We describe Swauka ypresiana n. gen. n. sp., the second fossil gossamerwing damselfly (Odonata, Zygoptera, Epallagidae, Epallaginae) and its oldest occurrence. It is the first fossil insect reported from the Swauk Formation of central Washington State, U.S.A. It was recovered from the “Sandstone facies of Swauk Pass,” a fluvial unit, immediately below the Silver Pass Volcanic Member of the Swauk Formation, which has a U–Pb zircon CA-ID-TIMS age of 51.364 ± 0.029 Ma. The host deposits probably represent mud-dominated floodplain lake or oxbow lake environments.

UUID: http://zoobank.org/20167852-bcbc-4f8b-b372-dffa591abd6a

The free-living, stalkless comatulids make up the bulk of living crinoid diversity and are the only crinoids remaining in shallow water, but compared to the stalked crinoids their fossil record is fragmentary and understudied, especially outside Europe. We present new Albian fossil comatulids from the Glen Rose Formation, central Texas, and study them using computed tomography, scanning electron microscopy, morphometry, and cladistic analysis of discrete and continuous characters. New material comprises the previously described Decameros wertheimi and Semiometra klari? and the new taxa Semiometra alveoradiata n. sp. and an extremely unusual new form Castaneametra hodgesi n. gen. n. sp. In addition to being exceptionally variable, this species is the largest known comatulid, has the most cirri of any known comatulid, and exhibits unique architectural features and voluminous, through-going coelomic cavities. We reconstruct its paleobiology, infer its phylogenetic affinities, argue for its origin from small Semiometra-like ancestors in a brief Albian North American radiation, and suggest new interpretations of early comatulid phylogeny based on our findings. Adaptive allometry related to respiratory demands, along with an origin by peramorphosis, may explain some features of this odd, short-lived giant.

A late Eocene (Priabonian) decapod crustacean (Arthropoda: Malacostraca: Decapoda) faunule from the sandstones and siltstones of the Tomášovce Member (Borové Formation) of northern Slovakia (Western Carpathians) is presented. Several decades of collecting at the Ďurkovec quarry in the Spišská Nová Ves district, the stratotype locality of the Tomášovce Member, yielded four decapod species, including an axiidean shrimp Ctenocheles sp. indet. (Ctenochelidae), and three brachyuran crabs Amphoranina hazslinszkyi (Reuss, 1859) new combination (Raninidae), Calappilia tridentata (Beurlen, 1939) (Calappidae), and Coeloma vigil A. Milne-Edwards, 1865 (Polybiidae). The faunule is dominated by A. hazslinszkyi and Coeloma vigil. The specimens often represent more-or-less intact individuals with preserved claws and walking legs, suggesting rapid burial and minimal to no postmortem transport. Additionally, specimens of A. hazslinszkyi are in some cases preserved perpendicularly to the bedding planes and interpreted as being covered by large amount of sediment while being buried in the substrate, causing death of the animals. The presence of trace fossils assigned to Thalassinoides Ehrenberg, 1944 are indirectly linked with the burrowing shrimp Ctenocheles sp. indet. The decapod faunule inhabited a shallow marine environment with the depth likely not exceeding 100 m.

Xiphosuran chelicerates, also known as horseshoe crabs, are a long-lived clade characterized by a highly distinctive morphology and are a classic example of supposed evolutionary stasis. One key feature of horseshoe crabs is the fusion of the opisthosomal segments into a single sclerite referred to as a thoracetron. There has been historical uncertainty as to whether the thoracetron originated once or multiple times within the clade. Here we review criteria for determining whether segments are fused and apply them to a broad census of taxa for which their ontogeny is known or the adult status of specimens can be reasonably asserted to explore the evolution of the thoracetron within a developmental framework. Our findings indicate that the thoracetron evolved once in the common ancestor to Xiphosura. However, subsequent independent loss of the thoracetron segment boundaries is identified and shown to be the result of heterochronic processes acting on a shared developmental pathway. The multiple cases of effacement of the thoracetron within Limuloidea are cases of peramorphically driven parallelism, while the effacement of the thoracetron in the pedomorphic Belinurina is a case of convergence. Xiphosurids therefore represent an interesting case study for recognizing parallelism and convergence on the same structure within closely related lineages. We also demonstrate that somite VII has been incorporated into the prosoma multiple times within the chelicerate lineage, which has implications for interpreting the ground pattern of the group.

