87Sr/86Sr chronostratigraphy is an important tool for dating and correlating vertebrate and invertebrate faunas preserved in marginal marine sequences. Freshwater flux in marginal marine environments can influence the 87Sr/86Sr of mollusks and, consequently, Sr-chronostratigraphic interpretations based upon them. To appraise the potential problem we have used a two-component mixing equation to evaluate levels of “measurable effects” (defined as ±5 × 10-5 departure from the marine 87Sr/86Sr ratio) in marginal marine environments. A measurable effect occurs at 12 parts per thousand salinity for a weighted world average river, but can occur at salinity > 34 ppt for rivers draining basins with ancient granitic rocks. Predictions were tested with analyses of mollusks from estuaries in the Mississippi Sound and coastal Florida. Analyses document the largely regular variation in 87Sr/86Sr predicted, but also show that a simple two-component model cannot account for all of the variation. Carbonates formed in restricted marine settings may not record a marine 87Sr/86Sr signal, emphasizing the need to consider freshwater flux for 87Sr/86Sr chronostratigraphy.

Integration of foraminiferal biostratigraphy, 87Sr/86Sr isotope stratigraphy, and traditional physical stratigraphy has provided a refined age control of a poorly known Oligocene-to-Pleistocene sedimentary sequence nonconformably covering the crystalline basement complex of the Calabrian microplate, a continental block which rifted off the southern margin of the European plate during Neogene time. In spite of the fossil-poor content of the sequence, the simultaneous use of paleontological and geochemical techniques have resulted in the following conclusions. 1) The age of an unnamed, thin calcarenite unit locally present at the base of the sequence, previously considered Rupelian to early Aquitanian in age, has been refined to Chattian (27.8–24.8 Ma). This calcarenite was considered a basal, conformable member of the overlying Stilo-Capo d'Orlando Formation. However, this study indicates that it is separated from the Stilo-Capo d'Orlando Formation either by an angular unconformity or by a disconformity representing a significant time interval. 2) The Stilo-Capo d'Orlando Formation has a latest Chattian–earliest Aquitanian to Burdigalian age. Previously published reports suggested deposition over a much longer time span, ranging from late Rupelian to Langhian. 3) An unnamed deep-marine siliciclastic unit mostly composed of conglomerate and sandstone and previously considered Tortonian in age is, in fact, Serravallian to Tortonian. 4) The depositional interval of the “trubi,” fine-grained marine deposits, has been independently confirmed to span the Pliocene-Pleistocene.

The results of this study provide a framework for future sequence–stratigraphic and paleotectonic studies in the area, and prove the effectiveness of an integrated paleontological and geochemical (87Sr/86Sr) approach in the study of fossil-poor sedimentary sequences.

The typical species of Parks' stromatoporoid genus Stictostroma designated as Stromatopora mammillata Nicholson, 1873, and renamed S. mamilliferum to avoid homonymy by Galloway and St. Jean (1957), had unknown internal structure because Nicholson's type specimens were not sectioned. Parks' (1936) diagnosis of generic characters was based on specimens from a location (Gorrie) far from the type locality of S. mammillata that he assumed were conspecific with Nicholson's species. Investigation of the type specimens of Stromatopora mammillata = Stictostroma mamilliferum by thin sections shows that they are very poorly preserved and not conspecific with the specimens on which Parks based the genus. Because paleontologists for many years have used Stictostroma as amended from Parks' description by Galloway and St. Jean, the species from Gorrie that clearly shows these characters should be recognized as the typical species and given a new name.

Two rhabdomesonid cryptostome bryozoans, Rhabdomeson progracile n. sp. and Rhabdomeson rhombiferum (Phillips, 1836), are described from the Lower Carboniferous of the British Isles. A revised familial diagnosis of Rhabdomesidae Vine, 1884, and a revised generic diagnosis of Rhabdomeson Young and Young, 1874, are presented. Taxonomic complications relating to the type species of the genus, which date from 1844, are discussed, and it is suggested that a new type species is required.

Two species of terebratulide brachiopods are described from the upper part of the Bateque Formation (middle Eocene) on the Pacific coast of Baja California Sur, Mexico, Terebratulina cf. Terebratulina louisianae Stenzel, 1940, and Terebratalia batequia n. sp. Terebratalia batequia n. sp. is the earliest confirmed record of the genus Terebratalia Beecher, 1893, which has been an important component of Pacific brachiopod faunas through to the present day. The occurrence of Terebratulina cf. Terebratulina louisianae Stenzel is one of the earliest records of the genus from the west coast of North America. These brachiopods, like other elements of the Bateque invertebrate fauna, may record Eocene migration from the Atlantic to Pacific Ocean via the Central American seaway.

