Pub Date : 2023-08-08DOI: 10.1080/02724634.2023.2232846
Alison M. Murray, Luke E. Nelson, D. Brinkman
Abstract The posterior portion of a sturgeon skull preserved in a nodule was recovered from the latest Campanian sediments of the Horseshoe Canyon Formation in the city of Edmonton, Alberta, Canada. It is described here as a new genus and species of Acipenseriformes. The skull represents an individual of at least 2 meters in total length. This species is of particular interest because different bones of the skull show a surface ornamentation with different patterns; the clavicle has large pits, the dermal skull bones have smaller pits and radiating ridges, and the subopercle shows fine radiating ridges. The new taxon, here named †Boreiosturion labyrinthicus, can be confidently included in the extant family Acipenseridae but a phylogenetic analysis does not further resolve relationships. This fossil is the first documentation of sturgeon in the latest Campanian of North America, and bridges the gap between the mid-Campanian assemblage of Dinosaur Park and the late Maastrichtian material from the Hell Creek Formation.
{"title":"A new sturgeon from the Upper Cretaceous Horseshoe Canyon Formation in central Alberta, Canada","authors":"Alison M. Murray, Luke E. Nelson, D. Brinkman","doi":"10.1080/02724634.2023.2232846","DOIUrl":"https://doi.org/10.1080/02724634.2023.2232846","url":null,"abstract":"Abstract The posterior portion of a sturgeon skull preserved in a nodule was recovered from the latest Campanian sediments of the Horseshoe Canyon Formation in the city of Edmonton, Alberta, Canada. It is described here as a new genus and species of Acipenseriformes. The skull represents an individual of at least 2 meters in total length. This species is of particular interest because different bones of the skull show a surface ornamentation with different patterns; the clavicle has large pits, the dermal skull bones have smaller pits and radiating ridges, and the subopercle shows fine radiating ridges. The new taxon, here named †Boreiosturion labyrinthicus, can be confidently included in the extant family Acipenseridae but a phylogenetic analysis does not further resolve relationships. This fossil is the first documentation of sturgeon in the latest Campanian of North America, and bridges the gap between the mid-Campanian assemblage of Dinosaur Park and the late Maastrichtian material from the Hell Creek Formation.","PeriodicalId":17597,"journal":{"name":"Journal of Vertebrate Paleontology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43282738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-03DOI: 10.1080/02724634.2023.2232829
Lachlan J. Hart, B. Gee, Patrick M. Smith, M. McCurry
ABSTRACT Compared with other Mesozoic tetrapod groups, chigutisaurid fossils from Australia are rare, with only three named taxa described from the continent. From Queensland, Keratobrachyops australis is known from the Triassic, and Siderops kehli from the Jurassic. Koolasuchus cleelandi, from the Cretaceous of Victoria, represents the youngest-known temnospondyl globally. Here we describe the first chigutisaurid from New South Wales, from the Early–Middle Triassic Terrigal Formation. The specimen (AM F125866) comprises an articulated, near-complete skeleton, presented in ventral aspect, as well as outlines of soft tissue. The new taxon preserves features that indicate an affinity with Chigutisauridae, confirming previous hypotheses on the presence of large-bodied chigutisaurids in the Triassic of Australia. The new Terrigal chigutisaurid is only the second chigutisaurid known from the Lower Triassic and fourth from Australia overall. The distribution of brachycephalic temnospondyls throughout the Mesozoic suggests specific adaptations led to the long-term survival of chigutisaurids, especially across the end-Triassic extinction event.
