Adam Stuart Smith

Ricardo Araújo, Octávio Mateus

Academic paper

Acta Palaeontologica Polonica

52

2

257-266

A partial plesiosauroid skull from the São Gião Formation (Toarcian, Lower Jurassic) of Alhadas, Portugal is re−evalu− ated and described as a new taxon, Lusonectes sauvagei gen. et sp. nov. It has a single autapomorphy, a broad triangular parasphenoid cultriform process that is as long as the posterior interpterygoid vacuities, and also a unique character com− bination, including a jugal that contacts the orbital margin, a distinct parasphenoid�basisphenoid suture exposed between the posterior interpterygoid vacuities, lack of an anterior interpterygoid vacuity, and striations on the ventral surface of the pterygoids. Phylogenetic analysis of Jurassic plesiosauroids places Lusonectes as outgroup to �microcleidid elasmo− saurs�, equivalent to the clade Plesiosauridae. Lusonectes sauvagei is the only diagnostic plesiosaur from Portugal, and the westernmost occurrence of any plesiosaurian in Europe.

Elasmosauridae, Plesiosauridae, Plesiosauria, Lusonectes sauvagei, plesiosaur, Jurassic, Toarcian, Lusita− nian basin, Portugal.

English