Today, the range of the genus Euthria encompasses the Mediterranean and the eastern Atlantic, the region around southern Africa, and extends into the western Indo-Pacific. The genus, which has a geological history dating back to the Eocene of Europe, has recently undergone taxonomic revision in several European Neogene basins. These studies revealed a pronounced expansion during the Oligocene and Neogene in the Atlanto-Mediterranean region and the Paratethys, and these studies highlighted the overall diversity of the genus combined with a pronounced regional endemism. This paper reviews the fossil record of the genus in the western Iberian Pliocene of the Cainozoic Mondego Basin of Portugal. Two new species endemic to western Iberia with protoconchs showing non-planktotrophic developmental traits have emerged: Euthria galopimi n. sp. and Euthria lockleyi n. sp. These results reinforce the glocal character of Euthria, a genus that is both widespread and diversified, but simultaneously showing a high endemism. The contribution of nonplanktotrophic development to this scenario is discussed. Although well represented in the fossil record of Atlantic France, in present-day European waters, Euthria is represented by a single species, E. cornea (Linnaeus, 1758), and only in the Mediterranean and the northern shores of the Gulf of Cadiz. As with other warm-water molluscan taxa, the northern distribution limit of Euthria in the Atlantic has shifted southward since the Early to mid-Pliocene due to global cooling events and decreasing sea surface temperatures.

http://zoobank.org/2A64f041-8e17-491e-8782-a31a9c5dfd57

From re-examination of the type and additional specimens of Munida nishioi Karasawa, 1993 and Kazuoia ogaensis Hatai and Kotaka, 1970 from the Miocene deposits of Japan, both species are assigned to Grimothea Leach, 1821 [1820] of the squat lobster family Munididae Ahyong et al., 2010. The revised diagnosis and description are given for Grimothea nishioi (Karasawa, 1993) new combination and Grimothea ogaensis (Hatai and Kotaka, 1970) new combination. The monotypic genus Kazuoia Hatai and Kotaka, 1970 becomes a junior subjective synonym of Grimothea. Trapezionida chiyoensis new species is described from the lower Miocene of central Japan. These species represent the first records of Grimothea and Trapezionida Macpherson and Baba in Machordom et al., 2022 recognized as fossils.

UUID: http://zoobank.org/5917b8a9-2c16-443f-a64f-964cb78fce16

A new genus is established for species of late Paleozoic pterioid bivalves that have substantial ontogenetic change in hinge characters during growth. Juvenile shells have small cardinal and posterior lateral teeth on the hinge that are overgrown on the adult shell and the hinge become edentulous. The shell has a wide ligament plate with a clinovincular ligament (new term). Adjacent to the cardinal teeth on juvenile shell, ligament sheets tend to have small, low amplitude folding and wavy alignment of ligament grooves. A new genus and species, Willipteria nestelli, is described and the species Leptodesma falcata Boyd and Newell, is transferred to genus Willipteria n. gen. Comparison of Willipteria n. gen. to Leptodesma reveals a need to revise Leptodesma. A study of the type lot of genotype species Leptodesma potens Hall, provides a redescription for the genus, presented here. Definition of the new term, clinovincular ligament, is presented. Discussion of muti-sheet ligaments is presented for duplivincular, monovincular, and clinovincular configurations.

http://zoobank.org/014f32de-414d-4cda-a5d4-790c35d0bfa5

The allosauroid theropod dinosaurs of the clade Carcharodontosauridae were the apex predators in terrestrial ecosystems of the Early Cretaceous but were replaced in this ecological niche by Tyrannnosauridae in the Late Cretaceous. Details of this turnover are poorly known because only two transitional ecosystems, containing both carcharodontosaurids and tyrannosauroids, had been recognized to date (Cenomanian Cedar Mountain Formation of Utah, USA, and Turonian Bissekty Formation of Uzbekistan). Moreover, the presence of carcharodontosaurids in the Bissekty Formation, based on a maxilla fragment identified as Ulughbegsaurus uzbekistanensis Tanaka et al., 2021, has been recently questioned. Here we report on the third ecosystem containing both clades of apex predators, the Cenomanian Khodzhakul Formation in Uzbekistan. This new occurrence of Carcharodontosauridae is based on a newly identified maxilla that closely resembles the holotype maxilla of U. uzbekistanensis and is identified as Ulughbegsaurus sp. The revised morphological characters of both specimens support attribution of Ulughbegsaurus to Carcharodontosauridae. We report a novel neurovascular feature of the theropod maxilla—a medial alveolar canal that supplied the alveoli medially and contained tributaries of the palatine vessels in Ulughbegsaurus.

