Chroniosaurus is an extinct genus of chroniosuchid stegocephalian, often considered a reptiliomorph but possibly a stem-tetrapod, from upper Permian (upper Tatarian age) deposits of Novgorod, Orenburg and Vologda Regions, Russia. It was first named by Tverdokhlebova in 1972 and the type species is Chroniosaurus dongusensis. Its lifestyle is uncertain. An early study suggested a fairly aquatic lifestyle, but its femoral microanatomy and dorsal dermal plates suggest a rather terrestrial lifestyle.