{"title":"A new chigutisaurid (Brachyopoidea, Temnospondyli) with soft tissue preservation from the Triassic Sydney Basin, New South Wales, Australia","authors":"Lachlan J. Hart, B. Gee, Patrick M. Smith, M. McCurry","doi":"10.1080/02724634.2023.2232829","DOIUrl":"https://doi.org/10.1080/02724634.2023.2232829","url":null,"abstract":"ABSTRACT Compared with other Mesozoic tetrapod groups, chigutisaurid fossils from Australia are rare, with only three named taxa described from the continent. From Queensland, Keratobrachyops australis is known from the Triassic, and Siderops kehli from the Jurassic. Koolasuchus cleelandi, from the Cretaceous of Victoria, represents the youngest-known temnospondyl globally. Here we describe the first chigutisaurid from New South Wales, from the Early–Middle Triassic Terrigal Formation. The specimen (AM F125866) comprises an articulated, near-complete skeleton, presented in ventral aspect, as well as outlines of soft tissue. The new taxon preserves features that indicate an affinity with Chigutisauridae, confirming previous hypotheses on the presence of large-bodied chigutisaurids in the Triassic of Australia. The new Terrigal chigutisaurid is only the second chigutisaurid known from the Lower Triassic and fourth from Australia overall. The distribution of brachycephalic temnospondyls throughout the Mesozoic suggests specific adaptations led to the long-term survival of chigutisaurids, especially across the end-Triassic extinction event.","PeriodicalId":17597,"journal":{"name":"Journal of Vertebrate Paleontology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43657950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-03DOI: 10.1080/02724634.2023.2232833
M. S. Bhat, Debajit Datta, S. Ray, P. M. Datta
ABSTRACT A new clevosaurid rhynchocephalian is described from the Upper Triassic Tiki Formation of the Rewa Gondwana Basin of India. The material is based on several partial craniomandibular elements containing acrodont and fully ankylosed tooth implantations and on the basis of multiple diagnostic features is assigned to a new taxon, Clevosaurus nicholasi. Phylogenetic analysis nests the Tiki rhynchocephalian within the clade Clevosauridae, where it is recovered as an early-diverging taxon basal to the other clevosaurs except for a clade comprising C. convallis + Sigmala sigmala. The autapomorphic characters of Clevosaurus nicholasi include a very robust dentary with an obliquely angled narrow lip of the secondary bone at the symphysis, anteriorly bifurcated Meckelian canal, a sub-dental shelf on the dentary, acrodont marginal anterior teeth, and absence of or smooth lateral and medial wear facets on the marginal dentary and maxillary teeth, respectively. The Late Triassic rhynchocephalian record of the Gondwana is relatively sparse in comparison with that of the Laurasian regions, and the new clevosaur represents the first Late Triassic record from India. Based on the paleobiogeographic distribution, a possible Gondwanan origin for Clevosauridae is hypothesized.
{"title":"A new clevosaurid (Lepidosauria: Rhynchocephalia) from the Upper Triassic of India","authors":"M. S. Bhat, Debajit Datta, S. Ray, P. M. Datta","doi":"10.1080/02724634.2023.2232833","DOIUrl":"https://doi.org/10.1080/02724634.2023.2232833","url":null,"abstract":"ABSTRACT A new clevosaurid rhynchocephalian is described from the Upper Triassic Tiki Formation of the Rewa Gondwana Basin of India. The material is based on several partial craniomandibular elements containing acrodont and fully ankylosed tooth implantations and on the basis of multiple diagnostic features is assigned to a new taxon, Clevosaurus nicholasi. Phylogenetic analysis nests the Tiki rhynchocephalian within the clade Clevosauridae, where it is recovered as an early-diverging taxon basal to the other clevosaurs except for a clade comprising C. convallis + Sigmala sigmala. The autapomorphic characters of Clevosaurus nicholasi include a very robust dentary with an obliquely angled narrow lip of the secondary bone at the symphysis, anteriorly bifurcated Meckelian canal, a sub-dental shelf on the dentary, acrodont marginal anterior teeth, and absence of or smooth lateral and medial wear facets on the marginal dentary and maxillary teeth, respectively. The Late Triassic rhynchocephalian record of the Gondwana is relatively sparse in comparison with that of the Laurasian regions, and the new clevosaur represents the first Late Triassic record from India. Based on the paleobiogeographic distribution, a possible Gondwanan origin for Clevosauridae is hypothesized.","PeriodicalId":17597,"journal":{"name":"Journal of Vertebrate Paleontology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47682679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.1080/02724634.2023.2231994
