference Ruzhentsev1938, Synartinskia meyaoense n. sp., Subkargalites liuzhaiensis (Zhou, Reference Zhou1987), Kargalites nandanensis Zhou, Reference Zhou1987, Almites multisulcatus Bogoslovskaia, Reference Bogoslovskaia1978, Aristoceras liuzhaiense n. sp., Emilites globosus n. sp., Agathiceras sequaxilirae n. sp., Eoasianites subhanieli Ruzhentsev, Reference Ruzhentsev1933, Prostacheoceras juresanense (Maximova, Reference Maximova1935), Svetlanoceras serpentinum (Maximova, Reference Maximova1948), and Properrinites gigantus n. sp.

Five genera (Neopronorites, Metapronorites, Boesites, Artinskia and Synartinskia) belong to the order Prolecanitida. Individuals of the first three genera are relatively rich in number; but the latter two occur only as a few crushed specimens. The other 10 genera (Agathiceras, Emilites, Properrinites, Eoasianites, Almites, Kargalites, Subkargalites, Svetlanoceras, Prostacheoceras, and Aristoceras) belong to the order Goniatitida, of which Eoasianites, Emilites, and Agathiceras are plentiful in the assemblage.

At the generic level, the present Asselian assemblage is conspicuously cosmopolitan, and resembles the synchronous faunas of the Urals, Texas, Pamirs, and Timor, with a basic similarity ratio of 0.8, 0.73, 0.47, and 0.33, respectively (the ratio is calculated by dividing the number of genera in common by the sum of all the genera in the fauna; the meaning is the same in the following faunal comparisons and discussion). All of the old species listed above had been found in Asselian-age strata, and some of them were exclusive to that stage. All genera, except Properrinites, are common forms in the type area of the Asselian Stage in Urals.

The seven species of Svetlanoceras that have been found thus far range from the lower Asselian through the Tastubian (lower Sakmarian), and, except for Timor, are found in the South Urals, Pamirs, ?East Himalaya, Western Australia, West Texas, Yukon, and Guangxi. Svetlanoceras serpentinum (Maximova, Reference Maximova1948) is only recorded in South Urals (Russia) and Guangxi, herein. As a classic Asselian index, it has been collected from the Kholodnolozhian Substage (the lower Asselian Stage) (Chuvashov et al., Reference Chuvashov, Chernykh and Bogoslovskaia2002), and now from the Second (2nd) Member of the Nandan Formation of Meyao (Sec. V).

Properrinites also has seven species, ranging from Asselian through Sakmarian, and is distributed in Texas, New Mexico, Kansas, Nebraska, Nevada, Pamirs, and Guangxi. Properrinites gigantus n. sp. is probably the more primitive form in the genus, based on the noticably wider but simply digitate lobes, and therefore, inferred as an Asselian representative. Some of specimens of P. gigantus n. sp. had been described as P. plummeri Elias, Reference Elias1938 (Zhou, Reference Zhou1987), but they actually are distinguished from the latter by the wider and simply digitate lobes.

Subkargalites mainly lived during the Carboniferous in the USA, Pamirs, Uzbekistan (Fergana), South Urals of Russia, and the Northwest Territories of Canada, but in South China it seems to have extended its range into the Asselian. Reexamiation of the Asselian species ‘Kargalitesliuzhaiensis Zhou, Reference Zhou1987 indicated that the material has a wider and tripartite dorsal lobe—the distinct features of Subkargalites, which confirmed the generic revision made by Leonova (Reference Leonova2002, p. S78).

The association of Properrinites and Svetlanoceras in Nanpangjiang is an interesting fact in paleobiogeography because the former had been considered as the distinctive representative of the Tethys realm, whereas the latter was considered a Boreal representative. Actually, the same association previously had been reported from Pamirs as early as the 1970s (Ruzhentsev, Reference Ruzhentsev1978).

It is noteworthy that the present ammonoid zone (Zone 1—Properrinites gigantus-Svetlanoceras serpentinum) occurs with fusulinid fauna characterized by Pseudoschwagerina, Sphaeroschwagerina, Rugosofusulina, Triticites and Schwagerina in Liuzhai Quarry (Loc. 5) (Zhou, Reference Zhou1987) and Meyao section (Sec. V). Both fossil groups were widely distributed in carbonate talus, various clastic limestones, and the micrite matrix around the debris flows. They were considered as “approximately simultaneous in age on account of that the debris-flow took place in the upper slope not far from the source area” (Jiang et al., Reference Jiang, Zhou and Huang1987, p. 286).

Zone 2. Svetlanoceras uraloceraformis-Prothalassoceras biforme

The possible Sakmarian ammonoid assemblage occurs in Bed 26, the Third (3rd) Member of the Nandan Formation in Meyao section (Sec. V) (Figs. 1.3.D, 7, 8). Ammonoids of collection 7084 here include following taxa: Neopronorites leonovae n. sp., Metapronorites timorensis (Haniel, Reference Haniel1915), Agathiceras sequaxilirae n. sp., Svetlanoceras uraloceraformis n. sp., and Prothalassoceras biforme (Gerasimov, Reference Gerasimov1937).

There is no typical Sakmarian form in the list above; however, the facts below are reasonably good indicators of the possible Sakmarian age of this fossil complex: (1) ammonoid-bearing deposits at the Third (3rd) Member of the Nandan Formation directly overlie the Asselian Second (2nd) Member of the same formation, and underlie the Artinskian Longma Member of the Sidazhai Formation stratigraphically; (2) the tendency of generic evolution in conch shape of Svetlanoceras is towards broader whorl section and diminished umbilical diameter, therefore S. uraloceraformis, with an equidimensional whorl section and smaller umbilicus, is relatively more advanced in evolution than the Asselian species, S. serpendium; and (3) the consistent association with the Robustoschwagerina-Charaloschwagerina fusulinid fauna additionally indicates a Sakmarian age.

Metapronorites timorensis Haniel, Reference Haniel1915 in the list previously had been reported from Timor and Kazakhstan in the South Urals, from Asselian through Artinskian ages. Prothalassoceras biforme (Gerasimov, Reference Gerasimov1937) was reported only from Asselian-age rocks in the Urals, but it seems more desirable to extend its geological range to the Sakmarian outside of its type area.

Zone 3. Popanoceras kueichowense-Medlicottia orbignyanus

This is the most comprehensively distributed pandemic assemblage in the study area. There are as many as seven occurrences: the Nadang locality (Loc. 1), beds 12–3 of the Longyin section (Sec. I), and beds 19–17 of the Huagong section (Sec. II) in Area A; the Huohongchong locality (Loc. 2) and beds 35–32 of the Yangchang section (Sec. III) in Area B; and the Mading locality (Loc. 6) and collection 7085 in Bed 31 of the Meyao section (Sec. V) in Area D (Figs. 1.3, 2, 3, 7, 8).

The assemblage comprises 16 species (including five new and four unidentified), belonging to 14 genera: Daraelites elegans Chernov, Reference Chernov1907, Parapronorites cf. P. rectus Leonova, Reference Leonova1989, Neopronorites cf. N. darvasicus Leonova, Reference Leonova1988, Bamyaniceras yangchangense n. sp., B. nandanense n. sp., B. knighti (Miller and Furnish, Reference Miller and Furnish1940a), Miklukhoceras guizhouense n. sp., Akmilleria parahuecoensis n. sp., Medlicottia orbignyanus (Verneuil, Reference Verneuil1845), Sicanites notabilis (Ruzhentsev, Reference Ruzhentsev1940c), Eothinites cf. E. kargalensis Ruzhentsev (Reference Ruzhentsev1933), Pseudoschistoceras sp., Bransonoceras longyinense n. sp., Almites sp., Agathiceras sp., and Popanoceras kueichowense (Zhao in Zhao and Liang, Reference Zhao and Liang1974).

The ammonoid fauna exhibits a fairly worldwide distribution. Genus-level similarities to classic areas in the Pamirs, Urals, West USA, and Timor are 0.86, 0.79, 0.64, and 0.64, respectively, with the greatest similarity to the Pamirs. The ‘Boreal’ representatives, Paragastrioceras and Uraloceras, do not appear in the fauna, but this may be due to inadequate investigation.

The geological ranges of the taxa listed-above are concentrated within the interval Artinskian though Kungurian, but the most likely age of the assemblage is Artinskian based upon the stratigraphic sequence and the evolution level of the major index taxon Popanoceras kueichowense (Zhao in Zhao and Liang, Reference Zhao and Liang1974). The solitary monotype of P. kueichowense was collected from the ‘Tongkuangxi Formation’ (i.e., the shale below the ‘Chihsia limestone’ at Ladang Village; Loc. 1), about 13 km southwest of Langdai, Liuzhi County, Guizhou (Chao, Reference Chao1965, p. 1815; Zhao in Zhao and Liang, Reference Zhao and Liang1974, pl. 159, figs. 9–11). The other plesiotypes were collected from Bed 3 of the Longyin Formation, Longyin (Sec. II), Pu’an County, Guizhou and collection 7085 of the Longma Member, Sidazhai Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi. Stratigraphically, the ammonoid-bearing claystone overlies the Nandang Formation (formerly, the Shazitang Member of the Maping Formation) of Sakmarian age, and underlies the ‘Chihsia Formation’, a limestone with the fusulinid Misellina claudiae (Deprat, Reference Deprat1912). Actually, the species Popanoceras kueichowense (Zhao in Zhao and Liang, Reference Zhao and Liang1974) is close to the primitive end in evolution of the genus, judging by its simpler serration of the lobe base and relatively less wide prong-width. All the features effectively indicate an Artinskian-age Popanoceras group (e.g., P. annae Ruzhentsev, Reference Ruzhentsev1940d, P. tschernowi Maximova, Reference Maximova1935, and P. kueichowense [Zhao in Zhao and Liang, Reference Zhao and Liang1974]).

Zone 4. Metaperrinites shaiwaensis-Popanoceras ziyunense

This assemblage in the basin has at least five localities that could be traced. The major occurrence is in the Sidazhai Formation of the Shaiwa section (Sec. IV-IV’) (Zhou, 1985–Reference Zhou1986; Xiao et al., Reference Xiao, Wang, Zhang and Dong1986), which consists of two horizons: the mudstone of Bed 6 in the Gaijiao Member below, and the siliceous limestone lens of Bed 12 in the lower Chongtou Member above (Figs. 1.3.B, 3, 4, 6).

The upper part of the ammonoid zone, a thin siliceous limestone lens that is ~45 cm thick, is intercalated in the thin-bedded micrite and calcarenite of Bed 12 in the lower Chongtou Member of the Sidazhai Formation. It directly overlies Bed 11, the fusulinid-bearing bioclastic limestone with Misellina claudiae (Deprat), Parafusulina splendens Dunbar and Skinner, Laxifusulina neimongolensis (Han), and Nankinella sp., and underlies beds 14–13 (interbedded radiolarian-bearing siliceous rocks with micrite-calcarenite) containing the fusulinids Misellina sp., Parafuslinia sp., Pseudofusulina sp. and Yangchienia sp.

The lower part mainly includes the ammonoid-bearing claystones of Bed 6, the upper Gaijiao Member, which overlies the micrite and claystone alternations of beds 5–4, with the fusulinids Robustoschwagerina aff. R. schellwieni (Hanzawa), Pamirina sp., Toriyamaia sp., Parafusulina sp., and Pseudofusulina sp. All the ammonoid-bearing beds here certainly belong to the local Chihsian Stage based on both the stratigraphic sequence and the Misellina claudiae fusulinid assemblage. Additionally, the underlying Robustoschwagerina-Pamirina beds might be collectively recognized as Longlinian Stage.

The localities of Metaperrinites sp. and Neocrimites guangsiensis are within the areas where the ‘Chihsia Limestone’ is distributed, basically corresponding to the lower Chongtou Member in the Shaiwa section. These localities include: (1) Banqi (Loc. 10), Cehong County, Guizhou (Figs. 1.3.G, 3.G); (2) Lingyun (Loc. 9), Lingyun County, Guangxi (Fig. 1.3.F); (3) Tian’e (Loc. 7), the suburb of the town-city, Tian’e County, Guangxi (Fig. 1.3.E); and (4) Shiangyang Village (Loc. 8), Tian’e County, Guangxi (Fig. 1.3.E).

The Metaperrinites shaiwaensis-Popanoceras ziyunense zone is of Kungurian age based on the following 13 species (including two unidentified) of 10 genera (including two new genera): Parapronorites timorensis Haniel, Reference Haniel1915, Bamyaniceras cf. B. spatiosum Leonova, Reference Leonova1992, B. knighti (Miller and Furnish, Reference Miller and Furnish1940a), Prostacheoceras sp., Glenisteroceras sidazhaiense n. gen. n. sp., Neocrimites guizhouensis n. sp., N. guangsiensis Zhao and Liang, Reference Zhao and Liang1974, Fusicrimites nanpanjiangensis n. gen. n. sp., Cardiella gracia Pavlov, Reference Pavlov1967, Agathiceras mediterraneum Toumanskaya, Reference Toumanskaya1949, A. sp., Popanoceras ziyunense n. sp., and Metaperrinites shaiwaensis n. sp.

Generally, the fauna resembles that of the Bolorian Kochusuisk Formation of the southeast Pamirs in both the generic composition and the association of Metaperrinites with Popanoceras at a middle evolutionary level. Although Fusicrimites is a new genus, diagnostic materials from the Kochusuisk Formation of the Pamirs led to its establishment. Other than the new species described herein, Fusicrimites actually contains another four previously established species (S. pavlovi [Leonova, Reference Leonova1988], S. dutkevitchi [Pavlov, Reference Pavlov1972], S. stuckenbergi [Karpinskii, Reference Karpinskii1889], and S. nalivkini [Toumanskaya, Reference Toumanskaya1949], in which the first one, Neocrimites pavlovi Leonova, Reference Leonova1988 is designed as the type species of the new genus). As has been well established, the Kochusuisk Formation in Pamirs is equal to the local Bolorian (Kungurian) Stage biostratigraphically.

Cardiella gracia Pavlov, Reference Pavlov1967 is abundant in the assemblage here in the ‘Chihsia Limestone’ in Tian’e suburb, which reinforces its equivalence to the Kochusuisk Formation from the Pamirs. However, the species in the present zone is not only an index of the biostratigraphy, but also a fairly good example of ammonoid dimorphism with the paired microconch and macroconch sizes.

So far, there are eight areas in the Tethys in which Kungurian and/or Roadian perrinitids-popanocertids ammonoid faunas are found: (1) Pamirs (Kochusuisk and Shindy Formations), (2) Afghanistan (Perrinites hilli and Bamyaniceras Fauna), (3) Timor (Bitauni beds), (4) Thailand (Nong Pong and Khao Khad formations), (5) South China (Sidazhai Formation in Nanpanjiang Basin), (6) North-West China (Yesonggan Formation in south Xinjiang), (7) Russian Far East (Abreskiy Bed), and (8) Japanese Kitakami Mountains (Sotokawami Formation). Comparing with above-mentioned areas, the Metaperrinites shaiwaensis-Popanoceras ziyunense Zone in South China seems a little bit lower in horizon due to its more primitive taxonomic position of the nominate genera and the association with primitive fusulinid verbeekinids Misellina, rather than with the neoschwagerinids with septula. Furthermore, the present fauna is approximately equal to or slightly older than the perrinitid localities in North America (e.g., Leonardian Cathedral Mountain Formation in the Glass Mountains of west Texas and the early Las Sardinas beds in Coahuila, Mexico with the Perrinites hilli Fauna).

Zone 5. Waagenoceras sp.-Propinacoceras beyrichi

The Wordian ammonoid assemblage in the Nanpanjiang Basin includes four taxa: Waagenoceras sp., Eumedlicottia kabiensis n. sp., Propinacoceras beyrichi Gemmellaro, Reference Gemmellaro1887, and Agathiceras suessi Gemmellaro, Reference Gemmellaro1887.

The only specimen of Waagenoceras was sampled from the bottom of the Siliceous Rocks (1st) Member of the Shaiwa Formation at the Shaiwa section (Sec. IV-IV’) (Figs. 46). Three other species, Eumedlicottia kabiensis n. sp., Propinacoceras beyrichi Gemmellaro, and Agathiceras suessi Gemmellaro, Reference Gemmellaro1887, were collected from the claystone intercalation in the top of the 12th Member of the Houziguan Formation at Kabi (Loc. 3) (Figs. 2, 3.B). The occurrence at Kabi is supposedly a little lower than the horizon of Waagenoceras sp. in the Shaiwa-Sidazhai general section (IV-VI”), but both are certainly of Wordian age.

Only five of the 13 species of Waagenoceras are found in the Capitanian Stage. The other eight species are from the Wordian Stage. However, in those ‘Capitanian’ species, only W. karpingskyi Miller, Reference Miller1944 comes from reliably dated Capitanian strata at Coahuila, Mexico. The other four species come from horizons that are thought to be ‘Capitanian’ (Tibet of China and Amur of Russia), but not reliably dated. In the case of Nanpanjiang, the generally primitive suture and the lower appearace stratigraphically both indicate a Wordian age.

Propinacoceras beyrichi Gemmellaro, Reference Gemmellaro1887, as the type species of the genus, originally was collected from the Wordian Sosio Limestone of Palermo, Sicily, and successively reported from Wordian rocks northeast Iraq, the Cephalopod limestone of Rustaq in north Aman, the Kubergandian of Afghanistan, and the Cache Creek Series of the west Pacific coast at Kamloops, British Columbia, Canada. Especially at Kamloops, P. beyrichi, as the senior synonym of P. americanum Miller and Warren, Reference Miller and Warren1933, corroborated the Wordian age owing to its association with the Wordian Waagenoceras species group and fusulinid fauna Yabeina cordillerensis, Afghanella sp., and Pseudodoliolina sp. etc. (Nassichuk, Reference Nassichuk1977).

Eumedlicottia is a distinctive genus that is present in Artinskian through Wuchiapingian/Capitanian and distributed widely in Texas, Mexico, British Columbia, Sicily, Oman, Salt Range, Far East Primor’e, Iran Adadeh, Japan Kitakami, and Nanpanjiang Basin. As a component of Waagenoceras-Propinacoceras-Eumedlicottia complex in North America, the species Eumedlicottia burckhardti (Böse, Reference Böse1919) appeared in the Wordian Cache Creek Series of Canada. Eumedlicottia kabiensis n. sp. is somewhat close to E. burckhardti in general suture characters, although the former has one more adventitious lobule in both flanks of the external saddle, even at smaller diameters (D 22 mm versus D 50–80 mm).

Zone 6. Eoaraxoceras spinosai-Difuntites furnishi

The Eoaraxoceras spinosai-Difuntites furnishi assemblage appears around beds 31–23 of the Claystone (3rd) Member, Shaiwa Formation in the Sidazhai section (Sec. VI’-VI”) (Figs. 5, 6). Ammonoids mostly occur in the claystone, siliceous mudstone, and lime siltstone as mass-coexisting molds and casts, and in a few cases as solitary individuals. Representatives of the zone include Eoaraxoceras spinosai n. sp., Difuntites furnishi n. sp., Stacheoceras shaiwaense n. sp., Epadrianites involutus (Haniel, Reference Haniel1915), ?Xenodiscus sp., and ?Timorites sp.

The ammonoid zone herein is almost identical with the upper La Colorada beds at Arroyo La Colorada, Las Delicias, Coahuila, Mexico in generic composition, especially the presence of Eoaraxoceras and Difuntites. In addition, the entire zonation sequence that is present in the Shaiwa-Sidazhai general section (Sec. IV-IV”) also is the same as in the Permian section at Las Delicias. As a whole, the basic sequence in both areas may be summerized in ascending order as: the perrinitids (Metaperrinites herein, instead of Perrnites in Coahuila)→WaagenocerasTimoritesEoaraxoceras (Fig. 9) (King, Reference King1944; Spinosa et al., Reference Spinosa, Furnish and Glenister1970, 2000; Wardlaw et al., Reference Wardlaw, Rudine and Nestell2000). Correlation of this zonal sequence will greatly increase the reliability of regionally stratigraphic correlations.

Eoaraxoceras is a critical index taxon for this assemblage, although its occurrence is quite rare globally. Undoubted localities are restricted to Coahuila and Nanpanjiang, and possibly Abadeh, central Iran (Bando, Reference Bando1979; Spinosa and Glenister, Reference Spinosa and Glenister2000). Xenodiscus in the ceratitids herein is inadequate; however, it is still a possibly important element in the Claystone (3rd) Member of the Shaiwa Formation.

Difuntites, as a representative of the terminal progenesis of the Paleozoic ammonoid family Medlicottidae, is a secondarily important component of the association in the La Colorada beds and Claystone (3rd) Member of Shaiwa Formation. Because its association with Cyclolobus has been reported from the Amarassi beds in Timor (Haniel, Reference Haniel1915; Glenister and Furnish, Reference Glenister and Furnish1988), the upper Liudianzin Suite in Shkotovo, Maritime Territory in Far East of Russia (Zakharov and Pavlov, Reference Zakharov and Pavlov1986, p. 10, fig. 3), and the Ambilobe beds in Anaborano, north Madagascar (Treat, Reference Treat1933; Besairie, Reference Besairie1936), the geological range of the genus may extend from the upper Capitanian (or the earliest Wuchiapingian, as defined by Spinosa and Glenister, Reference Spinosa and Glenister2000) through the Changhsingian (or Chiddruan). So far, it contains only three species (including an unidentified species): the type species, Difuntites hidius (Ruzhentsev, Reference Ruzhentsev1976), the new species, D. furnishi here, and D. sp. from Madagascar.

Timorites is an especially key component in the fauna. Unfortunately, the specimen herein is only a piece of an external cast of the ultimate whorl. The generic designation is only based on conch shape, strong rib-sculpture, and the whole ammonoid association. There have been 16 species of Timorites reported previously, with exception of the Pamirs’ ‘Timoritespamiriensis (Zakharov, Reference Zakharov1983a). The genus is widely distributed in the Xiukang Formation in Tibet, the ‘Maokou’ Formation (assigned by cross-comparison with the traditional scheme) in Yunnan, the Amarassi beds in Timor, the Wordian through Capitanian formations in both Texas and Coahuila, the Liudianzin Formation in Maritime and the ‘Capitanian’ in Amur area in far eastern Russia, the Suenosaki Formation of the Toyaman Series in the Kitakami Massif in Japan, and Dzhulfian strata in Iran and Transcaucasia.

Earlier workers first reported that the Capitanian was characterized by appearance of the genus Timorites, and overlaid by the Dzhulfian (Wuchiapingian) rocks with Araxoceras fauna in an ideal stratigraphic sequence; however, this theoretical sequence is not present in the real world. On the contrary, two unquestionable Timorites specimens occur in the collection from Abadeh, Iran area, which is associated with the Dzhulfian Araxoceras Fauna in sections at Kuh-e-Ali-Bashi (about 38.9417°N, 45.5154°E) and Kuh-e-Hambast in Abadeh, central Iran (Zhou et al., Reference Zhou, Glenister and Furnish1989). Additionally, Glenister and Zhou had acquired a common viewpoint that the solitary specimen of Krafftoceras sp. nov. from the Araxoceras Bed of the Dzhulfian Stage at section Vedi 2 (about 39.94°N, 44.8842°E) in Armenia (Ruzhentsev, Reference Ruzhentsev1965, pl. 17, fig. 3, PIN 1425/194, ~125 km north of the Kuh-e-Ali-Bashi locality in Iran) should be recombined into the same taxon as the one from Abadeh. Zakharov (Reference Zakharov1983a) restudied the Armenian specimen, upon which the species Cyclolobus ruzhentsevi Zakharov, Reference Zakharov1983a was established. Comparing the suture of the holotype PIN 1425/194 drawn by Zakharov (Reference Zakharov1983a, fig. 2b) with those of Timorites sp. from Abadeh (Zhou et al., Reference Zhou, Glenister and Furnish1989, fig. 3a, b), it seems to be basicly in accordance with the arched trace of the suture, with nine more lateral lobes and the digit outline of both ventral prongs and the first lateral lobe. After restudy of specimen PIN 1425/194 in Moscow by Glenister and Zhou (in 1991, after the Perm conference), they all agreed that the simplified suture details probably resulted from abrasion of the specimen, while the ‘tertiary subdivision’ near the crest of first external lateral saddle in Zakharov’s drawing was probably formed by secondary damage near the first lateral saddle. Actually, all the three specimens from Vedi, Armenia and Adadeh, Iran belong to the same species of Timorites, and according to the priority of ICZN Code, T. ruzhencevi (Zakharov, Reference Zakharov1983a) would be reserved (Spinosa and Glenister, Reference Spinosa and Glenister2000).

Epadrianites is a very common component in the present zone, as well as in the Amarassi beds of Timor (Haniel, Reference Haniel1915), the Araxoceras latissimum Zone (Dzhulfian Stage) in Transcaucasia (Zakharov, Reference Zakharov1983b, p. 152), the Timorites Zone in Coahuila, Mexico (Miller and Furnish, 1944, p. 97), the Langcuo (and Qianggong) Formation from the Indus-Yarlung Suture Zone, and the Upper Cephalopod Limestone (Wordian Age) in north Oman. Review of the type species Epadrianites timorensis, and two other related species, E. involutus (Haniel, Reference Haniel1915) and E. kotljarae (Zakharov, Reference Zakharov1983a), reveals that they may belong to the same morphological group with fairly close relationship each other. The morphologies are so close that the last form from the Dzhulfian Transcaucasia was even thought to be the junior synonym of E. involutus. Irrespective of their taxonomic relationships, all the forms of the Amarassi beds, the Langcuo (and Qianggong) Formation, the Dzhulfian Stage of the Transcaucasia, and the Claystone (3rd) Member of the Shaiwa Formation of Nanpanjiang are within the same chronological interval, based on current knowledge.

As a eurytopic form, the genus Stacheoceras certainly exists in the present ammonoid zone. Among the total 46 species of the genus known, ranging from the Artinskian through the Changhsingian, about one-third (14 species) occur in the Capitanian Stage and the Lopingian Series biostratigraphically. Comparisons among these species show that Stacheoceras shaiwaense is closest to S. toumanskaye Miller and Furnish, Reference Miller and Furnish1940a from the Capitanian of La Difunta, Las Delicias, Coahuila in both morphology of individuals and composition of the assemblages, which is similar to the faunal composition from the two areas. It is also interesting that the present species and its whole assemblage are similar to the ammonoids from the Langcuo Formation in south Tibet (Sheng, Reference Sheng1988), in which the species S. megamultidentatum Sheng, Reference Sheng1988 shows close similarity to the species here in both the suture and conch shape.

There are three species of Stacheoceras from northeast Asia: Stacheoceras orientale Zakharov and Pavlov, Reference Zakharov and Pavlov1986 from the bottom of the Lydianzin Formation; S. iwaizakiense Mabuti, Reference Mabuti1935 from the lower part of the Suenosaki Formation (Lowermost Toyoman), southern Kitakami Massif in northeastern Japan (Ehiro and Bando, Reference Ehiro and Bando1985); and S. otomoi Ehiro et al., Reference Ehiro, Shimoyama and Murata1986 from the basal part of the Toyama Formation on the north coast of Obama, Ogatsu District of South Kitakami. All of three species are associated with the Timorites and the Dzhulfian araxoceratids, and convincingly show the correlation between the Capitanian from North America and the Dzhulfian from the Tethys.

Two other potential zones

A complete basinal sequence of Permian ammonoids still is missing two links in the present zonation in Nanpanjiang area: the Cyclolobus-Xenodiscus-Episageceras fauna above and the Perrinites-Demarezites-Paraceltites-Daubichites fauna below. The former is of Chhidruan/Changhsingian age, and the latter of Roadian age, both of which are expected to be found in the following two stratum intervals: the Calcirudite (4th) Member of the Shaiwa Formation, and the upper part of the Chongtou Member (Bed 17–26) of the Sidazhai Formation, respectively (Figs. 2, 6, 9). Supposedly, inadequate investigation is the only reason for their absence from the present basinal ammonoid zonal sequence in South China.

Shaiwa Formation with Guadalupian ammonoid sequence, but deposited within the Lopingian geological time frame—evidence from conodonts and others

The First (1st) Siliceous Rocks and Third (3rd) Claystone members of the Shaiwa Formation yielded Guadalupian ammonoid zones of definitively Guadalupian age, however, the formation was deposited in the geological interval between the Maokouan fusulinid-bearing limestone below and the lowest Triassic Claraia-Ophiceras-bearing Luolou Formation above, which is exactly the Lopingian Series, as acknowledged by most geologists, on various geological maps and publications, and including the updated “Permian System” in the Chinese Stratigraphic Lexicon (Jin et al., Reference Jin, Shang, Hou, Li, Wang, Zhu and Fei2000). Such recognition upon the basinal ammonoid sequence definitely calls into question all the traditional time scales, even the most recent one (Shen et al., Reference Shen, Schneider, Angiolini and Henderson2013).

Unfortunately, conodonts, which are the main biostratigraphic group, are not well known from the area, probably due to their sparse distribution and/or inadequate sampling. Therefore, records are available only from a few layers, but even these limited works are still helpful for establishing the age interpretation above.

Hao et al. (Reference Hao, Yao and Liu1999) first reported Clarkina cf. C. guangyuanensis (Dai et al., 1984), Clarkina subcarinata (Behnken, 1975), and Xaniognathus sp. from the calcarenite of the upper part of the Calcirudite (4th) Member of the Shaiwa Formation, which indicates a Changhsingian age. However, Jingondolella aserrata (Clark and Behnken, 1979) and J. postserrata (Behnken, 1975) from the biocalcarenite and the top calcirudite of the Chongtou Member of the Sidazhai Formation, respectively, indicate Wordian through earliest Capitanian age (Shen et al., Reference Shen, Schneider, Angiolini and Henderson2013). The primary conodont sequence confirms a normal Capitanian through Changhsingian interval in the upper part of their Sidazhai section, albeit the real Wuchiapingian conodont record is absent.

Ji et al. (Reference Ji, Li and Feng2009) reported the conodonts from the Claystone (3rd) Member, including Sweetognathus inornatus Ritter, Reference Ritter1986, S. paraguizhouensis Wang, Ritter, and Clark, Reference Wang, Ritter and Clark1987, and others. The authors pointed out that the range of Sweetognathus inornatus in North America may be Wordian through Capitanian, which appears to meet the age of the ammonoid sequence, whereas the S. paraguizhouensis seems questionable either in the identification or the occurrence. The Maokouan age of the fossil-bearing strata probably is assigned by cross-correlation with the traditional scheme.

