Here we report and describe a new assemblage of Thylacocephala (Crustacea) from the late Spathian (Early Triassic) of Chaohu, Anhui Province, South China. The assemblage consists of at least three species from different genera: the small-sized Microcaris rectilineatus n. sp. appears the most abundant, while the large-sized Ankitokazocaris sp. and Diplacanthocaris chaohuensis n. gen. n. sp. are rare. A morphometric analysis of the carapace outline separates Diplacanthocaris chaohuensis n. gen. n. sp. from other genera. Along with Ankitokazocaris chaohuensis Ji et al., 2017 and Kitakamicaris sp. from the horizon 28 m above this assemblage, four different genera of Thylacocephala occur in the Chaohu Fauna. With additional materials reported from Japan and North America, the Early Triassic is now known as the period when Thylacocephala reached their highest diversity and widest geographical distribution. Thylacocephala quickly diversified shortly after the Permian–Triassic mass extinction, probably because of their ability to survive in a relatively low-oxygen environment. Thylacocephalan fossils from Chaohu are found in dense concentrations, suggesting they might have constituted a food source for the fishes and marine reptiles in the Chaohu Fauna.

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Most Cambrian Series 2 faunas of Laurentia are dominated by olenelline trilobites; however, non-olenelline trilobites occur with the olenellines and sometimes dominate the assemblages. Reported here are such non-olenelline trilobites from the Harkless Formation and Mule Spring Limestone at Clayton Ridge, Nevada. At the bottom of the Saline Valley Tongue, Harkless Formation, are two assemblages that are characterized by corynexochines and/or ptychoparioids, with olenellines occurring as only rare components. The corynexochines present in these assemblages include Bonnia cf. B. brennus (Walcott, 1916), Ovatoryctocara cf. O. yaxiensis Yuan et al., 2009, Protoryctocephalus? aff. P.? arcticus Geyer and Peel, 2011, Ogygopsis sp. indet., and Oryctocephalops frischenfeldi Lermontova, 1940. These assemblages are from the mid-Dyeran Stage, below the lowermost zone in the upper Dyeran (Arcuolenellus arcuatus Biozone), and can be correlated to Series 2 Stage 4 (Cambrian) assemblages in Greenland, Siberia, and South China based on the corynexochines.

Also in the Saline Valley Tongue and the overlying Mule Spring Limestone and lowermost Emigrant Formation are olenelloid-dominated assemblages that contain the corynexochines Bonnia columbensis Resser, 1936, Zacanthopsis aff. Z. levis (Walcott, 1886), and Z. sp. indet.

A new Saldidae (MCT 6959-I) from the Crato Formation (Lower Cretaceous, late Aptian), Santana Group, Araripe Basin (northeastern Brazil) is described and illustrated. Olindasalda gondwanica n. gen. n. sp. is the first fossil Saldidae recorded from the Gondwanan supercontinent. The new genus can be distinguished from other members of the subfamily Chiloxanthinae by its small (4.49 mm) and oval-elongated body, absence of spots on the corium of the hemelytron, long R vein, and much-reduced first cell of the membrane. Remarks on the geology of the type locality and a comparison of the new genus with other saldids are provided.

UUID: http://zoobank.org/5ef8db72-3d7c-4de0-9a7c-e8fd80a9c8ba

A variety of pits representing symbiotic embedments, sometimes associated with pathological deformation in the host, are known from the skeletons of Paleozoic stalked echinoderms. These structures are well known from multiple genera of crinoids and a limited number of blastozoans but have not previously been described in detail from the skeletons of rhombiferans. This is surprising given the abundance of rhombiferans in certain deposits, the co-occurrence of rhombiferans with frequently infested taxa, including diploporitans, in multiple assemblages, and the morphological similarity between certain rhombiferan taxa and coeval infested crinoids. The common hemicosmitid rhombiferan Caryocrinites Say, 1825 is widespread throughout the middle Silurian of eastern North America and is herein reported to contain symbiotic (potentially parasitic) embedment structures. Specimens were collected from the lower portion of the mudstone lithofacies of the Massie Formation (Wenlock, Sheinwoodian) at the Napoleon quarry of southeastern Indiana, USA. Strong host specificity is indicated by the absence of pits in C. ornatus Say, 1825 and exclusive infestation of a smaller co-occurring species of Caryocrinites. Thecae with embedment structures are consistently smaller than thecae without such structures, with pitted specimens being restricted to a narrow range of thecal heights (20–24 mm). All embedment structures are present only on the proximal portion of thecae, with individual specimens containing between one and 30 pits. No elevated rims or significant swelling were observed on any specimens, and all pits are relatively small (~1 mm in diameter). The presence of symbiotic embedment structures represents an additional example of a crinoid-like aspect to the ecology of Caryocrinites.

