Tanystropheidae is an extinct family of archosauromorph reptiles that lived throughout the Triassic Period, often considered to be "protorosaurs".

[7] However, species in western North America are found in terrestrial deposits, suggesting that as a group, tanystropheids were ecologically diverse.

[5] In 2021, a phylogenetic study was conducted by S. Spiekman, N. Fraser, and T. Scheyer in an attempt to clarify the systematics of "protorosaur" groups.

A total of 16 individual trees were found using different character scoring methods and unstable OTU exclusions.

hydroides Tanystropheus longobardicus Allokotosauria Rhynchosauria Teyujagua Archosauriformes A later 2024 study grouped Tanystropheidae along with Trachelosauridae in the new clade Tanysauria.