Late Cretaceous marine reptile feeding biomechanics from Western Interior Seaway + Guarinisuchus (Paleocene dyrosaurid) tooth histology + turtle diet and K/Pg survivorship
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Ben Creisler
Mar 25, 2026, 1:50:12 PM (9 days ago) Mar 25
to DinosaurMa...@googlegroups.com
Ben Creisler
New reptile papers:
Francesco Della Giustina, Valentin Fallon Gaudichon, Romain Boman, Narimane Chatar, Jamie A. MacLaren & Valentin Fischer (2026)
Distinct feeding biomechanics in Late Cretaceous marine reptiles from the Western Interior Seaway
Palaeontology 69(2): e70051
doi: https://doi.org/10.1111/pala.70051
https://onlinelibrary.wiley.com/doi/10.1111/pala.70051
Sympatry of numerous predatory marine reptiles appears to be the rule rather than the exception in many Mesozoic formations, implying that these lineages are likely to have evolved some form of ecological partitioning. Many studies have focused on dental morphology as a proxy for the feeding habits of aquatic tetrapods, but much more ecological insight may be gained through simulations of the mechanical performance of craniomandibular elements. Here, we conducted the first, large-scale comparative study of marine reptile jaw biomechanics, applying muscle-driven finite element analyses (FEA) on a dataset of high-resolution three-dimensional models. Our study-system included mosasaurids and polycotylid plesiosaurians from the Santonian–Maastrichtian of the Western Interior Seaway (WIS), a vast inland sea that stretched longitudinally across North America during the Late Cretaceous. Muscle insertions were identified to reconstruct jaw adductor muscles and simulate respective muscle and bite forces. We simulated realistic muscle traction dynamics during biting, including simulations at multiple opening angles and bite locations. We recover clearly distinct biomechanical performances among the sample, notably between the slender-snouted mosasaurids (e.g. Clidastes) plus polycotylids, and the robust-jawed mosasaurids (e.g. Prognathodon). By integrating jaw length and other biomechanical metrics derived from our analyses, we provide strong support for differential biting mechanics among these marine predators, which doubtless influenced their ecological roles. Our results offer deeper insight into the feeding ecologies of Late Cretaceous marine reptiles, and provide a unified protocol to assess the role of feeding biomechanics in niche partitioning among sympatric marine reptiles from well-sampled regions.
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Guilherme Hermanson & Serjoscha W. Evers (2026)
Ecological selectivity of diet on turtle K/Pg survivorship
Biology Letters 22 (3): 20250790
doi: https://doi.org/10.1098/rsbl.2025.0790
https://royalsocietypublishing.org/rsbl/article/22/3/20250790/481023/Ecological-selectivity-of-diet-on-turtle-K-Pg
The Cretaceous/Palaeogene (K/Pg) mass extinction was catastrophic, eliminating much of terrestrial life and entire iconic vertebrate groups, such as non-avian dinosaurs and many large marine reptiles. Turtles, however, were one of the less affected reptilian groups, persisting into the Cenozoic with minimal diversity loss. Diet has been suggested to explain high turtle survivorship, as multiple K/Pg survivors exhibit durophagous adaptations, but this has never been properly tested. We use phylogenetic comparative methods to map durophagy across turtle evolution and statistically test a relationship between turtle survivorship and durophagy. Turtles evolved durophagy multiple times over the course of their history, and our results indicate that the number of durophage lineages was more stable across the K/Pg transition than that of non-durophages. Additionally, our findings show that durophagy is positively correlated with turtle K/Pg survivorship, whereby durophagous species exhibit higher predicted survival probabilities. As non-durophagous turtle lineages also survive, albeit with lower probability, other factors might also influence turtle survivorship. Overall, this study provides numerical evidence for dietary ecological selectivity among turtle survivors at the end-Cretaceous crisis. Future taxonomic assessments of the turtle fossil record around the K/Pg boundary will be key to refine these results.
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Francesco Della Giustina, Valentin Fallon Gaudichon, Romain Boman, Narimane Chatar, Jamie A. MacLaren & Valentin Fischer (2026)
Distinct feeding biomechanics in Late Cretaceous marine reptiles from the Western Interior Seaway
Palaeontology 69(2): e70051
doi: https://doi.org/10.1111/pala.70051
https://onlinelibrary.wiley.com/doi/10.1111/pala.70051
Sympatry of numerous predatory marine reptiles appears to be the rule rather than the exception in many Mesozoic formations, implying that these lineages are likely to have evolved some form of ecological partitioning. Many studies have focused on dental morphology as a proxy for the feeding habits of aquatic tetrapods, but much more ecological insight may be gained through simulations of the mechanical performance of craniomandibular elements. Here, we conducted the first, large-scale comparative study of marine reptile jaw biomechanics, applying muscle-driven finite element analyses (FEA) on a dataset of high-resolution three-dimensional models. Our study-system included mosasaurids and polycotylid plesiosaurians from the Santonian–Maastrichtian of the Western Interior Seaway (WIS), a vast inland sea that stretched longitudinally across North America during the Late Cretaceous. Muscle insertions were identified to reconstruct jaw adductor muscles and simulate respective muscle and bite forces. We simulated realistic muscle traction dynamics during biting, including simulations at multiple opening angles and bite locations. We recover clearly distinct biomechanical performances among the sample, notably between the slender-snouted mosasaurids (e.g. Clidastes) plus polycotylids, and the robust-jawed mosasaurids (e.g. Prognathodon). By integrating jaw length and other biomechanical metrics derived from our analyses, we provide strong support for differential biting mechanics among these marine predators, which doubtless influenced their ecological roles. Our results offer deeper insight into the feeding ecologies of Late Cretaceous marine reptiles, and provide a unified protocol to assess the role of feeding biomechanics in niche partitioning among sympatric marine reptiles from well-sampled regions.