The mollusk Hemithecella, which occurs abundantly both above and below the Cambrian-Ordovician boundary in the Ozark region of Missouri, is discussed and compared with Matthevia and with the polyplacophoran order Paleoloricata and found to be distinctly different. Based upon the presence of monoplacophoran-like multiple muscle scars and asymmetrical valves, Hemithecella and related forms described here are considered to be molluscan problematica. Hemithecellids are mollusks; however, their affinity to other classes is unclear although structural similarities to the Monoplacophora are noted. The new order Hemithecellitina is proposed. It contains two new families, the Hemithecellidae and the Robustidae. Three new genera, Conodia, Robustum, and Elongata, and nine new species are proposed: Conodia levicosta, C. acuminata, Robustum nodum, R. phallarium, Elongata perplexa, Hemithecella elongata, H. abrupta, H. quinquelites, and H. eminensis.

New discoveries of trigonioid bivalves are documented from three areas in the Antartic Peninsula: the Fossil Bluff Group of Alexander Island, the Latady Formation of the Orville Coast, and the Byers Group of Livingston Island, South Shetland Islands. Eleven taxa are described, representing six genera or subgenera. The faunas are characterized by genera including Vaugonia (Vaugonia), the first Early Jurassic trigonioid recognized on the continent; Vaugonia (V.) and V. (Orthotrigonia?) in the Late Jurassic; and Iotrigonia (Iotrigonia), Myophorella (Scaphogonia), and Pterotrigonia (Pterotrigonia), which span the Jurassic–Cretaceous boundary, reaching the Berriasian stage. The following species are new: Pterotrigonia (P.) cramei n. sp., Pterotrigonia (P.) thomsoni n. sp., Vaugonia (V.) orvillensis n. sp., and V. (Orthotrigonia?) quiltyi n. sp. The faunas show affinities with those of New Zealand and southern Africa. Trigonioids characterize the shallower marine biofacies in the Jurassic of the Antarctic and reflect the principal shallowing events in the history of the region.

Stirpulina saulae n. sp. is the first reported clavagellid from the Pacific Province of North America. Specimens of this clavagellid are from the Ladd Formation of the Santa Ana Mountains, Orange County, southern California. The age of these specimens is Late Turonian based upon the presence of the ammonite Subprionocyclus spp. both above and below the clavagellids in the section. These are, therefore, the oldest reported clavagellids from the western hemisphere, and they give positive support to the European Turonian reports of the genus Stirpulina. The deposits indicate an open-shelf habitat of shallow to moderate depth, and the associated fauna suggests a warm temperate to subtropical marine climate. This is consistent with the previously reported Cretaceous distribution for the group.

Previous studies of the Toarcian of the North American Cordillera have mentioned the rare occurrence of Paroniceras in the Queen Charlotte Islands. Recent work has identified the presence of Leukadiella in the Middle Toarcian of the Queen Charlotte Islands, the Spatsizi area, and the Hazelton area. They occur with Rarenodia planulata, Peronoceras pacificum, Peronoceras verticosum, and Phymatoceras cf. P. pseudoerbaense. The Leukadiella specimens are well preserved and generally larger than those found in the Mediterranean region. Taxa present in North America include Paroniceras sternale, Leukadiella ionica, Leukadiella amuratica, Leukadiella aff. L. helenae, and Leukadiella aff. L. ionica. Morphologically Leukadiella is closely related to such genera as Hildaites and Hildoceras and is more suitably placed within the subfamily Hildoceratinae rather than the Bouleiceratinae. The distribution of Leukadiella and Paroniceras indicates the influence of the Hispanic Corridor linking western Tethys and the eastern Pacific during the Middle Toarcian.

One of the most severe restrictions in taxonomic diversity of trilobites coincides with the Late Devonian “Hangenberg” Event, which is characterized by a pronounced eustatic low-stand. One of the survivors of this event is Pudoproetus, which, being adapted to shallow water conditions, experienced an opportunistic worldwide spread during this time. The oldest representatives of this genus are reported from the pre-Hangenberg Late Famennian of the Urals and Kazakhstan. Other known occurrences of this genus, midcontinent U.S.A., Utah, southern China, and southern France, occur at the Devonian-Carboniferous boundary, shortly after the Hangenberg event, and in the earliest Carboniferous. This pattern of distribution suggests that neither climatic nor geographic migration barriers existed around the Old Red landmass at that time. On the other hand, the Hangenberg crisis severely affected outer shelf benthic habitats, whereas nearshore trilobites were largely unaffected by the event.