Zeng and Yang (Reference Zeng and Yang2014) studied Sidazhai and Shaiwa Formations of the Kecheng section in Zhengning County, ~43 km, 313°NW from the Shaiwa-Sidazhai general section (VI-VI”) in Ziyun County, roughly along the regional structure strike. They reported that the Shaiwa Formation disconformably overlies the Emeishan Basalt and found the bottom conglomerate of the Shaiwa Formation from the opposite limb of the same anticline. It appears that the Shaiwa Formation should be of Late Permian age based on the presence of the basalt and the bottom conglomerate, both of which, as the series-boundary marker, are broadly distributed in the southwest Yangtze Croton (1) (Fig. 1). Additional evidence reported by Zheng and Yang (Reference Zeng and Yang2014) include the conodonts Jingondolella granti (Mei and Wardlaw in Mei et al., Reference Mei, Jin and Wardlaw1994), and Prioniodella ctenoides Tatge, Reference Tatge1956 from the limestone immediately underlying the Lopingian bottom conglomerate, although there is dispute on the fossil identification (Shen, S.-Z., personal communication, 2016).

As early as the 1990s, Kozur (Reference Kozur1992) reported that the Changhsingian conodonts Clarkina cf. C. changxingensis and C. welcoxi were present in the uppermost Altuda Formation of the latest Capitanian in the Glass Mountains of Texas, and confirmed the overlap between the Guadalupian and the Wuchiapingian (Zhou et al., Reference Zhou, Glenister and Furnish1989). However, Henderson and Mei (Reference Henderson and Mei2003) maintained that Clarkina cf. C. changxingensis reported by Kozur (Reference Kozur1992) is a homeomorphic form of Jingondolella altudaensis of the Capitanian, while the Clarkina welcoxi is Jingondolella shannoni Wardlaw, Reference Wardlaw1994.

Probably due to insufficienct parameters of shape and sculpture to serve as classification characters in the group, widespread homeomorphism was present in the conodonts (Henderson and May, Reference Henderson and Mei2003; Henderson et al., Reference Henderson, Mei, Shen and Wardlaw2008). Nonetheless, it was reasonable to believe that Altuda Formation (Kozur, Reference Kozur1992) identifications were accurate given the ammonoid sequence (e.g., both Clarkina cf. C. changxingensis and C. welcoxi representing the real Clarkina rather than Jingondolella). Actually, there is a methodological problem of circular reasoning that is overtly employed with fossil identification based on stratigraphic occurrence in the Permian conodont study.

As Kozur (Reference Kozur1995, p. 165) summarized, “Conodont provincialism is insignificant, but the facies control of conodonts may be considerable. Problem of conodont zonation are caused by migrations due to large scale facies changes, especially in the Middle Permian Guadalupian Series and at the Guadalupian-Lopingian boundary. Migration events of conodonts are not suitable for definitions of stage boundaries and large scale correlations because they are diachronous.” In fact, there is not a believable conodont sequence that commonly occurs in both the Capitanian of North America and the “equivalent” Maokouan of South China. Perhaps future biostratigraphic correlations should give more attention to the index ammonoids, due to their abundant characteristic parameters exteriorly and traceable evolutionary progress interiorly.

Conclusions

This study provided the first systematically based Permian basinal ammonoid sequence, with six comparable pandemic zones, primarily from the well-correlated sections in the Nanpanjiang Basin (Figs. 2, 49). The six pandemic zone are, in descending order:

Zone 6. Eoaraxoceras spinosai-CapitanianDifuntites furnishi

Zone 5. Waagenoceras sp.-WordianPropinacoceras beyrichi

Zone 4. Metaperrinites shaiwaensis-Kungurian Popanoceras ziyunense

Zone 3 . Popanoceras kueichowense- Artinskian Medlicottia orbignyanus

Zone 2. Svetlanoceras uraloceraformis- Asselian–Sakmarian Prothalassoceras biforme

Zone 1 . Properrinites gigantus- Asselian Svetlanoceras serpentinum

A remote intercontinental correlation between South China and North America/South Urals is therefore transformed into an intracontinental relationship between the basin and platform regions in a single South China Block (Figs. 1, 2, 9). Since the basinal Shaiwa Formation is essentially equal to the platform-based Lopingian Series, as stated in the previous section, the upper Guadalupian Series from North America, which characterized by the 6th and 5th Zones, overlaps the lower Lopingian Series of South China. Previous primary reports of the ammonoids of the 4th to 1st Zones from the basinal Sidazhai Formation and the upper Nandan Formation (Zhou, 1985–Reference Zhou1986, Reference Zhou1987, Reference Zhou1988Reference Zhou1989; Zhou et al., Reference Zhou, Glenister and Furnish1989) had already helped to lower the bottom and the internal boundaries of the Permian in South China at 1–2 stages, respectively, in order to be in accordance with the international time scale (Jin et al., Reference Jin, Shang, Hou, Li, Wang, Zhu and Fei2000; Shen et al., Reference Shen, Schneider, Angiolini and Henderson2013). In other words, moving the Wuchiapingian down to the Guadalupian Series would be the last step in adjusting the Permian regional correlation scheme of the South China, and even the entire Tethys.

The major gap in the present study is the absence of the Chhidruan/Changhsingian Cyclolobus- Xenodiscus- Episageceras fauna above the 6th Zone and the Roadian Perrinites- Demarezites- Paraceltites- Daubichites fauna between the 5th and 4th Zones in the sequence. Additional investigation on ammonoids around the corresponding layers in the Nanpanjiang Basin possibly could connect these missing links.

Materials

Repository and institutional abbreviation

All the specimens studied here are deposited in the Repository of Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, #39 East Beijing Road, Nanjing, Jiangsu, P. R. China.

Systematic paleontology

Order Prolecanitida Miller and Furnish, Reference Miller and Furnish1954

Superfamily Prolecanitoidea Hyatt, Reference Hyatt1884

Family Daraelitidae Chernov, Reference Chernov1907

Genus Daraelites Gemmellaro, Reference Gemmellaro1887

Type species

Daraelites meeki Gemmellaro, Reference Gemmellaro1887; original designation; Sosio Limestone (Wordian), Sosio Valley, Sicily, Palermo, Italy.

Diagnosis

Conch small (<5 cm diameter), discoidal (W/D, 0.35), evolute (Umin/D, 0.25 at 20 mm diameter). Suture characterized by ventral lobe twice width of lateral, serrate lobe bases from venter to mid flank, up to nine pairs of umbilically derived lobes (two pairs of which may be internal) separated by asymmetrical saddles. Sutural formula: (V2V1V2) LUU1U2U3U5U7:U6U4I(D1D1).

Occurrence

Lower Permian (Asselian) to Middle Permian (Wordian); Italy (Sicily), Iraq (Kurdistan), Russia and Kazakhstan (South Urals), Indonesia (Timor), Tajikistan (Pamirs), Afghanistan, Canada (British Columbia), USA (West Texas, Nevada), and South China (southwest Guizhou and northeast Guangxi).

Remarks

Daraelites, the most advanced representative of the family, is similar to Boesites in general conch form and sutural pattern, but the ventral lobe of Daraelites is twice as broad as the lateral lobe, quite different from Boesites, with equal or somewhat narrower width of the corresponding lobes.

Daraelites elegans Chernov, Reference Chernov1907

Figures 10.1–10.6, 11.5

Figure 10 Daraelitids. (1–6) Daraelites elegans Chernov, Reference Chernov1907; (1–4) Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi; (1) lateral view, NIGP 93700, ×2.5; (2, 3) ventrolateral and lateral views, NIGP 93699, ×3; (4) lateral view, NIGP 93701, ×2; (5, 6) Bed 3, Longyin Formation, Longyin section (Sec. I), Pu’an, Guizhou; (5) lateral view, NIGP 88981, ×2; (6) lateral view, NIGP 88980, ×3 (specimen damaged by dehydrated shrinkage); (7–12) Boesites intercalaris Ruzhentsev, Reference Ruzhentsev1978, Asselian talus limestone, 2nd Member, Nandan Formation, Liuzhai Quarry (Loc. 5), Liuzhai, Nandan County, Guangxi (Zhou, Reference Zhou1987, p. 136); (7, 8) lateral and ventral views, NIGP 94453 (Zhou, Reference Zhou1987, pl. 1, figs. 9, 10), ×1.5; (9, 10) lateral and ventral views, NIGP 94454 (Zhou, Reference Zhou1987, pl. 2, figs. 4, 3), ×4; (11, 12) lateral and ventral views, NIGP 94455 (Zhou, Reference Zhou1987, pl. 2, figs. 1, 2), ×1.5.

Figure 11 External sutures of daraelitids and cross-section of genus Boesites Miller and Furnish, Reference Miller and Furnish1940b. (1–4) Boesites intercalaris Ruzhentsev, Reference Ruzhentsev1978, Asselian talus limestone, 2nd Member, Nandan Formation, Liuzhai Quarry (Loc. 5), Liuzhai, Nandan County, Guangxi; (1) NIGP 94455, D 7.3 mm; (2) NIGP 94454, D ~12 mm; (3) NIGP 94453, D ~21 mm; (4) cross-section, NIGP 94458, D 13.9 mm. (5) Daraelites elegans Chernov, Reference Chernov1907, NIGP 93699, D ~15 mm; Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi.

1907 Daraelites elegans Reference ChernovChernov, p. 374, pl. 1, fig. 9.

1956 Daraelites elegans; Reference RuzhentsevRuzhentsev, p. 80, pl. 1, figs. 1, 2.

1962 Daraelites elegans; Reference BogoslovskaiaBogoslovskaia, p. 30, pl. 1, figs. 1, 2.

Description

All internal molds, with well-preserved but incomplete sutures. Living chamber might be one volution long at least, based on specimen NIGP 88981 (Fig. 10.5). Conch discoidal, with fairly evolute umbilicus, about one fourth the conch (U/D, 0.25). No sculpture observed on molds. Ventral lobe wide, more than twice the width of the lateral lobe. Medium tooth longer than the wide and shallow lateral subdivisions of the ventral lobe. Lateral and umbilical lobes asymmetrically club-shaped, the former large and curved ventrad; all the umbilically derived lobes curved toward the umbilicus and gradually decreasing in size. Irregularly small serrations appearing in base of the lateral subdivision of the ventral lobe, the lateral lobe, and the first several umbilical lobes.

Materials

Five internal molds preserved in mudstone, representing five individuals, NIGP 88980, 88981, and 93699–93701.

Occurrence

Bed 3, Longyin section (Sec. I), Pu’an County, Guizhou, and Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi.

Remarks

The specimens here are identical with the type materials from Urals in overall conch shape and sutural pattern (e.g., U/D about 0.25 at diameter 25–30 mm), with the lowest middle tooth comparing to the lateral subdivisions of ventral lobe, and the more complicated serration continuously showing up to the third umbilical-derived lobe.

Genus Boesites Miller and Furnish, Reference Miller and Furnish1940b

Type species

Daraelites texanus Böse, Reference Böse1919; original designation; Virgilian (Gzhelian) Gaptank Formation (Upper Pennsylvanian), Glass Mountains, Texas, USA.

Diagnosis

Similar to Daraelites, but ventral and lateral lobes subequal, and with fewer umbilical lobes (5 or 6 pairs, one of which may be internal). Sutural formula: (V2V1V2)LUU1U2U3U5:U4I(D1D1).

Occurrence

Pennsylvanian (Bashkirian) through Early Permian (Sakmarian); Russia and Kazakhstan (South Urals), USA (Texas, Oklahoma, Arkansas), Canada (Arctic Archipelago: Ellesmere Island), Spain (Cantabrian Mountains), Tajikistan (Pamirs), Uzbekistan (Fergana), Kyrgyzstan (Tian-Shan), South China (Guangxi), and Japan (SW Honshu).

Remarks

Boesites is similar to Daraelites, actually in a transitional series in both suture and conch shape.

Boesites intercalaris Ruzhentsev, Reference Ruzhentsev1978

Figures 10.7–10.12, 11.1–11.4

1978 Boesites intercalaris Reference RuzhentsevRuzentsev, p. 39, pl. 3, fig. 1.

1987 Boesites intercalaris; Reference ZhouZhou, p. 136, pl. 1, figs. 9, 10, pl. 2, figs. 1–10.

Description

Specimen NIGP 94453 (Fig. 10.7, 10.8) with almost complete living chamber, 37.9 mm in diameter, representing the largest one known hitherto in the genus (Table 1). Conch usually discoidal and fairly evolute. Venter narrowly and flank broadly rounded; dorsum slightly depressed. Living chamber at least three-fourths of volution. Sculpture unknown.

Table 1 Dimensions and ratios of Boesites intercalis Ruzhentsev, Reference Ruzhentsev1978. D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Ventral lobe slightly narrower than lateral lobe in width, WV (width of ventral lobe)/WL (width of lateral lobe) 0.91–0.98, tripartite basally. Both lateral subdivisions shallow and rounded at base in adolescent, and slightly sharpened in adult, with straight ventral flank and gently curved dorsal flank, sometimes, with questionably incipient serration at the subdivision bottom. Middle tooth related with the siphon is long and narrow in shape, and intersected with the lateral subdivision at right angle in adolescent and at bluntly acute angle in adult. Lateral lobe club-shaped, with irregularly denticulated lobe bottom. Four or five pairs of umbilically derived lobes in external suture, decreasing in size dorsad.

Materials

Six molds, NIGP 94453–94458, only NIGP 94453 shows a relatively well-preserved body chamber.

Occurrence

Asselian talus limestone, 2nd Member, Nandan Formation, Liuzhai Quarry (Loc. 5), Liuzhai, Nandan County, Guangxi.

Remarks

The present specimens were described as Boesites intercalaris Ruzhentsev (Zhou, Reference Zhou1987), due to the same WV/WL (~0.9), and the similar compressed whorl section with the Pamirs specimens. However, they still have some differences, such as, the oversized conch in the Guangxi specimen, reaching 37.9 mm in diameter, much larger than those from Pamirs. Additionally, the H/W ratios in the Pamirs specimens range from 1.16 to 1.21, obviously smaller than the 1.38 in the Guangxi specimen, so the sections look much wider than those from the Pamirs. Nevertheless, these differences in conch shape are still thought as an intraspecific variation.

Superfamily Medlicottioidea Karpinskii, Reference Karpinskii1889

Family Pronoritidae Frech, Reference Frech1901

Subfamily Pronoritinae Frech, Reference Frech1901

Genus Metapronorites Librovich, Reference Librovich1938

Type species

Pronorites uralensis var . timorensis Haniel, Reference Haniel1915; original designation; Somohole and Bitauni beds (Cisuralian), Timor, Indonesia.

Diagnosis

Conch discoidal, moderately evolute (U/D, commonly 0.1), with flat flanks and rounded to flat venter. Characterized by suture with 26–32 lobes, including 7–9 pairs of external, umbilically derived lobes and 3–5 pairs of internal umbilicals. Sutural formula: (V2V1V2)(L1L1)UU1U2U4U6U8U10.....U9U7U5U3ID. Saddle separating two prongs of external lateral lobe unconstricted, low, with strongly divergent flanks. Either prong of lateral lobe may be denticulate, as many adjacent primary umbilical lobe.

Occurrence

Pennsylvanian (Moscovian) through Permian (Artinskian); Kazakhstan (South Urals), Russia (South Urals, north Verkhoyan, Moscow Basin), Tajikistan (Pamirs), Indonesia (Timor), USA (Texas, ?Arkansas), Canada (Yukon, Artic Archipelago), Austria (Carnic Alps), and China (Guangxi).

Remarks

Metapronorites differs from Stenopronorites by possessing more umbilical lobes (7–9 instead of 5–6 pairs of external umbilical lobes), and sometimes by serration of lobe bases. The genus differs from Neopronorites by possessing a more primitive suture: the undivided dorsal lobe, and the entirely simple prongs of the wide lateral lobe and the entirely simple, umbilically derived lobes.

Metapronorites timorensis (Haniel, Reference Haniel1915)

Figures 12.10–12.18, 13.1, 13.2

Figure 12 Neopronorites Ruzhentsev, Reference Ruzhentsev1936a and Metapronorites Librovich, Reference Librovich1938. (1–8) Neopronorites leonovae n. sp., Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi, ×2.5; (1, 2) ventral and lateral views, NIGP 88967, holotype, Bed 19, 2nd Member; (3, 4) apertural and lateral views, NIGP 88968, Bed 19, 2nd Member; (5, 6) lateral and ventral views, NIGP 88969, Bed 26, 3rd Member; (7, 8) lateral and ventral views, NIGP 88970, Bed 19, 2nd Member; (9) Neopronorites cf. N. darvasicus Leonova, Reference Leonova1988, lateral view, NIGP 93663, ×2, beds 19–17, Longyin Formation, Huagong section (Sec. II), Huagong Tea-Plantation, Qinglong County, Guizhou; (10–18) Metapronorites timorensis (Haniel, Reference Haniel1915), Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi; (10, 11) NIGP 88965, lateral and ventral views, ×1.5, Bed 19, 2nd Member; (12–18) Bed 26, 3rd Member; (12–14) lateral, apertural, and ventral views, ×1.5, NIGP 88966; (15, 16) ventral and lateral views, ×1.5, NIGP 88964; (17, 18) lateral and ventral views, ×1, NIGP 88963.

Figure 13 External sutures of Metapronorites Librovich, Reference Librovich1938 and Parapronorites Gemmellaro, Reference Gemmellaro1887. (1, 2) Metapronorites timorensis (Haniel, Reference Haniel1915), Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi; (1) NIGP 88965, Bed 19, 2nd Member, D 28 mm; (2) NIGP 88963, Bed 26, 3rd Member, D 55 mm; (3, 4) Parapronorites timorensis Haniel, Reference Haniel1915; (3) NIGP 88962, D 22 mm, ‘Chihsia’ Limestone, Tian’e suburb (Loc. 7), north of Hongshuihe River, Tian’e County, Guangxi; (4) NIGP 93654, D 30 mm, Bed 12, Chongtou Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou; (5, 6) Parapronorites cf. P. lectus Leonova, Reference Leonova1989; (5) NIGP 88971, D ~20 mm, beds 34–32, Yangchang Formation, Yangchang section (Sec. III), Ziyun County, Guizhou; (6) NIGP 93657, D 26 mm, Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi.

1915 Pronorites uralensis var. timorensis Reference HanielHaniel, p. 25, pl. 46, figs. 1–5.

1927 Pronorites timorensis; Reference SmithSmith, p. 13, pl. 10, figs. 1–15.

1938 Metapronorites timorensis; Reference LibrovichLibrovich, p. 82.

1987 Metapronorites timorensis; Reference ZhouZhou, p. 134, pl. 1, figs. 1–8, pl. 2, figs. 11, 12.

Description

Conch large, discoidal, involute, and smooth superficially. Venter rounded; flank flat, broad, nearly parallel each other. Umbilicus small, with steep wall and rounded lateral-umbilical shoulder (Table 2). Ventral lobe trifid, more than one-half width of the lateral lobe. Lateral lobe divided by an equilaterally triangular median saddle. Prong undivided, with sharp base. External umbilically derived lobes undivided, as many as eight or nine in number, all with asymmetrically lanceolate shape.

Table 2 Dimensions and conch ratios of Metapronorites timorensis (Haniel, Reference Haniel1915). D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Materials

Four specimens, with different completeness, preserved in limestone, NIGP 88963–88966.

Occurrence

Occurs in the 2nd and 3rd members, Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi.

Remarks

Metapronorites timorensis specimens are closely similar to the type specimens from Timor in both conch shape and sutural characters. The same forms also have been described from the Asselian talus limestone, 2nd Member, Nandan Formation, the Liuzhai Quarry (Loc. 5) (Zhou, Reference Zhou1987, p. 134, pl. 1, figs. 1–8, pl. 2, figs 11, 12).

Metapronorites timorensis from the Pamirs generally are the same forms with almost the same conch shape and suture, except the bidentate ventrad prong of the lateral lobe (see Ruzhentsev, Reference Ruzhentsev1978). However, the difference in lobe base might be only the result of intraspecific variation. Generally, the present species is characterized by eight or nine umbilically derived lobes, instead of seven lobes of the other species from Russia and North America.

Subfamily Neopronoritinae Weyer, Reference Weyer1972

Genus Neopronorites Ruzhentsev, Reference Ruzhentsev1936a

Type species

Parapronorites permicus Chernov, Reference Chernov1907; original designation; upper Artinskian Stage, Us’va River, South Urals, Russia.

Diagnosis

Neopronoritins characterized by irregular serration in prongs of mature external lateral lobe and one to three adjacent umbilical lobes. Dorsal and adjacent internal lobes bidentate. Seven or eight pairs of umbilically derived lobes in external suture, one-half as many internally. Sutural formula: (V2V1V2)(L1L1)UU1U2U4U6U8.....U7U5U3I(D1D1).

Occurrence

Pennsylvanian (Gzhelian) through Permian (Kungurian); Kazakhstan (South Urals), Russia (Urals, Verkhoyan), Tajikistan (Pamirs), China (Guangxi, Guizhou, Xinjiang, Xizang, Gansu), Indonesia (Timor), Thailand (Loei), USA (Texas), and Canada (Ellesmere Island).

Remarks

Neopronorites resembles Parapronorites by the general conch form and bidentate dorsal lobe in internal suture, but is dinstinguised from the latter by the flat venter, more numerous external umbilically derived lobes, and the irregularly secondary serration of the lateral lobe.

Neopronorites represents a special genus with probable progenesis in genetic evolution. The earlier representatives of the genus are characterized by irregular serration of prongs of the large lateral lobe and several adjacent umbilically derived lobes; whereas the later forms by the shallower lateral lobe, absence of serrations, and obvious reduction in conch size. The evolutionary tendency of the genus had been summarized as ‘regressive’ evolution in paedomorphic suture and smaller conch size since the later Artinskian (Ruzhentsev, Reference Ruzhentsev1949, p. 90; Leonova, Reference Leonova1988, p. 106, Reference Leonova2002, p. S17). Of the fourteen total species, ten occur from the Pennsylvanian through Sakmarian, with only four ranging from Artinskian through Kungurian. Species in the first group usually have larger conch sizes with stronger serration in lobe base; whereas the second group, in contrast, has smaller conch sizes with simpler digits in lobe base.

Neopronorites leonovae new species

Figures 12.1–12.8, 14.2–14.5

Figure 14 External sutures of Neopronorites Ruzhentsev, Reference Ruzhentsev1936a. (1) Neopronorites cf. N. darvasicus Leonova, Reference Leonova1988, NIGP 93663, D 20 mm, beds 19–17, Longyin Formation, Huagong section (Sec. II), Huagong Tea-Plantation, Qinglong County, Guizhou; (2–5) Neopronorites leonovae n. sp., Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi; (2) NIGP 88970, D 13 mm, Bed 19, 2nd Member; (3) NIGP 88968, D 15 mm, Bed 19, 2nd Member; (4) NIGP 88969, D 18 mm, Bed 26, 3rd Member; (5) NIGP 88967, holotype, D 22 mm, Bed 19, 2nd Member.

Diagnosis

Species with very short lateral lobe and six umbilically derived lobes in external suture.

Description

Conch discoidal and small, ranging from 20 to 30 mm in diameter. Venter flat with obvious ventrolateral shoulder; flanks nearly flat. Umbilicus moderate in size, U/D ranging from 1/5 to 1/4, with obvious umbilical shoulder and steep wall (Table 3). Sutures characterized by a large, shallow lateral lobe, with as many as six pairs of umbilically derived lobes. The digitations of the lobe bases vary ontogenetically, revealing an increase in the number of bidentate umbilical lobes.

Table 3 Dimensions and ratios of Neopronorites leonovae n. sp. D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Etymology

Named in honor of Professor T.B. Leonova of the Borissiak Paleontological Institute, Russian Academy of Sciences.

Materials

Four phragmocones from silicified limestone, NIGP 88967 (holotype) and NIGP 88968–88970.

Occurrence

Bed 19, 2nd Member and Bed 26, 3rd Member, Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi.

Remarks

All four specimens from northwest Guangxi assigned to Neopronorites are characterized by a flat venter, smaller number of umbilical lobes, and irregular secondary serration of the lateral lobe and first one or two umbilical lobes. Taken together, these features could not be referred to any of the preexisting species of the genus. Neopronorites leonovae n. sp. resembles N. asianus Leonova, Reference Leonova1988 in the basic outline of the suture, short lateral lobe, and six pairs of umbilical lobes; however, it has a larger conch size, much narrower ventrolateral and first lateral saddles, and is more strongly bidentate in the first two umbilical lobes. Neopronorites leonovae n. sp. resembles N. darvasicus Leonova, Reference Leonova1988 in both conch size and the serration of lobes, but has a much shorter lateral lobe and relatively narrower ventrolateral and first lateral saddles. The new species is similar to N. permicus (Chernov, Reference Chernov1907) in possessing a large conch size and six pairs of umbilically derived lobes; however, its lateral lobe is much shorter and the ventrolateral and the first lateral saddle relatively narrower.

Neopronorites cf. N. darvasicus Leonova, Reference Leonova1988

Figures 12.9, 14.1

1988 Neopronorites darvasicus Reference LeonovaLeonova, p. 107.

2004 Neopronorites cf. darvasicus; Reference Zhou and LiengjarernZhou and Liengjarern, p. 322, figs. 6.1, 6.2, 7.1–7.4.

Description

Conch poorly preserved in mudstone, partially exposed. By estimate, the flat discoidal phragmocone may reach 16–18 mm in diameter. Lateral lobe short and bifid, prongs of which are secondarily bidentate. Ventrolateral and first lateral saddles broad with rounded top. First three umbilical lobes bidentate.

Materials

One specimen, NIGP 93663.

Occurrence

Beds 19–17, Longyin Formation, Huagong section (Sec. II), Huagong Tea-Plantation, Qinglong County, Guizhou.

Remarks

The specimen resembles types of the Darvas species in sutural details, shorter lateral lobe, and being bidentate both in the prongs of the lateral lobe and the first two umbilically derived lobes. Inadequate material prevents accurate identification. Generally, the specimen here is quite different from the others in the genus by the shorter lateral lobe and absence of irregular serrations at prong and lobe bases.

Genus Parapronorites Gemmellaro, Reference Gemmellaro1887

Type species

Parapronorites konincki Gemmellaro, Reference Gemmellaro1887; original designation; Sosio Limestone (Wordian), Sosio Valley, Sicily, Palermo, Italy.

Diagnosis

Advanced neopronoritins characterized by subequal bidentition of both prongs of external lateral lobe; ventral four to virtually all eight adjacent umbilically derived lobe pairs also bidentate. Internal suture inadequately known (except for P. rectus Leonova in Leonova and Dmitriev, 1989), but mature D and I probably bidentate throughout, and umbilical elements simple and number one or two fewer than in external suture.

Occurrence

Sakmarian through Wordian Stage; Ukraine (Crimea), Tajikistan (Pamirs), Russia (South Urals), Italy (Sicily), Indonesia (Timor), north Oman, Thailand (Muak Lek), and China (Xizang, Xinjiang, Guangxi, and Guizhou).

Remarks

In general conch shape and suture, Parapronorites is most similar to Neopronorites in the subfamily, but obviously distinct from the latter by its flatter venter and absence of irregular serration in prongs of mature external lateral lobe and the adjacent umbilically derived lobes. Internal suture with bidentate D and I1 in maturity (Leonova, Reference Leonova1989).

Parapronorites timorensis Haniel, Reference Haniel1915

Figures 13.3, 13.4, 15.1–15.18

Figure 15 Parapronorites timorensis Haniel, Reference Haniel1915. (1–12) ‘Chihsia’ Limestone, Tian’e suburb (Loc. 7), north of Hongshuihe River, Tian’e County, Guangxi; (1–3) apertural, ventral, and lateral views, NIGP 154096, ×2.5; (4–6) apertural, ventral, and lateral views, NIGP 154097, ×2.5; (7–9) lateral, apertural, and ventral views, NIGP 88961, ×1.5; (10–12) ventral, lateral, and apertural views, NIGP 88962, ×1.5; (13–18) Bed 12, Chongtou Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou; (13, 14) ventral and lateral views, NIGP 93655, ×2.0; (15, 16) apertural and lateral views, NIGP 93656, ×2.5; (17, 18) ventral and lateral views, NIGP 93654, ×1.5.

1915 Parapronorites konincki var. timorensis Reference HanielHaniel, p. 29, pl. 46, figs. 8–11.

1927 Parapronorites timorensis; Reference SmithSmith, pl. 10, figs. 16–19.

1983 Parapronorites cf. timorensis; Reference Sheng and LiuSheng and Liu, p. 239, pl. 20, figs. 1a, b.

1988 Parapronorites timorensis; Reference ZhouZhou, p. 381, pl. 2, figs. 1–4.

Description

Conch discoidal and involute, with narrow and rounded venter and flat flanks. Umbilicus slightly wider (Table 4). Lateral lobe broad and bipartite, prongs of which and the next two or three umbilically derived lobes strongly bidentate. Outer saddle much lower and narrower than first lateral saddle, while somewhat similar to second one in shape.

Table 4 Dimensions and ratios of Parapronorites timorensis Haniel, Reference Haniel1915. D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Materials

Seven specimens, rather well preserved from limestone, NIGP 88961, 88962, 93654–93656, 154096, and 154097.

Occurrence

Bed 12, Chongtou Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Shaiwa, Sidazhai, Ziyun County, Guizhou; ‘Chihsia’ Limestone, Tian’e suburb (Loc. 7), north of Hongshuihe River, Tian’e County, Guangxi.

Remarks

The present species may represent the primitive form in the genus, with simple bidentate prongs of the lateral lobe and the next two or three umbilically derived lobes. Specimens here have the same conch shape and general characteristics in suture as the holotype from Timor, except the ventral lobe seems slightly narrower and obviously constricted adorally and the ventral median saddle much more advanced ontogenetically. However, all these differences might be the result of intraspecific variation. Because the living chamber is fully intact in most cases, the ammonoids are supposed to have stayed here (i.e., autochthonous).

Parapronorites cf. P. rectus Leonova, Reference Leonova1989

Figures 13.5, 13.6, 16.1–16.5

Figure 16 Parapronorites Gemmellaro, Reference Gemmellaro1887 and Propinacoceras, Gemmellaro, Reference Gemmellaro1887. (1–5) Parapronorites cf. P. rectus Leonova, Reference Leonova1989; (1) lateral view, NIGP 93657, ×2.5, Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi; (2, 3) beds 34–32, Yangchang Formation, Yangchang section (Sec. III), Ziyun County, Guizhou; (2) lateral view, NIGP 88972, ×4.0; (3) lateral view, NIGP 88971, ×3.0; (4, 5) lateral views, Bed 6, Gaijiao Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou, ×1.5; (4) NIGP 93659; (5) NIGP 93658; (6–13) Propinacoceras beyrichi Gemmellaro, Reference Gemmellaro1887, the ammonoid-bearing claystone intercalated in Member XII, upper Houziguan Formation, Kabi (Loc. 3), Houchang, Ziyun County, Guizhou; (6, 7) ventral and lateral views, NIGP 93667, ×3; (8, 9) lateral and ventral views, NIGP 93665, ×3; (10, 11) lateral and ventral views, NIGP 93664, ×2; (12, 13) lateral and ventral views, NIGP 93666, ×1.5.

