Tangasauridae

Tangasauridae is an extinct family of diapsids known from fossils found in Late Permian to Early Triassic rocks in Madagascar, Kenya and Tanzania. Fossils have been found of members of this family in different stages of ontogenic development. Material from the early Triassic Middle Sakamena Formation of the Morondava Basin of Madagascar indicates that the Tangasauridae survived the Permian-Triassic extinction event.

==Description and phylogeny== thumb|left|Speculative life restoration of [[Hovasaurus]] Tangasaurids are known to have been a highly derived group of diapsids. Kenyasaurus and Thadeosaurus, sometimes placed in a distinct subfamily , were likely fully terrestrial. They had long toes and highly developed sterna that made them well-suited to life on land. In comparison, Hovasaurus and Tangasaurus (placed in the subfamily Tangasaurinae), were adapted to a more aquatic life. They laterally compressed tails and likely webbed feet that allowed them to swim in the freshwater lacustrine environment present at the time. Because of their highly derived aquatic characteristics and occurrence in time, it has historically been suggested that the tangasaurids were a direct ancestor of the superorder Sauropterygia, which includes many highly derived marine aquatic reptiles such as placodonts, nothosaurs, and plesiosaurs.