Zolhafah (Cretaceous turtle) neuroanatomy + Allaeochelys (Eocene turtle) osteology (free pdfs)

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

Additional recent turtle papers:

Free pdf:

Marcos Martín-Jiménez & Adán Pérez-García (2026)
Neuroanatomical study and ecological implications of the Maastrichtian pleurodiran bothremydid turtle Zolhafah bella
Frontiers in Ecology and Evolution 14: 1889939.
Doi: https://doi.org/10.3389/fevo.2026.1889939
https://www.frontiersin.org/journals/ecology-and-evolution/articles/10.3389/fevo.2026.1889939/full


Bothremydidae was a succesful clade of pleurodiran turtles recognized from the Lower Cretaceous to at least the Eocene. This group included freshwater taxa (i.e., the members of Cearachelyini and most of Bothremydini) but also others recognized as littoral or even pelagic forms (i.e., Taphrosphyini and Nigeremydini). The Bothremydini Zolhafah bella was identified from the Maastrichtian of Egypt, only a skull being indisputably attributable to it. It was recovered from coastal sediments so that a marine way of life was inferred for it. The detailed external and internal anatomical analysis of the holotype of this species is performed here, from the three-dimensional models obtained from CT scan images, so that knowledge about its anatomy is increased. In addition, the study of neuroanatomical structures, nerve and vascular canals included into the endocranial and labyrinth cavities, is performed for the first time for the species, increasing the relatively scarce neuroanatomical information available for Bothremydidae. The anatomical and neuroanatomical comparisons between Zolhafah bella and other freshwater and marine bothremydids, including representatives of all lineages of this clade (i.e., Cearachelyini, Bothremydini, Nigeremydini, and Taphrosphyini), provide direct evidence to support a marine way of life for the species.

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Free pdf:

Yann Rollot, Marcus Zuber, Elias Hamann & Walter G. Joyce (2026)
Osteology, paleoecology, and phylogenetic relationships of the carettochelyid turtle Allaeochelys crassesculpta from the middle Eocene Konservat-Lagerstätte of Messel, Germany.
Fossil Record 29(2): 611-674.
doi: https://doi.org/10.3897/fr.29.195537
https://fr.pensoft.net/article/195537/list/9/


Allaeochelys crassesculpta is a carettochelyid turtle from the middle Eocene Messel Pit, near Messel, Germany. The species is known by one of the richest fossil records among turtles consisting of dozens of specimens, of which most represent near-complete and articulated skeletons. Despite this richness, the osteology of Allaeochelys crassesculpta is only known superficially as its anatomy was never described in detail. Here, we use micro-computed laminography and tomography to investigate the anatomy of the skull, shell, and appendicular skeleton and provide high-resolution 3D reconstructions of the cranium, mandible, and fore- and hindlimb. Allaeochelys crassesculpta exhibits an interesting mosaic of features, which are typical of early branching carettochelyids (e.g. a deeper and larger antrum postoticum, a foramen posterius canalis carotici interni located more anteriorly) and more advanced taxa (e.g. presence of a maxilla-quadratojugal contact below the jugal, complete loss of carapace and plastral scutes). We assemble and analyze a new phylogenetic matrix to test the impact of recent anatomical works on the evolutionary history of carettochelyids. We also provide evidence that Allaeochelys crassesculpta was capable of ‘synchronous rowing,’ the unique locomotor mode employed by the extant pig-nosed turtle Carettochelys insculpta and suggest that the acquisition of this peculiar trait may have occurred during the Late Cretaceous to Paleocene.

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