1960 Parapronorites timorensis; Reference RuzhentsevRuzhentsev, fig. 61.

1963 Parapronorites timorensis; Reference ToumanskayaToumanskaya, p. 94, pl. 22, figs. 1–3.

1963 ? Parapronorites timorensis; Reference ToumanskayaToumanskaya, p. 95, pl. 22, figs. 6, 7.

1989 Parapronorites rectus Reference LeonovaLeonova, p. 81, pl. 1, figs. 3–5.

2004 Parapronorites rectus; Reference Zhou and LiengjarernZhou and Liengjarern, p. 324, figs. 6.3, 8.1.

Description

Specimens somewhat deformed during preservation, but basically recognizable to be forms of smooth surface, flat flanks, rounded venter, and small umbilicus, with rounded umbilical shoulder. Diameter of specimen NIGP 93658 may reach to ~40 mm, while the umbilicus may be as small as one fifth of the conch (W/D, 0.14). Venter not exposed in all specimens, width of conch unknown. Suture not completely exposed, but clearly shows the wide lateral lobe and eight umbilically derived lobes beyond the umbilical seam. Wide lateral lobe subdivided by a small and low saddle into two bidentate prongs. The adjacent four umbilical lobes are bidentate.

Materials

Five specimens, NIGP 88971, 88972, 93657–93659.

Occurrence

Bed 6, lower Gaijiao Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou; and beds 34–32, lower part of Yangchang Formation, Yangchang section (Sec. III), Ziyun County, Guizhou, and Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi. The species may range from Artinskian through Kungurian in age; however, additional sampling needs to be done in order to have more exact identification.

Remarks

Although the conch shape is not precisely described owing to poor preservation, the well-preserved part of the external suture of NIGP 93657 (Fig. 16.1) is useful for specific identification. As many as four adjacent umbilically derived lobes are relatively coincident with the type specimens of Parapronorites rectus Leonova, Reference Leonova1989 (p. 81, pl. 1, figs. 3–5, text-fig. 25a) and the plesiotype from Thailand (Zhou and Liengjarern, Reference Zhou and Liengjarern2004, p. 324, figs. 6.3, 8.1). The specimens have some similarity to P. timorensis Haniel, Reference Haniel1915 from Timor in conch shape and generality of external suture; however, they possess four bidentate umbilically derived lobes, while only two occur in the latter.

Family Medlicottidae Karpinskii, Reference Karpinskii1889

Remarks

All juveniles of medlicottids possess evolute conch forms, without exception.

Subfamily Propinacoceratinae Plummer and Scott, Reference Plummer and Scott1937

Genus Propinacoceras Gemmellaro, Reference Gemmellaro1887

Type species

Propinacoceras beyrichi Gemmellaro, Reference Gemmellaro1887; subsequent designation by Diener, 1912; Sosio Limestone (Wordian), Sosio Valley, Sicily, Palermo, Italy.

Diagnosis

Conch large (diameter to 20 cm) with strong ventral ribs or nodes separated by median furrow. Suture characterized by undivided ventral flank of ventrolateral saddle and by dorsal subdivision of primary external lateral lobe (L1(d)) that is less than one-half size of adjacent primary umbilical lobe. Sutural formula: (V2V1V2)s1s1L1(d)UU1U2......

Occurrence

Sakmarian through Wordian; Italy (Sicily), Croatia, Iraq (Kurdistan), Oman, Russia and Kazakhstan (South Urals), Tajikistan (Pamirs), Afghanistan, Ukraine (Crimea), China (Xizang, Xinjiang, Guizhou, Guangxi, Jilin, Gansu), Mexico (Coahuila), Indonesia (Timor), USA (Texas), Japan (Kitakami Massif), and Canada (British Columbia).

Remarks

Ruzhentsev (Reference Ruzhentsev1949, Reference Ruzhentsev1956) divided the species of Propinacoceras into three groups based on subdivision of the ventrolateral saddle: (1) Propinacoceras aktubense Ruzhentsev, Reference Ruzhentsev1939a; (2) Propinacoceras knighti Miller and Furnish, Reference Miller and Furnish1940a; and (3) Propinacoceras beyrichi Gemmellaro, Reference Gemmellaro1887.

The P. knighti group is remarkably different from the other two in having apical and lateral adventitious lobules. Leonova (Reference Leonova1989) reassigned four species of the group ( P. knighti Miller and Furnish, Reference Miller and Furnish1940a, P. bornemani Toumanskaya, Reference Toumanskaya1937 , P. australe Teichert, Reference Teichert1942, and P. simile Haniel, Reference Haniel1915) to the genus Bamyaniceras Termier and Termier, Reference Termier and Termier1970, and preserved the genus Propinacoceras only for the first and the third groups. The apical lobules of Propinacoceras might be designated as s1s1. The ventrad and/or dorsad branch, s1, might be further subdivided into s1.1s1.1. Sometimes, only the dorsad s1 might be modified in shape and/or somewhat bidentate at lobule base. All variations may serve as a taxonomic basis at the species level.

Comparing with Miklukhoceras, the present genus possesses a much smaller and shorter lateral lobe (L1(d)). Conch form and sutural generality of Propinacoceras are very similar to Difuntites; but the latter, as a paedomorphic genus, is characterized by much smaller conch size, with wider venter and much broader and deeper lateral lobe (L1(d)).

Propinacoceras beyrichi Gemmellaro, Reference Gemmellaro1887

Figures 16.6–16.13, 18.1

1887 Propinacoceras beyrichi Reference GemmellaroGemmellaro, p. 56, pl. 5, figs. 12–15, pl. 7.

1933 Propinacoceras americanum Reference Miller and WarrenMiller and Warren, p. 297, figs. 1–3.

1935 Propinacoceras beyrichi; Reference GrecoGreco, p. 178, pl. 15, fig. 5.

1940a Propinacoceras beyrichi; Reference Miller and FurnishMiller and Furnish, p. 40, pl. 5, fig. 5.

1972 Propinacoceras beyrichi; Reference Termier, Termier, Desparmet and MonyenatTermier et al., p. 109, pl. 14, figs. 1, 2.

1977 Propinacoceras beyrichi; Reference NassichukNassichuk, p. 564, pl. 1, figs. 1–3.

1982 Propinacoceras affine Gemmellaro; Reference LiangLiang, p. 647, pl. 2, figs. 1, 2.

1983 Propinacoceras cf. beyrichi Gemmellaro; Reference Sheng and LiuSheng and Liu, p. 241, pl. 20, figs. 3–6.

Description

Conch involute and thickly discoidal, with flat flanks and nearly flat venter. As shown by phragmoconch NIGP 93664 (Fig. 16.10, 16.11), may reach ~38 mm diameter and ~11.5 mm width. Ventral ribs very strong with flattened crest and narrower interspace (about 2/5 rib width), ventral rib rows separated by a strong median furrow. Ventral lobe narrow, ventrolateral saddle broad, with two nearly equidimensional lobules (s1s1) on the crest. The lateral lobe L1(d) small and bidentate. The primary umbilical lobe (U) suddenly enlarged in size more than the lateral lobe ahead and the other umbilically derived lobes behind. The primary umbilical lobe and following first four umbically derived lobes bidentate. Dorsal subdivision of the primary external lateral lobe (L1(d)) obviously less than one-half of the adjacent primary umbilical lobe.

Materials

Four specimens, NIGP 93664–93667, inner mold in mudstone, representing four individuals.

Occurrence

The ammonoid-bearing claystone intercalated in Member XII, top of the Houziguan Formation, Kabi (Loc. 3), Houchang, Ziyun County, Guizhou.

Remarks

Specimens here possess two lobules (s1s1) on crest of ventrolateral saddle, a large-sized umbilical lobe (U) with strongly bidentate and broader venter with strong ribs. All features are exactly identical to the holotype. There somewhat similarity to Propinacoceras affine Gemmellaro, Reference Gemmellaro1887 in conch shape and simple subdivision of ventrolateral saddle with two lobules (s1s1); however, P. affine has smaller size, different node arrangement on ventrolateral rims, and narrower ventrolateral saddle. According to Gemmellaro (Reference Gemmellaro1887), syntypes of P. affine have diameters of 17.0 mm at most; whereas P. beyrichi Gemmellaro have diameters of at least 22.0 mm, ranging up to more than 50.0 mm.

Termier et al. (Reference Termier, Termier, Desparmet and Monyenat1972) considered P. affine as the synonym of P. beyrichi by ignoring the classification significance of conch size. The present study maintains both as independent taxa by emphasizing the different arrangement of nodes on the ventrolateral shoulder and the different width of the ventrolateral saddle. However, P. affine described by Liang (Reference Liang1981) from central Jilin has such a large size, 32 mm in diameter, with parallel arrangement of nodes in both shoulders and fairly wider ventrolateral saddle, that it has to be a real P. beyrichi from Northeast China.

The suture and conch of Propinacoceras americanum Miller and Warren, Reference Miller and Warren1933 (p. 297, figs. 3, 4) are closely similar to the present species. Nassichuk (Reference Nassichuk1977) mentioned these similarities between Timor and America species, and treated P. americanum as a junior synonymy of the present species. Actually, the small difference in the height of the dorsal half of the external saddle in specimens from Sicily and America possibly reflects ontogenetic development or/and preservation. The suture in Nassichuk (Reference Nassichuk1977, text-fig. 2) was exactly cited from Miller and Warren (Reference Miller and Warren1933, fig. 4), which was drawn based on the specimen from Sicily, but not based on the specimen (UA type 139) from North America, as stated in the figure caption.

Six specimens from the Jiala Formation of Tibet had been compared by Sheng and Liu (Reference Sheng and Liu1983) to the Sicilian types of Propinacoceras beyrichi. Based on the illustrated details of conch form and suture, they are exactly conspecific.

Propinacoceras toumanskayae Leonova, Reference Leonova1989

Figures 17.1–17.3, 18.2

Figure 17 Propinacoceras Gemmellaro, Reference Gemmellaro1887 and Bamyaniceras Termier and Termier, Reference Termier and Termier1970. (1–3) Propinacoceras toumanskayae Leonova, Reference Leonova1989. Bed 6, Gaijiao Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou, ×2: (1) lateral view, NIGP 93673; (2, 3) lateral and ventral views of a phragmocone fragment, NIGP 93672; (4–9) Bamyaniceras knighti (Miller and Furnish, Reference Miller and Furnish1940a), lateral views (except 6, 7); (4–7) Bed 6, Gaijiao Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou; (4) NIGP 93668, ×2; (5) NIGP 93671, ×1.2; (6) ventrolateral view, NIGP 93670, ×1.5; (7) ventrolateral view, NIGP 154104, ×2; (8, 9) beds 34–32, Yangchang Formation, Yangchang section (Sec. III), Ziyun County, Guizhou, ×1; (8) NIGP 154106 (associated with NIGP 154105, Miklukhoceras guizhouense, on the other side of the same example); (9) NIGP 154107; (10, 11) Bamyaniceras cf. B. spatiosum Leonova, Reference Leonova1992; NIGP 93669, ventral and lateral views, ×2.5, Bed 6, Gaijiao Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou; (12–16) Bamyaniceras yangchangense n. sp.; (12, 13) lateral and ventral views, NIGP 154095, holotype, ×1, Yangchang Formation, Huohongchong (Loc. 2); Yangchang, Ziyun County, Guizhou; (14–16) beds 34–32, Yangchang Formation, Yangchang section (Sec. III), Ziyun County, Guizhou; (14) lateral, somewhat ventral view of the largest individual, NIGP 154099, ×1; (15) lateral view, phragmoconch, NIGP 154098; (16) lateral views of two individuals, inner molds; 16.1, NIGP 154100, with the ultimate volution outside, and 16.2, NIGP 154101, embedded during the preservation, all ×1.

Figure 18 External sutures of the propinacocertins. (1) Propinacoceras beyrichi Gemmellaro, Reference Gemmellaro1887, NIGP 93665, D ~29 mm, the ammonoid-bearing claystone intercalated in Member XII, the top Houziguan Formation, Kabi (Loc. 3), Houchang, Ziyun County, Guizhou; (2) Propinacoceras toumanskayae Leonova, Reference Leonova1989, NIGP 93672, W 9 mm, and inferring D ~37 mm, Bed 6, Gaijiao Member, Sidazhai Formation, Shaiwa section (Sec. VI–VI’), Sidazhai, Ziyun County, Guizhou; (3, 4) Difuntites furnishi n. sp. Claystone (3rd) Member of Shaiwa Formation, Sidazhai section (Sec. VI’–VI’), Sidazhai, Ziyun County, Guizhou; (3) NIGP 139932 (holotype), D ~15.5 mm, Bed 26; (4) NIGP 139933, D ~18 mm, Bed 31; (5, 6) Miklukhoceras guizhouense n. sp., beds 19–17, Longyin Formation, Huagong section (Sec. II), Huagong Tea-Plantation, Qinglong County, Guizhou; (5) NIGP 93680, D 13 mm: (6) NIGP 93678, holotype, D 43 mm; (7) Akmilleria parahuecoensis n. sp., NIGP 93688, holotype, D 30 mm, Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi; (8) Akmilleria huecoensis (Miller and Furnish, Reference Miller and Furnish1940a). syntype (University of Iowa, SUI 2042), H 25 mm, lower part of Hueco Limestone at southern end of Hueco Mountains, Texas, United of America (Miller and Furnish, Reference Miller and Furnish1940a, p. 45, fig. 8C), for comparing with A. parahuecoensis n. sp., herein.

1989 Propinacoceras toumanskayae Reference LeonovaLeonova, p. 85, pl. 2, figs. 1–4.

Description

Phragmoconch, internal molds, poorly preserved in mudstone, representing two individuals. Flank flat; venter flat, sculptured by two rows of transversal elongate nodes, which abruptly disappeared by the rim of flank. External suture includes narrow and deep ventral lobe, broad external saddle with well-preserved three adventitious lobules: basically symmetric ventrad s1.1 and dorsad s1.1, and the independent bidentate s1. Lateral lobe (L1(d)) intermediately sized and bidentate. Umbilical lobe (U) is long, narrow, and bidentate; other umbilically derived lobes not preserved.

Materials

Two fragments of phragmoconch, NIGP 93672 and 93673, with ventral and partially lateral parts of external sutures.

Occurrence

Bed 6, Gaijiao Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou.

Remarks

The present specimens generally resemble the type of Propinacoceras toumanskayae Leonova in general characters of suture and three adventitious apical lobules (s1.1s1.1s1) on crest of external saddle, especially the third one (s1) dorsad obviously bidentate. The transverse nodes on venter shown in Figure 17.3 are quite similar to those of the paratype N3591/215 (Leonova, Reference Leonova1989, pl. 2, fig. 2b). Comparing with corresponding umbilical lobe (U), the lateral lobe (L1(d)) in the present specimens is relatively longer than that of the holotype from Pamirs, but such variation seems to be intraspecific.

Genus Bamyaniceras Termier and Termier, Reference Termier and Termier1970

1889 Propinacoceras; Reference KarpinskiiKarpinskii, p 37 (part).

1970 Bamyaniceras Reference Termier and TermierTermier and Termier, p. 94.

1984 Bamyaniceras; Reference LeonovaLeonova, p. 41 (part).

Type species

Bamyaniceras bouyxi Termier and Termier, Reference Termier and Termier1970; original designation; Artinskian–Kungurian, Bamiyan Mountains, Afghanistan.

Diagnosis

Conch similar to Propinacoceras, suture with undivided ventral flank and 2–4 subdivisions in crest of ventrolateral saddle. Differs in possession of relatively large simple or bifid dorsal subdivision of ventrolateral saddle and retention to maturity of large dorsal subdivision of primary external lateral lobe (L1(d)) greater than one-half size of adjacent primary umbilical lobe U, or two elements subequal in extreme cases. Sutural formula (V2V1V2)s1s1l1L1(d)UU1......

Occurrence

Artinskian through Capitanian; Tajikistan (Pamirs), Afghanistan, USA (Texas), South China (Guizhou, Guangxi), Thailand (Loei), Indonesia (Timor), and Australia (north-west).

Remarks

Bamyaniceras is similar to Propinacoceras in both conch shape and general sutural features, but distinct by larger size of the lateral lobe (L1(d)) compared with the umbilically derived lobes, and by having a small lateral adventitious lobule (l1). Although Miklukhoceras also possesses the lateral adventitious lobule in the dorsal flank of the ventrolateral saddle, it is characterized by having a conspicuously longer lateral lobe (L1(d)) with less alignment to the umbilical lobe (U).

Certainly the origin of lateral and apical adventitious lobules is very important for subdivision of the genera Propinacoceras and Bamyaniceras. Ontogenetic details of the external saddle would be helpful for distinguishing among similar genera.

Bamyaniceras knighti (Miller and Furnish, Reference Miller and Furnish1940a)

Figures 17.4–17.9, 19.4

Figure 19 External sutures of Bamyaniceras Termier and Termier, Reference Termier and Termier1970. (1–3) Bamyaniceras nandanense n. sp.; (1, 2) Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi; (1) NIGP 93676, D ~11 mm; (2) NIGP 93675, D 19 mm; (3) NIGP 93751, holotype, D 40 mm, Bed 3, Longyin Formation, Longyin section (Sec. I), Pu’an County, Guizhou; (4) Bamyaniceras knighti Miller and Furnish, Reference Miller and Furnish1940a, NIGP 93668, D 24 mm, Bed 6, Gaijiao Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou; (5) Bamyaniceras cf. B. spatiosum Leonova, Reference Leonova1992, NIGP 93669, D 21 mm, Bed 6, Gaijiao Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou; (6) Bamyaniceras yangchangense n. sp. NIGP 154095, holotype, W 10 mm, and inferring D 40 mm or so, Yangchang Formation, Huohongchong (Loc. 2), Yangchang, Ziyun County, Guizhou.

1940a Propinacoceras knight Reference Miller and FurnishMiller and Furnish, p. 42, pl. 5, figs. 1–4, pl. 6, fig. 7.

Description

Conch discoidal, involute, with broad venter and strong ventrolateral nodes. Franks flat and broad. The specimen NIGP 93671, as the largest and relatively well preserved, ~62 mm diameter and ~14 mm wide. A living chamber present in the first half volution. Two small adventitious apical lobules (s1s1) on top of broad external saddle, and one small adventitious lateral lobule (l1) obliquely developed at dorsal flank of external saddle. Lateral lobe (L1(d)) fairly small and asymmetric. Umbilical lobe large and bifid; remaining umbilically derived lobes decreasing in size, bidentate in the first three.

Materials

Six mold specimens preserved in mudstone, NIGP 93668, 93670, 93671, 154104, 154106, 154107, with various taphonomic modification.

Occurrence

Bed 6, Gaijiao Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Sidazhai; beds 34–32, Yangchang Formation, Yangchang section (Sec. III). All from Ziyun County, Guizhou. The type materials from West Texas might come from different formations, aged from upper Artinskian through Roadian; while the appearances in Guizhou seem the same as in Texas, from the higher level in the Bed 6 of the Gaijiao Member of the Sidazhai Formation and the lower level in the beds 34–32 of Yangchang Formation.

Remarks

Some sutural details, such as wider and more rounded lobes, might differ from those in B. knighti, but the basic subdivisions and the relative position of adventitious elements are fairly similar. The minute differences mentioned above were considered to be a result of conch size and/or preservation, given that the suture of the holotype was measured at 65 mm diameter, but the suture herein at only 24 mm. Bamyaniceras polae (Toumanskaya, Reference Toumanskaya1949) from the Central Pamirs also possesses similar adventitious subdivisions and shape of ventrolateral saddle, but its third umbilical lobe is very deep and broad, and the adventitious lateral lobe (l) is very small.

Bamyaniceras yangchangense new species

Figures 17.12–17.16, 19.6

Diagnosis

Species with transversal ventral rib-like nodes and asymmetrically narrower apical lobules (s1s1).

Description

Platyconch, large, involute with broad and flat venter. A deep furrow subdivides venter into two rows of transversal rib-like nodes. Suture somewhat varied in different individuals. Ventral lobe narrow and deep, with three digits. Ventrolateral saddle wide, with two asymmetrically apical lobules (s1s1), ventrad deeper than dorsad. The only lateral lobule (l1) small and oblique, with two digits on bottom. Lateral lobe (L1(d)) separated from lateral lobule by somewhat stronger saddle. Umbilical lobe (U), the largest lobe in all external lobes, almost twice the successive umbically derived lobe. All preserved (three to four) umbilically derived lobes bidentate.

Etymology

Name is derived from the locality where the fossils were found.

Materials

Four samples, representing five individuals: NIGP 154095 (holotype), and NIGP 154098–154101.

Occurrence

Bed 34–32, Yangchang Formation, Yangchang section (Sec. III), Ziyun County, Guizhou; and the Yangchang Formation, Huohongchong (Loc. 2), 500 m southwest from the Yangchang section.

Remarks

Bamyaniceras yangchangense n. sp. is similar to B. simplex Leonova, Reference Leonova1984 and B. spatiosum Leonova, Reference Leonova1992 in basic subdivision of ventrolateral saddle. However, the apical lobules (s1s1) in the new species are obviously asymmetrical, and much narrower than those of the corresponding adventitious lobules in the Pamirs species.

Bamyaniceras nandanense new species

Figures 19.1–19.3, 20.1–20.12

Figure 20 Bamyaniceras nandanense n. sp., all lateral views (except 6). (1) One of two opposite parts, NIGP 88973, ×1, Bed 12, Longyin Formation, Longyin section (Sec. I), Pu’an County, Guizhou; (2, 3, 11) Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi; (2) NIGP 93676, ×3; (3) NIGP 93675, ×4; (11) NIGP 93677, ×2; (4–6, 8, 9, 12) Bed 3, Longyin Formation, Longyin section (Sec. I), Pu’an County, Guizhou; (4) NIGP 93750, ×4; (5) NIGP 93748, ×1.5; (6) ventral view, NIGP 88974, ×1.5; (8) NIGP 93751, holotype, ×1.5; (9) NIGP 93747, ×1.5; (12) NIGP 93749; (7, 10) beds 34–32, Yangchang Formation, Yangchang section (Sec. III), Ziyun County, Guizhou, ×1.5: (7) NIGP 93745; (10) NIGP 93746.

1989 Propinacoceras sp. nov. Reference ZhouZhou, p. 1368, fig. 1c (nom. nud.)

Diagnosis

Four entirely adventitious elements on ventrolateral saddle, three (s1.1s1.1s1) on flat crest and one (l1) at dorsal flank of saddle, probably representing the earlier evolution of Bamyaniceras loeiense (Ishibashi et al., Reference Ishibashi, Fujikawa and Nakornsri1996).

Description

The biggest phragmoconch (NIGP 93749) ~55.0 mm in diameter (Fig. 20.12). Ventral furrow and rows of nodes on the venter shown in NIGP 88974 (Fig. 20.6), and the transverse lines on partial flank shown in NIGP 88973 (Fig. 20.1). Unfortunately, conch width not clear from these specimens. Sutures well preserved in most specimens in lateral flanks and illustrated in ontogenetic sequence in two stages (Fig. 19.1–19.3): (1) the adolescent, apical adventitious lobules still in developing process, with the primitive character of the incipient lobules (Fig. 19.1, 19.2); and (2) the adult, lobules fully developed, with the permanently regular shape (Fig. 19.3).

Etymology

Name is derived from the locality where the fossils were found.

Materials

Twelve specimens, 11 more or less complete inner molds and one piece of an outer whorl fragment. NIGP 88973, 88974, 93675–93677, 93745–93751, in which NIGP 93751 is assigned as the holotype.

Occurrence

Bed 3 and Bed 12, Longyin Formation, Longyin section (Sec. I), Pu’an County, Guizhou; Bed 34–32, Yangchang Formation, Yangchang section (Sec. III), Ziyun County, Guizhou; and the Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi.

Remarks

Bamyaniceras nandanense n. sp. is similar with the type species of Bamyaniceras bouyxi Termier and Termier, Reference Termier and Termier1970 in both generality of suture and components of adventitious; however, the conspicuously smaller saddle elements V/s and s/l on top of ventrolateral saddle in B. nandanense n. sp. make it easy to distinguish from the latter. Bamyaniceras nandanense n. sp. resembles B. loeiense from Thailand in generality of sutures, but the former is much more primitive in development of the sutures than the latter. The maturity of sutures in Bamyaniceras nandanense n. sp. at a diameter of 40 mm may be only equal to that at about 20 mm in the latter. It is probable that B. nandanense n. sp., with its early Artinskian age, only represents the predecessor of B. loeiense in evolution. The presence of one more lateral adventitious lobules in Bamyaniceras nandanense n. sp. easily distinguishes it from B. yangchangense n. sp. described above.

Bamyaniceras cf. B. spatiosum Leonova, Reference Leonova1992

Figures 17.10, 17.11, 19.5

1992 cf. Bamyaniceras spatiosum Reference LeonovaLeonova, p. 135, pl. 30, figs. 5, 6.

Description

A phragmoconch, small, flat discoidal, with almost closed umbilicus; 21 mm in diameter, ~5.9 mm in width (W/D, about 0.28). Venter relatively narrow and subdivided by an intermediate furrow between two rows of prominently rounded nodes. About 5–6 nodes per centimeter in the outer volution. Suture only preserves two adventitious apical lobules (s1s1) on the top and a bidentate lateral lobule (l1) on the dorsal flank of the ventrolateral saddle. Saddle between lobules l1 and L1(d) fairly large in size and prominent in position. Three of the six preserved umbilically derived lobes bidentate.

Materials

One solitarily specimen, NIGP 93669, preserved in mudstone.

Occurrence

Bed 6, Gaijiao Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou.

Remarks

The specimen is similar to the holotype from Pamirs in possessing an almost identical general suture, but its exact taxonomic relationship cannot be confirmed due to inadequate knowledge of the ventral lobe. It is close to Bamyaniceras yangchangense n. sp. in having the same general sutural elements, but differs by the much wider external saddle than the latter.

Genus Miklukhoceras Pavlov, Reference Pavlov1967

Type species

Miklukhoceras pamiricum Pavlov, Reference Pavlov1967; original designation; Kochusuisk Member, Bolorian Stage (lower Kungurian), southeast Pamirs.

Diagnosis

Narrowly discoidal propinacoceratins with two rows of ventral nodes. Juveniles characterized by evolute form. At larger size, umbilicus remains open (U/D, 0.2–0.3 at 30 mm diameter), and conspicuous ribs are confined to sigmoidal extensions across ventrolateral flanks from ventral nodes. Suture somewhat as in Akmilleria, with single subdivision on ventral flank of ventrolateral saddle.

Occurrence

Sakmarian through Kungurian; Tajikistan (Pamirs), China (Xinjiang, Guizhou, Guangxi), and Thailand (Muak Lek).

Remarks

The affiliation Miklukhoceras with other medlicottiids is still unclear. The evolute juvenile conch form is a characteristic of the entire family Medlicottiidae, but the open umbilicus in Miklukhoceras remained even until the mature stage. The conspicuous ribs present in the internal volutions seem not to be a definitely identical character of the genus, so that the occurrence or not of them in the early stage probably represents only a variety between the species. Miklukhoceras differs from Kunlunoceras Wang, Reference Wang1983 from Xinjiang by its distinctively higher ventrolateral saddle. Probably, there is not any relationship between them.

Miklukhoceras guizhouense new species

Figures 18.5, 18.6, 21.1–21.11

Figure 21 Miklukhoceras guizhouense n. sp., all lateral views. (1, 2) Bed 3, Longyin Formation, Longyin section (Sec. I), Longyin, Pu’an County, Guizhou, ×1; (1) NIGP 154102; (2) NIGP 154103; (3) beds 34–32, Yangchang Formation, Yangchang section (Sec. III), Ziyun County, Guizhou, NIGP 154105 (associated with NIGP 154106, Bamyaniceras knighti, on the other side of the same example), ×1; (4–6) beds 19–17, Longyin Formation, Huagong section (Sec. II), Huagong Tea-Plantation, Qinglong County, Guizhou; (4) NIGP 93680, ×1.5; (5) NIGP 93681, ×1; (6) NIGP 93678, holotype, ×1; (7–11) Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi; (7) NIGP 93684, ×2; (8) NIGP 93682, ×3; (9) NIGP 93683, ×2; (10, 11) counterparts of an individual, NIGP 93679, ×1.

Diagnosis

Miklukhoceras species without ribs present in the first three volutions.

Description

Specimens poorly preserved as molds, however, features for generic and specific identification still available. Mature conch semi-evolute, with wider umbilicus (U/D may be >0.3), and juvenile totally evolute. Holotype NIGP 93678 and paratype NIGP 93680, with wholly evolute inner 2–3 volutions, but no transversal ribs present in these volutions. Conch may reach up to 55–60 mm in diameter. Venter looks broad and flat, divided by a medium furrow to show rows of strong nodes on each side. Transverse ribs (lines) with bi-project and sinus developed on lateral flanks and ended by nodes. All the specimens similar in possessing large and bidentate lateral lobe (L1(d)) and umbilical lobe (U), while the other umbilically derived lobes have only the first three or four bidentate, and decrease in size rapidly. The adventitious lobules are obscure in details, except the bidentate lateral lobule (l1) on the dorsal flank of the ventrolateral saddle.

Etymology

Name derived from Guizhou Province, where the Permian open sea with pandemic ammonoid faunas were well developed.

Materials

Ten specimens, NIGP 93678–93684, 154102, 154103, and 154105. NIGP 154105 associated with NIGP 154106, Bamyaniceras knighti (Miller and Furnish, Reference Miller and Furnish1940a), on the other side of the same sample.

Occurrence

Bed 3, Longyin Formation, Longyin section (Sec. I), Longyin, Pu’an; beds 19–17, Longyin Formation, Huagong section (Sec. II), Huagong Tea-Plantation, Qinglong, Guizhou; Bed 34–32, Yangchang Formation, Yangchang section (Sec. III), Ziyun County, Guizhou; Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi.

Remarks

Assignation to Miklukhoceras is based mainly on the evolute to semi-evolute conch shape, and the distinctive sigmoid ribs (lines) extending across the flanks and ending at the ventral nodes, although there are no ribs present in the first three internal volutions. The evoluted conch shape, the basic sculpture in outer volutions, and the preserved sutural features essentially ensure the generic identification. Miklukhoceras guizhouense n. sp. is similar to the type species of M. pamiricum Pavlov, Reference Pavlov1967 in the evolute inner volutions and generality of the sutures. However, it may distinguish from the latter by lacking the ribs in the exposed inner volutions, and having an advanced bidentate lateral lobule (l1). Miklukhoceras guizhouense new species resembles M. pressulum Leonova, Reference Leonova1984 in having a completely evolute conch shape and having no transverse ribs on the inner volutions, but it has a much larger and longer lateral lobe (L1(d)) than the latter.

Genus Difuntites Glenister and Furnish, Reference Glenister and Furnish1988

1915 Propinacoceras; Reference HanielHaniel, p. 36 (part).

1976 Propinacoceras; Reference RuzhentsevRuzhentsev, p. 39 (part).

Type species

Propinacoceras hidium Ruzhentsev, Reference Ruzhentsev1976; original designation; Maritime Territory, Far East, Russia; ‘Capitanian’ (probably Wuchiapingian).

