Rhytidostea

Rhytidostea is a clade of stereospondyl temnospondyls. It was erected in 2000 to include several temnospondyl groups distinct from the "higher" group of capitosaurs, including lydekkerinids, brachyopoids, and rhytidosteids. Rhytidosteans first appeared in the Permian period and underwent an evolutionary radiation during the Induan stage of the Early Triassic. Along with capitosaurs, rhytidosteans comprise much of the larger suborder Stereospondyli. Rhytidostea has often been considered the sister group of the clade Capitosauria, but has been placed in various other phylogenetic positions. In many studies, members of Rhytidostea are split, with lydekkerinids having a more basal position among stereospondyls while rhytidosteids and brachyopoids form a group placed among the more derived trematosaurian stereospondyls.