Five land snails and the borings of marine bivalves are reported from Hkamti (Khamti) amber whose age was recently uranium-lead dated to be ca. 110 Ma, in contrast to the nearby Kachin (‘Burmese’) amber considered to be ca. 99 Ma. Four of the snails belong to Cyclophoridae, and although their condition does not allow unambiguous identification or description of the species, one of them strongly resembles Archaeocyclotus plicatula Asato and Hirano in Hirano et al., 2019 from Kachin amber. The fifth snail, Euthema myanmarica n. sp. (Diplommatinidae), is a representative of a genus that was known exclusively from Kachin amber until now. The genus Euthema Yu, Wang, and Pan, 2018 is revised, with a new synonym, Xenostoma Bullis et al., 2020. The recently described ‘Truncatellina dilatatus’ Yu, 2020 from Kachin amber is placed in Euthema. A comparison of the distinguishing characters of the eight Euthema species is provided. The borings of bivalves in Hkamti amber correspond to the ichnospecies Teredolites clavatus Leymerie, 1842, associated with the bivalve genus Martesia Sowerby, 1824 (Pholadidae), and are common in Kachin amber. Similarity of the malacofauna from Hkamti and Kachin ambers, as well as the presence of numerous, similar Teredolites clavatus, indicates that these ambers were formed in very similar paleoenvironments. This indication suggests that forests with very similar conditions existed throughout the entire Albian to the early Cenomanian, or that the dating of at least one of these amber deposits is incorrect. In the latter case, it would mean that Kachin amber is at least 110 Ma or older.

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A single specimen of Oriostoma globosum (von Schlotheim, 1820) from the Silurian-age (Wenlockian) Laurel Limestone in southeastern Indiana preserves a partial, multispiral operculum in situ within the aperture. Only eight specimens of in situ Oriostoma opercula have previously been illustrated from Canada and Europe, and this is the first from the United States. Oriostoma huntingtonensis Kindle, 1904, from younger Silurian (Ludlovian–Pridolian) strata in northern Indiana is considered a synonym of the more widespread O. globosum, and it was described as having associated loose multispiral calcareous opercula in the same strata.

Abundant articulated specimens of the oryctocarine trilobite Oryctocarella duyunensis from the lower Cambrian (Stage 4, Series 2) Balang Formation at the Bulin section in western Hunan Province, South China, permit the description of all meraspid degrees. The maximum number of thoracic segments observed in this collection is 11. Meraspid growth was accompanied by progressive and gradual change in overall form, and this animal showed an homonymously segmented trunk with variation in the number of pygidial segments during ontogeny. Such variation permits a variety of plausible explanations, but a model of successive instars defined by the number of thoracic segments, and in suborder by the number of pygidial segments, is highly unlikely to explain the growth pattern because it would result in the loss of trunk segments between some instars. Degree-based ontogenetic staging is compatible with the variation observed.