Diagnosis

Conch small (possibly <35 mm at maturity), broadly discoidal (W/D, 0.3–0.4). Whorl flanks flat and parallel sided. Umbilicus small. Ventrolateral shoulders narrowly and uniformly rounded. Conspicuous median groove on venter confined by two rows of large ventral nodes on shoulders. Suture formula (V2V1V2)s1s1L1(d)UU1U2..... ; lateral lobe L1(d) one-quarter larger than the adjacent umbilical lobe U.

Occurrence

Wuchiapingian, probably through Changhsingian; Russia (Maritime Territory, Far East), Indonesia (Timor), Madagascar, Mexico (Coahuila), and South China (Southwest Guizhou).

Remarks

Suture generally similar to Propinacoceras, but characterized by dorsal prong of primary lateral lobe (L1(d)), the breadth of which exceeds that of adjacent primary umbilical lobe (U) in all growth stages. Representatives of the uddenitins resemble Difuntites in possession of a relatively simple first lateral saddle; however, lobes of uddenitins are generally entire, whereas most in Difuntites are bidentate.

Difuntites, as the rarest and latest taxon of the Paleozoic propinacoceratins, is an important progenesis representative of the group, but it is a significant component of the Eoaraxoceras association as well. The author of its type species (Ruzhentsev, Reference Ruzhentsev1976, p. 38) noted that the Capitanian age of the type material in the Maritime Territory occurrence (Shkotovo Area near Vladivostok, Far East) was possibly conspecific with ‘ Propinacoceras sp.’ from the La Colorada beds in Mexico (Miller, Reference Miller1944). However, the latest ammonoid sequence in the uppermost part of the Permian section from the Las Delicias area, Coahuila, summarized by Spinosa and Glenister (Reference Spinosa and Glenister2000, fig. 18–2) is earliest Dzhulfian (Wuchiapingian) age. Actually, Zakharov and Pavlov (Reference Zakharov and Pavlov1986) had already indicated that the uppermost occurrence of ‘ Propinacoceras hidium’ Ruzhentsev, Reference Ruzhentsev1976 was located at the left bank of the Artemovka River, in the upper part of Liudianzin Formation, about 60m above the layer of Cyclolobus kiselevae Zakharov, Reference Zakharov1983a in the Neizvest Bay section near the Trud Peninsula. Therefore, both latest Capitanian and Lopingian occurrences of the genus are possible. The present author considers that the occurrences mentioned above actually represent Lopingian deposits. Furthermore, the ammonoid association from the ‘Lower Layer’ of the Permian-Triassic Terrain of Anaborano, north Madagascar contains Episageceras, Xenodiscus, Difuntites, and advanced Cyclolobus Waagen, Reference Waagen1879, which could serve as additional evidence of the Lopingian Epoch, including Changhsingian Stage.

Difuntites furnishi new species

Figures 18.3, 18.4, 22.1–22.7

Figure 22 Difuntites Glenister and Furnish, Reference Glenister and Furnish1988, Artinskia Karpinskii, Reference Karpinskii1926, and Akmilleria Ruzhentsev, Reference Ruzhentsev1940c. (1–7) Difuntites furnishi n. sp., Claystone (3rd) Member, Shaiwa Formation, Sidazhai section (Sec. IV’-IV”), Sidazhai, Ziyun County, Guizhou; (1–3) lateral, ventral, and apertural views, NIGP 139932 (holotype), Bed 26, ×3; (4, 5) ventral and lateral views, NIGP 139931, Bed 23, ×2; (6, 7) ventral and lateral views, NIGP 139933, Bed 31, ×3; (8–12) Artinskia nalivkini Ruzhentsev, Reference Ruzhentsev1938, Bed 19, 2nd Member, Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan, Guangxi; (8, 9) lateral and ventral views, NIGP 88975, ×2; (10) lateral view, NIGP 88977, ×1; (11, 12) lateral and ventral views, NIGP 88976, ×1; (13–16) Akmilleria parahuecoensis n. sp., all lateral views; (13) NIGP 93686, ×3, beds 19–17, Longyin Formation, Huagong section (Sec. II), Tea-Plantation, Qinglong County, Guizhou; (14–16) Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi, ×1; (14) NIGP 93688, holotype; (15, 16) NIGP 93687, counterparts of the same individual.

Diagnosis

A species of Difuntites with relatively compressed conch shape, and wider umbilical lobe (U).

Description

Conchs small, diameter 20–31 mm, W/D close to 0.3 in the large specimen. Umbilicus closed or very small (1 mm). Flanks flat, parallel sided, and smooth on surface; ventrolateral shoulders narrowly and uniformly rounded, venter divided by a conspicuous median groove; prominent rounded nodes paired in opposite positions on the ventrolateral shoulders, ~50 pairs in outer volution occurring in the larger specimen. Sutures have small modifications in shape of lobules (s1s1), perhaps due to preservation, dorsal prong of primary lateral lobe (L1(d)) wider than the adjacent primary umbilical lobe (U) and aligning approximately in general arc of suture; four of the seven external lobes bidentate.

Etymology

Nomenclature in honor of late Professor W.M. Furnish, University of Iowa, USA.

Materials

Three specimens, NIGP 139931, 139932 (holotype), and 139933.

Occurrence

Beds 23, 26, and 31, Claystone (3rd) Member, Shaiwa Formation, Sidazhai section (Sec. IV’-IV”), Sidazhai, Ziyun County, Guizhou.

Remarks

Based on conch form and sutural features, the present specimens can be assigned to the genus Difuntites, and are considered to be a new species when compared with the previous monotype, D. hidius Ruzhentsev, Reference Ruzhentsev1976, by the relatively compressed conch shape (W/D, about 0.27 vs. 0.37) and apparently wider umbilical lobe (U) in Difuntites furnishi n. sp. Two sutures illustrated in Figure 18.3 and 18.4 show apical lobules (s1s1) quite different from each other in both shape and relative length. However, these differences might be caused by deformation of lobules in preservation, similar to the conch deformation shown in NIGP 139932 (Fig. 22.1–22.3) and NIGP 139933 (Fig. 22.6, 22.7).

Genus Akmilleria Ruzhentsev, Reference Ruzhentsev1940c

1915 Propinacoceras; Reference HanielHaniel, p. 34 (part).

1936 Artinskia; Reference MillerMiller, p. 491 (part).

1939b Synartinskia Reference RuzhentsevRuzhentsev, p. 461 (part).

Type species

Propinacoceras transitorium Haniel, Reference Haniel1915; original designation; Atsabe and Bitauni beds, Artinskian–Kungurian, Timor, Indonesia.

Diagnosis

Conch narrowly discoidal, with two rows of ventral tubercles. Suture characterized by ventrolateral saddle with 5–8 subdivisions, one on ventral flank, 2–5 on crest, two dorsad, the first of which is bidentate. Sutural formula: (V2V1V2)v1s1s1l2l1L1(d)UU1U2......

Occurrence

Asselian through Kungurian; Kazakhstan (Southern Urals), Indonesia (Timor), USA (Texas, Kansas, Nevada), Thailand (Loei), and South China (Guizhou and Guangxi).

Remarks

Akmilleria resembles Synartinskia in conch form, but distinguished from the latter by the sutural alignment. Synartinskia belongs to the subfamily Sicanitinae, possessing a longer lateral lobe (L1(d)), significantly below alignment of adjacent umbilically derived lobes. Compared with Artinskia of the subfamily Medlicottinae, the present genus has one less ventral lobule (v2) and one lateral lobule (l3) in adventitious elements.

Akmilleria parahuecoensis new species

Figures 18.7, 22.13–22.16

Diagnosis

Similar to Akmilleria huecoensis (Miller and Furnish, Reference Miller and Furnish1940a) and A. electraensis (Plummer and Scott, Reference Plummer and Scott1937) in generality of the suture, but different from the former by possessing a much narrower ventrolateral saddle, and from the latter by an obviously wider ventrolateral saddle.

Description

Conch large, thin, discoidal, may reach to 60 mm diameter, flanks flat, and umbilicus small. Venter divided by a prominent medium groove, on both sides exhibiting a row of rounded nodes, largely confined to the ventral side of the ventrolateral shoulder. The ventrolateral saddle is relatively narrower compared with others in the genus, and adventitious elements contain five subdivisions: one ventral (v1), two apical (s1s1), and two lateral (l1l2). Lateral lobe (L1(d)) bidentate, only a little smaller than the adjacent umbilical (U) in size. The following umbilically derived lobes (only four preserved) all bidentate.

Etymology

Name is derived from the similarity to the North American species A. huecoensis (Miller and Furnish, Reference Miller and Furnish1940b).

Occurrence

Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi; beds 19–17, Longyin Formation, Huagong section (Sec. II), Tea-Plantation, Qinglong County, Guizhou.

Materials

Four specimens, in different preservation condition, representing three individuals, NIGP 93686, 93687, and 93688 (holotype).

Remarks

Akmilleria parahuecoensis n. sp. is identical with A. huecoensis (Miller and Furnish, Reference Miller and Furnish1940a, p. 45, fig. 8C) (Fig. 18.8) in the general appearance of the suture and subdivisions of the ventrolateral saddle. However, its ventrolateral saddle is much narrower than that of the American species, with concominantly much thinner subdivisions on the saddle as well. Akmilleria parahuecoensis n. sp. is similar to A. whortani (Miller, Reference Miller1936) in width and subdivisions of the ventrolateral saddle, but different from the latter by the bidentate lateral lobe (L1(d)) instead of latter’s tridentate lateral lobe. It is also similar A. electraensis (Plummer and Scott, Reference Plummer and Scott1937) in subdivisions of the ventrolateral saddle, but distinguished from the latter by clearly wider ventrolateral saddle.

Subfamily Medlicottinae Karpinskii, Reference Karpinskii1889

Genus Artinskia Karpinskii, Reference Karpinskii1926

1889 Promedlicottia Reference KarpinskiiKarpinskii, p. 23 (nom. nud.).

1907 Prosicanites Reference ChernovChernov, p. 359 (nom. nud.; non Toumanskaya and Borneman, Reference Toumanskaya and Borneman1937, p. 113).

1940a Artinskia; Reference Miller and FurnishMiller and Furnish, p. 44 (part).

Type species

Goniatites artiensis Grünewaldt, Reference Grünewaldt1860; original designation; Artinskian Stage, South Urals.

Diagnosis

Ancestral medlicottiins with subdivision of ventrolateral saddle intermediate in degree between characteristic Medlicottiinae and Propinacoceratinae, and conch resembling Sicanitinae. Conch thinly discoidal, with grooved venter between two rows of prominent ventrolateral nodes bounded by less-conspicuous ribs on ventrolateral flanks. Suture resembles Medlicottia, but ventrolateral saddle broader and lower, with 6–8 subdivisions (commonly two ventrad, two or three in crest, three dorsad). Sutural formula: (V2V1V2)v1v2s1s1l3l2l1L1(d)UU1U2U3U5......

Occurrence

Pennsylvanian (Gzhelian/Virgilian)–Cisuralian (Artinskian); Kazakhstan (Southern Urals), Tajikistan (Pamirs), Russia (Urals, North Verkhoyan), South China (Guangxi), Thailand (Loei), Japan (Kitakami Massif), Indonesia (Timor), USA (Texas, New Mexico), and Austria (Carnic Alps).

Remarks

Complex subdivision of the ventrolateral saddle in rare Gzhelian representatives from the Urals initiated lineages that diversified in the Early Permian (Asselian), were rare in the succeeding Sakmarian, but then diversified again in the Artinskian to extend through the Late Permian and eventual extinction of the order in the Early Triassic (Induan).

Artinskia nalivkini Ruzhentsev, Reference Ruzhentsev1938

Figures 22.8–22.12, 24.1–24.3

1938 Artinskia nalivkini Reference RuzhentsevRuzhentsev, p. 248, pl. 1, figs. 8–11.

1951 Artinskia nalivkini; Reference RuzhentsevRuzhentsev, p. 91, pl. 4, figs. 6, 7.

Description

Inner molds with varied diameters from 19 mm to ~80 mm, subdiscoidal with small umbilicus. Venter narrowly rounded, subdivided by a furrow into two rows with prominent ventrolateral nodes bounded by less-conspicuous ribs on ventrolateral flanks. Lateral flanks flat, in specimen NIGP 88978 showing an obvious depression belt around the ventrolateral shoulder. External saddle consisting of two ventral adventitious lobules (v1v2) on ventral flank, entirely apical lobule (s) or slightly subdivided adventitious lobule (s1s1) on top of the saddle, and three lateral adventitious lobules (l3l2l1) on lateral flank, in which l1 is bidentate. The really lateral lobe (L1(d)) large in size and bidentate; the umbilical lobe (U) generally the largest one in the external lobe series; the remaining umbilically derived lobes decrease in size subsequently. Lateral lobe and adjacent first three or four umbilically derived lobes bidentate.

Occurrence

Bed 19, 2nd Member, Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi.

Materials

Three specimens, NIGP 88975–88977, phragmoconchs preserved in limestone matrix.

Remarks

The specimens resemble Artinskia nalivkini Ruzhentsev, Reference Ruzhentsev1938 in conch form and generality of external suture, with a depressed out-zone in flank and six or seven adventitious lobules, v1v2s1s1l3l2l1 and 12 external ‘lateral’ lobes in adults. However, the shape of lateral lobules l1 and l2 in the present materials are consistent with asymmetrically bidentate l1 and entire l2, but not as variable as the holotype of the species, tridentate or bidentate. Artinskia nalivkini also is similar to the type species A. artiensis (Grünewaldt, Reference Grünewaldt1860) in subdivision of ventrolateral saddle, but many fewer bidentate umbilically derived lobes.

Genus Medlicottia Waagen, Reference Waagen1880

1845 Goniatites; Reference VerneuilVerneuil, p. 375 (part).

1874 Sageceras ( Goniatites); Reference KarpinskiiKarpinskii, p. 287.

1880 Medlicottia Reference WaagenWaagen, p. 83 (part).

1937 ? Prosicanites Reference ToumanskayaToumanskaya, p. 113 (part).

1938 Artinskia; Reference RuzhentsevRuzhentsev, p. 246 (part).

1940a Medlicottia Reference Miller and FurnishMiller and Furnish, p. 49 (part).

1992 ? Paramedlicottia; Leonova, Reference Leonova1992, p. 138.

2002 ? Prosicanites; Reference LeonovaLeonova, p. S23 (part).

Type species

Goniatites orbignyanus Verneuil, Reference Verneuil1845, original designation; Artinskian Stage, Urals, Russia.

Diagnosis

Conch thinly lenticular; narrow furrowed venter bounded by pair of sharp ventrolateral keels (generally without nodes). Ventrolateral saddle has 8–12 subdivisions, remaining saddles rounded or slightly indented near midheight. External lateral lobe and adjacent umbilical lobes in arched alignment, subequal, but decreasing in size to umbilicus. Sutural formula: (V2V1V2)v1v2v3–6s1s1l7–5l4l3l2l1L1(d))UU1U2......

Occurrence

Sakmarian though Wordian; Italy (Sicily), Russia (Urals, Volga-Urals), Kazakhstan (South Urals), Ukraine (Crimea), Tajikistan (Pamirs), Indonesia (Timor), China (Guizhou, Gansu, ?Xizang, Xinjiang), Japan (southern Kitakami Massif), Indonesia (Timor), Italy (Sicily), Columbia, Mexico (Coahuila), USA (Texas, New Mexico, Nevada), and Canada (British Columbia, Yukon, Arctic Archipelago, Devon Island).

Remarks

Medlicottia is easily distinguished from genera of the family based on conch form and outline of suture. The oldest species of Medlicottia, M. vetusta Ruzhentsev, Reference Ruzhentsev1949, is similar to Sicanites in conch shape, but the latter has a longer lateral lobe (L1(d)), significantly below alignment of the adjacent subequal umbilically derived lobes. The younger Medlicottia has a narrow and weaker or non-sculptured venter, but the sutures are quite different from other genera in the family. Artinskia usually has two ventral and three lateral adventitious lobules, whereas Medlicottia has at least three and five, respectively. In addition, the ventrolateral saddle in Artinskia is higher and narrower than that in Medlicottia.

Medlicottia orbignyana (Verneuil, Reference Verneuil1845)

Figures 23.1–23.3, 24.4

Figure 23 Medlicottia Waagen, Reference Waagen1880 and Eumedlicottia Spath, Reference Spath1934. (1–3) Medlicottia orbignyana (Verneuil, Reference Verneuil1845), lateral views, beds 19–17, Longyin Formation, Huagong section (Sec. II), Huagon Tea-Plantation, Qinglong County, Guizhou, ×1.5; (1) NIGP 93692; (2, 3) counterparts of an individual, NIGP 93691; (4–14) Eumedlicottia kabiensis n. sp., the ammonoid-bearing claystone intercalated in Member XII, upper Houziguan Formation, Kabi (Loc. 3), Houchang, Ziyun County, Guizhou; (4, 5) lateral and apertural views, NIGP 93698, ×3; (6, 7) lateral and ventral views, NIGP 93694, ×2; (8–10) lateral, apertural, and ventral views, NIGP 93693, holotype, ×3; (11) lateral view, NIGP 93697, ×1.5; (12) lateral view, NIGP 93695, ×1; (13, 14) lateral views, counterparts of the same individual, NIGP 93696, ×1.

Figure 24 External sutures of medlicottiins. (1–3) Artinskia nalivkini Ruzhentsev, Reference Ruzhentsev1938, Bed 19, 2nd Member, Nandan Formation, Meyao section (Sec. V), Nandan, Guangxi; (1) NIGP 88975, D 18 mm; (2) NIGP 88976, D 42 mm; (3) NIGP 88977, D ~80 mm; (4) Medlicottia orbignyana (Verneuil, Reference Verneuil1845), NIGP 93692, D ~36 mm, beds 19–17, Longyin Formation, Huagong section (Sec. II), Huagon Tea-Plantation, Qinglong County, Guizhou; (5) Eumedlicottia kabiensis n. sp. NIGP 93693, holotype, D 22 mm, the ammonoid-bearing claystone intercalated in Member XII, upper Houziguan Formation, Kabi (Loc. 3), Houchang, Ziyun County, Guizhou.

1845 Goniatites orbignyanus Reference VerneuilVerneuil, p. 375, pl. 26, fig. 6.

1874 Sageceras ( Goniatites) orbignyanus; Reference KarpinskiiKarpinskii, p. 287.

1880 Medlicottia orbignyana; Reference WaagenWaagen, p. 83.

1907 Medlicottia orbignyi; Reference ChernovChernov, p. 367, pl. 1, fig. 8.

1989 Medlicottia sp. Reference ZhouZhou, p. 1367.

2005 Medlicottia cf . orbignyana; Reference Zhou and YangZhou and Yang, p. 381, figs. 4.3, 5.21–5.23.

Description

Shell lenticular with nearly closed umbilicus. Venter narrow with ventral groove, bordered by smooth keels at ventrolateral shoulders, which might be weakly node-sculptured in early ontogeny, and serrated by adventitious lateral lobules on the ventrolateral saddle in the last volution. The phragmoconch (Fig. 23.2, 23.3) of NIGP 93691 reached ~43 mm in diameter.

Ventral and apical adventitious subdivisions (probably v1–4 and s1s1) of ventrolateral saddle unknown due to incomplete preservation of the external suture. Ventrolateral saddle high and narrow as usual. Lateral adventitious lobules definitely of five elements (l1l2l3l4l5), although somewhat abraded during preservation, the first one (l1) the largest with strong bidentition, the secondary saddle between l1 and L1(d) heavily reduced by secondary erosion, while other secondary saddles, numbered from second to fourth or sixth, decreasing in size upward to top of the saddle. Nine external ‘lateral’ lobes preserved (Fig. 24.4). Lateral lobe (L1(d)) strongly bidentate and shorter than the adjacent umbilical lobe (U), the next umbilically derived lobe (U1) representing the longest in external lobes. All preserved external lobes bidentate.

Occurrence

Beds 19–17, Longyin Formation, Huagong section (Sec. II), Huagong Tea-Plantation, Qinglong County, Guizhou.

Materials

Three specimens, representing two individuals, NIGP 93691 (two opposite pieces) and 93692, poorly preserved in mudstone.

Remarks

Sutural outline resembles those of the type species, M. orbignyana, in shape of ventrolateral saddle, number of lateral adventitious, and subdivisions on ventrolateral saddle. However, the secondary saddles between the lateral lobe (L1(d)) and first lateral adventitious lobule (l1), and between any other two lateral adventitious lobules are shorter than those in the type specimens of the Urals species. After comparison of the components and figures of the adventitious lobules between types and the present specimens, the differences noted above probably are due simply to erosion of specimens.

Genus Eumedlicottia Spath, Reference Spath1934

1880 Medlicottia Reference WaagenWaagen, p. 83 (part).

Type species

Medlicottia bifrons Gemmellaro, Reference Gemmellaro1887; original designation; Sosio Limestone (Wordian), Rupe del Pass, Sosio Valley, Province Palermo, Sicily, Italy.

Diagnosis

Conch and suture generally similar to Medlicottia, but includes larger specimens (phragmocone may exceed 15 cm diameter), and most saddles in external suture are characterized by distinct paired notches above midheight. Prongs of primary external lateral lobe lie off (above) general lobe alignment.

Occurrence

Artinskian through Changhsingian (e.g., Chiddruan); Greece (Chios Island), Oman, Pakistan (Salt Range), Japan (Kitakami Massif), Russia (Maritime Territory), Indonesia (Timor), Mexico Coahuila), USA (west and central Texas, Wyoming), Canada (British Columbia), East Greenland, and South China (Guizhou).

Remarks

Eumedlicottia has been accepted by most authors as an independent valid genus, distinguished from Medlicottia by palpable notches of the most outer lobes, even including some lateral adventitious lobules at the lower part.

Eumedlicottia kabiensis new species

Figures 23.4–23.14, 24.5

Diagnosis

Species characterized by relatively broader ventral lobe, symmetrical fish-bone-like ventrolateral saddle, five adventitious lobules laterally (l1l2l3l4l5), and four ventrally (v1v2v3v4). Lateral lobe (L1(d)) not obviously shorter than the umbilically derived lobes (UU1U2U3….).

Description

Shell sublenticular with narrow, bicarinate, furrowed venter. Keels on ventral rim smooth, flanks generally flat, umbilicus very small. Diameter and basic ratios of holotype NIGP 93693: D 23.6 mm, H/D 0.59, and W/D 0.28, respectively. A shallow longitudinal depression belt and fine transversal growth lines with a broad and shallow lateral salient observed from the outer and inner casts of paratype NIGP 93696. Both ventral lobe and ventrolateral saddle relatively broad with parallel flanks generally; the adventitious elements on the saddle include four square ventral lobules (v1v2v3v4), five square lateral lobules (l1l2l3l4l5), and two apicals (s1s1). First lateral adventitious lobule (l1) large and bidentate. Lateral lobe (L1(d)) and umbilically derived lobes (UU1U2U3) broad and bidentate, with obvious and regular notches on flanks; especially, prongs of the former seem not as usual above the general alignment of the latter.

Etymology

Named from the locality where the new species was found.

Materials

Six specimens, four phragmocone molds and two casts of body chamber; NIGP 93693 (holotype), and NIGP 93694–93698.

Occurrence

The ammonoid-bearing claystone, intercalated in the limestone of the XII Member, top of the Houziguan Formation, Kabi (Loc. 3), Houchang, Ziyun County, Guizhou.

Remarks

Eumedlicottia kabiensis n. sp. is similar to the type species, E. bifrons Gemmellaro, Reference Gemmellaro1887, in general outline of suture, the wider ventral lobe, and the robust ‘lateral’ lobes; but differs from the latter by one or two more ventral and lateral adventitious lobules, and fairly longer lateral lobe (L1(d)). Eumedlicottia kabiensis n. sp. is similar to E. whitneyi (Böse, Reference Böse1919), with broader ventral lobe and ventrolateral saddle, square-like ventral and lateral adventitious lobules, but with more robust ‘lateral’ lobes, the width/length of lobe (~0.45) different from 0.38 in the latter. Although the species here is similar E. burckhardti (Böse, Reference Böse1919) in the fossil combination in occurrence, the former possesses one more adventitious lobule both laterally and ventrally, even at smaller diameters (D=22 mm).

Subfamily Sicanitinae Noetling, Reference Noetling1904 (=Artioceratinae Leonova, Reference Leonova1989)

Genus Sicanites Gemmellaro, Reference Gemmellaro1887

1887 Medlicottia; Reference GemmellaroGemmellaro, p. 50 (part).

1937a ? Prosicanites Toumanskaya, p. 113 (part).

1940c Artinskia; Reference RuzhentsevRuzhentsev, p. 475 (part).

1947 Aktubinskia; Reference RuzhentsevRuzhentsev, p. 641.

1978 Vanartinskia Ruzhentsev, Reference Ruzhentsev1978, p. 41.

Type species

Medlicottia schopeni Gemmellaro, Reference Gemmellaro1887; subsequent designation by Miller and Furnish, Reference Miller and Furnish1940a, based on page priority to the junior synonym, Sicanites mojsisovicsi Gemmellaro, Reference Gemmellaro1887; Sosio Limestone (Wordian), Rupe del Pass, Sosio Valley, Province Palermo, Sicily, Italy.

Diagnosis

Conch lenticular, with ventral nodes varyingly bladelike in most species to simulate paired ventrolateral keels. Ventrolateral saddle intermediate in height, with 7–10 subdivisions, the primary external lateral lobe (L1(d)) significantly below alignment of subequal adjacent umbilically derived lobes. Sutural formula: (V2V1V2)v1v2–3s1s1l5–3l2l1L1(d)UU1U2.....U11.

Occurrence

Asselian through Wordian; Italy (Sicily), Croatia, Iraq (Kurdistan), Oman, Ukraine (Crimea), Kazakhstan (Southern Urals), Tajikistan (Pamirs), Thailand (Loei), Indonesia (Timor), USA (western Texas, Nevada), Mexico (Coahuila), and South China (Guizhou, Guangxi).

Remarks

The type specimen of Scicanites schopeni exhibits the polygonal coiling up to a diameter of 15 mm. It may serve eventually for separate generic recognition, but there is insufficient current information about other assigned species. Sicanites is very similar to Artinskia in subdivision of the adventitious elements on ventrolateral saddle, especially for some Asselian species (e.g., Artinskia irinae Ruzhentsev), because it has a long external lateral lobe (L1(d)) and nearly the same adventitious subdivision of ventrolateral saddle. However, the difference between them is still obvious in at least three respects: (1) Sicanites is characterized by narrower venter, whereas in Artinskia the venter is relatively broader; (2) Sicanites has obvious lateral ribs and much smaller tubercles near the ventrolateral part of conch, whereas in Artinskia the nodes usually are bigger, but not as prominent; and (3) although some primitive species of Artinskia possess a longer external lateral lobe like Sicanites, the latter has a very large first lateral adventitious lobe and more bidentate umbilical lobes in number.

Sicanites notabilis (Ruzhentsev, Reference Ruzhentsev1940c)

Figures 25.1–25.3, 26.1, 26.2

Figure 25 Sicanitins. (1–3) Sicanites notabilis Ruzhentsev, Reference Ruzhentsev1940c; (1) NIGP 88982, ×4, beds 34–32, Yangchang Formation, Yangchang section (Sec. III), Ziyun County, Guizhou; (2) NIGP 154109, ×2, Bed 3, Longyin Formation, Longyin section (Sec. I), Pu’an County, Guizhou; (3) NIGP 93689, ×4, Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi; (4–7) Synartinskia meyaoense n. sp. Bed 19, 2nd Member, Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi, ×3; (4, 5) lateral and ventral views, NIGP 88978, holotype; (6, 7) ventral and lateral views, NIGP 88979.

Figure 26 External sutures of sicanitins, the genera Sicanites Gemmellaro, Reference Gemmellaro1887 and Synartinskia Ruzhentsev, Reference Ruzhentsev1939b. (1, 2) Sicanites notabilis Ruzhentsev, Reference Ruzhentsev1940c; (1) NIGP 88982, D 17 mm, beds 34–32, Yangchang Formation, Yangchang section, Ziyun County, Guizhou; (2) NIGP 93689, D ~28 mm, Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi; (3, 4) Synartinskia meyaoense n. sp. Bed 19, 2nd Member, Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi: (3) NIGP 88979, D 17 mm; (4) NIGP 88978, holotype, D 20 mm.

1940c Artinskia notabilis Reference RuzhentsevRuzhentsev, p. 475.

1947 Aktubinskia notabilis; Reference RuzhentsevRuzhentsev, p. 641.

2004 Aktubinskia cf. notabilis; Reference Zhou and LiengjarernZhou and Liengjarern, p. 327, figs. 7.5–7.7, 9.5, 9.6.

2009 Sicanites notabilis; Reference Glenister, Furnish and ZhouGlenister et al., p. 210, figs. 135, l–n.

Description

Juvenile evolute, gradually becoming involute when mature. Two rows of tubercles developed on the ventrolateral shoulder and separated by the medium groove. Three lateral adventitious lobules (l3l2l1) on lateral flank of the ventrolateral saddle, in which the first one (l1) is quite large in size and strongly bidentate at base. As shown in NIGP 93689 (Fig. 26.2), the lower digit of the first adventitious lobule (l1) bidentate secondarily.

Materials

Three specimens, NIGP 88982, 93689, and 154109, representing three individuals collected from yellow, weathered mudstone of three different localities, but all from the same horizon in the area.

Occurrence

Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi; Bed 34–32, Yangchang Formation, Yangchang section (Sec. III), Ziyun County, Guizhou; Bed 3, Longyin Formation, Longyin section (Sec. I), Pu’an County, Guizhou.

Remarks

Sicanites notabilis specimens in this study, with a longer lateral lobe (L1(d)) and a large and bidentate first lateral adventitious lobule (l1), are rather similar to the type specimen of Sicanites notabilis (Ruzhentsev). The secondary bidentate in the first lateral adventitious lobule (Fig. 26.2) is considered to be a result of intraspecific variation.

Genus Synartinskia Ruzhentsev, Reference Ruzhentsev1939b

1889 Propinacoceras; Reference KarpinskiiKarpinskii, p. 37 (part).

1939b Synartinskia Reference RuzhentsevRuzhentsev, p. 461.

1985 Parasicanites Reference LeonovaLeonova, p. 77.

Type species

Synartinskia pricipalis Ruzhentsev, Reference Ruzhentsev1939b; original designation; Sakmarian, Aktubinsk District, Kazakhstan (Southern Urals).

Diagnosis

Conch form and ventral sculpture as in Artioceras. Suture characterized by deep dorsal prong of primary external lateral lobe in combination with ventrolateral saddle with four or five subdivisions, one of which is ventrad; first dorsal subdivision (l1) large and variously dentate. Sutural formula: (V2V1V2)v1s1s1l1l2L1(d)UU1U2......