A proetine origin of Pudoproetus, as originally proposed by Hessler (1963), is emphasized on the basis of paleoecologic, stratigraphic, and morphological arguments. In particular, the presence of ancestral features, such as the possession of 10 thoracic segments and lateral occipital lobes still occurring in early Pudoproetus species, points to a phylogenetic link with proetines rather than with phillipsiids. Within this group two new species are named: P. priscus and P. mediterraneus.

Exceptionally well preserved Lower Triassic conodonts from Oman include an array of Neospathodus species, many of which are new. Those from the upper Lower Triassic, or Spathian, are described in conjunction with a restudy of conodont type material from Chios, Greece, and an assessment of contemporary collections from Pakistan and western North America. The taxonomic scope of three key species from Chios, Neospathodus homeri, N. triangularis, and N. gondolelloides, is revised. Seven new species are described from Oman: N. abruptus, N. brevissimus, N. brochus, N. crassatus, N. curtatus, N. pusillus, and N. symmetricus; and one new species, N. clinatus, is described from Pakistan. The allied Icriospathodus collinsoni is also described from Oman. The occurrence and range of Neospathodus species are presented in the context of the ammonoid succession in the Spathian of North America. Both N. homeri and N. triangularis, as revised, have shorter ranges and are more age diagnostic than previously thought. Neospathodus gondolelloides is a distinct taxon, and not synonymous with Chiosella timorensis. Five informal faunal divisions are identified based on Neospathodus and allied species. In ascending stratigraphic order, these are typified by Icriospathodus collinsoni, Neospathodus homeri, N. triangularis, N. symmetricus, and N. gondolelloides. Oman collections represent three of these faunas, which occur also in the Columbites through Prohungarites/Subcolumbites ammonoid beds of western U.S.A.

An incomplete skull of a small sphenodontian lepidosaur from the upper part of the Stormberg Group of southern Africa is referable to Clevosaurus Swinton, 1939. It is most closely related to C. bairdi from the McCoy Brook Formation (Lower Jurassic) of Nova Scotia (Canada) and C. mcgilli from the Dark Red Beds of the Lower Lufeng Formation (Lower Jurassic) of Yunnan (China). The new specimen is important because it represents the first record of Clevosaurus from the Southern Hemisphere. Like many other taxa of Early Jurassic continental tetrapods (crocodylomorph archosaurs, dinosaurs, synapsids), Clevosaurus had an apparently Pangaean distribution.

Yarala burchfieldi n. gen. and sp. is described from Oligo-Miocene deposits of Riversleigh Station, northwestern Queensland. Although the smallest and most plesiomorphic bandicoot known, it shares unique synapomorphies with other peramelemorphs, such as the posteriorly orientated preparacrista on M2, posterolingual location of the hypoconulids, and the buccal position of the centrocrista. However, Y. burchfieldi lacks synapomorphies that would unambiguously allow it to be placed in any of the modern families as currently understood. In its plesiomorphic features, Y. burchfieldi provides a structural link between peramelemorphs and dasyuromorphs and appears to be a descendant of an annectant group that separated long prior to the origin of “typical” bandicoots. This species is present in many sites within the Riversleigh area. It possibly filled an insectivorous-carnivorous niche presently occupied by small dasyurids that are relatively more abundant today than they were when the Riversleigh deposits accumulated.

The concept of “land-mammal age” as developed in South America is examined. The “Uquian Land-mammal age” is used as a study case. “Land-mammal age” parataxonomy is here considered methodologically but not conceptually different from chronostratigraphic taxonomy. “Land-mammal ages” in South America are based on stages. However, we consider that accurate biostratigraphic studies must be done in South America for establishing the biostratigraphy and precise boundary stratotypes of most stages-ages. The Uquia outcrops are here considered inadequate as a stratotype. A new South American continental stage-age is proposed. This stage is based on a biostratigraphic scheme. The stratotypes of the stage and biozones are located in the fossiliferous southeastern Buenos Aires Province marine cliffs. The lower boundary stratotype is proposed. The stage-age is probably correlated with the Gauss Chron and the lower Matuyama Chron. Additionally, some major units of Ameghino are validated and a different timing for the arrival of North American mammals to southern South America is presented.

