cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14845075.v2
title: First record of mawsoniid coelacanths (Actinistia, Sarcopterygii) from the marine Rhaetian (Upper Triassic) of Bonenburg, Germany

description: Coelacanths are represented today by a single genus, <i>Latimeria</i>. They are known to be ‘living fossils’, because their evolutionary history dates back into the Devonian. Through the Upper Triassic, coelacanths are represented by two families, the Latimeriidae and Mawsoniidae. While latimeriids represent their marine lineage, mawsoniids were, until recently (Deesri et al., 2018), thought to be exclusively freshwater inhabitants. Through the Late Triassic, mawsoniids originated in freshwater environments of America, and only little is known about their evolution in Europe during this time period. Here we report on two morphotypes of mawsoniid basisphenoids from the marine Rhaetian (Upper Triassic) Bonenburg locality (Kreis Höxter, North Rhine-Westphalia, Germany) showing that (1) Late Triassic coelacanths from Germany can be assigned to the family level, specifically to Mawsoniidae, (2) mawsoniid coelacanths were already present in Europe in the Late Triassic, and (3) these inhabited marine environments at the end of the Triassic, supporting the affinities of habitat preference of previous finds from France (Deesri et al., 2018). The results strengthen the hypothesis an intermediate marine phase between the origin of Mawsoniidae in freshwater environments of nowadays North America during the Late Triassic and their final occurrence in continental deposits of Western Gondwana (Africa and South America) and nowadays Europe in the Late Cretaceous (Cavin et al., 2019).
DOI: 10.6084/m9.figshare.14839487
title: Scarce ctenacanthiform sharks from the Mississippian of Austria with an analysis of Carboniferous elasmobranch diversity in response to climatic and environmental changes

description: The Carboniferous is characterized by drastic climatic and environmental fluctuations, which include multiple phases of glaciation resulting in an icehouse climate. Additionally, dynamic continental reconfigurations forced the contraction of the Rheic Ocean resulting in the closure of the Rheic–Tethyan Gateway, which precluded further faunal exchanges between the North American and Eurasian marine realms. Interestingly, cartilaginous fishes seem to be relatively immune to these drastic climatic and environmental changes. The Eurasian fossil record of Paleozoic sharks is strongly biased towards intensively sampled localities from England, Ireland, Scotland, and the Russian Platform. Here we present rare dental material from the Serpukhovian (early Carboniferous) of Austria, adding new information to the paleogeographic distribution of ctenacanthiform sharks. The new material revealed the first record of the genus <i>Saivodus</i> in Central Europe and allowed us to recognize a new species, <i>Cladodus gailensis</i> sp. nov., and a remnant of fossilized cartilage. In an attempt to identify possible linkages between climatic or environmental fluctuations on shark diversity throughout the Carboniferous, we provide a synopsis of the distribution and diversity of elasmobranchs based on primary literature. This preliminary assessment at genus level indicates two pronounced events of extinction, with the first one occurring during the latest Mississippian and the second one towards the end of the Pennsylvanian. The first extinction event distinctly correlates with the known diversity decline of other marine inhabitants and the second occurred during an unstable period of multiple phases of glaciation.
DOI: 10.6084/m9.figshare.14931763.v1
title: A new diapsid with a unique tooth structure from the Middle Triassic (Ladinian) of Germany

description: The Middle Triassic was an important time in the evolutionary history of reptiles because it was during this time that many modern groups originated and initially diversified. In this context, the rich fossiliferous deposits of the Ladinian-age Erfurt Formation in southern Germany play an important role in elucidating reptilian diversity during this interval. Here we present an interesting record of a reptile with an unusual dentition. The material comprises a fragment of a left dentary. The teeth are tightly spaced and have chisel-shaped crowns, with the posterolingually extending apices abutting those of the successive teeth and forming a continuous cutting edge. Micro-computed tomography scanning of the jaw fragment revealed the teeth have expanded roots and sit on an open, shallow groove. The Meckelian canal is partially open lingually and a second canal for the inferior alveolar nerve and artery extends parallel to it. Although the preserved anatomical features of the material are insufficient for precise phylogenetic placement, the structure of the robust dentary and its teeth resembles those of some lepidosaurs and certain early Mesozoic marine diapsids. The distinctive morphology of the teeth, combined with the apparent lack of tooth wear, makes it difficult to assess their functional significance. It is interesting that extinct tetrapods with similar tooth morphologies come from strata representing freshwater and brackish-water paleoenvironments, which may serve as an additional line of evidence for future Morpho-functional assessments.
DOI: 10.6084/m9.figshare.15035032.v1
title: Osteology and digital reconstruction of the skull of the early tetrapod <i>Whatcheeria deltae</i>