Occurrence

Sakmarian through Roadian; Russia and Kazakhstan (Southern Urals), Tajikistan (Pamirs), Canada (Arctic Archipelago: Devon Island), and South China (Guangxi).

Remarks

As a sicanitins, the systematic character of Synartinskia is possessing the deep, lateral lobe (L1(d)), which is apparently below the alignment of subequal adjacent umbilically derived lobes, although the generic classification is based on possessing only one ventral adventitious lobule (v1), and as few as only one lateral adventitious lobule (l1), Synartinskia is easily distinguished from Sicanites and Artioceras in the subfamily.

Synartinskia meyaoense new species

Figures 25.4–25.7, 26.3, 26.4

Diagnosis

Forms with obviously longer lateral lobe (L1(d)), characterized by adventitious components of ventrolateral saddle, which shows a transition to Artinskia.

Description

Conch flat laterally, flanks nearly parallel, but a rather obviously depressed zone around margin of conch (Fig. 25.4). Umbilicus small, U/D ~0.12 at diameter 18.4 mm. Two rows of slightly oblique, but prominent nodes mainly confined in venter (Table 5). External suture includes a narrow ventral lobe, a high and relatively broad ventrolateral saddle with five to six adventitious lobules (e.g., v1s1s1l2l1 (Fig. 26.3) to v1v2sl3l2l1 (Fig. 26.4) ontogenetically, a deep and bidentate lateral lobe (L1(d)), and several bidentate umbilically derived lobes (U U1U2….).

Table 5 Dimensions and ratios of Synartinskia meyaoense n. sp. D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Etymology

Named from the Meyao section (Sec. V), Liuzhai area in Nandan County, Guangxi.

Materials

Two internal molds of phragmocone, septated throughout, NIGP 88978 (holotype) and 88979.

Occurrence

Bed 19, 2nd Member, Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi.

Remarks

Synartinskia meyaoense n. sp. belongs to Synartinskia because of its longer lateral lobe (L1(d)), which has less than the average alignment of the umbilically derived lateral lobes and the basical adventitious subdivisions of the ventrolateral saddle. It is distinct from other species in the genus by the characters of the adventitious lobules of the ventrolateral saddle, which form a transition to the genus Artinskia in subdivision of the ventrolateral lobe. However, there is a depressed zone around margin of the conch (Fig. 25.1), which is quite similar to the genus Artinskia. The question is if the genetic feature of the longer lateral lobe (L1(d)) could be polyphyletic?

Order Goniatitida Hyatt, Reference Hyatt1884

Suborder Goniatitina Hyatt, Reference Hyatt1884

Superfamily Agathioceratoidea Arthaber, Reference Arthaber1911

Family Agathiceratidae Arthaber, Reference Arthaber1911

Genus Agathiceras Gemmellaro, Reference Gemmellaro1887

1874 Goniatites; Reference KarpinskiiKarpinskii, p. 288 (part).

1887 Agathiceras Reference GemmellaroGemmellaro, p. 75 (part).

1915 Agathiceras; Reference HanielHaniel, p. 66 (part).

1950 Agathiceras ( Paragathiceras) Reference RuzhentsevRuzhentsev, p. 92.

Type species

Agathiceras suessi Gemmellaro, Reference Gemmellaro1887; original designation; Sosio Limestone (Wordian), Sosio Valley, Sicily, Palermo, Italy.

Diagnosis

Conch subdiscoidal, involute, commonly with apertural constrictions. Sculpture merely prominent longitudinal lirae. Ventral lobe broad, with pouched and apically pointed branches; median saddle in some forms reaching almost total height of ventral lobe. In adult, adventitious lobe of early whorls developing three discrete and subequal spatulate lobes.

Occurrence

Upper Carboniferous (Moscovian) through Middle Permian (Wordian); Italy (Sicily), Russia and Kazakhstan (South Urals), Ukraine (Crimea), Slovenia, Tunisia, Iraq, Afghanistan, Oman, Indonesia (Timor), Japan, USA (Texas), Mexico (Coahuila), Canada (British Columbia, North West Territories), Russia (Siberia), Tajikistan (Pamirs), Western Australia, Thailand (Loei, Saraburi), and China (Guangxi, Guizhou, Xinjiang, Xizang, Nei Mongol, Jilin).

Remarks

Species of Agathiceras were the most abundant (number of individuals) late Paleozoic ammonoids in the open sea. In Chinese records, Agathiceras is apparently exclusively distributed in a particular environment. The definition of the genus worked out by the earlier workers is relatively extensive. Haniel (Reference Haniel1915) even included genera Adrianites and Doryceras, which actually have totally different phylogenetic origins and can be easily distinguished based on suture and sculpture of test. Ruzhentsev (Reference Ruzhentsev1938) grouped the forms with transverse lines, represented by ‘ Agathiceras martini Haniel, Reference Haniel1915’ into subgenus Agathiceras ( Gaetanoceras), which Gerth (Reference Gerth1950) raised in rank to an independent genus. At the same time, Ruzhentsev (Reference Ruzhentsev1950) established another new subgenus, Agathiceras ( Paragathiceras), based to the much-flattened shell forms. However, if subgenus subdivision is based only on conch shape, it may be disturbed by the secondary deformation during preservation.

Agathiceras changed very little with time both in conch shape and suture. Dixon (Reference Dixon1960) compared several representative species of Agathiceras from various localities and horizons, but in the same ontogenetic phase, and suggested that species in the early stage had more inflated shells, while those in the late stage had more compressed shells. Dixon (Reference Dixon1960) recognized a series of trends in conch dimensions with stratigraphic level, certainly is a promising biostratigraphic result for a genus with such a long geological range. Three intervals with different appearance of sculpture are recognized herein in conchs of Agathiceras specimens from South China, which is significant for identifying species and avoiding potential preservation variation that could occur from using inflation alone.

Agathiceras sequaxilirae new species

Figures 27.5–27.21, 29.3, 30.1–30.3

Figure 27 Agathiceras Gemmellaro, Reference Gemmellaro1887. (1–4) Agathiceras suessi Gemmellaro, Reference Gemmellaro1887, the ammonoid-bearing claystone intercalated in Member XII, upper Houziguan Formation, Kabi (Loc. 3), Houchang, Ziyun County, Guizhou. ×2.5; (1, 2) lateral and apertural views, NIGP 93703; (3, 4) apertural and lateral views, NIGP 93702; (5–21) Agathiceras sequaxilirae n. sp. Nandan Formation, Meyao section (Sec. V) (except 8, 9, 12–14), Liuzhai, Nandan County, Guangxi; (5–7) lateral, apertural, and ventral views, NIGP 88983, Bed 19, 2nd Member, ×3; (8, 9) apertural and lateral views, NIGP 88984, Bed 11, 2nd Member, Zhuangli section (Sec. VI), ×3; (10, 11) lateral and ventral views, NIGP 88985, Bed 19, 2nd Member, ×3; (12–14) lateral, apertural, and ventral views, NIGP 94462 (Zhou, Reference Zhou1987, pl. 3, figs. 3–5), Asselian talus limestone, 2nd Member, Liuzhai Quarry (Loc. 5), ×2; (15, 16) ventral and lateral views, NIGP 88986, Bed 19, 2nd Member, ×3; (17–19) ventral, lateral, and apertural views, NIGP 88987, Bed 26, 3rd Member, ×1.5; (20, 21) ventral and lateral views, NIGP 88988, holotype, Bed 26, 3rd Member, ×1.5.

1987 Agathiceras vulgatum; Reference ZhouZhou, p. 137, pl. 2, figs. 13–18, pl. 3, figs. 1–11.

Diagnosis

A species with relatively large conch size, possessing the secondarily intercalated spiral lirae in maturity.

Description

Conch subspherical and involute, with diameter >40 mm in the largest specimen, the holotype NIGP 88988 (Fig. 27.20, 27.21). Umbilicus small (U/D usually <0.1). Conch becoming compressed in shape with growth ontogenetically (Table 6). Conch recrystalized during preservation, but the holotype still exhibits well-preserved stratified structure of test. Three layers at least could be recognized from venter and flanks of body chamber (Fig. 30). Inner mold, as the base of the test layers, exhibits faint longitudinal lira traces, indicating that the major sculpture, lirae, even impressed into the inner surface of the test. From interior to exterior: the inner prismatic layer, ~0.23 mm thick, consisting of coarse-grained light calcite; the nacreous layer, about the same thickness as inner prismatic layer, consists of dark, fine-grained calcite, with regular, wide-spaced fine lirae on the bottom of the layer; the outer prismatic layer, consists of coarse-grained, light calcite, with primary and secondaty lirae on surface, and layer thickness usually ~0.4 mm or so, possibly increasing due to some extra calcite wedging during preservation. Diverse colors and grain sizes of calcite in the layers noted above might reveal differences in the primary structure, and, probably, the aragonite component of the ammonoid conch. Primary lirae are stronger and spaced normally, while the secondary lirae are weaker in intensity and intercalated between the primary ones; generally, 22 lirae per 10 mm on the venter at diameter 32.6 mm. However, lirae on the second layer are relatively sparse and slender (Figs. 27.21, 30.3).

Table 6 Dimensions and ratios of Agathiceras sequaxilirae n. sp. D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Four or five constrictions present in outer volution, becoming stronger on flanks, and weakening again towards venter, with gentle sinus appearing on both venter and flank. Ventral lobe is broad and subdivided by a bottle-shaped medium saddle; all lateral lobes are inflated at rear, slightly pointed at bottom, and constricted in front. Saddles are club-shaped and decrease in height toward the umbilicus.

Etymology

Sequax means secondarily ranked, and lirae meaning longitudinal lines on conch surface; both are Latin.

Materials

Eighteen specimens, of which NIGP 88983–88987 and 88988 (holotype) newly collected, and NIGP 94459–94470, restudied here, which previously had been identified as Agathiceras volgatum Ruzhentsev, Reference Ruzhentsev1978 (Zhou, Reference Zhou1987, p. 137, pl. 2, figs. 13–18, pl. 3, figs. 1–11).

Occurrence

Bed 19, Meyao section (Sec. V), Bed 11, Zhuangli section (Sec. VI), and the Asselian talus limestone, Liuzhai Quarry (Loc. 5) are within the 2nd Member; while the Bed 26, Meyao section (Sec. V) is within the 3rd Member. Both members compose the Permian part of the Nandan Formation in Liuzhai, Nandan County, Guangxi.

Remarks

According to Kulicki (Reference Kulicki1996), ammonoid walls consist of four consecutive layers, from exterior to interior: periostracum, outer prismatic, nacreous, and inner prismatic. In the present case, specimens here are entirely recrystalized without any possibility to identify the individual layers listed above. However, it may be concluded that the shell of Agathiceras sequaxilirae n. sp. possesses three conch layers at least, without the structure details being preserved. Two of the layers, the second and third, bear different types of lirae (with secondary lirae or not) on the layer surface, respectively. It is thus evident that identification of specific taxa in the genus based on lirae has to rely on identification of conch layers.

It is interesting that the specimen of Agathiceras suessi Gemmellaro, Reference Gemmellaro1887 illustrated in Miller and Furnish (Reference Miller and Furnish1940a, pl. 31, fig. 12; Yale Peabody Museum 15229, collected from Sosio beds, Calcare Compatto, Palermo) has noticeably two conch layers with lirae, but which have almost the same shape and numbers on these layers. Some lirae might even be traced on the inner mold of that specimen, which would distinguish it easily from A. sequaxilirae n. sp. here by lira type, although the species of Gemmellaro (Reference Gemmellaro1887) is the best analogue to recognize new species in conch shape and size.

The specimens identified as A. vulgatum Ruzhentsev, Reference Ruzhentsev1978 by Zhou (Reference Zhou1987) were collected from the Asselian talus limestone at Liuzhai Quarry (Loc. 5), near Liuzhai. After review, these specimens, which are characterized by two-ranked lirae, also should be conspecific with Agathiceras sequaxilirae n. sp., herein.

Agathiceras suessi Gemmellaro, Reference Gemmellaro1887

Figures 27.1–27.4, 29.2

1940a Agathiceras suessi; Reference Miller and FurnishMiller and Furnish, p. 118, pl. 31, figs. 8–12

Description

Shell small, involute and discoidal with a small umbilicus. The larger specimen (NIGP 93702, Fig. 27.3, 27.4) more compressed than the smaller one (NIGP 93703, Fig. 27.1, 27.2) in conch shape. About 60 fine but distinct spiral lirae on conch surface, consistently maintain such a number on volutions observed. The smaller conch is measured as: D 14.7 mm, W/D 0.65, H/D 0.61, U/D <0.1. Ventral lobe subdivided by a wider medium saddle; prongs near the same or a little broader than the first lateral lobe. Lobes apparently constricted at the middle of flanks, third lateral lobe unusually broad. Saddles club-shaped with rounded top.

Occurrence

The ammonoid-bearing claystone intercalated in the limestone of the Member XII of the top Houziguan Formation, Kabi (Loc. 3), Houchang, Ziyun County, Guizhou.

Materials

Only two specimens preserved in mudstone, NIGP 93702, 93703.

Remarks

Both the fine spiral lirae and the general suture appearance have the same features as the types from Sicily at a similar diameter,. Specimens herein also resemble Agathiceras uralicus (Karpinskii, Reference Karpinskii1874) in the expanded rear part and the almost rounded base of the lobes; but the former has broader branches, and much sparser spiral lirae than the latter.

Agathiceras mediterraneum Toumanskaya, Reference Toumanskaya1949

Figures 28.1–28.10, 29.4

Figure 28 Agathiceras Gemmellaro, Reference Gemmellaro1887. (1–10) Agathiceras mediterraneum Toumanskaya, Reference Toumanskaya1949, Bed 12, Chongtou Member, Sidazhai Formation; Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou, ×2; (1–3) ventral, lateral, and apertural views, NIGP 93707; (4, 5) lateral and ventral views, NIGP 93705; (6, 7) ventral and lateral views, NIGP 93706; (8–10) apertural, ventral, and lateral views, NIGP 93704; (11–14) Agathiceras sp.; (11, 12) NIGP 93708, ×3, counterparts of the same individual, lateral view, beds 19–17, Longyin Formation, Huagong section (Sec. II), Huagong Tea-Plantation, Qinglong County, Guizhou; (13, 14) Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi; (13) lateral view of phragmocone piece NIGP 93709, ×2.5; (14) lateral view, NIGP 93710, ×3.

Figure 29 The external sutures of Agathiceras Gemmellaro, Reference Gemmellaro1887. (1) Agathiceras sp. NIGP 93708, D 15 mm, beds 19–17, Longyin Formation, Huagong section (Sec. II), Huagong Tea-Plantation, Qinglong County, Guizhou; (2) Agathiceras suessi Gemmellaro, Reference Gemmellaro1887, NIGP 93703, D 12 mm, the ammonoid-bearing claystone intercalated in Member XII, upper Houziguan Formation, Kabi (Loc. 3), Houchang, Ziyun County, Guizhou; (3) Agathiceras sequaxilirae n. sp., NIGP 88986, D 15 mm, Bed 19, 2nd Member, Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi, Guangxi; (4) Agathiceras mediterraneum Toumanskaya, Reference Toumanskaya1949, NIGP 93706, D 26 mm, Bed 12, Chongtou Member, Sidazhai Formation; Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou.

1915 Agathiceras sundaicum Reference HanielHaniel, p. 66, pl. 49, figs. 15a, b.

2004 Agathiceras mediterraneum; Reference Zhou and LiengjarernZhou and Liengjarern, p. 327, figs. 8.2–8.7, 10.1, 10.2.

2005 Agathiceras mediterraneum; Reference Zhou and YangZhou and Yang, p. 383, figs. 5.6–5.12, 6.1, 6.2, 8.8–8.15.

Description

Shell thickly discoidal, involute with a small umbilicus. Venter narrowly rounded; flanks fairly convex. Four to five constrictions present on the outer volution. Sculpture preserved only as faint trail of spiral lirae and some transverse growth lines. Ventral lobe rather broad and subdivided by a high, medium saddle into two prongs, which approximately equals the first lateral lobe in width. All lobes constricted in front, expanded at rear, sharpened at base. The third lateral saddle high, broad, and asymmetric.

Materials

Four phragmoconchs preserved in silicified limestone, NIGP 93704–93707.

Occurrence

Bed 12, Chongtou Member, Sidazhai Formation; Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou.

Remarks

Specimens here are similar to the holotype from the Pamirs in having a narrowly rounded venter, convex flanks, small umbilicus with constrictions, spiral lirae, and some transverse growth lines. Additionally, the relatively higher medium saddle of the ventral lobe, the high and broad third lateral saddle, and the broader prongs, also are present in the Pamirs types. The specimens studied here resemble Agathiceras suessi in general shell shape, but their medium saddles are higher and the lobes are longer than the latter.

Agathiceras sp.

Figures 28.11–28.14, 29.1

Description

Shells involute, with small umbilicus. About 16 thin and sparse spiral lirae appearing on the flank of the outer cast. Total number of lirae nearly 50 or fewer. No constriction observed. Only three lateral lobes preserved, all of them expanded at rear, constricted in front and sharpened at the base.

Materials

Three individuals, NIGP 93708–93710, but preserved as four pieces, in which NIGP 93708 includes an external cast and an internal mold.

Occurrence

Beds 19–17, Longyin Formation, Huagong section (Sec. II), Huagong Tea-Plantation, Qinglong County, Guizhou; and Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan, Guangxi.

Remarks

Specimens are similar to Agathiceras uralicum (Karpinskii, Reference Karpinskii1874) in general lobe shape, but they are apparently sharpened at the base and lack constrictions. They are somewhat similar to Agathiceras suessi in suture, but their spiral lirae on exterior shell are much fewer in number than the latter.

Superfamily Adrianitoidea Schindewolf, Reference Schindewolf1931

Family Adrianitidae Schindewolf, Reference Schindewolf1931

Subfamily Adrianitinae Schindewolf, Reference Schindewolf1931

Genus Neocrimites Ruzhentsev, Reference Ruzhentsev1940a

1885 Waagenia Reference KrotovKrotov, p. 204 (part).

1887 Adrianites Reference GemmellaroGemmellaro, p. 19 (part).

1888 Waagenina Reference KrotovKrotov, p. 474 (part).

1889 Agathiceras; Reference KarpinskiiKarpinskii, p. 63, (part).

1915 Agathiceras; Reference HanielHaniel, p. 66 (part).

1940a Neocrimites Reference RuzhentsevRuzhentsev, p. 838.

1943 Adrianites ( Neocrimites); Reference Teichert and FletcherTeichert and Fletcher, p. 161.

1997 Millerites Reference Cantú ChapaCantú Chapa, p. 66.

Type species

Adrianites fredericksi Emel’iancev, Reference Emel’iancev1929; original designation; Baigendzhinian, Artinskian Stage, South Urals.

Diagnosis

Similar to Crimites, globular and involute, but longitudinal sculpture may be much stronger than transverse. Sutural trace directly transverse with four or five pairs of external ‘lateral’ lobes, three or four pairs of internal ‘laterals’, and two or three smaller lobes on umbilical wall.

Occurrence

Late Artinskian through Capitanian; Kazakhstan (Southern Urals), Tajikistan (Pamirs), Russia (Urals, Northern Caucasus), USA (Texas), Mexico (Coahuila), Indonesia (Timor), ?Western Australia, and China (Xizang, Guangxi, Guizhou, Gansu).

Remarks

Ruzhentsev (Reference Ruzhentsev1950), based upon the number of lateral lobes, subdivided Neocrimites into three subgenera: N. ( Metacrimites), with four external and three internal ‘lateral’ lobes; N. ( Neocrimites), with four lobes in both exterior and interior; and N. ( Sosiocrimites), with seven external lobes. However, as independent genus-level taxa, only Sosiocrimites and Neocrimites were retained. The subgenus Metacrimites was included within Neocrimites (Glenister et al., Reference Glenister, Furnish and Zhou2009), because the number of ‘lateral’ lobes in both Metacrimites and Neocrimites successively varied and any subdivision of them might be artificial. There probably is a modification in the genus ontogenetically that the whorls are more depressed in juveniles and more compressed in adults.

Neocrimites guizhouensis new species

Figures 31.2–31.4, 34.3

1980 Neocrimites cf. N. guangsiensis; Reference LeeLee, p. 67, pl. 3, figs. 4–6.

Diagnosis

Shell small and relatively narrower in width, five pairs of external lobes.

Description

Conch small, globular and involute. Both venter and flanks rounded, with small umbilicus and rounded umbilical shoulder. Conch surface covered by fine reticule sculpture; 2–3 broad and shallow constrictions in the outer volution. Suture includes a bipartite ventral lobe with narrow and undivided prongs, five pairs of external ‘lateral’ lobes, slightly constricted adorally and sharpened at base. All lobes slightly narrower than the saddles next to them.

Etymology

Name derived from Guizhou, southwest part of the province, which constitutes the major part of the Permian Nanpanjiang Basin.

Materials

Two pieces of inner and outer molds, imperfectly stripped from the matrix, representing two individuals, NIGP 93711 (holotype) and 93712.

Occurrence

Bed 12, Chongtou Member, Sidazhai Formation; Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou.

Remarks

Neocrimites guizhouensis n. sp. resembles Neocrimites guangsiensis Zhao and Liang, Reference Zhao and Liang1974 in sculpture, but is distinct from the latter by the relatively narrower conch form. Neocrimites guizhouensis n. sp. is similar to the type species of genus Aricoceras, A. discoidalis (Haniel, Reference Haniel1915), in conch form and the reticulate sculpture, but different from the latter by suture, with at least one more external ‘lateral’ lobe.

Neocrimites guangsiensis Zhao and Liang, Reference Zhao and Liang1974

Figures 31.5–31.7

1965 Neocrimites sp. Reference ChaoChao, p. 1815, pl. 2, figs. 1–3.

1974 Neocrimites guangsiensis Reference Zhao and LiangZhao and Liang, p. 303, pl. 159, figs. 4, 5.

Materials

One specimen, NIGP 22028 (holotype).

Occurrence

The locality and the horizon of the specimen are not exactly known. According to the label attached on the specimen, it was collected from limestone of the ‘Chihsian Formation’ of Shiangyang Village (i.e., Xiangyang Cun) (Loc. 8) of Tian’e County, Guangxi (Zhao and Liang, Reference Zhao and Liang1974).

Description

Shell small, globular and involute, with small umbilicus and steep umbilical wall. Umbilical shoulder somewhat angular. Venter and flanks rounded uniformly, whorl section crescent. Conch surface decorated with fine reticule sculpture. Two to three broad and shallow constrictions in outer volution. Dimension and ratios of the conch are: D 18.4 (mm), W/D 1.0, H/W 0.57, U/D 0.18. Although suture not exposed on conch surface of monotype, five pairs of external and internal ‘lateral’ lobes well preserved in septal folds at aperture, respectively.

Remarks

The specimen discussed here was first reported and illustrated by Chao (Reference Chao1965). although formal description of the monotypic species was made by the original author and Liang about ten years later (Zhao and Liang, Reference Zhao and Liang1974). The single specimen is an entire phragmoconch with the suture not exposed, although the apertural septa look well preserved.

Neocrimites guangsiensis resembles Neocrimites guizhouensis n. sp. in having five pairs of external lobes; but differs from the latter by more globular in conch shape, hence wider whorl section. Neocrimites globosa (Haniel, Reference Haniel1915), another species with five pairs of external lobes, may represent the closest form in the globular conch; however, the Timor species has a very small umbilicus.

Genus Fusicrimites new genus

1889 Agathiceras; Reference KarpinskiiKarpinskii, p. 65 (part).

1949 Adrianites; Reference ToumanskayaToumanskaya, p. 74 (part).

1962 Neocrimites ( Neocrimites); Reference BogoslovskaiaBogoslovskaia, p. 95.

1963 Waagenina; Reference ToumanskayaToumanskaya, p. 73.

1967 Adrianitids; Reference PavlovPavlov, p. 75, pl. 4, fig. 1 (upper-left specimen).

1972 Neocrimites; Reference PavlovPavlov, p. 109 (part).

1989 Neocrimites ( Neocrimites); Reference LeonovaLeonova, p. 164 (part).

Type species

Neocrimites ( Neocrimites) pavlovi Leonova, Reference Leonova1989, original designation herein, upper Kochusuisk Formation, Bolorian Stage (Kungurian), southeast Pamirs.

Other species

Fusicrimites stuckenbergi (Kapinskii, Reference Karpinskii1889), F. nalivkini (Toumanskaya, Reference Toumanskaya1949), and F. dutkevitchi (Pavlov, Reference Pavlov1972), from the Bolorian Stage, southeast Pamirs, along with the new species, F. nanpanjiangensis n. gen. n. sp., described herein.

Diagnosis

Conch small (usually <25 mm in diameter), obvious fusiform shape (W/D>1, usually ranging from 1.01 to 1.8), and completely involute. Convex venter uniformly shifts to lateral flanks without sudden change; however, umbilical shoulder between lateral flank and umbilical wall conspicuously with blunt angle. Umbilicus small, with steep umbilical wall. More than four to ten umbically derived external ‘lateral’ lobes in a traversal trace. All lobes narrow and pointed at base.

Etymology

Fusiform conch shape of the new adrianitid taxon.

Occurrence

Artinskian through Kungurian; Tajikistan (southeast Pamirs) and Guizhou (South China).

Remarks

The sutural of the new genus is close to the ancestor Neocrimites, but increasing 1–4 or more umbilically derived lobes, while the most identified character, the W/D value of the new genus, is always larger than 1.0, although in a few cases the value of Neocrimites may reach to 1.19 (Leonova and Boiko, Reference Leonova and Boiko2015). In genus Crimites, C. doliaris Leonova, Reference Leonova1988, the W/D value may be larger than 1.0, but the case only occurred in the very early ontogeny of the species.

As pointed out by T.B. Leonova (personal communication, 2016), B.F. Glenister and W.M. Furnish in the 1990s had suggested establishing the new genus ‘ Netrionoceras’ to cover the forms of Neocrimites with barrel and fusiform conch shape. Schiappa (Reference Schiappa1993) described such spindle representatives of adrianitids as Genus B (gen. nov.) in her unpublished thesis.

Fusicrimites nanpanjiangensis new species

Figures 31.1, 34.4

Diagnosis

Well-built fusiform shape, with the largest value of W/D (1.8) and the most numerous ‘lateral’ lobes in the genus.

Description

Small spindle-shaped inner mold, with small umbilicus. Venter and lateral flanks uniformly transitive without obvious subdivision; umbilical shoulder conspicuous, with rounded angle. Conch dimension and ratios: D 11.2 mm, W/D 1.8, U/D ~0.23. Sculpture unknown, however, it supposedly has longitudinal lirae and reticulately transverse lines as in the congenetic S. pavlovi (Leonova, Reference Leonova1988). Suture typical adrianitid, 9–10 ‘lateral’ lobes aligned with straight trace transversally. Ventral lobe divided by a broad medium saddle into two narrow and asymmetric prongs. All lobes narrow and entire, slightly constricted adorally and sharpened at base, with width about 2/3 of adjacent saddle.

Etymology

Name derived from the Nanpanjiang Basin.

Materials

One inner mold available, NIGP 93713 (holotype).

Occurrence

Bed 12, Chongtou Member, Sidazhai Formation, Shaiwa section (Sec. VI–VI’), Sidazhai, Ziyun County, Guizhou.

Remarks

Fusicrimites nanpanjiangensis n. sp. is similar to F. pavlovi (Leonova, Reference Leonova1988) in possessing obviously fusiform conch shape and numerous ‘lateral’ lobes, but distinct from the latter by more strongly fusiform shape and many more umbically derived lobes in number.

Genus Emilites Ruzhentsev, Reference Ruzhentsev1938

1919 Paralegoceras; Reference BöseBöse, p. 99 (part).

1937 Glaphyrites; Reference Plummer and ScottPlummer and Scott, p. 274 (part).

1940a Plummerites Reference Miller and FurnishMiller and Furnish, p. 103.

Type species

Paralegoceras incertum Böse, Reference Böse1919; original designation; Wolfcampian Formation, northwest Wolf Camp, Glass Mountains, west Texas, USA.

Diagnosis

Conch globular with small umbilicus (U/D, commonly 0.1) and scalloped transverse sculpture. Suture comprises two pairs of external lateral lobes and two pairs of internal laterals. External suture characterized by irregularly denticulate third lateral saddle across umbilical wall. Sutural formula: (V1V1)LU:U1ID.

Occurrence

Pennsylvanian in USA (Texas and Oklahoma), Orenburgian (Gzhelian) in Russia and Kazakhstan (Southern Urals), and Early Permian in Canadian Arctic, Tajikstan (Pamirs), Uzbekistan (Fergana), and South China (Guangxi).

Remarks

Emilites, a common form occurring from the Asselian fauna in northwest Guangxi, the Nanpanjiang Basin, represents the latest presence of the genus. It mainly is characterized by denticulated umbilical saddle, even the independent adventitious lobes in umbilical region in some specimens. However, Mapes and Boardman (Reference Mapes and Boardman1988) thought that the degree of denticulation was not of taxonomic importance because they noted a moderate amount of variation in different specimens of the same species, even in the left or right side in a single individual. Emilites was thought as the root stock for the family Adrianitidae because the goniatitic suture, consisting of two external and two internal ‘lateral’ lobes, and the denticulate umbilical saddle on each side, represent the most primitive pattern of the family.

Emilites globosus new species

Figures 32.1–32.23, 34.1, 34.2

1987 Emilites cf. prosperus; Reference ZhouZhou, p. 137, pl. 4, figs. 1–3.

Diagnosis

The youngest species of Emilites with almost spherical form, nearly closed umbilicus, and more advanced diversity of umbilical lobe.

Description

Conchs globular, with some sphericity variation ontogenetically. The largest sphericity appears at about 15.8 mm diameter, but flattens inversely with growth (Table 7). Sculpture not preserved. One or two faint and broad constrictions on the inner mold of the specimens NIGP 88996 (Fig. 32.11, 32.12) and 88994 (Fig. 32.13, 32.14), with oral constriction as an adult modification present in the largest specimen, NIGP 88997 (Fig. 32.22, 32.23) at 35 mm diameter. Ventral lobe divided into two narrow lanceolars. External ‘lateral’ lobes broad and V-shaped. Two small adventitious lobes with different shapes near the umbilicus in specimen NIGP 88997 (Fig. 34.2). The first lateral saddle somewhat pointed at crest and a little higher than the outer saddle.

Table 7 Dimensions and ratios of Emilites globosus n. sp. D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Etymology

Name derived from the spherical conch shape of the types.

Materials

Eleven specimens, NIGP 88997 (holotype), NIGP 88989–88996, 88998, and NIGP 94471, from the limestone matrix, usually well preserved with body chamber.

Occurrence

All from the 2nd Member, Nandan Formation, Liuzhai, Nandan County, Guangxi: including Bed 19, Meyao section (Sec. V); Bed 11, Zhuangli section (Sec. VI); and the Asselian talus limestone, Liuzhai Quarry (Loc. 5).

