They have featured in common with pelycosaurs (Carroll 1988) and Biarmosuchians (Chudinov 1965), and, with the Tapinocehalia, are part of the first major evolutionary radiation of the Therapsida (Rubidge & Sidor 2001).
Oni imaju osobine koje su zajedničke sa pelikosaurima (Carroll, 1988) i pripadnicima skupine Biarmosuchia (Chudinov, 1965), te su sa tapinocefalima bili dio prvog velikog evolutivnog širenja terapsida (Rubidge & Sidor, 2001).