thallatosaurs

Thalattosauria, commonly called thalattosaurs, are an extinct group of marine reptiles that lived during the Triassic period. They are among the earliest reptiles adapted to marine life after the Permian mass extinction. The group comprises two major lineages, the Askeptosauroidea and the Thalattosauroidea, which display a range of body plans from slender, eel-like forms to more compact, lizard-like shapes.

Anatomy: Thalattosaurs typically possessed elongated bodies with relatively short limbs bearing paddle-like appendages and tails. Most had long snouts and sharp teeth suited to a fish- or invertebrate-eating lifestyle, though tooth form varied between lineages. Skull and jaw morphology shows diverse feeding strategies.

Ecology and lifestyle: They inhabited shallow coastal seas and lagoons, using their streamlined bodies to swim and feed on marine prey. Their limb morphology indicates varying degrees of aquatic adaptation, with some forms more paddle-like. They probably occupied ecological roles similar to early aquatic predators.

Fossil record and distribution: Fossils are known from Europe, North America, and Asia. The clade appeared in the Early Triassic and persisted into the Middle Triassic, with declines by the Late Triassic.

Significance: Thalattosaurs provide insight into the early diversification of marine reptiles after the end-Permian extinction and illustrate how diapsids repeatedly adapted to marine life.