Camarasaurus and Stegosaurus finger motion + Cretaceous pliosaur, ichthyosaur, pterosaur food web + archosauromorph assemblage from Early Triassic of South Africa
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Ben Creisler
Jul 28, 2026, 1:49:13 PM (9 days ago) Jul 28
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Ben Creisler
Philip J. Senter (2026)
Investigation of finger motion in two quadrupedal dinosaurs: the sauropod Camarasaurus and stegosaur Stegosaurus
Alcheringa (advance online publication)
doi: https://doi.org/10.1080/03115518.2026.2697810
https://www.tandfonline.com/doi/full/10.1080/03115518.2026.2697810
Free pdf:
https://www.tandfonline.com/doi/epdf/10.1080/03115518.2026.2697810
The metacarpals of sauropod dinosaurs were arranged to form a tube or semi-tube, and those of stegosaurs were arranged to form a semi-tube. This orientation aimed the fingers toward each other during flexion and would have caused the fingers to crowd each other and obstruct each other’s movements during flexion if the fingers were as mobile as they were in other dinosaurs. I therefore sought to determine whether finger movement in members of these two lineages involved any special modifications to prevent such obstruction. I posed the bones of the hand skeletons of the sauropod Camarasaurus sp. and the stegosaur Stegosaurus sulcatus in sandboxes to measure their range of motion (ROM). The results indicate that limitations upon finger mobility in both Camarasaurus and Stegosaurus prevented the fingers from crowding each other or obstructing each other’s movement. In Camarasaurus, ROM in fingers I–IV was limited to the field of hyperextension. In Stegosaurus, ROM in finger II was limited to the field of hyperextension, and the other fingers were immobile. These two dinosaur lineages thus provide a remarkable example of convergent evolution, not only in metacarpal configuration but also in the special modification (limited finger mobility) to prevent the potential predicament (fingers obstructing each other’s movements) that said configuration would otherwise have caused.
====
Matt Andrew White, Joseph John Bevitt, Mackenzie Jordan Enchelmaier, Kevin William Petersen & Peter William Trusler (2026)
Beneath the waves: Extraordinary dietary insights from a dismembered ichthyosaur from the lower Cretaceous
Gondwana Research (advance online publication)
doi: https://doi.org/10.1016/j.gr.2026.05.014
https://www.sciencedirect.com/science/article/pii/S1342937X26001656
Highlights
Taphonomy of a Platypterygius specimen, with multiple pliosaur bite marks and stomach content.
First evidence that ichthyosaurs ate pterosaurs.
First evidence of food web interactions between pliosaurs, ichthyosaurs and pterosaurs.
Abstract
Marine reptile lineages thrived throughout the Mesozoic era and are known to have performed diverse roles in marine ecosystems. Ichthyosaurs are characterized by their often dolphin-like convergences and thunniform bodies, having evolved a variety of forms and sizes that presumably represent niche diversity within their bauplan. Here, we report a spectacular discovery from the Lower Cretaceous of Australia: a dismembered adult ichthyosaur, Platypterygius australis (∼6–7 m in length), with preserved gut contents alongside massive bite marks on its skeleton that together, illuminate its role as both predator and prey within the Eromanga Basin marine ecosystem.
Numerous bite marks are preserved on the vertebral centra of the ichthyosaur; some are split with corresponding halves missing, suggesting evidence of oral processing. Given their size, the bite marks were likely inflicted by the largest marine predator in the region, the pliosaur Kronosaurus queenslandicus. The gut contents of the P. australis specimen were preserved as globular concretions, likely formed from the ichthyosaur’s spilt digestive tract. Neutron tomography NT scanning revealed one of these concretions contained fragments of fish, cephalopods, and two pterosaur bones, including a dentary fragment. The pterosaur dentary fragment was identified as a near-exact match to a previously unnamed taxon within Ornithocheiroidae. This discovery provides the first definitive evidence of food web interactions among these three groups and marks the first recorded instance of an ichthyosaur consuming a pterosaur or part thereof.
F. B. Tolchard, V. Buffa, P. J. Hancox, A. B. Heckert, K. N. Dollman, J. Botha & J. N. Choiniere (2026)
Morphological diversity in humeral remains from a South African Konzentrat-Laggerstätte site provide new insights into the Early Triassic archosauromorph radiation
The Anatomical Record (advance online publication)
doi: https://doi.org/10.1002/ar.70258
https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.70258
The end-Permian mass extinction event was the largest faunal mass extinction in the history of life on Earth. Understanding the recovery of terrestrial diversity in the Early Triassic is confounded by a global scarcity of continental fossil-bearing deposits of this time frame. This is especially problematic for vertebrate paleontology because the clade encompassing living birds, crocodiles, and turtles (the Archosauromorpha) is hypothesized to undergo a rapid radiation at this time. The Langbergia-Garjainia Subzone (LGSz) of South Africa represents one of the few highly fossiliferous Early Triassic (Olenekian) localities worldwide. However, only one archosauromorph taxon is described from this site to date, the large-bodied Garjainia madiba. Here, we assess a newly discovered assemblage of fragmentary archosauromorph humeri from localities in Driefontein 11 revealing an impressive diversity of minimally six taxa. These include non-archosauriform archosauromorphs, non-archosaurian archosauriforms, and crown archosaurs, mirroring the contemporaneous diversity seen in Laurasian deposits. Importantly, we identify among this sample potentially the first records of azendohsaurids and aphanosaurs from South Africa. The archosauromorph assemblage from the LGSz displays a wide array of body sizes and anatomical characteristics. These findings further support mounting evidence to Early Triassic origins of the archosauromorph evolutionary radiation.
