The oldest plesiosaur fossil (Sauropterygia) from the Iberian Peninsula: a vertebra from the Hettangian-Sinemurianof Asturias, Northern Spain

摘要

In this paper, a pectoral vertebra of a plesiosaur is described. It comes from an exposure of the uppermember of the Gijón Formation (lower Hettangian - basal Upper Sinemurian) in the coastal cliffs of theVillar hamlet in the Villaviciosa municipality (Asturias, Northern Spain). The specimen is not diagnosticfurther away from the superfamily level, and is assigned to a Plesiosauroidea indet. The Villar vertebra isthe first vertebrate remain from the Gijón Formation and the oldest Mesozoic vertebrate fossil found inAsturias. Moreover, it represents currently the oldest record of plesiosaurs from the Iberian Peninsula,predating another indeterminate plesiosauroid specimen from the basalmost Pliensbachian of Villaviciosa(Asturias). It also represents the westernmost occurrence of Early Liassic plesiosaurs in the Tethys Ocean