Taniwhasaurus

Taniwhasaurus is an extinct genus of mosasaurs (a group of extinct marine lizards) that lived during the Campanian stage of the Late Cretaceous. It is a member of the subfamily Tylosaurinae, a lineage of mosasaurs characterized by a long toothless conical rostrum. Two valid species are attached to the genus, T. oweni and T. antarcticus, known respectively from the fossil record of present-day New Zealand and Antarctica. T. capensis from present-day South Africa represents a chimera of two different mosasaur genera, potentially Prognathodon and Taniwhasaurus, but not identifiable at the species level. The other formerly assigned species, T. mikasaensis from present-day Japan, remains problematic due to the fragmentary state of the attributed fossils. The generic name literally means "taniwha lizard", referring to a supernatural aquatic creature from Māori mythology.

Taniwhasaurus is a medium-sized mosasaurid, with maximum size estimates putting it at around in length. The rare fossils of the axial skeleton indicate that the animal would have had great mobility in the vertebral column, but the tail would generate the main propulsive movement, a method of swimming proposed for other mosasaurids. The constitution of the forelimb of Taniwhasaurus indicates that it would have had powerful paddles for swimming. CT scans performed on the snout foramina of T. antarcticus show that Taniwhasaurus, like various aquatic predators today, would likely have had an electro-sensitive organ capable of detecting the movements of prey underwater.