A juvenile Tuarangisaurus keyesi Wiffen and Moisley 1986 (Plesiosauria, Elasmosauridae) from the upper cretaceous of New Zealand, with remarks on its skull ontogeny

Abstract

This paper presents the detailed description of a remarkable skull and partial postcranial skeleton of a very juvenile elasmosaurid referred to Tuarangisaurus keyesi (CD 427), from the upper Campanian-lower Maastrichtian levels of the Tahora Formation, New Zealand. The following points are discussed: i) the conspecific status of CD 427 with T. keyesi, ii) clarification of several cranial sutures in the adult holotype of T keyesi by comparison with the clearly open sutures in the juvenile specimen: iii) morphologic changes undergone by the skull during the ontogeny of T keyesi; iv) a first look at the postcranial skeleton of T keyesi. The studied specimen holds a great significance because it represents one of the rarely-available juvenile elasmosaurid skulls known worldwide. As a result, we provide the first insights regarding the skull ontogeny of an austral elasmosaurid plesiosaurian.