Permian millipedes are rare, especially so considering the relative abundance of millipedes in Carboniferous rocks. We report an early Permian millipede fauna containing three new genera and species of millipedes (Oklahomasoma richardsspurense new genus new species, Karstiulus fortsillensis new genus new species, and Dolesea subtila new genus new species) found in fossil-producing pockets of the Fort Sill fissures exposed in the Dolese Quarry near Richards Spur, southwest Oklahoma, USA. These are the first new genera of invertebrates to be described from this site, one of the most prolific fossil-vertebrate sites in the world. We also comment on taxa with morphological similarities and note previously described occurrences of Permian millipedes as well as occurrences of fossil myriapods (millipedes and centipedes) in karst deposits (caves and fissure fills) in Europe, Africa, Asia, North America, and the Caribbean. In contrast with the forms found at Richards Spur, most of these previous accounts of millipedes found in caves and fissure fills are of Pleistocene forms that are closely allied to modern taxa. The taxa from Richards Spur bear some similarities to Pennsylvanian forms. Karst (cave and fissure) faunas should be ranked with concretion faunas, cannel coals, and amber faunas as a major source of fossil myriapods.

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Two new families and three new genera and species of Crinoidea from the Icla and Belén formations, Bolivian Devonian, are described. The material is identified as Meperocrinus angelina n. gen. n. sp., from the Icla Formation of the Sub-Andina region, Tuberocrinus lapazensis n. gen. n. sp. and Aenigmaticumcrinus rochacamposi n. gen. n. sp., both from the Belén Formation of the Bolivian Altiplano. Meperocrinus angelina n. gen. n. sp. is an Emperocrinidae, a family described from the Silurian of the United States of America. Tuberocrinus lapazensis n. gen. n. sp. is assigned to a new family of Dimerocrinitacea, the Tuberocrinidae n. fam., which is closely related to Pterinocrinidae that already has representatives in Bolivia (Apurocrinus sucrei McIntosh), Argentina (Pterinocrinus? australis Haude), and Colombia (Bogotacrinus scheibei McIntosh). Aenigmaticumcrinus rochacamposi n. gen. n. sp. is also as assigned to a new family of Dimerocrinitacea, the Aenigmaticumcrinidae n. fam.; a family with very distinctive features. These data demonstrate that the Malvinokaffric crinoid fauna in Bolivia has a mixed origin, with forms that arrived in South America from Europe (Old World Realm) and United States of America (Eastern America Realm) during the late Silurian or earliest Devonian, as well as a local stock, which evolved to highly endemic lineages.

UUID: http://zoobank.org/f03120c6-264a-4ae9-81e0-46bfe844e65e.

The genus Amaltheus, one of the representative late Pliensbachian ammonoids, has biostratigraphic and paleobiogeographic significance in Japan. Four species, Amaltheus stokesi (Sowerby, 1818), A. margaritatus de Montfort, 1808, A. repressus Dagis, 1976, and A. orientalis new species, have been found in the Kuruma Group in central Japan; A. stokesi and A. margaritatus are also from the Toyora Group in southwest Japan. On the basis of taxonomic analysis of the genus Amaltheus, we distinguish two successive ammonoid biozones in the lower part of the Teradani Formation of the Kuruma Group: the Amaltheus stokesi–Amaltheus repressus and the Amaltheus margaritatus assemblage zones, in stratigraphic ascending order. This study also establishes the presence of the Amaltheus stokesi Assemblage Zone in the Higashinagano Formation of the Toyora Group. The stokesi–repressus and the stokesi assemblage zones correspond biostratigraphically to the Amaltheus stokesi Standard Subzone of the margaritatus Zone. The margaritatus Assemblage Zone is correlated with the Amaltheus subnodosus and Amaltheus gibbosus standard subzones. The Japanese early–middle late Pliensbachian ammonoid faunas are composed almost entirely of pan-Boreal and Arctic species of the genus Amaltheus. This faunal composition has an affinity with that of the Northeast Russian region, and thus suggests a strong paleobiogeographic relationship between East Asian and Northeast Russian faunas throughout this time interval.

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New parasitoid wasps of the family Braconidae are documented from Eocene Baltic and Rovno ambers. A new fossil genus belonging to the braconid subfamily Exothecinae, Palaeocolastes n. gen., with its type species P. bruesi n. sp., is described and illustrated from Baltic amber. This represents the first reliable fossil record for a member of Exothecinae. Two additional new species from Baltic amber are also described: Ascogaster (Syntaphus) latitibialis n. sp. (Cheloninae) and Meteorus arasnitsyni n. sp. (Euphorinae). Another fossil species, Microtypus eocenus n. sp. (Microtypinae), is described from coeval Rovno amber (Ukraine), representing the first braconid species described from this deposit. A new record of a female of Diospilites brevicornis Brues, 1933 (Diospilitinae) from Baltic amber, together with variation of some diagnostic features of the species and redescription of its subfamily and genus, are also provided.