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Maria Erivânia Izidio, Esaú Victor de Araújo, Mariana Valéria Haase, Juliana Manso Sayão & Gustavo Ribeiro Oliveira (2026)
Dental histology of Guarinisuchus munizi (Crocodylomorpha, Dyrosauridae)
Historical Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2026.2643940
https://www.tandfonline.com/doi/full/10.1080/08912963.2026.2643940
Guarinisuchus munizi, a Paleocene dyrosaurid crocodyliform from the Maria Farinha Formation (Paraíba Basin, Brazil), survived the Cretaceous–Palaeogene mass extinction. While macromorphology suggests piscivory, its dietary flexibility remains unclear. This study presents the first histological analysis of G. munizi dentition, examining 11 teeth from multiple available specimens (10 isolated, one from jaw fragment) using standard thin-section techniques. Enamel thickness ranges from 0.05–0.13 mm, with thinner enamel (~0.05 mm) indicating soft-tissue piercing and thicker enamel (~0.13 mm) suggesting dietary versatility including hard-shelled prey. Hunter-Schreger bands (HSB) in enamel enhance fracture resistance under polarised light. Dentine deposition rates (von Ebner Incremental Width, VEIW: 3–42 µm) show high variability, exceeding uniformity in most crocodyliforms and likely reflecting environmental sensitivity to seasonal water temperature and resource fluctuations in the Paraíba Basin. This metabolic flexibility underscores Dyrosauridae’s post-K-Pg adaptive capacity. Combined enamel microstructure and growth-line variation suggest functional differentiation and individual diversity. Our findings demonstrate dental histology’s value for reconstructing extinct crocodyliform palaeoecology, establishing a foundation for dyrosaurid research.
Dental histology of Guarinisuchus munizi (Crocodylomorpha, Dyrosauridae)
Historical Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2026.2643940
https://www.tandfonline.com/doi/full/10.1080/08912963.2026.2643940
Guarinisuchus munizi, a Paleocene dyrosaurid crocodyliform from the Maria Farinha Formation (Paraíba Basin, Brazil), survived the Cretaceous–Palaeogene mass extinction. While macromorphology suggests piscivory, its dietary flexibility remains unclear. This study presents the first histological analysis of G. munizi dentition, examining 11 teeth from multiple available specimens (10 isolated, one from jaw fragment) using standard thin-section techniques. Enamel thickness ranges from 0.05–0.13 mm, with thinner enamel (~0.05 mm) indicating soft-tissue piercing and thicker enamel (~0.13 mm) suggesting dietary versatility including hard-shelled prey. Hunter-Schreger bands (HSB) in enamel enhance fracture resistance under polarised light. Dentine deposition rates (von Ebner Incremental Width, VEIW: 3–42 µm) show high variability, exceeding uniformity in most crocodyliforms and likely reflecting environmental sensitivity to seasonal water temperature and resource fluctuations in the Paraíba Basin. This metabolic flexibility underscores Dyrosauridae’s post-K-Pg adaptive capacity. Combined enamel microstructure and growth-line variation suggest functional differentiation and individual diversity. Our findings demonstrate dental histology’s value for reconstructing extinct crocodyliform palaeoecology, establishing a foundation for dyrosaurid research.
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Free pdf:
Guilherme Hermanson & Serjoscha W. Evers (2026)
Ecological selectivity of diet on turtle K/Pg survivorship
Biology Letters 22 (3): 20250790
doi: https://doi.org/10.1098/rsbl.2025.0790
https://royalsocietypublishing.org/rsbl/article/22/3/20250790/481023/Ecological-selectivity-of-diet-on-turtle-K-Pg
The Cretaceous/Palaeogene (K/Pg) mass extinction was catastrophic, eliminating much of terrestrial life and entire iconic vertebrate groups, such as non-avian dinosaurs and many large marine reptiles. Turtles, however, were one of the less affected reptilian groups, persisting into the Cenozoic with minimal diversity loss. Diet has been suggested to explain high turtle survivorship, as multiple K/Pg survivors exhibit durophagous adaptations, but this has never been properly tested. We use phylogenetic comparative methods to map durophagy across turtle evolution and statistically test a relationship between turtle survivorship and durophagy. Turtles evolved durophagy multiple times over the course of their history, and our results indicate that the number of durophage lineages was more stable across the K/Pg transition than that of non-durophages. Additionally, our findings show that durophagy is positively correlated with turtle K/Pg survivorship, whereby durophagous species exhibit higher predicted survival probabilities. As non-durophagous turtle lineages also survive, albeit with lower probability, other factors might also influence turtle survivorship. Overall, this study provides numerical evidence for dietary ecological selectivity among turtle survivors at the end-Cretaceous crisis. Future taxonomic assessments of the turtle fossil record around the K/Pg boundary will be key to refine these results.
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