Tuarangisaurus
Tuarangisaurus is an extinct genus of elasmosaurid known from New Zealand. The type and only known species is Tuarangisaurus keyesi, named by "Pont" Wiffen, Joan Wiffen and Bill Moisley in 1986. The specific name honours Ian W. Keyes of the New Zealand Geological Survey.
Discovery
Tuarangisaurus is known from the holotype New Zealand [Geological Survey|NZGS] CD425, a nearly complete skull and mandible, and from NZGS CD426, rear skull elements and nine anterior-most cervical vertebrae from the same individual. Some postcranial remains of juveniles were also provisionally attributed to Tuarangisaurus, with one specimen containing at least thirty gastroliths. It was on 20 March 1978 collected by amateur paleontologists from the Maungataniwha Sandstone Member of the Tahora Formation, dating to the upper Campanian to lower Maastrichtian stage of the Late Cretaceous.A second species, T. australis, was named in 2005; however, it was moved to the genus Eromangasaurus in 2007, becoming the senior synonym of E. carinognathus. Another species, T.? cabazai, was collected during the early 2000s and was also placed in Tuarangisaurus by Gasparini, Salgado and Casadio in 2003; however, it was most recently reassigned to an indeterminate aristonectine.
In 2017, a complete specimen, originally belonging to Mauisaurus, has been reassigned to this genus. In 2018, Otero and colleagues redescribed the juvenile specimen NZGS CD427 elucidating the ontogeny of this plesiosaur. The specimen had many features common with the holotype, but it differed in the orientation of the maxilla along with the number of teeth present in it.