Pistosauridae

Pistosauridae is a family of extinct marine reptiles within the broader group Sauropterygia. The family is typically considered to include early pistosaurs, with Pistosaurus as the type genus, and is viewed in many analyses as a basal or stem lineage related to Plesiosauria. The precise limits of the group and its exact position relative to other early sauropterygians have varied among classifications and phylogenetic studies.

Temporal and geographic range of pistosaurids is primarily Triassic. Fossils attributed to the group have been found in Europe, especially in Middle Triassic strata such as the Muschelkalk deposits, dating roughly to the early to middle part of the Triassic period. This places the lineage among some of the earlier sauropterygians in the marine reptile radiation after the end-Permian extinction.

Anatomy and lifestyle in pistosaurids reflect an early aquatic adaptation. They were marine reptiles with limb modifications toward paddle-like positions suitable for swimming. Their remains suggest an aquatic lifestyle that exploited marine environments, though the material for some species is incomplete, leaving details of their exact anatomy and feeding ecology open to interpretation. The skulls and dentition, where known, indicate a diet of fish or other marine organisms, consistent with many early sauropterygians.

Significance in paleontology stems from pistosaurs’ status as early relatives in the transition toward later plesiosaurs. As such, pistosaurids provide insight into the early evolution of Sauropterygia and the morphological experimentation that culminated in the diverse plesiosaur lineages of the Jurassic.