Taxonomic Revision of Therocephalians (Therapsida: Theriodontia) from the Lower Triassic of Antarctica
We reevaluate the taxonomic status of therocephalian fossils recovered from the lower Fremouw Formation (Lower Triassic) of the central Transantarctic Mountains, Antarctica. The material, which includes mostly fragmentary juvenile specimens, is reidentified using an apomorphy-based approach. We reco...
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ftbioone:10.1206/3738.2 2024-06-02T07:58:02+00:00 Taxonomic Revision of Therocephalians (Therapsida: Theriodontia) from the Lower Triassic of Antarctica Adam K. Huttenlocker Christian A. Sidor Adam K. Huttenlocker Christian A. Sidor world 2012-03-05 text/HTML https://doi.org/10.1206/3738.2 en eng American Museum of Natural History doi:10.1206/3738.2 All rights reserved. https://doi.org/10.1206/3738.2 Text 2012 ftbioone https://doi.org/10.1206/3738.2 2024-05-07T01:03:04Z We reevaluate the taxonomic status of therocephalian fossils recovered from the lower Fremouw Formation (Lower Triassic) of the central Transantarctic Mountains, Antarctica. The material, which includes mostly fragmentary juvenile specimens, is reidentified using an apomorphy-based approach. We recognize the presence of three higher-level taxa: Eutherocephalia, Akidnognathidae, and Baurioidea. The only genus-level identification is for a partial lower jaw and pterygoid tentatively attributed to the baurioid, Ericiolacerta parva. An indeterminate theriodont partial skull is reassigned to the therocephalian family Akidnognathidae. The holotypes of Pedaeosaurus parvus and Rhigosaurus glacialis are represented by indeterminate juvenile baurioids and, in the absence of clear autapomorphies, are considered nomina dubia. The results of the taxonomic revision indicate that the therocephalian fauna of Antarctica lacks endemic genera and thus corresponds to that of the Triassic Lystrosaurus Assemblage Zone fauna of South Africa's Karoo Basin. More generally, we consider the southern Gondwanan basins of South Africa and Antarctica to sample a broadly distributed Lower Triassic tetrapod fauna, although the latter basin documents the first occurrence of several taxa (e.g., Kombuisia, Palacrodon). More precise (i.e., species-level) identifications are needed to better constrain the biogeographic signal for therocephalians, but the presence of juveniles strongly suggests that this group of therapsids, like dicynodonts, were year-round high-latitude inhabitants during Early Triassic times. Text Antarc* Antarctica BioOne Online Journals Transantarctic Mountains American Museum Novitates 3738 3738 1 19 |
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English |
description |
We reevaluate the taxonomic status of therocephalian fossils recovered from the lower Fremouw Formation (Lower Triassic) of the central Transantarctic Mountains, Antarctica. The material, which includes mostly fragmentary juvenile specimens, is reidentified using an apomorphy-based approach. We recognize the presence of three higher-level taxa: Eutherocephalia, Akidnognathidae, and Baurioidea. The only genus-level identification is for a partial lower jaw and pterygoid tentatively attributed to the baurioid, Ericiolacerta parva. An indeterminate theriodont partial skull is reassigned to the therocephalian family Akidnognathidae. The holotypes of Pedaeosaurus parvus and Rhigosaurus glacialis are represented by indeterminate juvenile baurioids and, in the absence of clear autapomorphies, are considered nomina dubia. The results of the taxonomic revision indicate that the therocephalian fauna of Antarctica lacks endemic genera and thus corresponds to that of the Triassic Lystrosaurus Assemblage Zone fauna of South Africa's Karoo Basin. More generally, we consider the southern Gondwanan basins of South Africa and Antarctica to sample a broadly distributed Lower Triassic tetrapod fauna, although the latter basin documents the first occurrence of several taxa (e.g., Kombuisia, Palacrodon). More precise (i.e., species-level) identifications are needed to better constrain the biogeographic signal for therocephalians, but the presence of juveniles strongly suggests that this group of therapsids, like dicynodonts, were year-round high-latitude inhabitants during Early Triassic times. |
author2 |
Adam K. Huttenlocker Christian A. Sidor |
format |
Text |
author |
Adam K. Huttenlocker Christian A. Sidor |
spellingShingle |
Adam K. Huttenlocker Christian A. Sidor Taxonomic Revision of Therocephalians (Therapsida: Theriodontia) from the Lower Triassic of Antarctica |
author_facet |
Adam K. Huttenlocker Christian A. Sidor |
author_sort |
Adam K. Huttenlocker |
title |
Taxonomic Revision of Therocephalians (Therapsida: Theriodontia) from the Lower Triassic of Antarctica |
title_short |
Taxonomic Revision of Therocephalians (Therapsida: Theriodontia) from the Lower Triassic of Antarctica |
title_full |
Taxonomic Revision of Therocephalians (Therapsida: Theriodontia) from the Lower Triassic of Antarctica |
title_fullStr |
Taxonomic Revision of Therocephalians (Therapsida: Theriodontia) from the Lower Triassic of Antarctica |
title_full_unstemmed |
Taxonomic Revision of Therocephalians (Therapsida: Theriodontia) from the Lower Triassic of Antarctica |
title_sort |
taxonomic revision of therocephalians (therapsida: theriodontia) from the lower triassic of antarctica |
publisher |
American Museum of Natural History |
publishDate |
2012 |
url |
https://doi.org/10.1206/3738.2 |
op_coverage |
world |
geographic |
Transantarctic Mountains |
geographic_facet |
Transantarctic Mountains |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_source |
https://doi.org/10.1206/3738.2 |
op_relation |
doi:10.1206/3738.2 |
op_rights |
All rights reserved. |
op_doi |
https://doi.org/10.1206/3738.2 |
container_title |
American Museum Novitates |
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3738 |
container_issue |
3738 |
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1 |
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19 |
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1800741292081152000 |