=====
New papers:
Free pdf:
Philip J. Senter (2026)
Investigation of finger motion in two quadrupedal dinosaurs: the sauropod Camarasaurus and stegosaur Stegosaurus
Alcheringa (advance online publication)
doi: https://doi.org/10.1080/03115518.2026.2697810
https://www.tandfonline.com/doi/full/10.1080/03115518.2026.2697810
Free pdf:
https://www.tandfonline.com/doi/epdf/10.1080/03115518.2026.2697810
The metacarpals of sauropod dinosaurs were arranged to form a tube or semi-tube, and those of stegosaurs were arranged to form a semi-tube. This orientation aimed the fingers toward each other during flexion and would have caused the fingers to crowd each other and obstruct each other’s movements during flexion if the fingers were as mobile as they were in other dinosaurs. I therefore sought to determine whether finger movement in members of these two lineages involved any special modifications to prevent such obstruction. I posed the bones of the hand skeletons of the sauropod Camarasaurus sp. and the stegosaur Stegosaurus sulcatus in sandboxes to measure their range of motion (ROM). The results indicate that limitations upon finger mobility in both Camarasaurus and Stegosaurus prevented the fingers from crowding each other or obstructing each other’s movement. In Camarasaurus, ROM in fingers I–IV was limited to the field of hyperextension. In Stegosaurus, ROM in finger II was limited to the field of hyperextension, and the other fingers were immobile. These two dinosaur lineages thus provide a remarkable example of convergent evolution, not only in metacarpal configuration but also in the special modification (limited finger mobility) to prevent the potential predicament (fingers obstructing each other’s movements) that said configuration would otherwise have caused.
====
Free pdf:
Matt Andrew White, Joseph John Bevitt, Mackenzie Jordan Enchelmaier, Kevin William Petersen & Peter William Trusler (2026)
Beneath the waves: Extraordinary dietary insights from a dismembered ichthyosaur from the lower Cretaceous
Gondwana Research (advance online publication)
doi: https://doi.org/10.1016/j.gr.2026.05.014
https://www.sciencedirect.com/science/article/pii/S1342937X26001656
Highlights
Taphonomy of a Platypterygius specimen, with multiple pliosaur bite marks and stomach content.
First evidence that ichthyosaurs ate pterosaurs.
First evidence of food web interactions between pliosaurs, ichthyosaurs and pterosaurs.
Abstract
Marine reptile lineages thrived throughout the Mesozoic era and are known to have performed diverse roles in marine ecosystems. Ichthyosaurs are characterized by their often dolphin-like convergences and thunniform bodies, having evolved a variety of forms and sizes that presumably represent niche diversity within their bauplan. Here, we report a spectacular discovery from the Lower Cretaceous of Australia: a dismembered adult ichthyosaur, Platypterygius australis (∼6–7 m in length), with preserved gut contents alongside massive bite marks on its skeleton that together, illuminate its role as both predator and prey within the Eromanga Basin marine ecosystem.
Numerous bite marks are preserved on the vertebral centra of the ichthyosaur; some are split with corresponding halves missing, suggesting evidence of oral processing. Given their size, the bite marks were likely inflicted by the largest marine predator in the region, the pliosaur Kronosaurus queenslandicus. The gut contents of the P. australis specimen were preserved as globular concretions, likely formed from the ichthyosaur’s spilt digestive tract. Neutron tomography NT scanning revealed one of these concretions contained fragments of fish, cephalopods, and two pterosaur bones, including a dentary fragment. The pterosaur dentary fragment was identified as a near-exact match to a previously unnamed taxon within Ornithocheiroidae. This discovery provides the first definitive evidence of food web interactions among these three groups and marks the first recorded instance of an ichthyosaur consuming a pterosaur or part thereof.
=====
F. B. Tolchard, V. Buffa, P. J. Hancox, A. B. Heckert, K. N. Dollman, J. Botha & J. N. Choiniere (2026)
Morphological diversity in humeral remains from a South African Konzentrat-Laggerstätte site provide new insights into the Early Triassic archosauromorph radiation
The Anatomical Record (advance online publication)
doi: https://doi.org/10.1002/ar.70258
https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.70258
The end-Permian mass extinction event was the largest faunal mass extinction in the history of life on Earth. Understanding the recovery of terrestrial diversity in the Early Triassic is confounded by a global scarcity of continental fossil-bearing deposits of this time frame. This is especially problematic for vertebrate paleontology because the clade encompassing living birds, crocodiles, and turtles (the Archosauromorpha) is hypothesized to undergo a rapid radiation at this time. The Langbergia-Garjainia Subzone (LGSz) of South Africa represents one of the few highly fossiliferous Early Triassic (Olenekian) localities worldwide. However, only one archosauromorph taxon is described from this site to date, the large-bodied Garjainia madiba. Here, we assess a newly discovered assemblage of fragmentary archosauromorph humeri from localities in Driefontein 11 revealing an impressive diversity of minimally six taxa. These include non-archosauriform archosauromorphs, non-archosaurian archosauriforms, and crown archosaurs, mirroring the contemporaneous diversity seen in Laurasian deposits. Importantly, we identify among this sample potentially the first records of azendohsaurids and aphanosaurs from South Africa. The archosauromorph assemblage from the LGSz displays a wide array of body sizes and anatomical characteristics. These findings further support mounting evidence to Early Triassic origins of the archosauromorph evolutionary radiation.
=====
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