description: The Early Carboniferous stem tetrapod <i>Whatcheeria deltae</i> is among the earliest-branching limbed tetrapods represented by multiple near-complete specimens, making it an important taxon in understanding the vertebrate water-to-land transition. However, all preserved skulls of <i>Whatcheeria</i> suffer from post-mortem crushing and lateral compression, which has made cranial reconstruction problematic. In this study, computed tomography data of three <i>Whatcheeria</i> specimens were segmented using visualization software to digitally separate each individual skull bone from matrix. Digital methods were used to repair and retrodeform the bones and produce the first complete three-dimensional skull reconstruction of <i>Whatcheeria</i>. We provide a revised description of the cranial and lower jaw anatomy of <i>Whatcheeria</i> based on CT data, focusing on sutural morphology and previously unknown anatomical details. Our findings suggest that <i>Whatcheeria</i> had one of the narrowest skulls of any known early tetrapod, a gap between the nasals, and significant overlap of the lacrimal onto the nasal and prefrontal. Sutural morphology is used to infer loading regime in the skull during feeding and suggests the skull of <i>Whatcheeria</i> was well adapted to resist stresses induced by biting large prey with its enlarged anterior fangs.
DOI: 10.6084/m9.figshare.14845075.v1
title: First record of mawsoniid coelacanths (Actinistia, Sarcopterygii) from the marine Rhaetian (Upper Triassic) of Bonenburg, Germany

description: Coelacanths are represented today by a single genus, <i>Latimeria</i>. They are known to be ‘living fossils’, because their evolutionary history dates back into the Devonian. Through the Upper Triassic, coelacanths are represented by two families, the Latimeriidae and Mawsoniidae. While latimeriids represent their marine lineage, mawsoniids were, until recently (Deesri et al., 2018), thought to be exclusively freshwater inhabitants. Through the Late Triassic, mawsoniids originated in freshwater environments of America, and only little is known about their evolution in Europe during this time period. Here we report on two morphotypes of mawsoniid basisphenoids from the marine Rhaetian (Upper Triassic) Bonenburg locality (Kreis Höxter, North Rhine-Westphalia, Germany) showing that (1) Late Triassic coelacanths from Germany can be assigned to the family level, specifically to Mawsoniidae, (2) mawsoniid coelacanths were already present in Europe in the Late Triassic, and (3) these inhabited marine environments at the end of the Triassic, supporting the affinities of habitat preference of previous finds from France (Deesri et al., 2018). The results strengthen the hypothesis an intermediate marine phase between the origin of Mawsoniidae in freshwater environments of nowadays North America during the Late Triassic and their final occurrence in continental deposits of Western Gondwana (Africa and South America) and nowadays Europe in the Late Cretaceous (Cavin et al., 2019).
DOI: 10.6084/m9.figshare.14839487.v2
title: Scarce ctenacanthiform sharks from the Mississippian of Austria with an analysis of Carboniferous elasmobranch diversity in response to climatic and environmental changes

description: The Carboniferous is characterized by drastic climatic and environmental fluctuations, which include multiple phases of glaciation resulting in an icehouse climate. Additionally, dynamic continental reconfigurations forced the contraction of the Rheic Ocean resulting in the closure of the Rheic–Tethyan Gateway, which precluded further faunal exchanges between the North American and Eurasian marine realms. Interestingly, cartilaginous fishes seem to be relatively immune to these drastic climatic and environmental changes. The Eurasian fossil record of Paleozoic sharks is strongly biased towards intensively sampled localities from England, Ireland, Scotland, and the Russian Platform. Here we present rare dental material from the Serpukhovian (early Carboniferous) of Austria, adding new information to the paleogeographic distribution of ctenacanthiform sharks. The new material revealed the first record of the genus <i>Saivodus</i> in Central Europe and allowed us to recognize a new species, <i>Cladodus gailensis</i> sp. nov., and a remnant of fossilized cartilage. In an attempt to identify possible linkages between climatic or environmental fluctuations on shark diversity throughout the Carboniferous, we provide a synopsis of the distribution and diversity of elasmobranchs based on primary literature. This preliminary assessment at genus level indicates two pronounced events of extinction, with the first one occurring during the latest Mississippian and the second one towards the end of the Pennsylvanian. The first extinction event distinctly correlates with the known diversity decline of other marine inhabitants and the second occurred during an unstable period of multiple phases of glaciation.
DOI: 10.6084/m9.figshare.14994272.v2
title: The hand of <i>Tenontosaurus tilletti</i> (Dinosauria, Ornithopoda)

