Within Avicephala, Senter named the group Simiosauria ("monkey lizards") for the extremely derived tree-dwelling forms. Simiosauria was defined as "all taxa more closely related to Drepanosauridae than to "Coelurosauravus" or Sauria." However, Renesto and colleagues (see below) found drepanosaurids to lie within Sauria, which would make the clade Simiosauria obsolete. Senter found that "Hypuronector", originally described as a drepanosaurid, actually lies just outside that clade, along with the primitive drepanosaur "Vallesaurus". He also recovered a close relationship between the drepanosaurids "Dolabrosaurus" and "Megalancosaurus".