Remarks

Emilites globosus n. sp. resembles both E. plummeri Ruzhentsev, Reference Ruzhentsev1941 and E. prosperous Ruzhentsev, Reference Ruzhentsev1978 in conch shape and generality of suture, but is distinguished from them by more spherical shape and more acute first lateral saddle. The specimens of the Liuzhai Quarry previously had been described as E. cf. prosperous (Zhou, Reference Zhou1987). After reviewing, it is more desirable to unify all the Emilites forms from the 2nd Member, Nandan Formation of Liuzhai area as E. globosus n. sp.

Genus Epadrianites Schindewolf, Reference Schindewolf1931

1950 Basleoceras Reference RuzhentsevRuzhentsev, p. 203.

Type species

Agathiceras timorense Boehm, Reference Boehm1908; original designation; Amarassi beds (Capitanian, probably equal to the lower Lopingian), Amarassi, Timor, Indonesia.

Diagnosis

Conch large (diameter at maturity up to 7 cm), globular, with moderately large umbilicus and longitudinal lirae much stronger than transverse sculpture. Mature modifications incompletely known, but comprise slight geniculation, reduction of umbilical diameter, subterminal constriction, and terminal flare that probably extended into ventrolateral lappets. Sutural trace transverse; suture comprises four or five pairs of external lateral lobes, three or four pairs of internal lateral lobes, and two or three additional lobes on each umbilical wall.

Occurrence

Wordian through Lopingian; Indonesia (Timor), Italy (Sicily), Oman, Croatia, Mexico (Coahuila), Azerbaijan (Dzhulfa) and China (Jilin, Guizhou).

Remarks

Epadrianites is similar to the genus Sociocrimites in the longitudinal lirae, the subterminal constriction, and the numerous ‘lateral’ lobes, but distinct from the latter by much stranger lirae on surface and the transverse sutural trace.

Epadrianites involutus (Haniel, Reference Haniel1915)

Figures 31.8–31.12, 34.5, 34.6

1915 Agathiceras timorensis var. involuta Reference HanielHaniel, p. 80, pl. 5, figs. 8–11.

1979 Epadrianites timorensis var. involutus; Reference Zheng and ChenZheng and Chen, p. 17, pl. 1, figs. 26, 29, 30.

Description

Conchs incompletely preserved as compressed molds, moderate size and fairly involute, with relatively narrow umbilicus; umbilical shoulder bluntly rounded, sometimes indefinite; prominent longitudinal lirae with faint transverse growth lines on surface. Prongs of the ventral lobe curved, pointedly tongue-shaped; secondary medial saddle less than one-half of the ventral lobe in height; four to five ‘lateral’ lobes pointedly tongue-shaped on each side beyond the indefinite umbilical shoulder.

Materials

Four poorly preserved individuals, two of which show external sutures; NIGP 139941–139944.

Occurrence

Bed 23, Claystone (3rd) Member, Shaiwa Formation, Sidazhai section (Sec. VI’-VI”), Sidazhai, Ziyun County, Guizhou.

Remarks

Specimens resemble the type species, Epadrianites timorensis (Haniel, Reference Haniel1915), in basic conch form, sculptures, and generality of suture; however, they differ from the latter by one ‘lateral’ lobe less. They also resemble Epadrianites dunbari (Miller and Furnish, Reference Miller and Furnish1940a) from the Timorites Zone of the La Difunta Bed in Las Delicias in both conch shape and primary sutural characteristics, but they possess stronger longitudinal lirae and subequally broader interlirae. Additionally, Epadrianites kotljarae (Zakharov, Reference Zakharov1983a) from the Araxoceras Bed of Dorasham II, Transcaucasia, actually are the same as E. dunbari in suture and the wider interlirae, and probably represents the junior synonym of the latter. In any case, the reports on the Transcaucasia form are sufficient to interpret biostratigraphical equivalence of the Araxoceras bed in Transcaucasia to the Timorites beds in Coahuila of Mexico, and even with the 3rd Member containing E. involutus, Eoaraxoceras, Difuntites, and others from the Shaiwa Formation here.

Superfamily Shumarditoidea Plummer and Scott, Reference Plummer and Scott1937

Family Perrinitidae Miller and Furnish, Reference Miller and Furnish1940a

Remarks

Tharalson (Reference Tharalson1984) proposed the subfamily Paraperrinitinae (non Toumanskaya, Reference Toumanskaya1939) as differing from the Perrinitinae in complete subdivision of the third internal lateral lobe. Because the taxonomic character somewhat depends on ontogenetic development, the scheme was rejected (Glenister et al., Reference Glenister, Furnish and Zhou2009). An obvious evolutionary succession ProperrinitesMetaperrinites—Perrinites in the family is marked by a general tendency that may be summed up as: (1) increasing complexity of sutural subdivision, and (2) more compressing of conch shape with the reducing of umbilicus diameter.

Genus Properrinites Elias, Reference Elias1938

1932 Shumardites; Reference MillerMiller, p. 93.

1937 Perrinites; Reference Plummer and ScottPlummer and Scott, p. 303 (part).

1984 Properrinites; Reference TharalsonTharalson, p. 823 (part).

1984 Subperrinites Reference TharalsonTharalson, p. 809.

Type species

Perrinites bösei Plummer and Scott, Reference Plummer and Scott1937; original designation by Elias (Reference Elias1938), and confirmed by Miller and Furnish, Reference Miller and Furnish1940a on fide ICZN Code Article 24; Indian Creek Shale, Admiral Formation (Asselian–Sakmarian), Wichita Group of Coleman County, Texas, USA.

Diagnois

Ancestral perrinitids of medium size (maximum conch diameter 15 cm) with depressed whorls (H/W, 0.6–0.9), moderate umbilicus (Umin/D, 0.2–0.5), and shallow hyponomic sinus. Mature sutures have a single discrete first-order subdivision on ventral flank of each prong of ventral lobe (V1) and a dorsal lobe (D) that is prominently trifid; second-order subdivisions are either absent or incipient and confined to first lateral saddle. Crests of fourth external lateral saddle and fourth internal lateral saddle lie beneath general sutural alignment. Sutural formula: (V1V1)L2L1(L2.1L2.2)U2U1:U2(I2.2I2.1) I1I2D.

Occurrence

Asselian through Kungurian; southwest USA (Texas, New Mexico, Nevada, Kansas), Mexico (Puebla), Canada (Yukon), Pamirs (Tajikistan), and South China (Guangxi).

Remarks

Properrinites, which was established by Elias in 1938 to represent the most primitive perrinitids, is phylogenetically intermediate between Shumardites and Perrinites. Furthermore, Ruzhentsev (Reference Ruzhentsev1950) established Metaperrinites to include species possessing more complicated sutural diversity than Properrinites, but simpler than Perrinites. Although Properrinites is intermediate between Shumardites and Metaperrinites, it has already dissected near the upper part of the flanks of the lobes and gained the new systematic features of the family Perrinitidae.

Properrinites gigantus new species

Figures 33.1–33.9, 35.1, 35.2

1987 Properrinites plummeri; Reference ZhouZhou, p. 138, pl. 4, figs. 6–8. (non Elias, Reference Elias1938, p. 104, pl. 20, figs. 8a, b.).

Diagnosis

A Properrinites species possessing more compressed and largest conch size, and simpler sutural digitations, as compared with P. bösei (Plummer and Scott, Reference Plummer and Scott1937), and even the more primitive P. backeri (Plummer and Scott, Reference Plummer and Scott1937).

Description

Conch somewhat fusiform in juvenile, whereas large, thickly discoidal, and moderately involute in adult, with medium-sized umbilicus, but in attendance as a continuous variation ontogenetically; both W/D and U/D getting smaller with individual growth. Whorl section crescent-shaped in juvenile, gradually changing into bell-shaped, with rounded venter and fairly convex flanks. Umbilical shoulder bluntly rounded and umbilical wall steep with a few spiral lirae. Finely transverse growth lines on flanks and venter. Dimension and ratios of the holotype NIGP 94472 (Fig. 33.7–33.9): D 112 mm, W/D 0.49, H/D 0.50, U/D 0.22.

The juvenile specimen NIGP 89003 (Fig. 33.3) at diameter ~7.7 mm displays the external lateral lobe that is incipiently tripartite. In specimen NIGP 89002 (Fig. 33.1, 33.2) at diameter ~45.8 mm and NIGP 94472 at diameter 56.6 mm, the third external and internal lateral lobes subdivided into two nearly independent branches, respectively. The digitations of the first and the second external lobes in the fully mature specimen NIGP 94472 having four and five digits, respectively. Three small umbilical lobes on both umbilical shoulder and umbilical wall. Dorsal lobe preserved on the surface of the previous volution obviously tripartite (Fig. 33.1).

Etymology

Name derived from the character of huge size of the holotype.

Materials

Four specimens, NIGP 89002–89004, and NIGP 94472 (holotype, Zhou, Reference Zhou1987, p. 138, pl. 4, figs. 6–8, revised here).

Occurrence

Asselian talus limestone, Liuzhai Quarry (Loc. 5); Bed 19, Meyao section (Sec. V). Both are from the 2nd Member, Nandan Formation, Liuzhai, Nandan County, Guangxi.

Remarks

Miller and Furnish (Reference Miller and Furnish1940a) and Tharalson (Reference Tharalson1984) thought that Properrinites plummeri Elias, Reference Elias1938 is similar to the typical P. backeri (Plummer and Scott, Reference Plummer and Scott1937), so it was a junior synonym for the latter. Both restudy on the specimen NIGP 94472 (Zhou, Reference Zhou1987) and study of the newly collected specimens NIGP 89001–89004 indicate that the Guangxi materials are distinct from the species P. backeri by the wider lobes and the narrower saddles.

Properrinites gigantus n. sp. resembles Properrinites dmitrievi Ruzhentsev, Reference Ruzhentsev1978 from the Pamirs in conch shape and generality of suture; however, the former is thinner in conch shape and much narrower in the width of the ventral lobe. The secondary subdivision on the ventral flank of the first external lateral lobe in specimen NIGP 94472 is quite similar to P. furnishi Nassichuk, Reference Nassichuk1971, but the latter is more complicated in generality of suture. The similarity also exists between the new species and P. bösei (Plummer and Scott, Reference Plummer and Scott1937), but the latter has more complicated dissection in lobes.

Genus Metaperrinites Ruzhentsev, Reference Ruzhentsev1950

1915 Cyclolobus; Reference HanielHaniel, p. 113 (part).

1919 Perrinites Reference BöseBöse, p. 155 (part).

1939 Paraperrinites Reference ToumanskayaToumanskaya, p. 17.

1940a Properrinites; Reference Miller and FurnishMiller and Furnish, p. 143 (part).

1982 Shuangyangites Reference LiangLiang, p. 650.

1983 Mapirites Reference LeonovaLeonova, p. 44; 1989, p. 132.

1983 Shyndoceras Reference LeonovaLeonova, p. 47.

1983 Nepirrites Reference LeonovaLeonova, p. 48.

1983 Ripernites Reference LeonovaLeonova, p. 50.

Type species

Properrinites cumminsi vicinus Miller and Furnish, Reference Miller and Furnish1940a; original designation; Clyde Formation (Artinskian), Wichita County, Texas, USA.

Diagnosis

Perrinitids intermediate and gradational between Properrinites and Perrinites in size, conch form, depth of hyponomic sinus, and overall complexity of suture. Whorls generally depressed (H/W, 0.7–1.2), and umbilicus variable (Umin/D, 0.1–0.4). Mature sutures display 1–3 first-order subdivisions on ventral fl;ank of each prong of ventral lobe (V1); dorsal lobe (D) has either one or two prominent notches on each flank; second-order subdivisions generally weakly developed, but may occur in all external saddles in advanced species. Both fourth external lateral saddle and fourth internal lateral saddle generally lie beneath but close to alignment of adjacent saddles.

Occurrence

Artinskian through Kungurian; USA (Texas, New Mexico, California, Nevada), Tajikistan (Pamirs), Ukraine (?Crimea), Thailand (Loei), Indonesia (Timor), North China (Jilin, Qinghai, Xinjiang), and South China (Guizhou and Guangxi).

Remarks

The present genus previously had been referred to as Paraperrinites with type species P. brouweri (Smith, Reference Smith1927) by Toumanskaya (Reference Toumanskaya1939, 1940), but she did not give a generic definition. Hence, the name is an invalid nomen nudum. Metaperrinites, as used in this paper, approximately includes all of the species of Toumanskaya’s Paraperrinites.

Leonova (Reference Leonova1983) established another five new genera of perrinitids based on materials from Pamirs. Sutures and figures of the Pamirs specimens indicate that their classification features probably are within the specific level of Metaperrinites, with the singular exception of Perrimetanites, which represents a primitive taxon of the genus Perrinites. Tharalson (Reference Tharalson1984) referred all species of Metaperrinites into his Properrinites based on the incipient division of the third internal lateral lobe (I2) strengthening to become two independent lobes (I2.1I2.2). The classification scheme of perrinitids is considered as unrealistic, and probably contains too many different external suture types in Properrinites. Leonova (Reference Leonova2002) previously moved Perrinites tardus Miller and Furnish, Reference Miller and Furnish1940a into genus Metaperrinites. This probably is incorrect because it has such an advanced and complicated sutural system compared with the latter.

Metaperrinites shaiwaensis new species

Figures 33.10–33.13, 35.3, 35.4

Diagnosis

Subglobal form with smaller umbilicus and nearly independent branches of the third external lobe.

Description

Conch subglobular, involute with smaller umbilicus. Venter rounded, flank fairly convex, and whorl-section crescent in shape. Dimension and ratios of the holotype NIGP 93714: D 16.1 mm, W/D 0.75, H/D 0.58, U/D 0.14. All lobes broad with inverted triangle shape. In small specimen NIGP 93714, the serrated lobes possess six digits in prong of ventral lobe, seven in both first and second lateral lobes, and six and four in the nearly independent third and fourth lateral lobes, respectively. In the larger specimen NIGP 98005, in contrast, the digitation appears simpler than the former, but such simplifying is supposedly due to enhanced erosion of conch surface. Branches of third external lateral lobe in both specimens are subdivided into relatively independent lobes.

Etymology

Name derived from locality where the holotype was discovered.

Materials

Two specimens, NIGP 93714 (holotype), and NIGP 89005.

Occurrence

‘Chihsia’ Limestone, Tian’e suburb (Loc. 7), north of Hongshuihe River, Tian’e County, Guangxi; Bed 12, Chongtou Member, Sidazhai Formation; Shaiwa section (Sec. VI–VI’), Sidazhai, Ziyun County, Guizhou.

Remarks

Metaperrinites shaiwaensis n. sp. resembles the type species M. cumminsi vicinus Miller and Furnish in the generality of suture, but it has much thicker and subglobal conch, and smaller umbilicus than those of the North America species. Metaperrinites shaiwaensis n. sp. is similar to M. toumanskayae Leonova, Reference Leonova1983 in the subglobal conch and the generality of external suture, but it has smaller umbilicus and stronger digitations of the ventral lobe.

Superfamily Cycloloboidea Zittel, Reference Zittel1895

Family Vidrioceratidae Plummer and Scott, Reference Plummer and Scott1937

Remarks

The genera Prostacheoceras and Stacheoceras are fairly eurytopic ecologically, with broad distribution in both the Permian open-sea and restricted-sea settings in South China, and other areas.

Genus Prostacheoceras Ruzhentsev, Reference Ruzhentsev1937

1887 Stacheoceras Reference GemmellaroGemmellaro, p. 38 (part).

1935 Marathonites; Reference MaximovaMaximova, p. 283.

1938 Martoceras Reference ToumanskayaToumanskaya, p. 106 (part).

Type species

Martoceras juresanensis Maximova, Reference Maximova1935; original designation; Asselian, Russian South Urals.

Diagnosis

Conch relatively narrow, with rounded ventrolateral flanks. Two subdivisions of the third external lateral lobe (L2.1L2.1) almost fully isolated at 2 cm conch diameter. Sutural formula: (V1V1)L2L1(L2.1L2.1) U2U1U2.1:U2.1I2I1I2D.

Occurrence

Asselian through Wordian; Russia and Kazakhstan (South Urals), Ukraine (Crimea), Tajikistan (Pamirs), Italy (Sicily), Canada (British Columbia), Afghanistan (Bamiyan Mountains), USA (Texas), Malaysia (Perak), Thailand (central and north), North China (Jilin, Xinjiang), and South China (Hunan, Guangxi).

Remarks

Prostacheoceras is intermediately situated between Vidrioceras and Stacheoceras phylogenetically, however, they can be distinguished from each other by simply comparing their sutural formulas. Prostacheoceras is relatively close to Vidrioceras, but has one more internal ‘lateral’ lobe (U2.1). It differs from Martoceras by the paired lobes present only at the 3–4 lobes, and not at the 4–5 or 5–6 lobes.

Prostacheoceras juresanense (Maximova, Reference Maximova1935)

Figures 36.3–36.8, 38.2, 38.3

1935 Marathonites juresanensis Reference MaximovaMaximova, p. 283, figs. 9–11.

1938 Prostacheoceras juresanensis; Reference RuzhentsevRuzhentsev, p. 256, pl. 4, figs. 1–8.

Description

Conch thickly discoidal to subglobal, involute with very small umbilicus. Whorl-section a little squarish, slightly compressed due to obvious crushing of the venter near the end of the outer volution in specimen NIGP 89007 (Fig. 36.3–36.5) (Table 8). Sparse, fine lamellae, with a faint salient on the venter, decorating the surface of the shell. Two faint constrictions present on the outer volution of the large specimen. Ventral lobe subdivided into two relatively narrow and incipient bidentate prongs. The first external lobe bidentate, the second tridentate with a longer middle tooth, the third very broad and bipartite (ventrad branch narrow and simple; the dorsad wide and bidentate), the fourth (U2) small and simple, near the umbilical border.

Table 8 Dimensions and ratios of Prostacheoceras juresanense (Maximov, Reference Maximova1935). D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Occurrence

Bed 19, 2nd Member, Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi.

Materials

Two phragmoconchs from limestone matrix, body chambers lost during sample preparation, NIGP 89006 and 89007.

Remarks

The topotype of Prostacheoceras juresenense (Maximova, Reference Maximova1935) from Zaksy-Kargaly River of Aktyubinsk District, Kazakhstan (South Urals), which is deposited in the repository of the University of Iowa, displays identical features with the Guangxi specimens in conch form and generality of suture. However, the two digits of the prong of the ventral lobe are just incipient in the Guangxi specimens, while the saddles are slightly broader than those of the type specimens. Nevertheless, these differences are still considered as individual variations ontogenetically.

As an important Asselian fossil, Prostacheoceras juresenense is rather primitive, without the secondary digitation in the external lateral lobes. The absence of high-ranked digitation is just one of the indicative criteria that can be used to distinguish P. juresenense from other later species.

Prostacheoceras sp.

Figures 36.1, 36.2, 38.1

Description

Conch small, thickly discoidal and involute, with small umbilicus. Venter rounded, flank convex, with crescent whorl section. More than two constrictions on the outer volution. Measurements: D 13.2 mm, W/D 0.71, H/D 0.4, U/D ?0.05. Ventral lobe normally subdivided by a middle saddle into two narrow, very incipiently bidentate prongs. However, the external lateral lobes in both sides are asymmetric. The first external lateral lobes seem to be tridentate in both sides. The second ones display asymmetry: the right one very small, like a small adventitious lobe on a big saddle; the left one normally broad, tridentate with a longer middle tooth. The third external lateral lobes almost the same in both sides, very broad, bipartite, representing a pair of nearly independent lobes: the ventrad one broader, bidentate/tridentate; the dorsad one narrower, bidentate. There probably is a small fourth lateral lobe near the umbilicus, but it is incompletely exposed.

Occurrence

Bed 12, Chongtou Member, Sidazhai Formation; Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou.

Materials

A steinkern of phragmoconch from the siliceous limestone matrix, body chamber lost in preparation; NIGP 93717.

Remarks

Inadequate material prevents full description of sutural asymmetry. The single specimen may be merely a physically distorted individual.

Genus Stacheoceras Gemmellaro, Reference Gemmellaro1887

1885 Waagenia Reference KrotovKrotov, p. 204.

1888 Waagenina Reference KrotovKrotov, p. 474 (part).

1931 Neostacheoceras Reference SchindewolfSchindewolf, p. 201.

1997 Furnishites Cantú Chapa, Reference Cantú Chapa1997, p. 73.

2005 Parastacheoceras Reference Ehiro and MisakiEhiro and Misaki, p. 9.

Type species

Stacheoceras mediterraneum Gemmellaro, Reference Gemmellaro1887; subsequent designation by Diener, Reference Diener1921; Sosio Limestone (Wordian), Rupe del Pass, Sosio Valley, Province Palermo, Sicily, Italy.

Diagnosis

Advanced vidrioceratids that may exceed 10 cm in mature conch diameter. Mature modifications comprise deep subterminal constriction with associated flare (expansion) of the peristome and long narrow ventrolateral lappets. External suture consists of 6–12 pairs of lateral lobes; prongs of ventral lobe (V1) are bidentate or tridentate, and first external lateral lobe (L2) is bidentate to quadridentate. Internal suture generally has one less pair of lobes than external; most internal lobes exhibit conspicuous dorsal flexure adapically. Sutural formula for moderately complex forms: (V1V1)L2L1L2.1L2.1.1L2.1.1.1L2.1.1.1.1(L2.1.1.1.1.1L2.1.1.1.1.1)U2U1U2:I2.1.1.1L2.1.1.1I2.1.1I2.1I1I2D.

Occurrence

Artinskian through Changhsingian; Italy (Sicily), Slovenia, Ukraine (Crimea), Azerbaijan (Caucasus), Tajikistan (Pamir), Afghanistan, Iraq (Kurdistan), Oman, Tunisia (Djebel Tebaga), Pakistan (Salt Range), India (Himalayas), Indonesia (Timor), Malaysia, Madagascar, Japan (Kitakami), Mexico (Coahuila, ?Guerrero), USA (Texas, California, Wyoming), Canada (Ellesmere Island, British Columbia), East Greenland, North China (Gansu, Xinjiang, Xizang), and South China (Yunnan, Guizhou, ?Hunan, ?Guangxi, Zhejiang, Sichuan).

Remarks

As the most advanced vidriocertid, Stacheoceras has the most numerous lateral lobes, usually more than six pairs of external sutures. As an eurytopic component, Stacheoceras occurred in both open-sea and restricted-sea ammonoid assemblages. Among the total 46 species of the genus known so far, 14 species (about one third) appear to be related with the Capitanian Stage and Lopingian Series biostratigraphically.

Stacheoceras shaiwaense new species

Figures 31.13, 37.1–37.14, 38.4, 38.5

Diagnosis

Thick subdiscoidal conch, seven pairs lateral lobes, in which the sixth and seventh incompletely divided; secondarily ordered digitation appears in first lateral lobe.

Description

Conch thickly subdiscoidal, moderately large; whorl section rounded both ventrally and laterally, deeply impressed dorsally; umbilicus small, umbilical shoulder broadly rounded, indefinite; living chamber about one whorl long (Table 9). Two or three constrictions in the ultimate whorl; mature modifications, including deep subterminal constriction, associated flare (expansion) of the peristome, and a pair of long narrow ventrolateral lappets. Ventral lobe spherical, inflated at mediate part, subdivided by a low, secondary ventral saddle into two narrow curving bidentate prongs. Seven pairs of lingulate lateral lobes in flanks, but the sixth and seventh seem incompletely divided; three pairs of small lobes in umbilical areas; first lateral lobe asymmetrically bidentate with secondarily ordered digitation, second through fifth tridentate, and the rest intact.

Table 9 Dimensions and ratios of Stacheoceras shaiwanense n. sp. D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Etymology

Name derived from the Shaiwa Formation where the type material was collected.

Materials

Seven individuals, five of them are well-preserved individuals. NIGP 139934–139940.

Occurrence

Beds 23 and 31, Claystone (3rd) Member, Shaiwa Formation, Sidazhai section (VI’–VI’), Sidazhai, Ziyun County, Guizhou.

Remarks

Stacheoceras shaiwaense n. sp. is fairly similar to S. iwaizakiense Mabuti, Reference Mabuti1935 from the lowermost Toyama Formation of the southern Kitakami in both conch shape and generality of suture, especially the secondarily ordered digitation of the first lateral lobe, and the incompletely divided sixth and seventh lateral lobes in the type specimen of the latter (no. 51723). However, the new species is thicker than the latter in shape, with W/D 0.54–0.58 versus 0.44–0.49.

Stacheoceras shaiwaense n. sp. is similar to S. toumanskyae Miller and Furnish, Reference Miller and Furnish1940a from Capitanian of Coahuila in general conch shape and some sutural details; however, its conch is much smaller, and one lateral lobe less than the Mexico species in number. Stacheoceras shaiwaense n. sp. is similar to the earlier species in west Texas, S. rothi Miller and Furnish, Reference Miller and Furnish1940a in generality of suture, but it is quite different from the latter by more advanced sutural details, the spherical ventral lobe with lower ventral saddle, and lacking secondarily ordered digitation. Stacheoceras shaiwaense n. sp. also resembles S. timorensis forma delta (Haniel, Reference Haniel1915) and S. lijiangense Liang, Reference Liang1983 in the lateral lobe number and their dentition condition, but differs from them by much smaller mature conch size.

Family Cyclolobidae Zittel, Reference Zittel1895

Subfamily Cyclolobinae Zittel, Reference Zittel1895

Genus Waagenoceras Gemmellaro, Reference Gemmellaro1887

Type species

Waagenoceras mojsisovicsi Gemmellaro, Reference Gemmellaro1887; subsequent designation by Diener, Reference Diener1921; Sosio Limestone (Wordian), Rupe del Pass, Sosio Valley, Province Palermo, Sicily, Italy.

Diagnosis

Intermediate in size, conch form, and sutural complexity between Demarezites and Timorites. External suture has seven or eight pairs of lobes to umbilical shoulders, each more complexly denticulate than in Demarezites; lobe pairs seven to eight incompletely isolated. Sutural formula for advanced forms: (V1V1)L2L1L2.1L2.1.1L2.1.1.1L2.1.1.1.1(L2.1.1.1.1.1L2.1.1.1.1.1) U2U1U2:(I2.1.1.1.1I2.1.1.1.1)I2.1.1.1I2.1.1I2.1I1I2(D2D1D2).

Occurrence

Wordian to Capitanian; Italy (Sicily), Iraq (Kurdistan), Oman, Indonesia (Timor), Russia (Amur), Mexico (Coahuila, Sonora, ?Guerrero), USA (west Texas), Canada (British Columbia), South China (Fujian, Guizhou), and North China (Gansu).

Remarks

Waagenoceras is intermediate between Demarezites and Timorites in size, conch form, and sutural complexity. Demarezites possesses a spherical conch with the smallest umbilicus of the above three genera, the lateral lobe pair is incompletely isolated and occurs at the 5–6 lobe, the seventh denticulate lobe lies ventrad of the umbilical shoulder, and the ventrad flanks of the ventral lobe is complicated by a weak sinus rather than a denticulate form. Waagenoceras has a transitional subglobular conch with a relatively large umbilicus, in which the 7–8 lobe represent the incompletely separated pairs, and ventrad flanks of the ventral lobe are simply digitate.

The most advanced genus, Timorites, is a thickly discoidal conch, evolute in early ontogeny, with relative broad umbilicus and strong transversal ribs, retaining the characters until adult. External lateral lobes are more than nine and flanks of the ventral lobes are deeply digitate. The secondary dissection of lobes is common and strong.

Waagenoceras sp.

Figures 36.9, 39

Description

A fragment representing the venter of phragmoconch. Complete conch form not clear; only an apparent constriction, with accompanying growth lines, tracing a shallow and broad sinus on venter. Ventral lobe and two external lateral lobes well preserved. Ventral lobe broad ring-shaped, inflated rear and constricted front. Ventrad flank of ventral prong only one digit; dorsad flank has four first-ranked digits and two second-ranked digits. Dissection of lateral lobes reaches upper part of both flanks. First lateral lobe has eight first-ranked digits and approximately five second-ranked digits; second lateral lobe with seven first-ranked digits and three second-ranked digits; third lateral lobe has seven first digits and two second-ranked digits. Secondary digitation limited in lower part of lobes. Saddles mushroom-shaped. Three preserved lateral lobes follow an obviously arched trace.

Materials

One specimen, NIGP 93715, representing venter and ventrolateral part of phragmoconch.

Occurrence

Bed 29, Siliceous Rocks (1st) Member, Shaiwa Formation, ~22 m above base of formation, Shaiwa section (Sec. VI–VI’), Sidazhai, Ziyun County, Guizhou.

Remarks

In spite of poor preservation, the major features, such as broader ring-shaped ventral lobe, digitation of lobes of external suture, development of secondary digits, and arched trace of suture, are coincident with the definition of Waagenoceras. Present specimen somewhat similar to W. dieneri Böse in digitation of lobes and shape of ventral lobe; however, present material is inadequate for exact identification at the species level.

Genus Timorites Haniel, Reference Haniel1915

1933 Hanieloceras Reference MillerMiller, p. 413.

1937 Wanneroceras Reference ToumanskayaToumanskaya, p. 93.

1983b ? Subeothinites Reference ZakharovZakharov, p. 151.

1997 Coahuiloceras Reference Cantú ChapaCantú Chapa, p. 82.

Type species

Timorites curvicostatus Haniel, Reference Haniel1915; subsequent designation, by Diener, Reference Diener1921; Amarassi beds (Capitanian, probably equal to the lower Lopingian), Amarassi, Timor, Indonesia.

Diagnosis

Similar to Cyclolobus, but conch broader and commonly retaining ribs to maturity. External suture with 8–11 pairs of lobes to umbilical shoulders, lacking tertiary subdivision near crest of first lateral saddle.

Occurrence

Capitanian, supposedly equal to Wuchiapingian; Indonesia (Timor), USA (West Texas), Mexico (Coahuila), Russia (Maritime Territory, Amur), Azerbaijan (Julfa), Iran (north, central), Tajikistan (?Pamirs), Japan (Kitakami), and China (Yunnan, Xizang, ?Guizhou).

Remarks

In practice, some misidentifications occur between the genera Timorites and Cyclolobus because their generic assignments were mostly experienced on external conch features. Actually, the tertiary subdivision near the crest of the first lateral saddle in Cyclolobus might be the most effective character for disginguishing it from Timorites.

? Timorites sp.

Figure 36.10

Description

Specimen only a piece of external cast of living chamber. Conch larger in size, probably >110–120 mm in diameter, sculptured with very strongly transversal ribs. Ribs rounded at top, as wide as inter-rib, increased in number by furcating near the ventrolateral zone. Suture unknown.

Materials

An external cast, NIGP 154112.

Occurrence

Bed 23, Claystone (3rd) Member, Shaiwa Formation, Sidazhai section (Sec. VI’-VI”), Sidazhai, Ziyun County, Guizhou.

