L'anatomie de Lyrocephaliscus euri (wiman), Trématosaure du Trias inférieur du Spitsberg : arrière-crâne, squelette axial et ceinture scapulaire.

Jean-Michel Mazin and Philippe Janvier

The formic acid preparation of a nodule collected from the Lower Triassic of Spitsbergen, and containing a skull with some associated postcranial elements of Lyrocephaliscus euri (WIMAN), precises and enriches previous descriptions of the reputedly well-known trematosaur. lt permits more detailed descriptions of the occipital region, of the course of the carotid arteries and collateral vessels, and refutes the previous description of a stapedial foramen in trematosaurs. The discovery of pleurocentres associated with the other vertebral components confirms the primitive rhachitomy of trematosaurs.