A new record of the pliosaur Brachauchenius lucasi Williston, 1903 (Reptilia: Sauropterygia) of Turonian (Late Cretaceous) age, Morocco

The site of Goulmima (south Morocco) is well known for its rich marine fauna of Turonian age (Late Cretaceous). It has yielded a large variety of invertebrates but also of vertebrate taxa, represented by actinopterygians and marine reptiles including Plesiosauria (Sauropterygia) and Mosasauroidea (Squamata). The Plesiosauria are known so far by two major clades of Plesiosauroidea: the Elasmosauridae (Libonectes atlasenseBuchy, 2005) and the Polycotylidae (Thililua longicollis, Bardet, Suberbiola & Jalil, 2003a;Manemergus angirostrisBuchy, Metayer & Frey, 2005). Here we describe a new specimen of plesiosaur found in the same outcrop, differing from those previously cited and belonging to the other large plesiosaur clade, the Pliosauroidea. Comparison of this specimen with other Plesiosauria shows that it belongs toBrachauchenius lucasiWilliston (1903), a species previously known only from the Cenomanian-Turonian stages of the Western Interior Seaway of North America and in the upper Barremian succession of northern South America (Colombia). The description of this species on a contemporaneous site of North Africa significantly expands its palaeobiogeographic distribution. This discovery confirms the affinities between marine faunas of the Western Interior Seaway and those of North Africa at this time, and also permits a better understanding of the palaeobiology of the Goulmima outcrop. A discussion about the systematical status ofPolyptychodonOwen, 1841 is also provided.