Article: The mosasaur Goronyosaurus from the Upper Cretaceous of Sokoto State, Nigeria

New mosasaur material from the Upper Cretaceous of Sokoto State, Nigeria, was described in detail by Azzaroli et al. (1972, 1975). Largely on the basis of what they interpreted as a highly unusual jugal bone in the skull, they erected in 1972, the new genus Goronyosaurus, and subsequently (1975) placed it in a new subfamily, the Goronyosaurinae, representing a totally unique development of a squamate skull.A reassessment of the material suggests that the description of the jugal by Azzaroli et al. (1972, 1975) is incorrect. However, other characters described by them, plus new information added here, vindicates the erection of a new genus, which can be tentatively assigned to the Tylosaurinae.