description: The hand of <i>Tenontosaurus tilletti</i> (Dinosauria, Ornithopoda)
DOI: 10.6084/m9.figshare.14846979.v2
title: New late Oligocene caviomorph rodents from Mendoza Province, central-western Argentina

description: Late Oligocene caviomorphs represent one of the most important early adaptive radiations of this group of rodents. They show a high taxonomic diversity and a wide geographic distribution, with those found in the upper Oligocene of Salla (Bolivia) and Patagonia (Argentina) being particularly diverse. However, caviomorphs from the Deseadan South American Land Mammal Age in other latitudes are still scarcely known. In this contribution, we describe new caviomorph rodents from the Deseadan levels of Quebrada Fiera locality (Mendoza Province; central-western Argentina) and evaluate their systematic and paleobiogeographic significance. The taxonomic composition of the caviomorphs from Quebrada Fiera reveals a complex biogeographic history, as we recognize one endemic Cavioidea (<i>Asteromys puelche</i> sp. nov.) and two Chinchilloidea: one with Patagonian affinities (<i>Cephalomys</i> sp.) and another with a wide distribution in South America (<i>Incamys bolivianus</i>). <i>Asteromys puelche</i> sp. nov., shows closer phylogenetic affinities with the Bolivian <i>A. bolivianus</i> than with the Patagonian <i>A. punctus</i>. These rodents, in common with the whole mammalian association from Quebrada Fiera, show a mix of endemic taxa and others shared with higher and lower latitudes.
DOI: 10.6084/m9.figshare.14937962.v1
title: The first braincase of the basal aetosaur <i>Aetosauroides scagliai</i> (Archosauria: Pseudosuchia) from the Upper Triassic of Brazil

description: The phylogenetic relationships of Pseudosuchia, the crocodile-line of Archosauria, are still poorly resolved, in part, due to the lack of crucial braincase information for several key taxa. Recently, erpetosuchids and ornithosuchids have been recovered as close relatives to Aetosauria, sharing several braincase features. Here we provide the description of the first braincase of the basal aetosaur <i>Aetosauroides</i> based on specimens from the Upper Triassic Candelária Sequence of Brazil. Our study revealed the presence of an exoccipital lateral ridge and a medial ridge on the supraoccipital (both shared with all aetosaurs and erpetosuchids, but absent in ornithosuchids) and an anterolateral exit for the internal carotids (shared with all aetosaurs and ornithosuchids, but not with erpetosuchids). <i>Aetosauroides</i> lacks a medial contact between the exoccipitals (shared with the aetosaurs <i>Desmatosuchus smalli</i> and <i>Tecovasuchus</i>) and possesses a single hypoglossal foramen (contrasting with <i>Stagonolepis robertsoni</i> and <i>Desmatosuchus spurensis</i>). It also differs from the putative Argentinian <i>Aetosauroides</i> (PVSJ 326) by the presence of a ridge connecting the basal tubera medially (contrasting also with all stagonolepidoideans) and by a bulbous and ventrolaterally recurved basipterygoid process (contrasting with <i>Paratypothorax</i>). These features show that the braincase of aetosaurs is suitable for providing further phylogenetic information and may contribute to resolving controversies within Pseudosuchia relationships.
DOI: 10.6084/m9.figshare.14839487.v1
title: Scarce ctenacanthiform sharks from the Mississippian of Austria with an analysis of Carboniferous elasmobranch diversity in response to climatic and environmental changes