The Indo-West Pacific region serves as the primary habitat for the majority of extant hexapodid crabs. The hexapodids boast a rich evolutionary history dating back to the Cretaceous, marked by a significant radiation throughout the Cenozoic, while the Paleocene–Miocene of tropical America emerges as a pivotal center of radiation, evidenced by reported hexapodid species in Barbados, Panama, Peru, Trinidad, and Venezuela. Through an examination of the paleocarcinological collection at the Museu Paraense Emílio Goeldi, a new genus and species within Hexapodidae is described and illustrated. Rodneyellus feldmanni, the newly described taxon, is named in honor to Dr. Rodney Feldmann for his unwavering commitment to fossil crustacean research. This report marks the inaugural documentation of Hexapodidae in Brazil, encompassing both fossilized and extant representatives. Furthermore, the Pirabas Formation emerges as a critical locus for comprehending the contemporary distribution of decapod crustaceans across tropical America.

UUID: http://zoobank.org/9792bc1e-d06e-490b-a8e6-c23ee1c11fb1

Despite being a conspicuous group in many fossil-bearing beds from the Tepuel–Genoa Basin, the knowledge of bryozoans from Patagonia is scarce and outdated. The majority of bryozoan records are known from faunal components of the Lanipustula patagoniensis Biozone (Carboniferous, upper Serpukhovian–Moscovian), in lower to middle levels of the Pampa de Tepuel Formation, Tepuel Group. For the present contribution, we conducted a taxonomic study on bryozoan samples from the lower third of the Pampa de Tepuel Formation at the type section, Sierra de Tepuel, central-western Patagonia, Argentina. We found Paraptylopora gondwanica n. sp. along with species of Penniretepora, Polyporella, Septatopora, Levifenestella, Rectifenestella, Spinofenestella, and others still under study. Most studied fenestrate species are restricted to central-western Patagonia, indicating a degree of biogeographical isolation, while a few imply faunal migration between the western and eastern margins of southern Gondwana during the Late Paleozoic Ice Age. The bryozoan growth habits association and accompanying fauna suggests a mid-shelf to upper-slope environment characterized by deep, low-turbidity, euhaline waters and a soft to firm substrate.

UUID: http://zoobank.org/3bf56286-9fd7-43c2-b5f6-417e86994d08

Gnathodus pseudosemiglaber is an important conodont species for Lower Mississippian biostratigraphy, but differentiating it from morphologically similar species remains difficult due to uncertainties in the intraspecific, ontogenetic, and phylogenetic relationships between taxa. To clarify these uncertainties, a fauna from the Yudong Formation at the Yudong II section in Baoshan, southwestern China, that contains abundant G. pseudosemiglaber was analyzed using population thinking. Quantitative morphometric methods were employed to analyze G. pseudosemiglaber specimens. Six anatomical measurements were taken on specimens of different ontogenetic stages to conduct analyses on normal distribution, correlation, and regression. A geometric morphometric analysis based on 13 landmarks was also performed. The results demonstrated that all analyzed specimens belonged to a single population. The dorsal carina of G. pseudosemiglaber has a growth rate that far exceeds other features on the platform through ontogeny as well as exhibits a series of transverse ridges in adult individuals, which becomes the most prominent diagnostic characteristic of this species. Thus, an amended systematic description for G. pseudosemiglaber is presented. Gnathodus girtyi maxwelli, a previously named species, however, is regarded as a junior synonym of G. pseudosemiglaber. Based on the revised taxonomy of G. pseudosemiglaber, its possible phylogenetic lineages and biostratigraphic use were reviewed. The ancestor of G. pseudosemiglaber is probably G. semiglaber but its descendant is unknown. The range of G. pseudosemiglaber is from the Scaliognathus anchoralis–Doliognathus latus Zone of uppermost Tournaisian to the lower part of the G. bilineatus Zone of middle-upper Visean.