UUID: http://zoobank.org/656cb1a3-b9cf-4696-ae24-0d4df9545101.

Twelve specimens of Eumorphocystis Branson and Peck, 1940 provide the basis for new findings and a more informed assessment of whether this blastozoan (a group including eocrinoids, blastoids, diploporites, rhombiferans) constitutes the sister taxon to crinoids, as has been recently proposed. Both Eumorphocystis and earliest-known crinoid feeding appendages express longitudinal canals, a demonstrable trait exclusive to these taxa. However, the specimen series studied here shows that Eumorphocystis canals constrict proximally and travel within ambulacrals above the thecal cavity. This relationship is congruent with a documented blastozoan pattern but very unlike earliest crinoid topology. Earliest crinoid arm cavities lie fully beneath floor plates; these expand and merge directly with the main thecal coelomic cavity at thecal shoulders. Other associated anatomical features echo this contrasting comparison. Feeding appendages of Eumorphocystis lack two-tiered cover plates, podial basins/pores, and lateral arm plating, all features of earliest crinoid ‘true arms.’ Eumorphocystis feeding appendages are buttressed by solid block-like plates added during ontogeny at a generative zone below floor plates, a pattern with no known parallel among crinoids. Eumorphocystis feeding appendages express brachioles, erect extensions of floor plates, also unknown among crinoids. These several distinctions point to nonhomology of most feeding appendage anatomy, including longitudinal canals, removing Eumorphocystis and other blastozoans from exclusive relationship with crinoids. Eumorphocystis further differs from crinoids in that thecal plates express diplopores, respiratory structures not present among crinoids, but ubiquitous among certain groups of blastozoans. Phylogenetic analysis places Eumorphocystis as a crownward blastozoan, far removed from crinoids.

The Mesozoic mecopteran family Mesopsychidae has attracted extensive attention by their long proboscis that is presumably associated with pollination of early gymnosperms. Three previously reported species of Lichnomesopsyche Ren, Labandeira, and Shih, 2010 from the Middle−Upper Jurassic Haifanggou Formation at Daohugou (Inner Mongolia, northeastern China) display distinct resemblances in wing venation, so that their classification, based on currently described characters, remains elusive. Herein, we describe and figure exquisitely preserved male genital structures of L. gloriae Ren, Labandeira, and Shih, 2010, L. daohugouensis Ren, Labandeira, and Shih, 2010, and L. prochorista Lin et al., 2016, which can be used for defining and recognizing the three species. Our discovery indicates that the male genitalia are the major critical structures for species-level classification of the peculiar genus Lichnomesopsyche. Details of the maxillary palps and legs of L. gloriae and L. daohugouensis are also described.

A new taxon of sphenodontian reptile, Micromenodon pitti new genus new species is described from the Upper Triassic (Carnian) Vinita Formation of the Richmond basin of the Newark Supergroup in Virginia. It is diagnosed by a dorsoventrally deep facial process of the maxilla that extends for almost the entire anteroposterior length of the bone and by obtusely conical, strongly ribbed additional teeth in the maxilla that comprise a greatly enlarged tooth followed by smaller teeth posteriorly. Phylogenetic analysis found Micromenodon pitti n. gen. n. sp. as an early-diverging sphenodontian with fully acrodont tooth implantation. The maxillary dentition appears functionally suited for processing hard arthropod exoskeletons and snail shells.

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The youngest species of Amphoracrinus, A. tenax new species, is described from the Muldraugh Member of the Borden Formation (early Viséan) of north-central Kentucky. With this new occurrence, both the oldest and youngest named species of Amphoracrinus are from North America. Numerous Tournaisian and Viséan crinoid faunas are documented in the United States, but only four are known to contain Amphoracrinus. Morphological analysis indicates that A. tenax is more closely aligned with species from China than with species from Western Europe or other species from North America, where Amphoracrinus was most diverse and abundant, which has implications for understanding paleogeographic dispersal. The holotype of A. tenax was partially disarticulated on the seafloor before burial, and final burial occurred early during disarticulation. The relative state of disarticulation from pinnules to columnals suggests that plates bound only with ligaments disarticulated as a function of surface area of ligaments binding an articulation.