Alluvial fan and braided fluvial redbeds of the Triassic Lepreau Formation of southern New Brunswick, eastern Canada, contain a moderately diverse and abundant invertebrate ichnofauna. Fourteen formal ichnotaxa are recognized: Ancorichnus coronus, Ancorichnus cf. A. ancorichnus, Aulichnites isp., Cruziana problematica, Fuersichnus isp., Gordia marina, Palaeophycus striatus, Palaeophycus isp., Planolites isp., Rusophycus isp., Skolithos linearis, cf. Skolithos isp., and Taenidium isp. Two vernacular ichnotaxa, “inclined meniscate burrows” and “surface pit structures,” also occur. All these ichnotaxa are figured and briefly described. Collectively, the entire assemblage can confidently be assigned to the Scoyenia ichnofacies that, in the Lepreau Formation, represents a fluvial channel ichnocoenose.

Specimens have been subject to marked taphonomic effects due to weathering and preservation in lithologies showing either insufficient variation in grain size or a grain size too coarse to preserve subtle morphological variations; as a consequence, ichno-taxobases are commonly obscured or obliterated. This may have influenced the apparent diversity of the assemblage, especially with regard to meniscate and simple horizontal burrows. It is proposed that application of “taphoseries,” theoretical series including ichnotaxa that may potentially be mistaken for each other with increasing taphonomic overprint, provides a safeguard against ichnotaxonomic misidentifications.

Small holes of irregular outline and mainly 0.2 to 1.5 mm in diameter are present in the exteriors of molluscan shells obtained from the latest Quaternary transgressive sequence on the Orange Shelf, Benguela region, off southwestern Africa. In shell interiors, the shell surrounding the holes is broken out to form flaring, conical spalls. The holes are clearly not borings, but are punctures caused by a small, pointed object having been forcefully driven into the shell. The holes in bivalves occur preferentially in small, thin-shelled tellinids and are nonrandomly placed in the central portions of valves. It is proposed that the holes are praedichnia produced by the rapid, ballistic-like raptorial strikes of spearing stomatopods, the pointed dactyl tips having penetrated the shells. Associated evidence of shell smashing, consisting of large holes in valves and gastropod whorls, supports the suggestion of stomatopod activity. The only stomatopod that inhabits the Benguela ecosystem, the spearer Pterygosquilla armata capensis Manning, 1969, is the probable tracemaker. Although shell nearly 1 mm thick has been pierced, the apparent selection of thin-shelled tellinids (0.14 to 0.34 mm thick) may reflect the requirement of shelling smashing in order to access the tissues. Nevertheless, the spearing of shelled prey is atypical for stomatopods and therefore confirmatory zoological observations are required, particularly to clarify the context of shell spearing. The ichnogenus Belichnus is proposed to accommodate these unique traces of pointed impacts, with ichnospecies B. monos (single punctures) and B. dusos (combined punctures) to accommodate the main morphological varieties observed.

Upper cretaceous strata of the U. S. Gulf Coastal Plain are rich in species and numbers of Exogyra, which occurs in a wide range of facies including siliciclastics, marls, and chalks. Specimens of Exogyra belonging to numerous well-defined species are also common to abundant locally in Upper Cretaceous siliciclastic rocks at many localities within the U. S. Western Interior, but the genus is exceedingly sparse in marly and chalky rocks of the same region. Intensive collecting in the chalky outcrops of western Kansas has yielded only two specimens of Exogyra, which are notable not only for good shell preservation but also for uniqueness of their respective occurrence. One of these specimens was collected from the Smoky Hill Chalk Member, Niobrara Chalk (Figure 1), and the other was collected from the Fairport Member, Carlile Shale (Figure 1). Principal paleontological works that treat the Niobrara fauna, especially including those of Meek (1876), Stanton (1893), Logan (1898), Scott and Cobban (1964), Miller (1968), and Hattin (1982), make no mention of the genus in that formation. Hattin (1962) documented a lone occurrence of Exogyra in the Fairport Member of Kansas, and sparse occurrence of E. cf. E. suborbiculata Lamarck in the Fairport was recorded by Kauffman (1961), whose material was collected in Huerfano Park, Colorado, where the member is calcareous or marly shale. Stratigraphic occurrence of the two Kansas specimens is presented in Figure 1, which also depicts ranges of other Exogyra species that have been recorded in the Upper Cretaceous of western Kansas.