Younginidae

Younginidae was traditionally assigned to Eosuchia, an order containing an assemblage of basal diapsids now thought to represent an evolutionary grade rather than a true clade. In 1945 paleontologist Alfred Romer reclassified Younginidae within a new group, Younginiformes, grouping it with the families Tangasauridae and Prolacertidae. Romer considered Younginidae to include many genera that are no longer classified as younginids: Paliguana, Palaegama, and Saurosternon are now considered basal lepidosauromorphs, Galesphyrus and Heleosuchus are diapsids of uncertain affinities (incertae sedis), Heleophilus is now a millerettid, and Heleosaurus is now thought to be a varanopid synapsid. Like Eosuchia, Younginiformes is no longer considered valid; for example, the phylogenetic analysis of Reisz et al. place younginids close to Sauria, the clade including the still-living archosauromorph and lepidosauromorph reptiles, while the younginiform family Tangasauridae takes a more basal position in Neodiapsida. Below is a cladogram from that analysis: