Venetoraptor (Triassic lagerpetid) braincase anatomy + Permian synapsid skull shapes + Polycotylus bitten by Xiphactinus (free pdfs)
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Ben Creisler
Mar 13, 2026, 1:32:03 PM (4 days ago) Mar 13
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Ben Creisler
Lísie V.S. Damke, Leonardo Kerber, Mario Bronzati, Maurício S. Garcia, Martín D. Ezcurra, Sterling J. Nesbitt & Rodrigo T. Müller (2026)
Braincase anatomy and palaeoneurology of Venetoraptor gassenae, a lagerpetid pterosauromorph from the Late Triassic of southern Brazil
Palaeontology 69(2): e70047
doi: https://doi.org/10.1111/pala.70047
https://onlinelibrary.wiley.com/doi/10.1111/pala.70047
Free pdf:
https://onlinelibrary.wiley.com/doi/epdf/10.1111/pala.70047
There is a growing consensus that pterosaurs and the flightless Lagerpetidae are closely related. This relationship is supported by apomorphies throughout the skeleton, including endocranial character states such as a well-developed floccular fossa and a tall anterior semicircular canal. Our knowledge of lagerpetid anatomy has been improved by recent discoveries. Among them, the Brazilian record plays a significant role, having produced two described species, Ixalerpeton polesinensis and Venetoraptor gassenae, and several more fragmentary specimens. In this study, we used an x-ray micro-computed tomographic scan to describe the endocranial anatomy of the holotype of Venetoraptor gassenae. The endocranial anatomy of Venetoraptor gassenae is similar in shape to that of other described lagerpetids, and we reach the following conclusions: (1) in pterosaurs, the metotic foramen exits posteriorly, whereas in lagerpetids and dinosauromorphs it exits through the lateral wall of the braincase; and (2) Venetoraptor gassenae is unique among lagerpetids in having only one exit for cranial nerve XII, expanding its differential diagnosis. These differences highlight that the braincase anatomy of lagerpetids is aligned with the anatomical disparity observed in the group. Finally, we discuss why future studies should focus on comprehending patterns of braincase pneumaticity in avemetatarsalians.
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Elías Adán Warshaw, Suresh Anmol Singh & Michael James Benton (2026)
Trophic ecology outweighed intrinsic constraints in shaping skull evolution of carnivorous Permian synapsids
Communications Biology (advance online publication)
doi: https://doi.org/10.1038/s42003-026-09824-3
https://www.nature.com/articles/s42003-026-09824-3
We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.
Abstract
The first truly terrestrial apex predators were carnivorous synapsids, which emerged in the Permian over 260 million years ago and evolved against a backdrop of harsh ecological change. In many ways, these predators mirrored feeding modes and evolutionary trends seen in their much later descendants, the flesh-eating mammals; could apparent resemblances indicate evolutionary constraints on form, or were they shaped by natural selection? Here we show that the skulls of carnivorous Permian synapsids were shaped primarily by adaptation, their shapes reflecting trophic function, and with similarities between distant relatives arising by convergence through natural selection. Conversely, we find no evidence for constraint in terms of the direction or rate of evolution based on patterns of topological modularity. These findings illustrate methods of identifying evolutionary processes in deep time and emphasise the role of competition and adaptation over intrinsic constraints in macroevolution.
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New papers:
Free pdf:
Lísie V.S. Damke, Leonardo Kerber, Mario Bronzati, Maurício S. Garcia, Martín D. Ezcurra, Sterling J. Nesbitt & Rodrigo T. Müller (2026)
Braincase anatomy and palaeoneurology of Venetoraptor gassenae, a lagerpetid pterosauromorph from the Late Triassic of southern Brazil
Palaeontology 69(2): e70047
doi: https://doi.org/10.1111/pala.70047
https://onlinelibrary.wiley.com/doi/10.1111/pala.70047
Free pdf:
https://onlinelibrary.wiley.com/doi/epdf/10.1111/pala.70047
There is a growing consensus that pterosaurs and the flightless Lagerpetidae are closely related. This relationship is supported by apomorphies throughout the skeleton, including endocranial character states such as a well-developed floccular fossa and a tall anterior semicircular canal. Our knowledge of lagerpetid anatomy has been improved by recent discoveries. Among them, the Brazilian record plays a significant role, having produced two described species, Ixalerpeton polesinensis and Venetoraptor gassenae, and several more fragmentary specimens. In this study, we used an x-ray micro-computed tomographic scan to describe the endocranial anatomy of the holotype of Venetoraptor gassenae. The endocranial anatomy of Venetoraptor gassenae is similar in shape to that of other described lagerpetids, and we reach the following conclusions: (1) in pterosaurs, the metotic foramen exits posteriorly, whereas in lagerpetids and dinosauromorphs it exits through the lateral wall of the braincase; and (2) Venetoraptor gassenae is unique among lagerpetids in having only one exit for cranial nerve XII, expanding its differential diagnosis. These differences highlight that the braincase anatomy of lagerpetids is aligned with the anatomical disparity observed in the group. Finally, we discuss why future studies should focus on comprehending patterns of braincase pneumaticity in avemetatarsalians.
====
Free pdf:
Elías Adán Warshaw, Suresh Anmol Singh & Michael James Benton (2026)
Trophic ecology outweighed intrinsic constraints in shaping skull evolution of carnivorous Permian synapsids
Communications Biology (advance online publication)
doi: https://doi.org/10.1038/s42003-026-09824-3
https://www.nature.com/articles/s42003-026-09824-3
We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.
Abstract
The first truly terrestrial apex predators were carnivorous synapsids, which emerged in the Permian over 260 million years ago and evolved against a backdrop of harsh ecological change. In many ways, these predators mirrored feeding modes and evolutionary trends seen in their much later descendants, the flesh-eating mammals; could apparent resemblances indicate evolutionary constraints on form, or were they shaped by natural selection? Here we show that the skulls of carnivorous Permian synapsids were shaped primarily by adaptation, their shapes reflecting trophic function, and with similarities between distant relatives arising by convergence through natural selection. Conversely, we find no evidence for constraint in terms of the direction or rate of evolution based on patterns of topological modularity. These findings illustrate methods of identifying evolutionary processes in deep time and emphasise the role of competition and adaptation over intrinsic constraints in macroevolution.
====
Free access (to read):
Stephanie K. Drumheller, F. Robin O’keefe, Miles L. Mayhall, Emma Stalker & Christopher A. Brochu (2026)
A bite to the throat: A probable Xiphactinus attack on a Polycotylus from the Cretaceous Mooreville Chalk of Alabama, U.S.A.
Journal of Vertebrate Paleontology e2625732
doi: https://doi.org/10.1080/02724634.2026.2625732
https://www.tandfonline.com/doi/full/10.1080/02724634.2026.2625732
Free access:
https://www.tandfonline.com/doi/epdf/10.1080/02724634.2026.2625732
Fossil bite marks provide insights into trophic and agonistic behaviors, but they can be difficult to associate with a specific actor. Finding embedded teeth, while rare, removes this ambiguity. Here we describe a tooth embedded in a mid-cervical vertebra of a subadult plesiosaur, Polycotylus latipinnis, from the Santonian/Campanian Mooreville Chalk of Green County, Alabama, U.S.A. Exposed portions of the tooth are damaged, hindering identification, so internal visualization was accomplished via computed tomographic (CT) scanning. Sectioning revealed a conical, unornamented, slightly curved tooth with a large pulp cavity. These features are inconsistent with the marine reptiles and sharks present in the Mooreville Chalk. However, they are consistent with a large, osteichthyan fish, of which only the enormous, co-occurring ichthyodectid Xiphactinus had sufficiently large gape and dentition. Preservation of the Polycotylus suggests a short residence time near the surface, before sinking into anoxic waters, limiting the window during which extensive scavenging and decomposition could have occurred. The location and depth of the bite could certainly have been fatal, severing the carotid sheath and disrupting the trachea, causing a loss of lung pressure and associated buoyancy, highlighting the vulnerability of elongate necks to predatory attack. This find joins the surprising diversity of bite marks and gut contents known from the Mooreville and contemporaneous Smoky Hill Chalks. These lines of evidence reveal a complex, dynamic trophic structure in North America’s Late Cretaceous coastal waters, with large marine reptiles and osteichthyan fish vying for position at the top of the food chain.
Stephanie K. Drumheller, F. Robin O’keefe, Miles L. Mayhall, Emma Stalker & Christopher A. Brochu (2026)
A bite to the throat: A probable Xiphactinus attack on a Polycotylus from the Cretaceous Mooreville Chalk of Alabama, U.S.A.
Journal of Vertebrate Paleontology e2625732
doi: https://doi.org/10.1080/02724634.2026.2625732
https://www.tandfonline.com/doi/full/10.1080/02724634.2026.2625732
Free access:
https://www.tandfonline.com/doi/epdf/10.1080/02724634.2026.2625732
Fossil bite marks provide insights into trophic and agonistic behaviors, but they can be difficult to associate with a specific actor. Finding embedded teeth, while rare, removes this ambiguity. Here we describe a tooth embedded in a mid-cervical vertebra of a subadult plesiosaur, Polycotylus latipinnis, from the Santonian/Campanian Mooreville Chalk of Green County, Alabama, U.S.A. Exposed portions of the tooth are damaged, hindering identification, so internal visualization was accomplished via computed tomographic (CT) scanning. Sectioning revealed a conical, unornamented, slightly curved tooth with a large pulp cavity. These features are inconsistent with the marine reptiles and sharks present in the Mooreville Chalk. However, they are consistent with a large, osteichthyan fish, of which only the enormous, co-occurring ichthyodectid Xiphactinus had sufficiently large gape and dentition. Preservation of the Polycotylus suggests a short residence time near the surface, before sinking into anoxic waters, limiting the window during which extensive scavenging and decomposition could have occurred. The location and depth of the bite could certainly have been fatal, severing the carotid sheath and disrupting the trachea, causing a loss of lung pressure and associated buoyancy, highlighting the vulnerability of elongate necks to predatory attack. This find joins the surprising diversity of bite marks and gut contents known from the Mooreville and contemporaneous Smoky Hill Chalks. These lines of evidence reveal a complex, dynamic trophic structure in North America’s Late Cretaceous coastal waters, with large marine reptiles and osteichthyan fish vying for position at the top of the food chain.
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