Notorynchus primigenius

Notorynchus primigenius allegedly differs from the modern N. cepedianus (PERON, 1807)  by having more erect cusps. However variations in the modern tooth form (and the fossils as illustrated) makes this a somewhat dubious distinction. Thus, it is believed that the fossil species is the same as the modern one. A potential source of confusion occurs in that the fossil species naming predates the modern species. The posterior teeth are minute, irregular, and stubby and would be barely recognizable as a tooth. In addition to being smaller, these teeth differ from Hexanchus in having less cusps on the lower teeth (7 vs 8 - 12+) and larger more recurved serrations on the anterior side of the tooth which don't extend as far down along the front of the root.