The first unequivocal fossil of a tupinambine in North America is described on the basis of a single thoracic vertebra from a middle Miocene (Barstovian 2) paleocoastal deposit in southwestern Georgia, USA. Wautaugategu formidus n. gen. n. sp. is a mid- to large-bodied taxon with a unique mosaic of tupinambine features. Vertebral position of the fossil was determined both by qualitative and quantitative methods. This record is coeval with the warmest part of the Neogene, the Middle Miocene Climatic Optimum, when increased temperatures would have made the southeastern United Sates more habitable for this hyperthermic group of lizards. Although the arrival time of tupinambines into North America is still unclear, an increasing number of endemic South American reptiles, including the large-bodied iguanid Ctenosaura, dispersed as far North as Panama by the early Miocene before formation of the Panamanian Isthmus.

http://zoobank.org/58ded940-9082-46ae-8023-4b5f1b01691e

Scandentians, commonly known as treeshrews (tree shrews), are the sister group of primates and colugos within the Euarchonta, a clade with an evolutionary history rooted in the Cretaceous (Roberts et al., 2011; Melin et al., 2016). Scandentians are, however, extremely rare in the fossil record (Ni and Qiu, 2012; Li and Ni, 2016) and, other than the Oligocene species Ptilocercus kylin Li and Ni, 2016, their earliest undoubted representatives are not older than 18 Ma (Li and Ni, 2016, and references therein).

A new pylochelid hermit crab, Cretatrizocheles rodfeldmanni new species, is recorded from a Lower Cretaceous (Aptian/Albian) olistolith reefal limestone block near the village of Velika Strmica, southeast Slovenia. It adds to the fossil record of the symmetrical pagurid subfamily Trizochelinae, whose members appear to have been successful inhabitants of shallow-marine reefal settings during at the least the Late Jurassic and Early Cretaceous across Europe. Given their exclusive occurrence in shallow-marine, reef-related facies of Mesozoic age and the present-day confinement to deep-marine settings, trizocheline paguroids may also illustrate the effect of the Mesozoic Marine Revolution.

UUID: http://zoobank.org/b3f862ca-3b4d-44c1-911c-820af4426029

The Cambrian edrioasteroid “Totiglobus” spencensis Wen et al., 2019 is redescribed on the basis of a new and exquisitely preserved specimen from the Cambrian Wuliuan of the Spence Shale Member, Langston Formation (Utah). This new occurrence is associated with soft-body preservation of several invertebrate groups and other shelly fossils. The description of “T.” spencensis was originally based on a single poorly preserved specimen. As a result, some of its features, such as curvature of the ambulacra and morphology of floor and cover plates, were misinterpreted or unavailable. The new material allows a new placement in Sprinkleoglobus spencensis n. comb. (Wen et al., 2019) on the basis of the general shape of the theca, attachment disc, and biserial flooring plates with podial pores and multiple cover plate series. The attachment disc of the new specimen lies in contact with a trilobite librigena, supporting evidence that this taxon is one of the earliest known examples of attachment to hard, mineralized substrata among Edrioasteroidea.

Dysnoetoporidae is a family of cheilostome bryozoans including only the genus Dysnoetopora Canu and Bassler, 1926, with three recognized species from the Late Cretaceous of the United States, Crimea, and Germany. The aim of this study was to record for the first time the presence of a fossil dysnoetoporid bryozoan in South America by describing Chenquepora miocenica new genus new species. This taxon was found in Miocene deposits of the Chenque Formation (early Langhian, ~15.37 Ma), on the Atlantic coast of Argentine Patagonia. Chenquepora n. gen. differs from Dysnoetopora in its encrusting colony and, consequently, in the absence of an endozone with long zooids arranged parallel to growth direction. This new record extends its paleobiogeographic distribution to the Southern Hemisphere and its stratigraphic range from the Campanian (Late Cretaceous) to the Miocene, showing that this extinct family survived the Cretaceous-Paleogene (K-Pg) mass-extinction event.

One of the challenges for bryozoans is to avoid refiltering water that has already had its plankton removed. Larger colonies develop colony-wide maculae-centered feeding currents to avoid refiltering water and generally have elevated maculae (monticules). We hypothesize that the height and density of spacing of monticules are inversely proportional to curvature of the colony surface. Larger, flatter colonies should have higher and more closely spaced monticules. We compare two Permian stenolaemate bryozoans whose colonies form branches with elliptical cross sections: the smaller and more elliptical cystoporate Evactinostella crucialis (Hudleston, 1883) from Western Australia (N = 17) and the larger and flatter trepostome Tabulipora sp. from eastern North Greenland (N = 15). Using calipers and digital elevation models, we measured curvature, monticule height, and number of monticules per area. Results indicate that Evactinostella branches are at least twice as curved as those of Tabulipora, their monticules are half the height of Tabulipora, and their monticules are 22% less densely spaced than those of Tabulipora. In Evactinostella colonies, surface curvature is inversely proportional to monticule height and spatial density, which is not true for Tabulipora. Therefore, we conclude that the smaller and more curved the colony surface, the less the colony needs robust colony-wide feeding currents created by tall, closely spaced monticules.