R. Werneburg, J. Schneider, S. Štamberg, B. Legler, R. Schoch
ABSTRACT The temnospondyl clade Amphibamiformes includes small newt-like forms that dwelled in freshwater lakes in the Pennsylvanian and Lower Permian of Europe and North America. Here we report a new genus and species, Piasimotriton kochovi, from the early Permian Boskovice Basin, Czech Republic. It has a unique combination of characters, among which the following ones rank as most important: (1) extremely elongated basipterygoid process forming a paired elongate facet for articulation with basal plate, (2) parasphenoid with broad and much abbreviated basal plate, about 2.5 times wider than long, (3) tooth crown with lateral crest, (4) premaxilla with 18 tiny teeth, and (5) a strong dermal ornament on the median skull elements. Piasimotriton kochovi has probably pedicellate teeth. Phylogenetic analysis finds Piasimotriton nests with the Melanerpeton clade with Melanerpeton, Leptorophus, and Schoenfelderpeton, with “Melanerpeton” gracile forming its sister taxon. The possession of various features that are also found in lissamphibians indicates a more widespread distribution of these within their putative stem-group. The stomach content of Piasimotriton kochovi consists of segmented thorax remains of small crustaceans. Piasimotriton probably competed with osteichthyans for arthropod prey and was only present in a short time interval of the lake's existence.
{"title":"A new amphibamiform (Temnospondyli: Branchiosauridae) from the lower Permian of the Czech Boskovice Basin","authors":"R. Werneburg, J. Schneider, S. Štamberg, B. Legler, R. Schoch","doi":"10.1080/02724634.2023.2231994","DOIUrl":"https://doi.org/10.1080/02724634.2023.2231994","url":null,"abstract":"ABSTRACT The temnospondyl clade Amphibamiformes includes small newt-like forms that dwelled in freshwater lakes in the Pennsylvanian and Lower Permian of Europe and North America. Here we report a new genus and species, Piasimotriton kochovi, from the early Permian Boskovice Basin, Czech Republic. It has a unique combination of characters, among which the following ones rank as most important: (1) extremely elongated basipterygoid process forming a paired elongate facet for articulation with basal plate, (2) parasphenoid with broad and much abbreviated basal plate, about 2.5 times wider than long, (3) tooth crown with lateral crest, (4) premaxilla with 18 tiny teeth, and (5) a strong dermal ornament on the median skull elements. Piasimotriton kochovi has probably pedicellate teeth. Phylogenetic analysis finds Piasimotriton nests with the Melanerpeton clade with Melanerpeton, Leptorophus, and Schoenfelderpeton, with “Melanerpeton” gracile forming its sister taxon. The possession of various features that are also found in lissamphibians indicates a more widespread distribution of these within their putative stem-group. The stomach content of Piasimotriton kochovi consists of segmented thorax remains of small crustaceans. Piasimotriton probably competed with osteichthyans for arthropod prey and was only present in a short time interval of the lake's existence.","PeriodicalId":17597,"journal":{"name":"Journal of Vertebrate Paleontology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42450887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-28DOI: 10.1080/02724634.2023.2227236
Naveen Singh, A. Jukar, R. Rana, Ramanuj Patel
ABSTRACT Fossil horses are ubiquitous members of late Neogene and Quaternary ecosystems in Eurasia and Africa. The genus Equus is conventionally thought to be a Pleistocene immigrant into Eurasia from North America, and the concurrent appearance of these monodactyl equids in Eurasia around 2.58 Ma is accepted as the Equus Datum. Here, we report on a specimen of Equus found near the village of Jhil, from the latest Pliocene of the Upper Siwaliks of India. The specimen was recovered from sediments that are lithologically equivalent to the Upper Pliocene Saketi Formation, and have been dated paleomagnetically to lie just below the Gauss–Matuyama boundary, therefore, the latest Pliocene. Our comparative work shows that the anatomy of Jhil specimen is consistent with the Early Pleistocene Siwalik horse, Equus sivalensis. Our finding extends the temporal distribution of this species into the latest Pliocene, and adds to our understanding of the variation in this species of horse. We also argue that along with potential latest Pliocene occurrences of Equus from Europe, and accounting for the Signor–Lipps effect, the Equus Datum should be revised as a latest Pliocene event.
