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[dinosaur] New plesiosaur specimens from Upper Cretaceous of Morocco

Ben Creisler

A new paper:

Rémi Allemand, Nathalie Bardet, Alexandra Houssaye & Peggy Vincent (2017)
New plesiosaurian specimens (Reptilia, Plesiosauria) from the Upper Cretaceous (Turonian) of Goulmima (Southern Morocco).
Cretaceous Research (advance online publication)
doi: https://doi.org/10.1016/j.cretres.2017.09.017

Two new plesiosaurian specimens coming from lower Turonian deposits of Goulmima in Morocco are described. The three-dimensional digital reconstructions of both specimens provides details about their skull roof, mandible and atlas-axis complex. In addition, computed tomography allows to reconstruct their braincase, which is a part of the skull poorly known among plesiosaurians due to either poor preservation and/or insufficient preparation, but that offers a large number of characters used in phylogenetical analyses. After descriptions and comparisons, the two specimens D1-8213 and MNHN F-GOU14 are assigned to Libonectes morgani and to an undetermined Polycotylidae, respectively. The presence of the North American taxon Libonectes morgani in the deposits of Goulmima confirms a trans-Atlantic faunal connectivity at that time and that Elasmosauridae were able to exploit the open marine environment for dispersion. Polycotylids have already been described from Goulmima; however, the typical preservation of these specimens in nodules prevented their preparation and the access to their internal anatomy. Here, the use of X-ray computed tomography shows the strong interest to use such a technique and provide new anatomical details.

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