Remarks

Within the ammonoid assemblage found from the Bed 23, Claystone (3rd) Member, Shaiwa Formation, Sidazhai section (Sec. IV’-IV”), this fragment of living chamber probably represents the genus Timorites. The questionable specimen here also resembles Timorites yunnanensis Liang, Reference Liang1983 from Youhua, Yongning Town, Ninglong County, West Yunnan (Liang, Reference Liang1983).

Superfamily Marathonitoidea Ruzhentsev, Reference Ruzhentsev1938

Family Marathonitidae Ruzhentsev, Reference Ruzhentsev1938

Genus Almites Toumanskaya, Reference Toumanskaya1941

1921 Staceoceras Gemmellaro; Reference FredricksFredricks, p. 91 (part).

1927 Perrinites Reference SmithSmith, p. 55 (part).

1933 Marathonites; Reference RuzhentsevRuzhentsev, p. 173 (part).

1938 Kargalites Ruzhentsev, Reference Ruzhentsev1938, p. 259 (part).

1939 Paraperrinites Reference ToumanskayaToumanskaya, p. 17.

1940a Peritrochia; Miller and Furnish, Reference Miller and Furnish1940a, p. 121 (part).

1941 Marathonites ( Almites) Reference ToumanskayaToumanskaya, p. 261.

1950 Marathonites ( Neomarathonites) Reference RuzhentsevRuzhentsev, p. 190 (part).

1978 Almites; Bogoslovskaia, Reference Bogoslovskaia1978, p. 56.

Type species

Marathonites sellardsi Plummer and Scott, Reference Plummer and Scott1937; original designation; Indian Creek Shale, Admiral Formation (Sakmarian), Coleman County, central Texas.

Diagnosis

Similar to Marathonites, but dorsal lobe narrow and weakly tridentate.

Occurrence

Upper Pennsylvanian (Virgilian [Gzhelian]): USA (Texas); Lower Permian Cisuralian (Asselian—Artinskian): USA (Texas, New Mexico, California, Nevada), Guatemala, Ukraine (Crimea), Russia and Kazakhstan (South Urals), Tajikistani (Pamirs), Indonesia (Timor), Austria (Karawanken Mountains), and South China (Guangxi, Guizhou).

Remarks

Almites is distinguished from Marathonites by the narrower dorsal lobe, and from Pseudovidrioceras by the bidentate prongs of the ventral lobe. Almites resembles Cardiella in general suture, but is distinguished from the latter by regular coiling in conch growth, without geniculation. Smith (Reference Smith1927) described a new species, ‘ Perrinitesbrouweri, but restudy of the types by Glenister and Furnish in the 1970s indicated that his figs. 1 and 2 were really marathonitids, probably forms of genus Almites (Glenister et al., Reference Glenister, Furnish and Zhou2009, p. 160).

Almites multisulcatus Bogoslovskaia, Reference Bogoslovskaia1978

Figures 40.1–40.15, 41.2–41.6

1978 Almites multisulcatus Reference BogoslovskaiaBogoslovskaia, p. 56.

1987 Marathonites sp. Reference ZhouZhou, p. 140, pl. 4, figs. 4, 5.

Description

Pachyconic, involute, with body chamber at 31.7 mm diameter in the largest specimen (NIGP 89014, Fig. 40.13–40.15). Rounded venter merges with flanks continuously, without ventrolateral shoulder. Whorl-section semi-ellipsoidal. Umbilicus small, with narrow and stepped wall (Table 10). Shell surface covered by fine lamellae, extended obliquely forward from umbilical shoulder, subsequently backward to trace a broadly shallower sinus in venter. Five to six constrictions, parallel with lamellae, obviously present in internal mold, but faint on exterior of test. Ventral lobe relatively broad, subdivided into two wide and bidentate prongs. First three external lateral lobes clearly tridentate; fourth lobe situated near umbilical shoulder, much smaller than previous three, bidentate or undivided. Dorsal lobe narrow, tridentate (Fig. 41.6); first to third internal lateral lobes narrow and bidentate. Denticulation in ventral lobe and the first two lateral lobes somewhat irregular, probably caused by second-order subdivision of the denticles in the relatively large-sized specimen NIGP 89013 (Fig. 41.5).

Table 10 Dimensions and ratios of Almites multisulcatus Bogoslovskaia, Reference Bogoslovskaia1978. D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Materials

Six specimens, NIGP 89009–89014 from limestone matrix. Except NIGP 89014, all phragmoconchs; body chambers lost in process of specimen preparation.

Occurrence

Bed 19, Meyao section (Sec. V), Liuzhai; Bed 11, Zhuangli section (Sec. VI), Liuzhai; Asselian talus limestone, Liuzhai Quarry (Loc. 5), Liuzhai. All from the 2nd Member, Nandan Formation, Nandan County Guangxi.

Remarks

Specimens herein resemble types from the Pamirs in conch shape, sculpture, and sutural generality, especially possessing 5–6 constrictions on the internal mold of both phragmoconch and body chamber. However, the existence of irregular denticulation in NIGP 89013 (Fig. 41.5) is still questionably either intraspecific variation among individuals or new, distinct features with taxonomic significance. The specimen NIGP 94477 (Zhou, Reference Zhou1987) collected from the Liuzhai Quarry (Loc. 5) formerly was identified as Marathonites sp., but it has been reassigned to Almites now owing to discovery of a narrowly tridentate dorsal lobe in NIGP 89014 with the same conch shape in the fauna.

Almites sp.

Figures 40.16–40.21, 41.1

Description

Conchs compressed, fairly deformed in mudstone matrix. Original shells presumably pachyconic and involute, with very small umbilicus. Lamellae sculpture on conch surface; 3–4 constrictions on internal mold of outer volution. Ventral lobe relatively broad. Prongs bidentate, wider than ventral saddle, with a longer digit ventrad. First to third external lateral lobes wide, completely tridentate, with a longer middle digit; fourth external lateral lobe with two asymmetric teeth. All saddles constricted adorally. As an exception, NIGP 89015 possesses a bidentate third lateral lobe (see Fig. 40.17) instead of the usually tridentate third lateral lobe.

Materials

Five specimens, NIGP 93718–93721 and NIGP 89015.

Occurrence

Beds 17–19 of the Longyin Formation, Huagong section (Sec. II), Huagong Tea-Plantation of Qinlong County, Guizhou; Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi; Bed 3 of Longyin section (Sec. I), Longyin village, Pu’an County, Guizhou.

Remarks

Closely similar to Almites leveni Leonova, Reference Leonova1992 from Sakmarian Stage of the southeast Pamirs in conch shape and size, and general characters of suture, but the Pamirs species has and obviously wider secondary ventral saddle and less-constricted saddles. The species also resembles Almites ruzhentsevi Leonova, Reference Leonova1981 from the Urals in shape of ventral lobe, but differs from it by narrower and deeper lateral lobes.

Genus Cardiella Pavlov, Reference Pavlov1967

1949 Marathonites ( Almites) Reference ToumanskayaToumanskaya, p. 68 (part).

1967 Aksuites Reference PavlovPavlov, p. 77.

1972 Marathonites; Reference DavisDavis, p. 85 (part).

Type species

Cardiella gracia Pavlov, Reference Pavlov1967; original designation; Kochusuisk Formation, Kungurian, Lower Permian, Southeast Pamirs.

Diagnosis

Small- to medium-size marathonitids (1.5–4.0 cm mature diameter), similar to Almites in suture and juvenile conch, but characterized by moderate to extreme geniculate coiling and modification of cross section in ultimate volution. Terminal restriction reduced apertural area to one-half, accompanied by shell thickening that closed umbilicus and produced deep furrow on internal mold.

Occurrence

About 15 species, but some of these species might be the representatives of dimorphologic pairs; Upper Pennsylvanian (Missourian–Virgilian): USA (Texas, Oklahoma, Kansas); Permian (Asselian–Kungurian): Tajikistan (Pamir), Ukraine (Crimea), Russia and Kazakhstan (Southern Urals), southern China (Guangxi), Indonesia (Timor), and USA (Nevada).

Remarks

Cardiella is distinguished from similar marathonitids mainly by conch shape. Some modification on conch shape is present in the terminal stage of ontogeny (i.e., umbilicus becomes very narrow, even closed, and outer volution changes to steamline-shaped with an obvious geniculate). Modifications might be caused by changes of life style ontogenetically, including difference of dimorphology due to the sex producing relatively clear dimorphologic pairs in the genus. In addition, lamellae on the conch surface usually are much more curved, and the ventral lobe and its prongs are relatively wider, which are different from the other marathonitids.

Cardiella gracia Pavlov, Reference Pavlov1967

Figures 42.1–42.16, 44.5–44.7

1967 Cardiella gracia Reference PavlovPavlov, p. 76 (part), pl. 5, fig. 1.

1981 Cardiella amygdala Reference LeonovaLeonova, p. 43, pl. 2, figs. 7, 8.

Description

Conchs small to intermediate (20–47 mm), consisting of obviously two size-groups of individuals recognized as dimorphologic pairs (Table 11). Heart-shaped or irregularly oval, with geniculation observed at about half the ultimate volution in terminal stage. Secondary thickening around umbilical shoulder relatively tightened, even sealing the umbilicus. Conch interior thickening in living chamber probably emerged in the preservation process (NIGP 89020, Fig. 44.7). Conch surface covered with evenly spaced growth lamellae and trace a salient in flank and a wide and shallow sinus in venter. Several faint longitudinal lirae sparsely present in venter of specimen NIGP 89020, in which periostracum of test partially well preserved. Subterminal constriction approximately parallel to those of earlier growth lamellae, with a high dorsolateral salient, shallow ventrolateral sag, and a broadly rounded, shallow hyponomic sinus. First to third lateral lobes fairly well preserved. Lobe bases tridentate, axial denticle conspicuously longest.

Table 11 Dimensions and ratios of Cardiella gracia Pavlov, Reference Pavlov1967; measurements taken in both long- (Dmax, above) and short- (Dmin, lower) axis directions, respectively. D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Materials

15 individuals; NIGP 89021–89030 (microconchs), NIGP 89016–89020 (macroconchs); six of them illustrated herein.

Occurrence

‘Chihsia’ Limestone, Tian’e suburb (Loc. 7), north of Hongshuihe River, Tian’e County, Guangxi.

Remarks

All specimens of Cardiella herein were extracted from a limestone block, which was sampled from Tian’e suburb. The occurrence of ammonoids suggests a living assemblage. The mature individuals, except the ‘jumbo’-sized NIGP 89020, could be referred to two groups according to dimension of conchs: the smaller ones, including NIGP 89021–89030, with average Dmax (largest diameter) 22.4 mm and Dmin (smallest diameter) 19.5 mm; and the larger ones, including NIGP 89016–89020, with average Dmax 34.4 mm and Dmin 23.6 mm. Both groups are characterized by strongly geniculate body chamber due to modification of coiling radius, and alternation of whorl-section. It probably is more reasonable to refer the two size-groups of conchs to dimorphism pairs than to different species.

Comparing specimens from South China with those of the Pamirs, the smaller group coincides with Cardiella amygdala Leonova, Reference Leonova1981 in conch form, dimensions, ornament, and generality of suture, while the larger group is similar to Cardiella gracia Pavlov, Reference Pavlov1967 in the same items. In particular, the Pamirs species appear to be paired, and have similar early ontogenies with each other. Therefore, all of them from both South China and Pamirs probably represent a pair of dimorphic Cardiella. According to the priority of the nomenclature, the species Cardiella gracia Pavlov should be preserved.

Genus Kargalites Ruzhentsev, Reference Ruzhentsev1938

1915 Popanoceras; Reference HanielHaniel, p. 88 (part).

1927 Marathonites; Reference SmithSmith, p. 44 (part).

1931 Vidrioceras; Reference SchindewolfSchindewolf, p. 197 (part).

1941 Peritrochia; Reference Mullerried, Miller and FurnishMullerried et al., p. 404.

1949 Marathonites ( Almites) Reference ToumanskayaToumanskaya, p. 68 (part).

Type species

Marathonites timorensis Haniel var. typica Ruzhentsev, Reference Ruzhentsev1933; original designation; Artinskian, South Urals.

Diagnosis

Marathonitids, dorsal lobe is narrow and undivided to weakly tridentate.

Occurrence

Upper Pennsylvanian: USA (Texas and Ohio); Asselian through Kungurian: Indonesia (Timor), Urals (Russia and Kazakhstan), Tajikistan (Pamirs), Japan (Kitakami), Canada (Ellersmere Island), Mexico (Chiapas), and South China (Guangxi).

Remarks

As Ruzhentsev (Reference Ruzhentsev1956, p. 242) pointed out, intraspecific variation is extreme in this genus, and even in all the marathonitids, “populations of the type species display ventral prongs that range from undivided to bidentate; irregularly bidentate first external lateral lobes that may possess third-order subdivision of the denticles; and a dorsal lobe that ranges from undivided through asymmetrically bidentate to narrowly tridentate.” It seems true, given that the sutures shown in Figure 44.5 and 44.6 are so different in both shape and length, especially, the in the third lateral lobes near the umbilicus.

Kargalites is similar to Almites in conch form, ornament, and generality of suture, but is distinguished from the latter by bidentate first external lateral lobe. Kargalites and Subkargalites are similar to each other in major features, but the former, like Almites, possesses a relative narrow dorsal lobe, which is undivided through asymmetrically bidentate to narrowly tridentate, whereas in the latter, the dorsal lobe is broad and deeply tripartite (D2D1D2).

Kargalites nandanensis Zhou, Reference Zhou1987

Figures 43.4, 43.5, 44.3

1987 Kargalites nandanensis Reference ZhouZhou, p. 140, pl. 3, figs. 14–18.

Materials

Three specimens, NIGP 94474–94476.

Occurrence

Asselian talus limestone, 2nd Member, Nandan Formation, Liuzhai Quarry, Liuzhai, Nandan County, Guangxi.

Remarks

The present species is still assigned to the genus Kargalites as done in 1987 because no inner suture is available. The associated species ‘ Kargalitesliuzhaiensis is re-assigned to Subkargalites due to the well-preserved tripartite in the broad dorsal lobe (D2D1D2). The species is similar to Subkargalites liuzhaiensis in conch shape, but different in sutural details. It also is similar to Subkargalites neoparkeri Ruzhentsev, Reference Ruzhentsev1950, but the latter is characterized by a wider umbilicus and broader prong of the ventral lobe.

Kargalites sp.

Figures 43.3, 44.4

Description

Only a piece of internal mold, representing two different whorls, preserved in mudstone. Conch looks thicker discoidal with narrow umbilicus. Suture only preserved on first three external lateral lobes. First lateral lobe broad and bidentate, then secondary subdivisions appearing on the primary digits, respectively. Second and third lobes all tridentate, but third one quite asymmetric. Ventral lobe poorly preserved; its prongs presumably bidentate as usual.

Materials

Internal mold of phragmoconch, NIGP 93722.

Occurrence

Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi.

Remarks

Inadequate material makes it impossible to recognize species exactly. The basic character of the first lateral lobe confirms the generic assignment, although there is secondarily bidentate in each division.

Genus Subkargalites Ruzhentsev, Reference Ruzhentsev1950

1884 Ammonoites Reference HeilprinHeilprin, p. 53 (part).

1919 Marathonites Reference BöseBöse, p. 133 (part).

1938 Kargalites Reference RuzhentsevRuzhentsev, p. 259 (part).

1950 Kargalites ( Subkargalites) Reference RuzhentsevRuzhentsev, p. 191.

1992 Subkargalites; Reference PopovPopov, p. 57.

Type species

Marathonites hargisi Böse, Reference Böse1919; original designation, Asselian, lower Gaptank Formation, West Texas, USA.

Diagnosis

Ancestral marathonitids, similar to Kargalites, but dorsal lobe broad and deeply tripartite (D2D1D2), conch diameters may exceeding 2 cm.

Occurrence

Carboniferous in Russia (South Urals) and Uzbekistan (Fergana: Karachatyr); Asselian in USA (Texas, Oklahoma, Kansas), Canada (Ellesmere Island), and South China (Guangxi).

Remarks

The critically generic feature (e.g., broader dorsal lobe, with a deeply tripartite base or completely separated three lobules) lies in the inner suture.

Subkargalites liuzhaiensis (Zhou, Reference Zhou1987)

Figures 43.1, 43.2, 44.1, 44.2

1987 Kargalites liuzhaiensis Reference ZhouZhou, p. 139, pl. 3, figs. 12, 13.

2002 Subkargalites liuzhaiensis; Reference LeonovaLeonova, p. S76.

Materials

Monotype NIGP 94473.

Occurrence

Asselian talus limestone, 2nd Member, Nandan Formation, Liuzhai Quarry (Loc. 5), Liuzhai, Nandan County, Guangxi.

Remarks

Leonova (Reference Leonova2002) emended the generic assignment of the present Asselian species, which is characterized by smaller umbilicus, narrower prongs of ventral lobe, secondarily ranked dentition of the first lateral lobe, and tripartite dorsal lobe. It can be distinguished from the type species, S. hargisi (Böse, Reference Böse1919), and Late Carboniferous S. neoparkeri Ruzhentsev, Reference Ruzhentsev1950 by the features mentioned above.

Superfamily Neoicoceratoidea Hyatt, Reference Hyatt1900

Family Neoicoceratidae Hyatt, Reference Hyatt1900

Genus Eoasianites Ruzhentsev, Reference Ruzhentsev1933

1927 Gastrioceras; Smith, Reference Smith1927, p. 27 (part).

1936b Prometalegoceras Reference RuzhentsevRuzhentsev, p. 505.

1937 Trochilioceras Reference Plummer and ScottPlummer and Scott, p. 181.

Type species

Eoasianites subhanieli Ruzhentsev, Reference Ruzhentsev1933; original designation; Artinskian, Aktyubinsk, South Urals, Kazakhstan.

Diagnosis

Conch subdiscoidal, evolute, with low height of aperture. Transverse striae usually with oral salient. Umbilical tubercles confined to immature stages; constrictions may be present. Ventral lobe with slightly pouched prongs, median saddle exceeding two-thirds height of entire ventral lobe. First lateral saddle subacute.

Occurrence

Pennsylvanian (Kasimovian) through Permian (Asselian); Russia and Kazakhstan (South Urals), USA (Texas, Oklahoma, Kansas, Alaska), Canada (Yukon), Tajikistan (Pamirs), and China (Guangxi, Xinjiang).

Remarks

The type species of Trochilioceras and Pronoceras are regarded as congeneric with Eoasianites. Eoasianites resembles shumarditoidean Somoholites and Preshumardites in outline of both conch shape and sutural elements, but differs from them by the obviously less-pouched lateral lobe and dorsal lobe that resulted basically from phylogenetic divergence. Eoasianites, which lacks spiral lirae in its sculpture, also is distinct from Somoholites. Eoasianites is similar to the gastrioceratoidean Glaphyrites in generality of conch shape and suture, but mature Glaphyrites is more involute with smaller umbilicus, and possesses spiral lirae in the sculpture.

Eoasianites subhanieli Ruzhentsev, Reference Ruzhentsev1933

Figures 45.1–45.9, 46.1, 46.2

1948 Eoasianites subhanieli morpha alta; Reference MaximovaMaximova, p. 15, pl. 2, figs. 4–6.

Description

Conchs subglobal, fairly evolute, with wide and deep umbilicus; estimated full size with living chamber may reach to 70–80 mm diameter (Table 12). Sculpture unknown, supposedly smooth, no nodes or ribs except for fine transverse striae. Ventral lobe relatively narrow. Median saddle as high as half to two-thirds of lobe height; prongs aside narrow, pouched at middle part, pointed at base. External lateral lobe almost same in width as first lateral saddle. Lateral lobe rather pouched, asymmetric, pointed at base. First lateral saddle somewhat subacute at top.

Table 12 Dimensions and rations of Eoasianites subhanieli Ruzhentsev, Reference Ruzhentsev1933. D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Occurrence

Asselian talus limestone, Liuzhai Quarry (Loc. 5) and Bed 19, Meyao section (Sec. V), all from the 2nd Member, Nandan Formation, Nandan County, Guangxi

Materials

Four specimens, three incomplete phragmoconchs, most external suture details well-exposed, NIGP 88999–89001 herein, and one specimen, NIGP 94478 in Zhou (Reference Zhou1987).

Remarks

The present specimens are identical with the types of Eoasianites subhanieli Ruzhentsev from the Urals in both conch shape and outline of suture, although they are much larger in conch size than the holotype PIN 318/1207 from the Asselian Stage of the Sholak-Say River, Aktyubinsk, Kazakhstan. However, the paratypes, PIN 318/411 from the Yuresan River, Bashkorstan, Russia (Ruzhentsev, Reference Ruzhentsev1951, pl. 7, figs. 1a, b), are even larger (to 57 mm in diameter). Therefore, conch size in the species may have a very large range.

Family Paragastrioceratidae Ruzhentsev, Reference Ruzhentsev1951

Subfamily Paragastrioceratinae Ruzhentsev, Reference Ruzhentsev1951

Genus Svetlanoceras Ruzhentsev, Reference Ruzhentsev1974

1948 Uraloceras; Reference MaximovaMaximova, p. 7 (part).

1951 Paragastrioceras; Reference RuzhentsevRuzhentsev, p. 142 (part).

1963 Ruzhentsevites Reference MoyleMoyle, p. 183 (nom. nud.).

Type species

Uraloceras serpentinum Maximova, Reference Maximova1948; original designation; Asselian Stage, Bashkortostan, Yuresan River, South Urals.

Diagnosis

Small (commonly <2.5 cm mature diameter), thinly discoidal paragastrioceratins (W/D, <0.4) with depressed whorls (H/W, <0.8) and wide umbilicus (Umin/D, 0.4–0.7). Numerous ribs across umbilical wall and shoulder multiply by intercalation and bifurcation to produce finer ornament across flanks and venter; ribs and constrictions form high ventral salient; longitudinal lirae less pronounced than transverse ornament. Suture primitive: prongs of ventral lobe narrower and deeper than lateral lobe; lateral lobe approximately symmetrical, with flanks diverging adorally.

Occurrence

Asselian through the lower Sakmarian (Tastubian); Russia and Kazakhstan (South Urals), Tajikistan (Pamirs), India (?Eastern Himalaya), West Australia, USA (west Texas), Canada (Yukon), and South China (Guangxi).

Remarks

As an ancestral paragastrioceratid, Svetlanoceras is characterized by small mature size, along with wide umbilicus, numerous, but weakly umbilical plicae, weaker longitudinal lirae, and primitive suture (e.g., narrower prongs and shorter lateral lobe). Svetlanoceras is transitional to descendant Uraloceras, but a very broad prong, smaller umbilicus, and closely equidimensional whorl section in the latter distinguish it from the former. Although Svetlanoceras resembles Paragastrioceras by similar width of prong, the latter has a longer lateral lobe, more depressed and wide whorl section, obviously stronger transverse ribs or nodes around the umbilical region, and, especially, more pronounced longitudinal lirae on the venter and flanks.

Svetlanoceras resembles Stenolobulites of the subfamily Pseudogastriocertinae in both suture and conch shape, with open umbilicus, strong ribs near umbilical shoulder, and numerous constriction, even with ventral salient. However, both genera belong to different subfamilies, with the major difference being a sinus at the crest of the salient in Stenolobulites, which is a major character of the subfamily Pseudogastrioceratinae.

Svetlanoceras serpentium (Maximova, Reference Maximova1948)

Figures 47.1–47.13, 48.1, 48.2

1940 Uraloceras serpentinum Reference Maximova and RuzhentsevMaximova and Ruzhentsev, p. 161 (nom. nud.).

1951 Paragastrioceras serpentinum; Reference RuzhentsevRuzhentsev, p. 143, pl. 11, figs. 7–9.

1974 Svetlanoceras serpentinum; Reference RuzhentsevRuzhentsev, p. 23.

Description

Whorl section depressed, with rounded venter and ventrolateral shoulder, and bluntly rounded umbilical shoulder. Umbilicus broad, slightly convex umbilical wall, decorated by numerous transverse ribs. Specimen NIGP 154087 (Fig. 47.12, 47.13), with diameter 31 mm, probably represents the maximum-sized individual in the species (Table 13). Surface weakly ornamented by growth lines and less-pronounced lirae. Prominently ventral salient traces in growth lines. Deeply incised constrictions in most specimens examined. Ventral lobe with broad medium saddle and narrow lanceolate prongs conspicuously constricted at two-thirds height of lobe. Lateral lobe asymmetric, broadening adorally, shorter than ventral lobe. Umbilical lobe broad, funnel-shaped.

Table 13 Dimensions and conch proportions of Svetlanoceras serpentinum (Maximova) and S. uraloceraformis n. sp.. D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Materials

Seven solitary specimens in different growth stages from the detritus limestone, NIGP 154081–154087.

Occurrence

Bed 19, 2nd Member, Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi.

Remarks

Eight species of Svetlanoceras have been established: S. serpentinum (Maximova, Reference Maximova1948) (upper Asselian–Sakmarian); S. strigosum (Ruzhentsev, Reference Ruzhentsev1952) (upper Asselian–Sakmarian); S. notium Ruzhentsev, Reference Ruzhentsev1978 (upper Asselian–Sakmarian); S. primore Bogoslovskaia and Popov, Reference Bogoslovskaia and Popov1986 (upper Asselian–Sakmarian); S. uraloceraformis n. sp. (Sakmarian); S. tenue Bogoslovskaia, Leonova, and Shkolin, Reference Bogoslovskaia, Leonova and Shkolin1995 (Sakmarian–lower Artinskian); S. irwinense (Teichert and Glenister, Reference Teichert and Glenister1952) (Artinskian); and S. moylei Mikesh in Glenister, Baker, Furnish, and Thomas, Reference Glenister, Baker, Furnish and Thomas1990 (Artinskian). As shown in the sequence above, the ratios of U/D reduce within the series from 0.6 to 0.4, while the stratigraphic levels go from upper Asselian, via Sakmarian, through Artinskian, successively. The present specimens are evolute with the largest U/D value, most close to that of S. serpentinum (Maximova), in addition to general conch form, ornament, and basic feature of suture. Although slightly larger in size than those from Urals, it probably represents the result of different individual development among special regional populations. The specimens herein also are similar to S. moylei Mikesh in basic features of the external suture, but the former has a wider whorl section (H/W 0.69 versus 0.75), allowing it to be distinguished from the latter.

Svetlanoceras uraloceraformis new species

Figures 47.14–47.21, 48.3, 48.4

Diagnosis

A species with the typical sutural pattern of genus Svetlanoceras, with a conch shape somewhat like the genus Uraloceras.

Description

Shell discoidal, evolute with approximately equidimensional whorl section, H/W 0.93–1.00; umbilicus relatively small for genus, U/D 0.43–0.48 (Table 13). Shell surface marked by closely spaced longitudinal lirae, four or five in a millimeter on venter, and growth lines, both resulting in finely reticular pattern. Numerous ribs across umbilical wall and shoulder, multiplying by intercalation and bifurcation to produce finer growth lines across flanks and venter to form fasciculate bands. Transverse lines generally more prominent and more irregular than longitudinal lirae, especially on rounded umbilical shoulder where the former bifurcate and the latter are interposed between rib-like coarser lines. Three or more constrictions in a whorl, along with transverse growth lines to form pronounced salient on venter. Ventral lobe possesses wider medium saddle and symmetric lanceolate prongs; lateral lobe relatively shorter and umbilical lobe funnel-like.

Etymology

Name derived from the relative similarity to genus Uraloceras in basic conch shape and sculpture.

Materials

Three solitary individuals, relatively well preserved, NIGP 154089 (holotype), 154088, and 154090.

Occurrence

Bed 26, 3rd Member, Nandan Formation, Meyao section (Sec. V), Liuzhai,, Nandan County, Guangxi.

Remarks

Svetlanoceras uraloceraformis n. sp. is rather similar to the genus Uraloceras in conch shape and sculpture pattern, supposedly representing the innovative node in Svetlanoceras transition to descendant Uraloceras. However, its suture, with fairly narrower prongs and shorter lateral lobe, still allows assignment to Svetlanoceras rather than Uraloceras. The equidimensional whorl section and smaller umbilicus differ from the rest of the species of Svetlanoceras, except for S. irwinense (Teichert and Glenister). Nevertheless, Svetlanoceras uraloceraformis n. sp. is characterized by parallel flanks of the ventral lobe, which is different from the adorally widened ventral lobe of S. irwinense.

Svetlanoceras uraloceraformis n. sp. from the 3rd Member of the Nandan Formation is more advanced than S. serpentinum (Maximova) from the 2nd Member of the formation in both evolutive level and the practical stratigraphic position. Svetlanoceras uraloceraformis n. sp. is similar to the species of Stenolobulites in subfamily Pseudogastrioceratinae in general contour of suture, with relatively narrower ventral prong (V1/L <0.5); however, the former lacks the generic character of the latter (e.g., hyponomic sinus in the central venter, and much more depressed conch shape than the latter).

Family Metalegoceratidae Plummer and Scott, Reference Plummer and Scott1937

Subfamily Metalegoceratinae Plummer and Scott, Reference Plummer and Scott1937

Genus Pseudoschistoceras Teichert, Reference Teichert1944

1927 Paralegoceras; Reference SmithSmith, p. 30 (part).

1979 ? Gaoyaonites Reference XuXu, p. 42.

Type species

Pseudoschistoceras simile Teichert, Reference Teichert1944; original designation; Barrabiddy Shale Series, Artinskian–Kungurian, Cisuralian, Carnarvon Basin, West Austalia.

Diagnosis

Conch relatively narrow (W/D, 0.45–0.6) with small umbilicus (Umin/D, 0.25–0.35). Suture characterized by second tripartition of umbilical lobe to form a total of 16 lobes, nine external. Sutural formula: (V1V1)LU2(U1.2U1.1:U1.2)U3ID.

Occurrence

Artinskian; Indonesia (Timor), West Australia, and South China (Guizhou, ?Guangdong).

Remarks

Pseudoschistoceras is characterized by the second order of tripartition of the primary umbilical lobe to form a total of 16 lobes at maturity, nine external. The appearance of U1.2 inside the umbilical seam is the basis on which Pseudoschistoceras can be distinguished from Schistoceras. As the most advanced genus in the family, there are two or more extra lobes than in other metalegoceratins in the external suture.

Pseudoschistoceras sp.

Figures 49.13, 50.1

Description

Conch poorly preserved, pachyconch presumably moderately evolute, with open umbilicus, but measurement not available. Sculpture unknown. Ventral lobe narrow and subdivided into two extremely narrow prongs that are asymmetric and have sharpened posteriors. First and second external ‘lateral’ lobes (L and U2) broad, constricted in medium part, and sharpened adorally. Third external ‘lateral’ lobe (U2.1) well developed, almost compeletely independent, even a little deeper than first and second ones.

Materials

One phragmoconch inner mold in mudstone, NIGP 93723.

Occurrence

Beds 19–17, Longyin Formation, Huagong section (Sec. II), Qinglong County, Guizhou.

