Tylosaurinae

Tylosaurinae (Williston, 1895; Williston, 1897) is a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates.

Russell (1967, pp. 170) defined the Tylosaurinae as follows: "Large rostrum present anterior to premaxillary teeth. Twelve or more teeth in dentary and maxilla. Cranial nerves X, XI, and XII leave lateral wall of opsithotic through a single foramen. No canal in basioccipital or basispehnoid for basilar artery. Suprastapedial process of quadrate moderately large, distally pointed. Dorsal edge of surangular rounded and longitudinally horizontal...Twenty nine presacral vertebrae present. Length of presacral series less than that of postsacral series in Tylosaurus, neural spines of posterior caudal vertebrae at most only slightly elongated, do not form an appreciable fin. Haemal arches unfused to caudal centra. Appendicular elements lack smoothly finished articular surfaces." In his 1997 revision of the phylogeny of the Mosasauroidea, Bell (1997. p. 321) supported the monophyly of the Tylosaurinae.