description: The Carboniferous is characterized by drastic climatic and environmental fluctuations, which include multiple phases of glaciation resulting in an icehouse climate. Additionally, dynamic continental reconfigurations forced the contraction of the Rheic Ocean resulting in the closure of the Rheic–Tethyan Gateway, which precluded further faunal exchanges between the North American and Eurasian marine realms. Interestingly, cartilaginous fishes seem to be relatively immune to these drastic climatic and environmental changes. The Eurasian fossil record of Paleozoic sharks is strongly biased towards intensively sampled localities from England, Ireland, Scotland, and the Russian Platform. Here we present rare dental material from the Serpukhovian (early Carboniferous) of Austria, adding new information to the paleogeographic distribution of ctenacanthiform sharks. The new material revealed the first record of the genus <i>Saivodus</i> in Central Europe and allowed us to recognize a new species, <i>Cladodus gailensis</i> sp. nov., and a remnant of fossilized cartilage. In an attempt to identify possible linkages between climatic or environmental fluctuations on shark diversity throughout the Carboniferous, we provide a synopsis of the distribution and diversity of elasmobranchs based on primary literature. This preliminary assessment at genus level indicates two pronounced events of extinction, with the first one occurring during the latest Mississippian and the second one towards the end of the Pennsylvanian. The first extinction event distinctly correlates with the known diversity decline of other marine inhabitants and the second occurred during an unstable period of multiple phases of glaciation.
DOI: 10.6084/m9.figshare.14937956
title: The neurocranium of <i>Ekweeconfractus amorui</i> gen. et sp. nov. (Hyaenodonta, Mammalia) and the evolution of the brain in some hyaenodontan carnivores

description: We report on a nearly complete cranium of <i>Ekweeconfractus amorui</i> gen. et sp. nov. (Hyaenodonta, Teratodontinae), from the early Miocene of Moruorot, Kenya. The cranium is dorsoventrally compressed, but sufficiently intact to allow for digital reconstruction of the neurocranium, resulting in a digital endocast that gives us a first glimpse into teratodontine brain morphology. The virtual endocast is one of the most well preserved of any hyaenodont known to date, with many of the cranial nerves and blood vessels identifiable. Endocasts are known from only a handful of hyaenodont species and little work has been done on hyaenodont brains in recent decades. To better understand the evolution of the brain in these animals, we place the endocast of <i>E. amorui</i> gen. et sp. nov., as well as several other previously described endocasts, in the latest phylogenetic framework. This analysis suggests that the expansion of the neocortex occurred convergently in several clades of Hyaenodonta. Our study provides a basis for future research on brain evolution in Hyaenodonta.
DOI: 10.6084/m9.figshare.14994272.v1
title: The hand of <i>Tenontosaurus tilletti</i> (Dinosauria, Ornithopoda)

description: The hand of <i>Tenontosaurus tilletti</i> (Dinosauria, Ornithopoda)
DOI: 10.6084/m9.figshare.14937956.v2
title: The neurocranium of <i>Ekweeconfractus amorui</i> gen. et sp. nov. (Hyaenodonta, Mammalia) and the evolution of the brain in some hyaenodontan carnivores

description: We report on a nearly complete cranium of <i>Ekweeconfractus amorui</i> gen. et sp. nov. (Hyaenodonta, Teratodontinae), from the early Miocene of Moruorot, Kenya. The cranium is dorsoventrally compressed, but sufficiently intact to allow for digital reconstruction of the neurocranium, resulting in a digital endocast that gives us a first glimpse into teratodontine brain morphology. The virtual endocast is one of the most well preserved of any hyaenodont known to date, with many of the cranial nerves and blood vessels identifiable. Endocasts are known from only a handful of hyaenodont species and little work has been done on hyaenodont brains in recent decades. To better understand the evolution of the brain in these animals, we place the endocast of <i>E. amorui</i> gen. et sp. nov., as well as several other previously described endocasts, in the latest phylogenetic framework. This analysis suggests that the expansion of the neocortex occurred convergently in several clades of Hyaenodonta. Our study provides a basis for future research on brain evolution in Hyaenodonta.
DOI: 10.6084/m9.figshare.14937955
title: Osteohistology and paleobiological inferences of proterochampsids (Eucrocopoda: Proterochampsia) from the Chañares Formation (late Ladinian–early Carnian), La Rioja, Argentina

