In a later study Renesto "et al." (2010) demonstrated that Senter (2004) cladogram was based on poorly defined characters and dataset. The resulting phylogeny was therefore very unusual compared to any other previous study on drepanosaurs or related taxa. The new cladogram proposed in this last study abandoned both Avicephala (because it is polyphyletic) and Simiosauria. Senter's definition of Simiosauria included Sauria as an external specifier, causing the clade to become obsolete in Renesto "et al."'s study (where drepanosaurs nested within Sauria). Renesto and colleagues instead defined a new clade, Drepanosauromorpha, as the least inclusive clade containing "Hypuronector limnaios" and "Megalancosaurus pronenesis". Another more inclusive taxon, Elyurosauria ("lizard with coiled tails"), was erected, in order to include all the drepanosaurs with coiled tails, "Vallesaurus" is thus more derived than "Hypuronector" (as clearly shown by its morphology). "Drepanosaurus" and "Megalancosaurus" are also in a new taxon named Megalancosaurinae.