A new pan-chelydrid turtle, Tavachelydra stevensoni gen. et sp. nov., from the lower Paleocene (early Danian, Puercan) Corral Bluffs Study Area in the Denver Basin, Colorado

Abstract Isolated pan-chelydrid turtle shell fragments are common in Late Cretaceous and early Paleocene sediments across western North America, but more complete and associated specimens are rare, obfuscating our understanding of the group’s early evolution. Here we describe a new genus and species...

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Main Authors: Tyler R. Lyson, Holger Petermann, Salvador Bastien, Natalie Toth, Evan Tamez-Galvan, Sadie M. Sherman, Walter G. Joyce
Format: Article
Language:English
Published: SpringerOpen 2025-08-01
Series:Swiss Journal of Palaeontology
Subjects:
Online Access:https://doi.org/10.1186/s13358-025-00375-4
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author Tyler R. Lyson
Holger Petermann
Salvador Bastien
Natalie Toth
Evan Tamez-Galvan
Sadie M. Sherman
Walter G. Joyce
author_facet Tyler R. Lyson
Holger Petermann
Salvador Bastien
Natalie Toth
Evan Tamez-Galvan
Sadie M. Sherman
Walter G. Joyce
author_sort Tyler R. Lyson
collection DOAJ
description Abstract Isolated pan-chelydrid turtle shell fragments are common in Late Cretaceous and early Paleocene sediments across western North America, but more complete and associated specimens are rare, obfuscating our understanding of the group’s early evolution. Here we describe a new genus and species, Tavachelydra stevensoni, of stem-chelydrid turtle from the early Paleocene of the Denver Formation (Danian, Puercan I and II) of Colorado based on complete shells, associated pelvic material, and referred cranial material. Our phylogenetic analysis places T. stevensoni as the immediate sister to crown chelydrids based on, among others, a purely ligamentous attachment of the plastron and carapace. The costiform process of the nuchal, an important character complex in chelydroid turtles, shows variation in either ending in peripheral II or III. The T. stevensoni material was mostly found in laminated fine-grained deposits, suggesting this taxon inhabited ponded-water environments. The referred cranial material shows broad triturating surfaces indicating a durophagous diet, further underscoring durophagy as an important feeding strategy during the early Paleocene.
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spelling doaj-art-64e65cfd0be54d76bf8321c2b07644142025-08-20T03:43:11ZengSpringerOpenSwiss Journal of Palaeontology1664-23761664-23842025-08-01144111810.1186/s13358-025-00375-4A new pan-chelydrid turtle, Tavachelydra stevensoni gen. et sp. nov., from the lower Paleocene (early Danian, Puercan) Corral Bluffs Study Area in the Denver Basin, ColoradoTyler R. Lyson0Holger Petermann1Salvador Bastien2Natalie Toth3Evan Tamez-Galvan4Sadie M. Sherman5Walter G. Joyce6Department of Earth Sciences, Denver Museum of Nature & ScienceDepartment of Earth Sciences, Denver Museum of Nature & ScienceDepartment of Earth Sciences, Denver Museum of Nature & ScienceDepartment of Earth Sciences, Denver Museum of Nature & ScienceDepartment of Earth Sciences, Denver Museum of Nature & ScienceDepartment of Earth Sciences, Denver Museum of Nature & ScienceDepartment of Geosciences, University of FribourgAbstract Isolated pan-chelydrid turtle shell fragments are common in Late Cretaceous and early Paleocene sediments across western North America, but more complete and associated specimens are rare, obfuscating our understanding of the group’s early evolution. Here we describe a new genus and species, Tavachelydra stevensoni, of stem-chelydrid turtle from the early Paleocene of the Denver Formation (Danian, Puercan I and II) of Colorado based on complete shells, associated pelvic material, and referred cranial material. Our phylogenetic analysis places T. stevensoni as the immediate sister to crown chelydrids based on, among others, a purely ligamentous attachment of the plastron and carapace. The costiform process of the nuchal, an important character complex in chelydroid turtles, shows variation in either ending in peripheral II or III. The T. stevensoni material was mostly found in laminated fine-grained deposits, suggesting this taxon inhabited ponded-water environments. The referred cranial material shows broad triturating surfaces indicating a durophagous diet, further underscoring durophagy as an important feeding strategy during the early Paleocene.https://doi.org/10.1186/s13358-025-00375-4TestudinesChelydroideaPan-ChelydridaeTaphonomyDurophagy
spellingShingle Tyler R. Lyson
Holger Petermann
Salvador Bastien
Natalie Toth
Evan Tamez-Galvan
Sadie M. Sherman
Walter G. Joyce
A new pan-chelydrid turtle, Tavachelydra stevensoni gen. et sp. nov., from the lower Paleocene (early Danian, Puercan) Corral Bluffs Study Area in the Denver Basin, Colorado
Swiss Journal of Palaeontology
Testudines
Chelydroidea
Pan-Chelydridae
Taphonomy
Durophagy
title A new pan-chelydrid turtle, Tavachelydra stevensoni gen. et sp. nov., from the lower Paleocene (early Danian, Puercan) Corral Bluffs Study Area in the Denver Basin, Colorado
title_full A new pan-chelydrid turtle, Tavachelydra stevensoni gen. et sp. nov., from the lower Paleocene (early Danian, Puercan) Corral Bluffs Study Area in the Denver Basin, Colorado
title_fullStr A new pan-chelydrid turtle, Tavachelydra stevensoni gen. et sp. nov., from the lower Paleocene (early Danian, Puercan) Corral Bluffs Study Area in the Denver Basin, Colorado
title_full_unstemmed A new pan-chelydrid turtle, Tavachelydra stevensoni gen. et sp. nov., from the lower Paleocene (early Danian, Puercan) Corral Bluffs Study Area in the Denver Basin, Colorado
title_short A new pan-chelydrid turtle, Tavachelydra stevensoni gen. et sp. nov., from the lower Paleocene (early Danian, Puercan) Corral Bluffs Study Area in the Denver Basin, Colorado
title_sort new pan chelydrid turtle tavachelydra stevensoni gen et sp nov from the lower paleocene early danian puercan corral bluffs study area in the denver basin colorado
topic Testudines
Chelydroidea
Pan-Chelydridae
Taphonomy
Durophagy
url https://doi.org/10.1186/s13358-025-00375-4
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