description: Proterochampsids were a group of stem archosaurs from the Middle–Late Triassic of South America. Using for the first time in proterochampsids quantitative microanatomical and morphological data and an inference model, we analyze the microstructure of postcranial bones of proterochampsids to infer life-history traits dealing with growth dynamics, ontogenetic changes, dermal armor histogenesis and lifestyle. We studied proterochampsid individuals from the Middle–Late Triassic Chañares Formation: three specimens of <i>Chanaresuchus bonapartei</i>: PVL 4575 (osteoderms and femur), CRILAR-Pv 80 (osteoderm) and CRILAR-Pv 81 (humerus), and a femur of a non-identified Rhadinosuchinae specimen (CRILAR-Pv 488). The osteoderms show a compact-uniform composition of parallel-fibered bone and lines of arrested growth (LAGs). The long bones are composed mainly of highly vascularized, parallel-fibered bone and isolated areas of woven-fibered bone in the innermost portion of cortex (only in <i>C. bonapartei</i> PVL 4575). The absence of an external fundamental system (EFS) indicates that all of the sampled individuals were somatically immature at time of death. The absence of mineralized bundles of collagenous fibers supports intramembranous ossification as the developmental origin for the osteoderms. With an inference model used for the first time in proterochampsids, the lifestyle inferred for <i>C. bonapartei</i> is terrestrial. Histological evidence indicates that sexual maturity is reached before both somatic and skeletal maturity. The growth patterns among proterochampsids exhibit some degree of variation even within a single species. Such variation can be due to different causes, including possibly phenotypic plasticity.
DOI: 10.6084/m9.figshare.14937956.v1
title: The neurocranium of <i>Ekweeconfractus amorui</i> gen. et sp. nov. (Hyaenodonta, Mammalia) and the evolution of the brain in some hyaenodontan carnivores

description: We report on a nearly complete cranium of <i>Ekweeconfractus amorui</i> gen. et sp. nov. (Hyaenodonta, Teratodontinae), from the early Miocene of Moruorot, Kenya. The cranium is dorsoventrally compressed, but sufficiently intact to allow for digital reconstruction of the neurocranium, resulting in a digital endocast that gives us a first glimpse into teratodontine brain morphology. The virtual endocast is one of the most well preserved of any hyaenodont known to date, with many of the cranial nerves and blood vessels identifiable. Endocasts are known from only a handful of hyaenodont species and little work has been done on hyaenodont brains in recent decades. To better understand the evolution of the brain in these animals, we place the endocast of <i>E. amorui</i> gen. et sp. nov., as well as several other previously described endocasts, in the latest phylogenetic framework. This analysis suggests that the expansion of the neocortex occurred convergently in several clades of Hyaenodonta. Our study provides a basis for future research on brain evolution in Hyaenodonta.
DOI: 10.6084/m9.figshare.14797765
title: The stapes of stem and extinct Marsupialia: implications for the ancestral condition

description: This paper describes, for the first time, the stapedes of several non-marsupial species of the metatherian clade Sparassodonta (<i>Sipalocyon gracilis</i>, <i>Arctodictis sinclairi</i>, and <i>Borhyaena tuberata</i>) which were fortuitously encountered during routine microtomography. To augment our comparative set we also scanned and reconstructed single examples of the stapedes of the fossil taxa <i>Sparassocynus bahiai</i> and <i>Thylophorops</i> cf<i>. T. chapalmalensis</i> (Didelphimorphia), <i>Argyrolagus scagliai</i> (?Paucituberculata), as well as single examples drawn from extant members of Caenolestidae (<i>Caenolestes</i> sp.) and Microbiotheriidae (<i>Dromiciops gliroides</i>). The sparassodont, didelphid, and microbiotherian samples exhibit a common bauplan (stapes triangular, with intracrural foramen), whereas the paucituberculatan samples differ in possessing columelliform, imperforate stapes as also previously reported for various australidelphians. The stapedial footplate is rounded in sparassodonts (stapedial ratio, ∼1.6), in both of the fossil didelphimorphians (∼1.7), and in the fossil ?paucituberculatan (∼1.5). According to our optimization of our results of mammalian phylogeny, and in contrast to some other reconstructions, a triangular stapes with intracrural foramen and rounded footplate is likely the ancestral condition for Marsupialia. No particular function can be correlated with possession of the intracrural foramen as opposed to an imperforate stapes, apart from accommodation of the proximal stapedial artery (as seen also in many eutherians). The frequent presence of the intracrural foramen in members of both infraclasses suggests that the ontogenies of the second arch’s blood supply (stapedial artery) and its main skeletal element (stapes) have remained strongly integrated throughout therian evolution, even in cases in which the proximal part of the vessel involutes.