 Hapsidopareiontids are characterized by a large temporal embayment near the cheek region in which the quadratojugal is greatly reduced or absent.Members of Ostodolepidae, another microsaur family, also possess temporal embayments, but they not as extensive as those of hapsidopareiontids, which extend into the skull roof.In hapsidopareiontids, the embayment may have provided space for an enlarged jaw adductor musculature, although certain characteristics of the skull do not support this idea.