{"title":"The earliest occurrence of Equus in South Asia","authors":"Naveen Singh, A. Jukar, R. Rana, Ramanuj Patel","doi":"10.1080/02724634.2023.2227236","DOIUrl":"https://doi.org/10.1080/02724634.2023.2227236","url":null,"abstract":"ABSTRACT Fossil horses are ubiquitous members of late Neogene and Quaternary ecosystems in Eurasia and Africa. The genus Equus is conventionally thought to be a Pleistocene immigrant into Eurasia from North America, and the concurrent appearance of these monodactyl equids in Eurasia around 2.58 Ma is accepted as the Equus Datum. Here, we report on a specimen of Equus found near the village of Jhil, from the latest Pliocene of the Upper Siwaliks of India. The specimen was recovered from sediments that are lithologically equivalent to the Upper Pliocene Saketi Formation, and have been dated paleomagnetically to lie just below the Gauss–Matuyama boundary, therefore, the latest Pliocene. Our comparative work shows that the anatomy of Jhil specimen is consistent with the Early Pleistocene Siwalik horse, Equus sivalensis. Our finding extends the temporal distribution of this species into the latest Pliocene, and adds to our understanding of the variation in this species of horse. We also argue that along with potential latest Pliocene occurrences of Equus from Europe, and accounting for the Signor–Lipps effect, the Equus Datum should be revised as a latest Pliocene event.","PeriodicalId":17597,"journal":{"name":"Journal of Vertebrate Paleontology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46338232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-28DOI: 10.1080/02724634.2023.2232008
Maciej K. Pindakiewicz, K. Hryniewicz, A. Kaim
ABSTRACT We report a Valanginian (Early Cretaceous) otolith-based ichthyofauna from a section at Wąwał in central Poland. We describe one new genus (Palaeoargentina gen. nov.), six new otolith-based species (Pteralbula polonica sp. nov., Protalbula pentangularis sp. nov., Kokenichthys kuteki sp. nov., Protoelops gracilis sp. nov., Palaeoargentina plicata sp. nov., Archaeotolithus aptychoides sp. nov.) from Wąwał and compare them to species known from similar assemblages elsewhere. The comparison of teleost diversity shows similarity to the Aptian (late Early Cretaceous) and less distinctly to the Maastrichtian (latest Cretaceous) assemblages, rather than to its coeval equivalents from Germany and southern England, and indicates that a considerable teleost diversity already existed before the mid-Cretaceous. The vertical succession of otolith taxa in the Wąwał section is in concordance to the pattern already revealed from the succession of bivalves and other benthic invertebrates and it is attributed to sea level and temperature variations. Previously identified causes of benthic invertebrate succession in the Wąwał section are used to infer paleoenvironmental factors governing fish distribution in the Valanginian marine environment recorded at this site. The new findings suggest that the radiation of teleosts started before the Valanginian, and it was a relatively long and apparently gradual process. This fossil association also reveals a significant shift in the abundance ratio of fish otoliths vs. cephalopod statoliths in fully marine deposits, with otoliths much more abundant than the statoliths in Valanginian and younger sediments while it is otherwise in the Jurassic deposits.
