[N] 2005 A new mosasauroid from Morocco
Bardet, N. (2005) A new mosasauroid (Squamata) from the early Late Cretaceous of Morocco. Abstracts 1st Meeting of the EAVP Natural History Museum Basel
The Cenomanian-Turonian interval is a key period in lepidosauromorph evolution, evidencing the early diversification and radiation of aquatic squamates within the Tethys margin habitats of Europe and Middle-East. A new mosasauroid, based on both cranial and postcranial remains kept in the collections of the Museum National d\\\\\\\'Histoire Naturelle of Paris, is here described (Bardet et al., submitted). The specimens come from fossiliferous sites located in the Goulmima region, Er-Rachidia Province, southern Morocco. These sites have yielded a rich fauna of marine vertebrates, including actinopterygians (Cavin et al., 2001), mosasauroids, turtles and plesiosaurs, as well as ammonites. The fossils are preserved in ovoid calcareous nodules that are concentrated in the Unit 4 of the Cenomanian-Turonian limestone bar, a reference level in North Africa. The Unit 4 is Early Turonian in age and corresponds to an open platform environment related to the maximum of the Cenomanian- Turonian transgressive phase (Ferrandini et al., 1985). This new mosasauroid, less than 3 meters in length, is mainly characterized by a parietal table ending posteriorly in two pointed pegs, a jugal with a large ascending ramus, a splenial with a large notched dorsomedial process, a surangular exposed medially ventral to the coronoid, a dental formula of 19-20 maxillary, 15-19 pterygoid and 18-20 dentary teeth and, finally, large paracotylar foramina on vertebrae. It also exhibits a mosaic of plesiomorphic characters, the most notable being those observed on the girdles. A phylogenetic analysis based on the data matrix of Caldwell (2000) shows that, among Pythonomorpha, this new taxon shares many synapomorphies of Mosasauroidea (\\\\\\\"aigialosaurs\\\\\\\" + Mosasauridae) and appears to be the sister-taxon of Mosasauridae. The distribution in time and in space of this new taxon fills the gap between the basal mosasauroids (Middle-East and southern Europe; mainly Cenomanian in age) and the Mosasauridae (earliest records from the Late Turonian of Colombia and Angola).