Pleurosaurus

Pleurosaurus is an extinct genus of marine reptile belonging to the Rhynchosauria, an extinct order of archosauromorph reptiles. The genus is known from fossils found in the Late Triassic deposits of England and France. Pleurosaurus was a relatively small animal, with the type species, Pleurosaurus dawsoni, estimated to have reached about 1 meter in length. Its most distinctive feature was its highly unusual skull, which was very elongated and narrow, with the eyes positioned on the sides. The teeth were small and numerous, suggesting a diet of small invertebrates or soft-bodied prey. The jaw structure indicates that it may have been able to open its mouth very wide.

The exact phylogenetic position of Pleurosaurus within the Archosauromorpha has been debated. Initially, it was considered a rhynchosaur, a group characterized by their beaked snouts and distinct dental batteries. However, later analyses have suggested it might represent a more basal lineage or an aberrant form within the broader group of archosauromorphs. Its peculiar morphology, particularly the elongated skull, sets it apart from more typical rhynchosaurs. The limited fossil material available for Pleurosaurus makes a definitive placement challenging, and further discoveries could clarify its evolutionary relationships. The discovery of Pleurosaurus contributes to our understanding of the diversity of life during the Triassic period and the evolutionary experiments that occurred within reptilian lineages.