{"title":"Early Cretaceous radiation of teleosts recorded by the otolith-based ichthyofauna from the Valanginian of Wąwał, central Poland","authors":"Maciej K. Pindakiewicz, K. Hryniewicz, A. Kaim","doi":"10.1080/02724634.2023.2232008","DOIUrl":"https://doi.org/10.1080/02724634.2023.2232008","url":null,"abstract":"ABSTRACT We report a Valanginian (Early Cretaceous) otolith-based ichthyofauna from a section at Wąwał in central Poland. We describe one new genus (Palaeoargentina gen. nov.), six new otolith-based species (Pteralbula polonica sp. nov., Protalbula pentangularis sp. nov., Kokenichthys kuteki sp. nov., Protoelops gracilis sp. nov., Palaeoargentina plicata sp. nov., Archaeotolithus aptychoides sp. nov.) from Wąwał and compare them to species known from similar assemblages elsewhere. The comparison of teleost diversity shows similarity to the Aptian (late Early Cretaceous) and less distinctly to the Maastrichtian (latest Cretaceous) assemblages, rather than to its coeval equivalents from Germany and southern England, and indicates that a considerable teleost diversity already existed before the mid-Cretaceous. The vertical succession of otolith taxa in the Wąwał section is in concordance to the pattern already revealed from the succession of bivalves and other benthic invertebrates and it is attributed to sea level and temperature variations. Previously identified causes of benthic invertebrate succession in the Wąwał section are used to infer paleoenvironmental factors governing fish distribution in the Valanginian marine environment recorded at this site. The new findings suggest that the radiation of teleosts started before the Valanginian, and it was a relatively long and apparently gradual process. This fossil association also reveals a significant shift in the abundance ratio of fish otoliths vs. cephalopod statoliths in fully marine deposits, with otoliths much more abundant than the statoliths in Valanginian and younger sediments while it is otherwise in the Jurassic deposits.","PeriodicalId":17597,"journal":{"name":"Journal of Vertebrate Paleontology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48691767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-27DOI: 10.1080/02724634.2023.2224848
Thomas Martin, A. Averianov, J. Schultz, Achim H. Schwermann
{"title":"A stem therian mammal from the Lower Cretaceous of Germany","authors":"Thomas Martin, A. Averianov, J. Schultz, Achim H. Schwermann","doi":"10.1080/02724634.2023.2224848","DOIUrl":"https://doi.org/10.1080/02724634.2023.2224848","url":null,"abstract":"","PeriodicalId":17597,"journal":{"name":"Journal of Vertebrate Paleontology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47568435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-24DOI: 10.1080/02724634.2023.2220015
D. Foffa, S. Nesbitt, B. Kligman, R. Butler, M. Stocker
ABSTRACT Anisodontosaurus greeri is an enigmatic small-bodied tetrapod with a heterodont dentition from the Holbrook Member of the Moenkopi Formation (Middle Triassic) of Arizona (U.S.A.). The evolutionary relationships of this taxon have long been debated and remain uncertain. Using micro-computed tomography (µCT) scans we redescribe the holotype of Anisodontosaurus greeri (UCMP 37804), as well as an additional specimen (MNA.V.1478) that had been informally referred to this taxon. Our new data reveal hidden details of the dentition (i.e., ankylothecodonty and absence of replacement teeth) that, in combination with the tricuspid and mediolaterally expanded crowns, support a referral of both specimens to the archosauromorph clade Trilophosauridae. The referral of MNA.V.1478 to Anisodontosaurus greeri is supported by the unique anatomy of the highly differentiated dentition (i.e., ‘figure of 8’-shaped premolariforms in occlusal views; mesiodistally short tooth row; presence of a distal ‘molariform’ crown). Comparison of Anisodontosaurus greeri with other trilophosaurids highlights marked similarities with Variodens inopinatus from the Upper Triassic deposits of the U.K. Our cladistic analyses confirm these observations, and recover, for the first time, two distinct lineages within Trilophosauridae: one geologically long-lived and comprising Anisodontosaurus and Variodens; and one comprising Tricuspisaurus, Trilophosaurus spp., and Spinosuchus. These results imply that: (i) Anisodontosaurus is one of the oldest known trilophosaurids worldwide and the oldest in North America; (ii) trilophosaurids achieved a broad distribution at low latitudes within western Pangea by the Middle Triassic; (iii) small body sizes were more common than previously thought among trilophosaurids.
