[1][2] Basal ichthyopterygians (prior to and ancestral to true Ichthyosauria) were mostly small (a meter or less in length) with elongated bodies and long, spool-shaped vertebrae, indicating that they swam in a sinuous, eel-like manner.

[3] Even at this early stage, they were already very specialised animals with proper flippers, and would have been incapable of movement on land.

By the later part of the Middle Triassic, the stem group members were extinct, having been replaced by their descendants, the true ichthyosaurs.

These rocks are dated to just 2 million years after the Permian-Triassic extinction event, indicating that ichthyopterygians at the very least originated very early in the Triassic, before the Late Smithian crisis (a widespread ocean anoxic event that may have allowed ichthyopterygians to dominate deeper waters and temnospondyls to dominate shallow waters) and that ichthyosauromorphs as a whole originated during the Permian and were survivors of the Permian-Triassic mass extinction.

[6] Parvinatator wapitiensis Utatsusaurus hataii Xinminosaurus catactes Grippia longirostris Gulosaurus helmi Chaohusaurus geishanensis Cymbospondylus Mixosaurus cornalianus Phalarodon atavus Qianichthyosaurus zhoui Toretocnemus californicus Shonisaurus popularis Shastasaurus pacificus Callawayia neoscapularis Guizhouichthyosaurus tangae Besanosaurus leptorhynchus Californosaurus perrini Parvipelvia