Ben Creisler
New papers:
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Our understanding of early metriorhynchid evolution, the highly specialised pelagic clade of Mesozoic crocodylomorphs, is hampered by the paucity of basal metriorhynchoids and how poorly preserved most of these fossils are. This means the transition from a 'gharial-like' body-plan to a 'pseudo-dolphin-like' one, which characterises metriorhynchoid evolution, is still poorly understood. Herein the Middle Jurassic taxon Teleidosaurus calvadosii (J.A. Eudes-Deslongchamps, 1866) is re-evaluated. The holotype of T. calvadosii was destroyed during World War Two, as were all referred specimens. All that survived are plaster casts of the holotype. However, a recently discovered specimen from the middle Bathonian of EcouchÃ, Normandy, France is herein referred to T. calvadosii. This specimen preserves the antorbital region, an incomplete mandible and one cervical vertebra. This specimen is designated as neotype of T. calvadosii. The new specimen allows to re-evaluate the anatomy of T. calvadosii, in particular the antorbital fenestra, which has been misunderstood. Moreover, a comparison is made between the French Middle Jurassic metriorhynchoids Teleidosaurus and Eoneustes. Both genera appear as valid and E. bathonicus is considered to be a nomen dubium.
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J.Dridi (2020)
A new crocodylomorph tooth assemblage from the Tataouine Basin and comments on the stratigraphic context of the Douiret Formation.
Annales de PalÃontologie (advance online publication)
doi:
https://doi.org/10.1016/j.annpal.2020.102424https://www.sciencedirect.com/science/article/abs/pii/S0753396920300471
A new crocodylomorph tooth assemblage from the Lower Member of the Douiret Formation (uppermost Jurassicâlowermost Cretaceous) in southeastern Tunisia is described. These teeth have been grouped into five morphotypes based on their diagnostic morphological features. The sample includes teeth, which have not been reported until now, such as non-Machimosaurini teleosauroid teeth, and labiolingually compressed tooth crowns with cutting edges devoid of serrations. Certain minor morphometric differences have been interpreted as ontogenetic or being possibly related to the position of the teeth in the jaws. Three trophic entities have subsequently been defined on the basis of the morphological characteristics of the teeth, and a possible niche partitioning between at least three crocodylomorph taxa is highlighted for the first time in the Tataouine Basin. On the other hand, the stratigraphic context of the Douiret Formation is thoroughly discussed in order to show how stratigraphic uncertainties could significantly impact previous attempts at reconstructing the macroevolutionary history of Crocodylomorpha. The latter should be treated with caution when the stratigraphic context of the fossil bearing formation remains a subject of debate.
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