{"title":"New specimen and redescription of Anisodontosaurus greeri (Moenkopi Formation: Middle Triassic) and the spatiotemporal origins of Trilophosauridae","authors":"D. Foffa, S. Nesbitt, B. Kligman, R. Butler, M. Stocker","doi":"10.1080/02724634.2023.2220015","DOIUrl":"https://doi.org/10.1080/02724634.2023.2220015","url":null,"abstract":"ABSTRACT Anisodontosaurus greeri is an enigmatic small-bodied tetrapod with a heterodont dentition from the Holbrook Member of the Moenkopi Formation (Middle Triassic) of Arizona (U.S.A.). The evolutionary relationships of this taxon have long been debated and remain uncertain. Using micro-computed tomography (µCT) scans we redescribe the holotype of Anisodontosaurus greeri (UCMP 37804), as well as an additional specimen (MNA.V.1478) that had been informally referred to this taxon. Our new data reveal hidden details of the dentition (i.e., ankylothecodonty and absence of replacement teeth) that, in combination with the tricuspid and mediolaterally expanded crowns, support a referral of both specimens to the archosauromorph clade Trilophosauridae. The referral of MNA.V.1478 to Anisodontosaurus greeri is supported by the unique anatomy of the highly differentiated dentition (i.e., ‘figure of 8’-shaped premolariforms in occlusal views; mesiodistally short tooth row; presence of a distal ‘molariform’ crown). Comparison of Anisodontosaurus greeri with other trilophosaurids highlights marked similarities with Variodens inopinatus from the Upper Triassic deposits of the U.K. Our cladistic analyses confirm these observations, and recover, for the first time, two distinct lineages within Trilophosauridae: one geologically long-lived and comprising Anisodontosaurus and Variodens; and one comprising Tricuspisaurus, Trilophosaurus spp., and Spinosuchus. These results imply that: (i) Anisodontosaurus is one of the oldest known trilophosaurids worldwide and the oldest in North America; (ii) trilophosaurids achieved a broad distribution at low latitudes within western Pangea by the Middle Triassic; (iii) small body sizes were more common than previously thought among trilophosaurids.","PeriodicalId":17597,"journal":{"name":"Journal of Vertebrate Paleontology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42480391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-24DOI: 10.1080/02724634.2023.2222777
Jordan R. Claytor, Lucas N. Weaver, T. Tobin, Gregory P. Wilson Mantilla
ABSTRACT The earliest phases of mammalian recovery following the Cretaceous–Paleogene (K–Pg) mass extinction are incompletely known but crucial to understanding the development of modern terrestrial ecosystems. Here we report new mammalian faunal data from three vertebrate microfossil assemblages in the Hell Creek region of northeastern Montana, the deposition of which we constrain to within the first 28–80 ka of the Paleocene using new stratigraphic observations within a high-resolution chronostratigraphic framework. We quantified the taxonomic diversity among these three assemblages and five other assemblages from both the Hell Creek region and Denver Basin, together spanning the first ca. 300 ka post-K–Pg mass extinction. Our results allowed us to sub-divide the established ‘disaster’ and ‘recovery’ phases of recovery into the following sub-phases: (i) early disaster, characterized by the presence of ‘dead clades walking,’ high relative abundance of bloom taxa, and the appearance of post-mass-extinction immigrants, (ii) late disaster, characterized by a reduction in the number of ‘dead clades walking,’ continued high relative abundance of bloom taxa, and a more diverse assemblage of immigrants, (iii) early recovery, characterized by decreased relative abundance of bloom taxa, and continued immigration, and (iv) late recovery, characterized by the onset of in situ diversification. We note important differences in the pattern and timing of mammalian faunal succession between the Hell Creek and Denver Basin, suggesting that post-K–Pg mammalian recovery was spatially heterogeneous. Our results provided a new model for post-K–Pg mammalian biotic recovery that can now be tested with other earliest Paleocene assemblages across western North America.
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Pub Date : 2023-07-24DOI: 10.1080/02724634.2023.2231254
A. Čerňanský, Rodolphe Tabuce, Dominique Vidalenc
{"title":"A replacement name for Sullivania Čerňanský et al., 2023, non Sullivania Palmer, 1947","authors":"A. Čerňanský, Rodolphe Tabuce, Dominique Vidalenc","doi":"10.1080/02724634.2023.2231254","DOIUrl":"https://doi.org/10.1080/02724634.2023.2231254","url":null,"abstract":"","PeriodicalId":17597,"journal":{"name":"Journal of Vertebrate Paleontology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44267742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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