New plesiosaurian specimens (Reptilia, Plesiosauria) from the Upper Cretaceous (Turonian) of Goulmima (Southern Morocco)

Rémi Allemand (1, 2) , Nathalie Bardet (3) , Alexandra Houssaye (2) , Peggy Vincent (4)

1 CR2P - Centre de recherche sur la Paléobiodiversité et les Paléoenvironnements
2 MECADEV - Mécanismes Adaptatifs et Evolution
3 Paléobiodiversité et paléoenvironnements
4 Physiopathologie du système nerveux central - Institut François Magendie

Two new plesiosaurian specimens coming from lower Turonian deposits of Goulmima in Morocco are described. The three-dimensional digital reconstructions of both specimens provide 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 phy-logenetical 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 transAtlantic 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.

Domaines: Paléontologie

Rémi Allemand, Nathalie Bardet, Alexandra Houssaye, Peggy Vincent. New plesiosaurian specimens (Reptilia, Plesiosauria) from the Upper Cretaceous (Turonian) of Goulmima (Southern Morocco). Cretaceous Research, 2018, 82, pp.83-98. ⟨10.1016/j.cretres.2017.09.017⟩. ⟨hal-02115209⟩