Age of Triassic Niemeyer Complex tetrapods in Brazil + theropod feeding biomechanics
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Ben Creisler
Oct 9, 2025, 11:25:26 AM (10 days ago) Oct 9
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Ben Creisler
Recent papers:
Eric Snively (2025)
Biomechanics: Giant carnivore dinosaurs feeding at the edge
Current Biology 35(19): R925-R928
doi: https://doi.org/10.1016/j.cub.2025.08.045
https://www.sciencedirect.com/science/article/abs/pii/S096098222501111X
The largest theropod dinosaurs evolved strikingly different feeding modes. A new study models the stresses on their skulls and jaws. Tyrannosaurus devastated bones of prey at the price of greater stress in its skull. Spinosaurus and Giganotosaurus induced lower skull stresses when impaling or slashing into flesh.
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Mariana Doering, Maurício S. Garcia, Jeung Hee Schiefelbein, Leonardo Kerber & Rodrigo T. Müller (2025)
New tetrapod remains help constrain the age of a peculiar assemblage, including early dinosaurs and pterosaur precursors, from the Upper Triassic of southern Brazil
Journal of Vertebrate Paleontology e2552552
doi: https://doi.org/10.1080/02724634.2025.2552552
https://www.tandfonline.com/doi/full/10.1080/02724634.2025.2552552
The Hyperodapedon Assemblage Zone (AZ) is a key global marker of the Carnian stage in the Late Triassic. In the Candelária Sequence of Brazil (Rio Grande do Sul), it splits into the lower Hyperodapedon Acme Zone and the upper Exaeretodon Sub-AZ. Here we report new tetrapods from the previously overlooked lower exposures of the Niemeyer Complex (Agudo municipality). Intensive fieldwork yielded dozens of new specimens, including multiple hyperodapedontine rhynchosaur elements, as well as a partial skeleton referable to “Hyperodapedon” sanjuanensis via anatomical comparison and phylogenetic analysis, a lagerpetid, an early-diverging sauropodomorph, and a cynodont. This discovery provides evidence for the first definitive record of the Hyperodapedon Acme Zone in Agudo, with its fauna closely matching other late Carnian sites of southern Brazil, such as Buriol and Cerro da Alemoa, as well as correlative assemblages across southern Pangea. In contrast, the upper Niemeyer fauna is considered to be younger (latest Carnian–earliest Norian transition or early Norian) in age. Distinct lithologies, contrasting fossil assemblages, and the presence of index taxa support recognizing the lower and upper Niemeyer exposures as separate biozones. Our findings refine intercontinental correlations of Triassic tetrapods, enhance understanding of hyperodapedontine postcranial anatomy, and constrain the age of the lower beds of the Niemeyer Complex to the late Carnian.
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Mariana Doering, Maurício S. Garcia, Jeung Hee Schiefelbein, Leonardo Kerber & Rodrigo T. Müller (2025)
New tetrapod remains help constrain the age of a peculiar assemblage, including early dinosaurs and pterosaur precursors, from the Upper Triassic of southern Brazil
Journal of Vertebrate Paleontology e2552552
doi: https://doi.org/10.1080/02724634.2025.2552552
https://www.tandfonline.com/doi/full/10.1080/02724634.2025.2552552
The Hyperodapedon Assemblage Zone (AZ) is a key global marker of the Carnian stage in the Late Triassic. In the Candelária Sequence of Brazil (Rio Grande do Sul), it splits into the lower Hyperodapedon Acme Zone and the upper Exaeretodon Sub-AZ. Here we report new tetrapods from the previously overlooked lower exposures of the Niemeyer Complex (Agudo municipality). Intensive fieldwork yielded dozens of new specimens, including multiple hyperodapedontine rhynchosaur elements, as well as a partial skeleton referable to “Hyperodapedon” sanjuanensis via anatomical comparison and phylogenetic analysis, a lagerpetid, an early-diverging sauropodomorph, and a cynodont. This discovery provides evidence for the first definitive record of the Hyperodapedon Acme Zone in Agudo, with its fauna closely matching other late Carnian sites of southern Brazil, such as Buriol and Cerro da Alemoa, as well as correlative assemblages across southern Pangea. In contrast, the upper Niemeyer fauna is considered to be younger (latest Carnian–earliest Norian transition or early Norian) in age. Distinct lithologies, contrasting fossil assemblages, and the presence of index taxa support recognizing the lower and upper Niemeyer exposures as separate biozones. Our findings refine intercontinental correlations of Triassic tetrapods, enhance understanding of hyperodapedontine postcranial anatomy, and constrain the age of the lower beds of the Niemeyer Complex to the late Carnian.
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Eric Snively (2025)
Biomechanics: Giant carnivore dinosaurs feeding at the edge
Current Biology 35(19): R925-R928
doi: https://doi.org/10.1016/j.cub.2025.08.045
https://www.sciencedirect.com/science/article/abs/pii/S096098222501111X
The largest theropod dinosaurs evolved strikingly different feeding modes. A new study models the stresses on their skulls and jaws. Tyrannosaurus devastated bones of prey at the price of greater stress in its skull. Spinosaurus and Giganotosaurus induced lower skull stresses when impaling or slashing into flesh.
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