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The Early Ordovician (late Tremadocian; Stairsian) trilobite Gonioteloides Kobayashi has long been known from a small number of pygidia assigned to a single formally named species, and its affinities have not been assessed. Silicified material from western Utah and southeastern Idaho includes six distinct species assigned to the genus, one of which is the type species. Two others (G. moffitti and G. pankowskii) are new and formally named. An additional three species that are clearly new but known from sparse material are described in open nomenclature. Gonioteloides has a stratigraphic distribution through five consecutive trilobite zones in the mid-Stairsian Stage (upper Tremadocian). Although exoskeletal morphology of three species is almost completely known, the phylogenetic affinity of the taxon remains difficult to determine. It is tentatively assigned to Dimeropygidae Hupé.

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A new fossil ricinuleid, Curculioides bohemondi n. sp., from the Pennsylvanian Energy Shale of Illinois is described from a single specimen. It is the largest ricinuleid species yet described, living or extinct. The Energy Shale represents a new geographic locale for fossil ricinuleids, a sparsely distributed group. The species is distinguished from other members within the genus by the possession of very large (0.09 mm) carapace tubercles at a very low (30 mm-2) density. Statistical analyses are performed on extant and fossil ricinuleids to determine how their tubercles change throughout ontogeny, culminating in the recovery of a new ontogenetically stable diagnostic character: the tubercle coefficient (a measure of the size of the tubercles relative to body size).

UUID: http://zoobank.org/aa9f2de5-c49d-4f70-bba5-db12fdee406f.

Restudy of Proexenocrinus inyoensis Strimple and McGinnis, 1972, shows that this earliest-known rhodocrinitid diplobathrid camerate crinoid (late Floian, Early Ordovician) expresses the only known record of ambulacral floor plates within pinnules. These pinnule floor plates are remarkably conserved plesiomorphic expressions, with anatomy similar to floor plates of some of the earliest pentaradiate echinoderms, although on a smaller scale. Proexenocrinus floor plates provide direct skeletal evidence that the general resemblance of blastozoan (eocrinoid, diploporan, rhombiferan) brachioles and crinoid pinnules is the product of homoplasy. Proexenocrinus posterior cup morphology is interpreted to include an anitaxis, a distinctive posterior interray morphology.

The late Silurian Arceoaster hintei new genus new species (Asteroidea, Echinodermata) is based on a single complete specimen from the lower Hunton Group of southern Oklahoma. Overall ossicular arrangement enables assignment of the new genus to the Paleozoic stem-family Hudsonasteridae; however, Arceoaster n. gen. is homeomorphic with members of the post-Paleozoic crown-group Goniasteridae. Because Arceoaster n. gen. is a hudsonasterid, and because similar morphologic expressions are not known among described taxa from later in the Paleozoic or the early Mesozoic, similarities between Arceoaster n. gen. and later genera are homoplastic, thereby providing an example of iterative evolution within Asteroidea. The Arceoaster n. gen. specimen is associated with a rich and diverse invertebrate fauna typical of its time interval and environmental setting; nothing suggests an unusual habitat. Selective pressures leading to homoplasy are conjectural, although robust construction among extant asteroids has been associated with a defensive life strategy.

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Larvae of sea urchins, brittle stars, and allies are common, ecologically important, and diverse members of marine ecosystems in all of the world's oceans today. In contrast to modern representatives, the fossil record of echinoderm larvae is poorly known. This study reports the first ophiopluteus skeleton from Cretaceous sediments worldwide, obtained from chalky sediment of the Isle of Wolin, NW Poland. The evidence presented here, that it is possible to isolate fossil echinoderm larval skeletons from rocks, indicates a hidden diversity of such fragile fossils and thus the possibility of direct geological recording.