Remarks

The narrow prongs of the ventral lobe and three pairs of ‘lateral’ lobes exposed beyond the umbilical shoulder indicate the genus Pseudoschistoceras. Comparing three well-known species ( P. gigs [Smith, Reference Smith1927], P. simile Teichert, Reference Teichert1944, and P. irianense Glenister, Glenister, and Skwarko, Reference Glenister, Glenister and Skwarko1983), the specimen herein probably represents the most progressive in sutural development, because the third external ‘lateral’ lobe is compeletely differentiated as an independent lobe beyond the umbilical shoulder. It may be a new species, but could not be named based only on a single deformed specimen.

Genus Bransonoceras Miller and Parizek, Reference Miller and Parizek1948

1962 Metalegoceras; Reference RuzhentsevRuzhentsev, p. 385 (part).

1979 ? Pericycloceras; Reference Glenister, Nassichuk and FurnishGlenister, Nassichuk and Furnish, p. 238.

1989 Eolegoceras Reference LeonovaLeonova, p. 123.

Type species

Bransonoceras bakeri Miller and Parizek, Reference Miller and Parizek1948; original designation, middle Hueco Formation, Artinskian, Cisuralian, New Mexico, USA.

Diagnosis

Conch variable in relative width and umbilical diameter, with strong transverse ribs retained to maturity. Suture has 12 lobes, seven external; three umbilical elements (U2U1U3) are fully isolated; U2 subequal to or larger in area than U1, both external; U3 internal and subequal to U1. Sutural formula: (V1V1)LU2U1:U3ID.

Occurrence

Lower Artinskian through ?Roadian; USA (New Mexico), Tajikistan (Pamirs), and South China (Guizhou, Zhejiang).

Remarks

Bransonoceras is similar to Metalegoceras in conch form and suture details, but the former is distinct from the latter by its more compressed whorl-section and retention of strong ribs up to maturity. Glenister et al. (Reference Glenister, Nassichuk and Furnish1979) tended to synonymize the heavily ribbed genus Pericycloceras Zhao and Zheng, Reference Zhao and Zheng1977 with Bransonoceras owing to similarities in sutural outline and conch ornamentation; however, the ribs of Pericycloceras are quite sporadic and coarse as compared with those of Bransonoceras, and the conch of the former also is wider and much more depressed than the latter. It is supposed that Pericycloceras only represents the localized variety of the genus Bransonoceras in the restricted sea of South China, so it is provisionally listed as a synonym of the latter.

The single specimen referred to Pericycloceras costatum exhibits a shallow crenulation on the fourth external saddle, close to the umbilical seam. Such features, which are developed sporadically in other metalegoceratids, are regarded as presumably pathologic or capricious (Glenister et al., Reference Glenister, Windle and Furnish1973).

Bransonoceras longyinense new species

Figures 49.1–49.12, 50.2

Diagnosis

A species of Bransonoceras with apparent constrictions and fine spiral lirae.

Description

Mainly the inner molds of phragmoconch, partially with suture, preserved in mudstone matrix, with secondary deformation during preservation; however, the generality of conch form and sculpture still could be determined. Shell pachydiscoidal with fairly open umbilicus, estimated about one-fourth to one-third of conch diameter. Crowded small transverse lines and finer spiral lirae present in cast of NIGP 93726 (Fig. 49.12); traces of ribs and three or more clear constrictions present on surface of molds. Ventral lobe broad, with a wider middle saddle and two narrow prongs. First lateral lobe (L) broad and diverging adapically. Second ‘lateral’ lobe (U2) small and near umbilical shoulder. Umbilical lobe sharp and small.

Etymology

Name derived from the locality where the typical material was collected.

Occurrence

Bed 3 and Bed 12, Longyin Formation, Longyin Setion (Sec. I), Pu’an; beds 19–17, Longyin Formation, Huagong section (Sec. II), Qinglong. All from Guizhou.

Materials

12 specimens: NIGP 93660–93662, 93674, 93685, 93724–93727, 93739, 93740, 93743; including 93725 (holotype).

Remarks

Specimens of Bransonoceras longyinense n. sp. are similar to the type species of Bransonoceras in conch form and generality of suture, but apparent constrictions and finer spiral lirae are well developed in the present materials. Also, there are some similarities to the questionable Zhejiang species, ‘ Pericyclocerascostatum Zhao and Zheng, Reference Zhao and Zheng1977, but the umbilical lobe in Bransonoceras longyinense n. sp. displays a more primitively evolved suture, which is rather less differentiated than the latter.

Subfamily Eothinitinae Ruzhentsev, Reference Ruzhentsev1956

Genus Eothinites Ruzhentsev, Reference Ruzhentsev1933

1907 Uralites Reference ChernovChernov, p. 292 (nom. nud.).

1915 Paralegoceras Reference HanielHaniel, p. 58 (part).

1927 Lecanites Reference SmithSmith, p. 24 (part).

1930 Epiglyphioceras Reference SpathSpath, p. 40 (part).

1933 Rhiphaeites Reference RuzhentsevRuzhentsev, p. 171.

Type species

Eothinites kargalensis Ruzhentsev, Reference Ruzhentsev1933; original designation; Aktastinian (lower Artinskian), Aktubinsk area, South Urals.

Diagnosis

Conch subdiscoidal (W/D, 0.2–0.4) with moderately wide umbilicus (Umin/D, 0.35–0.7). Ribs commonly bifurcate on umbilical shoulder and may be associated with weaker longitudinal lirae; shallow sinus across flanks separated from deeper ventral sinus by prominent ventrolateral salient. Prongs of ventral lobe generally much narrower than corresponding lateral lobe, but may be up to 1.5 times that width.

Occurrence

Artinskian; Russia and Kazakhstan (Urals), Ukraine (Crimea), Tajikistan (Pamirs), Indonesia (Timor), USA (Texas), Northwest China (Xinjiang), and South China (Guizhou, Guangxi).

Remarks

Prongs of ventral lobe generally rather narrower than corresponding lateral lobe, but may be up to 1.5 times that width. Extreme variation in relative width of prongs of ventral lobe indicates polyphyletic derivation; narrow prongs resemble those of Paragastrioceras, while wider ones resemble Uraloceras, each of which may warrant full generic status.

Eothinites cf. E. kargalensis Ruzhentsev, Reference Ruzhentsev1933

Figures 50.3, 51.5–51.14

1933 cf. Eothinites kargalensis Reference RuzhentsevRuzhentsev, p. 170.

Description

Ophiocone flat discoidal, evolute with broad and shallow umbilicus. Volutions like worm-tube, growing slowly. Venter rounded, flanks relatively convex, umbilical border rounded but obvious. Sculpture mainly consisting of transverse ribs and a few spiral lines near umbilical border. Ribs stronger in inner volutions, getting slender in outer volutions; each 2–3 fine ribs combining to a rib-shaped node near umbilical border. Only two lateral lobes (L, U2) preserved on specimen NIGP 93752 (Fig. 50.3).

Materials

10 casts or molds incompletely preserved in mudstone, representing eight individuals, NIGP 93730–93733, 93752, 93753, 154079, 154080.

Occurrence

Longma Member, Sidazhai Formation, Mading (Loc. 6), Liuzhai, Nandan County, Guangxi; Bed 3 and Bed 12, Longyin Formation, Longyin Setion (Sec. I), Pu’an, Guizhou; Bed 34–32, Yangchang Formation, Yangchang section (Sec. III), Ziyun County, Guizhou.

Remarks

Conch form, sculpture, and even incomplete suture of specimens indicate the genus Eothinites. Furthermore, the specimens are similar to the Urals E. kargalensis Ruzhentsev, especially the sculpture in inner volutions and shape of the lateral lobe. However, inadequate feature combination prevents further exact identification.

Genus Glenisteroceras new genus

Type species

Glenisteroceras sidazhaiense n. gen. n. sp., monotypy, original designation herein; the lower Chongtou Member, Kungurian, Sidazhai Formation; Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou, South China.

Diagnosis

Conch small, compressed, evolutively discoidal with open umbilicus, sculptured by ribs, outlining deeper sinus across venter, and a few identically traced constrictions. Tripartition of primary umbilical lobe completed as early as about 10 mm diameter. Ventral lobe much shallower than lateral lobe (L) and extremely wide, consisting of a broad medium saddle and two widened, V-shaped prongs with strongly diverging flanks. Lateral lobe long, tongue-like, fairly asymmetric; second ‘lateral’ lobe triangle-shaped, much smaller and shallower than previous one.

Etymology

Named in honor of late Professor Brian F. Glenister, the University of Iowa, USA.

Occurrence

Kungurian, Cisuralian; South China (Guizhou).

Remarks

Glenisteroceras n. gen. resembles Epiglyphioceras in the same subfamily Eothinitinae in conch shape, sculpture, and outline of suture; however, Glenisteroceras n. gen. has an extremely short and wide ventral lobe with strongly diverging flanks. Glenisteroceras n. gen. resembles juveniles of the large ancestor Eothinites; it was probably the diminutive terminal paedomorph of subfamily Eothinitinae.

Glenisteroceras sidazhaiense new species

Figures 50.4, 50.5, 51.1–51.4

Diagnosis

Eothinitins, with evolute conch, and the especially broad, shallow, and divergent ventral lobe.

Description

Conch flat discoidal, evolute with broad umbilicus. Venter narrowly rounded, flank flat convex, dorsum slightly depressed. Height of whorl-section about equal to or a little greater than the width. Umbilical shoulder rounded; umbilical wall narrow and steep. Outer volution decorated with transverse ribs, which form deeper sinus on venter; 2–3 ribs converge as small nodes near umbilical shoulder; 3–4 constrictions appear in the outer volution. Ventral lobe very short, broad and opens adapically, subdivided by a wide medium saddle into two short and wide V-shaped prongs. First lateral lobe (L) tongue-like, asymmetrical, much narrower and longer than ventral lobe, whereas second ‘lateral’ lobe (U2) very small in size, looks like a ‘lobule’.

Etymology

Species name derived from the fossil locality, Sidazhai, Ziyun County, southwest Guizhou.

Materials

Two specimens, NIGP 93728 (holotype), NIGP 93729.

Occurrence

Bed 12, Chongtou Member, Sidazhai Formation, Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou.

Remarks

Glenisteroceras sidazhaiense n. gen. n. sp. is characterized by a wider and shorter ventral lobe and deeper and narrower first lateral lobe (L). Glenisteroceras sidazhaiense n. gen. n. sp. is similar to Eothinites stenomphalus Ruzhentsev, Reference Ruzhentsev1956 and E. pseudomeneghinii (Haniel, Reference Haniel1915) in the shape of whorl-section and the height being a little greater than the width, but the new species has a completely different suture than the latter two by its extremely wide and shallow ventral lobe. Glenisteroceras sidazhaiense n. gen. n. sp. resembles Epiglyphioceras meneghinii (Gemmellaro, Reference Gemmellaro1887) in the shallower and wider ventral lobe and basic conch shape, but is distinct from the latter by the much wider and specially diverging flanks of the ventral lobe.

Superfamily Popanoceratoidea Hyatt, Reference Hyatt1900

Family Popanoceratidae Hyatt, Reference Hyatt1900

Genus Popanoceras Hyatt, Reference Hyatt1884

1844 Popanoceras Hyatt, p. 337 (part).

1845 Goniatites Reference VerneuilVerneuil, p. 372 (part).

1919 Stacheoceras; Reference BöseBöse, p. 127 (part).

1965 Propopanoceras; Reference ChaoChao, p. 1815.

1989 Pamiropopanoceras Reference LeonovaLeonova. p. 174.

Type species

Goniatites sobolewskyanus Verneuil, Reference Verneuil1845; subsequent designation by Gemmellaro, Reference Gemmellaro1887; Artinskian Stage, South Urals.

Diagnosis

Prong of ventral lobe (V1) equal to or wider than adjacent lateral lobe, bidentate to quadridentate; four or five external lateral lobes moderately dentate.

Occurrence

Artinskian through Roadian; USA (Texas), Russia (Urals), Kazakhstan (South Urals), Ukraine (Crimea), Madagascar, Tajikistan (Pamirs), Indonesia (Timor), West Canada (north-west Territories), West Australia (Carnarvon Basin), North Thailand (Loei), Japan (Fukushima Prefecture), and China (Xizang, Jilin, Guizhou, and Guangxi).

Remarks

The genus is similar to Propopanoceras, but different from it in a transitional status: the prong of the ventral lobe in the former is equal to or slightly broader than the first lateral lobe, whereas in the latter it usually is narrower than the corresponding lateral lobe.

Popanoceras ziyunense new species

Figures 52.1–52.10, 53.3–53.5

Diagnosis

Venter flat, with simple, denticulated prongs, the second lateral lobe widest, and incompletely subdivided fourth lateral lobes (or the paired fourth and fifth lobe). Average diameter of umbilicus is larger than other species at the corresponding stage ontogenetically.

Description

Conch discoidal, compressed, and involute. Venter narrowly rounded in adolescence and flattened in adult. Flank broad and nearly flat; ventrolateral and umbilical shoulders bluntly angular. Umbilicus relatively larger (Table 14). All specimens inner molds, absent sculptures on conch surface; only 7–8 prominent transverse-elongate depressions occur on outer volution. Ventral prongs simply bidentate in base, approximately equal to adjacent lateral lobe in width. Four lateral lobes total, conspicuously constricted adorally, somewhat irregular in shape, second lobe widest, fourth primarily subdividing into two dependent bidentate lobules. First three lateral lobes tridentate or quadridentate with normally transversal trace; fourth complex lobe traces down adorally. Top of saddle globe-shaped. Umbilical lobe bipartite, ventrad group of U1U1 transferred to flank ontogenetically.

Table 14 Dimensions and conch proportions of Popanoceras ziyunese n. sp. and P. kueichowense (Chao, Reference Chao1965). D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Materials

Five well-preserved specimens, NIGP 93734 (holotype), and NIGP 93735–93738.

Occurrence

Bed 12, Chongtou Member, Sidazhai Formation; Shaiwa section (Sec. IV-IV’), Sidazhai, Ziyun County, Guizhou.

Remarks

Specimens described herein represent late adolescence, but not full maturity due to well-developed flank depressions. Popanoceras ziyunense n. sp. is characterized by the compressed conch, even venter in last volution with angularly ventrolateral shoulder, and distinct features of suture: only two serrations in prong of the ventral lobe, the widest and bipartite second lateral lobe, and incompletely subdivided fourth lateral lobe. Also, the umbilicus is relatively larger as compared with Popanoceras kueichowense Zhao in Zhao and Liang, Reference Zhao and Liang1974.

Popanoceras kueichowense (Zhao in Zhao and Liang, Reference Zhao and Liang1974)

Figure 52.11–52.19, 53.1, 53.2

1965 Propopanoceras kueichowense Reference ChaoChao, p. 1815, pl. 1, figs. 14, 15 (nom. nud.).

1974 Propopanoceras kueichowense Zhao in Reference Zhao and LiangZhao and Liang, p. 304, pl. 159, figs. 9, 10.

1989 Popanoceras kueichowense; Reference ZhouZhou, p. 1367, fig. 1b, pl. 1, figs. 8–10.

2002 Pamiropopanoceras kueichowense; Reference LeonovaLeonova, p. S96.

Description

Conch large, discoidal, and involute with small umbilicus. Venter narrowly rounded, flanks flattened. Ornamented by prominent fine ribs and/or strong plications transversely, depending on preservation status. Both ribs and plications form slight sinus on flanks and deeply rounded sinus on venter. Four constrictions present on outer volution. Apertural constriction present in ultimate volution of holotype (NIGP 22029). External suture forms a broad bifid ventral lobe, five lateral lobes, and two small subangular umbilical lobes. Bidentate prong slightly wider than adjacent lateral lobe. First four lateral lobes quadridentate or tridentate, fifth wide and bidentate. All lateral lobes successively decreasing in size toward umbilicus.

Materials

Six specimens, including original holotype NIGP 22029 (Zhao in Zhao and Liang, Reference Zhao and Liang1974), and newly collected plesiotypes NIGP 154091–154094 and 154094-1.

Occurrence

Tongkuangxi Formation (supposedly equal to Longyin Formation), Ladang (Loc. 1), Langdai, Liuzhi County, Guizhou; Bed 3, Longyin Formation, Longyin section (Sec. I), Pu’an County, Guizhou; Coll. 7085, Bed 31, Longma Member, Sidazhai Formation, Meyao section (Sec. IV) Liuzhai, Nandan County, Guangxi.

Remarks

Popanoceras kueichowense represents a primitive species of Popanoceras, with a small umbilicus, wide but bidentate prongs, and subequal lateral lobe series decreasing in size to umbilicus. The well-preserved holotype was named and figured as Propopanoceras kueichowense Chao, Reference Chao1965 without description. Afterwards, it was formally published by the original author (Zhao in Zhao and Liang, Reference Zhao and Liang1974), but still without providing the occurrence details. The new plesiotypes were collected from the lower part of the Longyin Formation and the Longma Member of the Sidazhai Formation in the typical area—the open-sea area of southwest Guizhou and northeast Guangxi. The prongs of the ventral lobe on the holotype NIGP 22029 are slightly wider than the adjacent lateral lobe in width. Therefore, the specimen had already been recombined as Popanoceras by the present author (Zhou, Reference Zhou1989). Popanoceras kueichowense (Zhao in Zhao and Liang, Reference Zhao and Liang1974) resembles P. walcotti White, Reference White1891 and P. annae Ruzhentsev, Reference Ruzhentsev1940d in the simple denticulation of the prongs in the ventral lobe and the lateral lobes, but is distinguished from both Urals and North America species by the position of the paired last two lateral lobes, which are the fifth and sixth lobes in Guizhou species versus the fourth and fifth lobes in the latter two.

Leonova (Reference Leonova1989, Reference Leonova2002) reassigned the present species into her new genus Pamiropopanoceras based on features of the inner sutures (e.g., lacking the ‘fused’ first internal lateral lobe). Actually, because the inner suture is not entirely exposed in the Chinese specimens, it is relatively reasonable to reassign the Popanoceras kueichowense-bearing stratum in Nanpanjiang Basin to Artinskian age, probabaly the early part of the stage.

Superfamily Thalassoceratoidea Hyatt, Reference Hyatt1900

Family Thalassoceratidae Hyatt, Reference Hyatt1900

Genus Aristoceras Ruzhentsev, Reference Ruzhentsev1940b

1934 Uralites Reference VoinovaVoinova, p. 352 (nom. nud.) (non. Chernov, Reference Chernov1907, p. 292).

1937 Prothalassoceras; Reference Plummer and ScottPlummer and Scott, p. 352 (part).

1940a Eothalassoceras Reference Miller and FurnishMiller and Furnish, p. 105 (part).

Type species

Aristoceras chkalovi Ruzhentsev, Reference Ruzhentsev1940b; original designation; Orenburgian Stage, Carboniferous, South Urals.

Diagnosis

Conch discoidal, with narrow or closed umbilicus; venter flat, with ventrolateral grooves. Coarse sinuous growth lamellae forming deep ventral sinus and narrow ventrolateral salient. Constrictions may be present. Suture similar to Eothalassoceras.

Occurrence

Kasimovian through Asselian, Lower Permian; Russia and Kazakhstan (South Urals), Spain, USA (Oklahoma, Texas), and South China (Guangxi).

Remarks

Aristoceras is rather close to Eothalassoceras and Prothalassoceras in general conch shape and suture, but distinguished from the latter genera by the prominent ventrolateral double-grooves on each side of conch.

Aristoceras liuzhaiense new species

Figures 54.1, 54.2, 55.1, 55.2

Diagnosis

Thickly discoidal conch with broader prong of ventral lobe, ~1.5 times width of lateral lobe. Both lobes of approximately even but denticulated base.

Description

Shell thickly discoidal, involute; venter rounded; flanks relatively flattened. Umbilicus narrow and umbilical shoulder indefinite. Greatest width of whorls near umbilical shoulder (Table 15). Double-spiral grooves present at ventrolateral shoulder on each side of conch, obscurely diminutive one situated ventrally, obviously principal one situated laterally. Ornament on surface unknown. Suture lines closely spaced adorally. Venter lobe broader, subdivided by a high and wide secondary saddle. Prongs about one-third wider than lateral lobe, both denticulated with asymmetric serrations in lobe base.

Table 15 Dimensions and conch proportions of Aristoceras liuzhaiense n. sp. and Prothalassoceras biforme (Gerassimov, Reference Gerasimov1937). D, diameter of conch; W, width of conch; H, height of whorl; U, diameter of umbilicus.

Etymology

Name derived from the locality where the fossil was collected.

Materials

One specimen, NIGP 89008 (holotype).

Occurrence

Bed 11, 2nd Member, Nandan Formation, Zhuangli section (Sec. VI), Liuzhai, Nandan County, Guangxi.

Remarks

Among the five species of Aristoceras, A. liuzhaiense n. sp. most closely resembles A. appressum Ruzhentsev, Reference Ruzhentsev1950 in both conch shape and sutural features. However, the prong of the former is narrower, while the first lateral saddle is wider than that of the latter. Aristoceras liuzhaiense n. sp. is similar to A. serum Bogoslovskaia and Popov, Reference Bogoslovskaia and Popov1986 in conch shape, but the former has a much wider ventral lobe than that of the latter.

Genus Prothalassoceras Böse, Reference Böse1919

1927 Thalassoceras; Reference SmithSmith, p. 23 (part).

1940a Eothalassoceras Reference Miller and FurnishMiller and Furnish, p. 105 (part).

Type species

Prothalassoceras welleri Böse, Reference Böse1919; subsequent designation by Plummer and Scott, Reference Plummer and Scott1937; upper part of the Hueco Limestone Formation, Sakmarian–?Artinskian, west Texas, USA.

Diagnosis

Subdiscoidal to subglobular conch, with very narrow to closed umbilicus. Prongs of ventral lobe wider than lateral lobe. Denticulation of external lobes limited in lobe-base and lower part of flanks, never reaches to saddles.

Occurrence

Kasimovian through Kungurian; Russia and Kazakhstan (South Urals), Tajikistan (Pamirs), USA (Kansas, Nevada, New Mexico, Oklahoma, Texas), Canada (Yukon Territory), Indonesia (Timor), and South China (Guangxi).

Remarks

Prothalassoceras is characterized by wider prongs of the ventral lobe and a narrower lateral lobe, whereas Eothalassoceras and Thalassoceras are characterized by a narrower prong and wider lateral lobe. Additionally, dentition in Eothalassoceras is more primitive and restricted only in the lobe base, whereas in Thalassoceras dentition is much stronger and extensively distributed in both lobe base and flanks, even reaching to the saddle. Prothalassoceras resembles Aristoceras in both conch shape and suture, but differs from the latter by lacking ventrolateral groves.

Prothalassoceras biforme (Gerasimov, Reference Gerasimov1937)

Figures 54.3–54.6, 55.3, 55.4

1937 Thalassoceras biforme Reference GerasimovGerasimov, p. 17, pl. 1, fig. 8.

1938 Prothalassoceras biforme; Reference RuzhentsevRuzhentsev, p. 253, pl. 3, figs. 6–8.

1948 Prothalassoceras biforme var. latilobata Reference MaximovaMaximova, p. 25, pl. 3, figs. 3, 4, 15.

Description

Shell thickly discoidal and involute, with small umbilicus. Whorl-section nearly ellipsoidal in form, with strong depression in dorsum. Ornament unknown. Ventral lobe subdivided by a high, narrow secondary saddle. Prong much broader than lateral lobe. Secondary saddle and first lateral saddle nearly equal in both height and width. Secondary lateral saddle lower, broader, and rounded. Denticulation of lobes restricted in base of lobes and asymmetric in both prongs. Umbilical lobe unknown.

Materials

Two specimens, NIGP 93741 and 93742.

Occurrence

Bed 26, 3rd Member, Nandan Formation, Meyao section (Sec. V), Liuzhai, Nandan County, Guangxi.

Remarks

Specimens here resemble the holotype of the species in general characters of external suture (e.g., high ventral secondary saddle and similar width of lobes and saddles). However, the conch shape of the Urals specimens looks thinner than those of the present specimens (e.g., W/D 0.45 at conch diameter 26.8 mm in holotype 472/118 versus 0.58 at conch diameter 12.9 mm in NIGP 93741). Even if the difference really is present, it presumably is the result of ontogenetic development. The present specimens are actually similar to the Sakmarian P. umbilicatum Ruzhentsev, Reference Ruzhentsev1952 from Urals in general features of the suture; however, their thinner conch shape and narrower ventrolateral saddle are quite distinctive.

Order Ceratitida Hyatt, Reference Hyatt1900?

Suborder Otoceratitina Hyatt, Reference Hyatt1900?

Superfamily Otoceratoidea Hyatt, Reference Hyatt1900

Family Araxoceratidae Ruzhentsev, Reference Ruzhentsev1959

Genus Eoaraxoceras Spinosa, Furnish, and Glenister, Reference Spinosa, Furnish and Glenister1970

1944 Kingoceras Reference MillerMiller, p. 125 (part).

Type species

Eoaraxoceras ruzhentsevi Spinosa, Furnish, and Glenister, Reference Spinosa, Furnish and Glenister1970; original designation; upper La Colorada beds (Capitanian/Wuchiapingian), the Valle de Las Delicias, Coahuila, Mexico.

Diagnosis

Conch moderately to strongly evolute with anglar venter and pronounced umbilical flange. Suture has ten basic lobes, primitively serrated at base of first two external “lateral lobes.” Ventral and dorsal lobes bifid; a complex of incipient lobules crosses umbilical area.

Occurrence

Capitanian (e.g., the equivalent Wuchiapingian); Mexico (Coahuila), South China (southwest Guizhou), and possibly Iran (Abadeh).

Remarks

The definition of Eoaraxoceras was summarized once again by two of the original authors since it was first published by Spinosa, Furnish, and Glenister in 1970: “Ancestral araxoceratins with strongly evolute conch (U/D ranges from 0.2 to 0.45 at D 25–35 mm), broadly acuminate venter and pronounced umbilical flange. Sutures of mature and submature specimens comprise ten lobes; lobes serrate, except dorsal and ventral elements bifid” (Spinosa and Glenister, Reference Spinosa and Glenister2000, p. 400). However, it is important to emphasize that the primitive property of the sutural serration might even persist until the conch diameter is as large as 23 mm (holotype, SUI 32895) (Spinosa et al., Reference Spinosa, Furnish and Glenister1970).

According to the characterization mentioned above, there probably are only two species could be accepted as Eoaraxoceras, sensu stricto: the type species, E. ruzhentsevi Spinosa et al., Reference Spinosa, Furnish and Glenister1970 and E. spinosai n. sp., herein. The former was collected from the type locality, Coahuila, Mexico, and from Abadeh, Iran (the hypotype GSI 69 T 123, but not GSI 69 T 127; Spinosa and Glenister, Reference Spinosa and Glenister2000), while the latter is from the upper Shaiwa Formation, southwest Guizhou. As for the third one, E. robusta Spinosa and Glenister, Reference Spinosa and Glenister2000 from Abadeh, Iran, it is actually a questionable designation because of the indistinct or simply absent flange along the umbilical shoulder on the holotype GSI 69 T 120, and possibly on specimens GSI Ab-72174 and Ab-72158 (Bando, Reference Bando1979, pl. 2, figs. 3a, b, 6a, b).

Eoaraxoceras spinosai new species

Figures 56.1–56.10, 57.1–57.4

Diagnosis

Eoaraxoceras with relatively smaller umbilicus and stronger serration in lobe base.

Description

Conch diameter 20–25 mm, with fairly open umbilicus, U/D approximately 0.3 or a bit less. Conch flanks subparalell but concave, ventrolateral shoulder somewhat prominent, venter tectiform, umbilical shoulder conspicuously flanged; prorsiradiate rib-shaped nodes well developed in inner volutions, growth lines apparent in out volutions. Sutures possess a pair of narrow underrate prongs in venter, two intervening lobes with simple serration in flank, and three to five incipient elements developed on umbilical wall.

Etymology

Named in honor of Professor Claude Spinosa, Boise State University, USA.

Materials

10 specimens, including nine laterally compressed molds (NIGP 139945–139953) and one ventral mold (NIGP 139954), of which NIGP 139953 is assigned as holotype.

Occurrence

Bed 23, Claystone (3rd) Member, Shaiwa Formation, Sidazhai section (Sec. IV’-IV”), Ziyun County, Guizhou.

Remarks

Eoaraxoceras spinosai n. sp. resembles the type species of the genus in conch shape, sculpture, and general shape of suture, but differs from the latter by its smaller conch size, obviously smaller umbilicus, and stronger serration in lobes L and I.

Suborder Paraceltitina Shevyrev, Reference Shevrev1968

Superfamily Xenodiscoidea Frech, Reference Frech1902

Family Xenodiscidae Frech, Reference Frech1902

Genus Xenodiscus Waagen, Reference Waagen1879

1895 Xenaspis Reference WaagenWaagen, p. 161.

1903 Proceratites Reference KittleKittle, p. 28.

1940a Xenodiscites Reference Miller and FurnishMiller and Furnish, p. 74.

Type species

Ceratites carbonarius Waagen, Reference Waagen1872 ( Xenodiscus plicatus Waagen, Reference Waagen1879, subjective synonym, by Spinosa et al., Reference Spinosa, Furnish and Glenister1975), subsequent designation by Waagen, Reference Waagen1895; Chhidru Formation, latest Permian, Salt Range, Pakistan.

Diagnosis

Conch subdiscoidal and evolute. Whorls flattened laterally, slightly depressed dorsally, and rounded or slightly flattened ventrally. No prominent ornamentation on conch. Suture forms broad bifid ventral lobe, two pairs of lateral lobes, a pair of small lobes near umbilical seam, and a narrow bifid dorsal lobe. Lateral lobes and prolongs of lateral lobe denticulate, but denticules confined to base of lobes.

Occurrence

Capitanian/Wuchiapingian through Changhsingian/Chhidruan; Indonesia (Timor), Mexico (Coahuila), Pakistan (Salt Range), India (Himalayas), Madagascar, New Zealand, Japan (Kitakami), Central and Northwest Iran, Azerbaijan (Caucasus), North Thailand, and China (Xizang, Sichuan, Guangxi, and Guizhou).

Remarks

Xenodiscus, paraceltitins with a serrated lobe base, while absent the flange around umbilical shoulder, represent eurytopic forms of the Late Permian with a broad distribution.

? Xenodiscus sp.

Figure 56.11

Description

Only a single specimen, discoidal, rather evolution, W/D ~0.38. Suture with only a serrated lateral lobe preserved.

Materials

A compressed specimen, NIGP 139955.

Occurrence

Bed 23, Claystone (3rd) Member, Shaiwa Formation of Sidazhai section, Ziyun County, Guizhou.

Remarks

The present specimen with a wider umbilicus and more advanced evolution is easily distinguished from other ceratitid specimens studied herein. Inadequate knowledge of the sutural details and conch shape prevent precise identification of the specimen.