Bolosaurus striatus (Cope 1878) Cisuralian, Early Permian ~294 mya, ~2.5 cm skull length was originally considered a pelycosaur like Dimetrodon, but the lateral temporal fenstra they both share was by convergence. Bolosaurus was derived from a sister to Romeria? primus and was a sister to Belebey. Eudibamus was considered a bolosaurid, but it is not related. Bolosaurid sisters all had bulky bodies and short limbs, not the lean, long-limbed morphology of Eudibamus.
Distinct from Belebey, the skull of Bolosaurus had a taller profile dominated by the large orbit. The maxilla was ventrally concave. The jugal was not so embayed by the lateral temporal fenestra. The postorbital reached the posterior margin of the skull.
The neural spines were inflated.