Insights into the paleoneurology and endocranial anatomy of ornithopod dinosaurs come largely from Northern Hemisphere taxa. The recently described non-hadrosaurid iguanodontian Fostoria dhimbangunmal from the Cenomanian of eastern Australia includes a partial skull that offers novel insights into its endocranial anatomy (i.e., the cavity housing the brain). Here, we describe the paleoneurology of F. dhimbangunmal based on a digital cranial endocast obtained from computed tomography. The endocast is mostly complete; however, it is diagenetically dorsoventrally compressed and its ventral limits are not preserved. The endocranial anatomy of F. dhimbangunmal is generally consistent with that of other non-hadrosaurid iguanodontians, including a well-developed olfactory apparatus, suggesting a good sense of smell. In contrast to hadrosaurids and some non-hadrosaurid iguanodontians, F. dhimbangunmal possesses the ancestral flexure condition, in which cranial and pontine flexure angles are subequal. The cerebrum makes up a significant portion of the endocast volume; however, the cerebral hemispheres are not as enlarged or bulbous as seen in hadrosaurids. The forebrain of F. dhimbangunmal did not fill the braincase to the same extent as in hadrosaurids. A distinct vacuity in the supraoccipital of F. dhimbangunmal may represent a new autapomorphy. This study provides the first insights into the neuroanatomy of an Australian iguanodontian dinosaur.

Jurassic cyrtocrinids from Spain are first documented here as representing relatively diverse assemblages from the western Tethys. The species Ascidicrinus pentagonus, Eugeniacrinites cariophilites, Gammarocrinites compressus, Pilocrinus moussoni, Sclerocrinus cf. S. strambergensis, and Tetracrinus moniliformis are described from Oxfordian marl levels belonging to the Yátova Formation, around Tosos (Zaragoza, NE Spain). Although based on partially disarticulated material, these fossils preserve cups, stem columnals, attachment structures, and brachial plates. Based on the sedimentology and associated invertebrate fauna, cyrtocrinids from this area lived below storm wave action but eventually were affected by storms, as opposed to their modern counterparts that occupy deep water environments. Some specimens preserve traces of interactions with other organisms, such as predation marks or epibiontic colonization during life and post-mortem. Attachment structures suggest cyrtocrinids mostly attached on sponges. We note that diversity of cyrtocrinids changed in step with the abundance of sponge reefs in the Jurassic, suggesting that both groups probably had an important link in that period related with similar ecological requirements.

Haliotis Linnaeus, 1758, a commercially important gastropod, is the only known genus in the family Haliotidae (Mollusca, Vetigastropoda, or abalone) worldwide. Its poor Cenozoic record and high intraspecific variability resulted in different interpretations of nomenclature, impeding a robust species-level taxonomy and biogeographic history. Among the best-studied forms, three subspecies of H. tuberculata Linnaeus, 1758 currently inhabit the temperate waters of the Mediterranean and the eastern Atlantic. New findings in the Pliocene of Tuscany (Italy) are presented here, and the taxonomy of the European record is revised. On the basis of a multivariate analysis of shell morphometrics for the first time applied to the study of fossil abalones, and consistent with the chronostratigraphic and geographic framework, H. plioetrusca n. sp. is introduced and H. volhynica Eichwald, 1829 and H. lamellosoides Sacco, 1897 are reinstated as valid species. Some recently described forms from the Pliocene of Spain are placed in synonymy with H. lamellosoides. Haliotis ovata Michelotti, 1847 is proposed as the ancestral taxon of modern H. tuberculata, via H. lamellosoides. This lineage diversified in the subtropical/warm temperate Pliocene Mediterranean, represented by H. lamellosoides, H. bertinii Forli et al., 2003 and H. plioetrusca. The progressive global cooling starting at around 3.0 Ma is associated with the appearance of H. tuberculata at temperate latitudes. H. plioetrusca is not known from younger strata, whereas H. bertinii survived into the Calabrian.

UUID: http://zoobank.org/7c2f2258-2574-4976-a2f5-804c54c86679