 While the premaxillary bones are fused in more derived dicynodonts, a thin suture extending dorsally up from the palatal facet reveals that they are paired in "Eodicynodon," an ancestral feature they share with their primitive relatives Venyukovia, Otsheria, and Pelycosauria.Similarly, while the vomers of later dicynodonts are fused, they are paired in "Eodicynodon" and together with the pterygoid border the intervomero-pterygoidal vacuity; in more derived dicynodonts, this vacuity is more posteriorly located and exclusively bordered by the pterygoid.These features are also present in more primitive relatives of dicynodonts, including Pristerodon, sphenacodont pelycosaurs, cotylosaurs, and Venyukovia.