The taxon was originally named ‘Turneria seymourensis‘ by Chatterjee and Small (1989) but this genus was preoccupied and so Chatterjee and Creisler (1994) later revised the name to Morturneria seymourensis. The holotype specimen is TTU P 9219, an incomplete skull and mandible plus associated cervical vertebrae, from the Lopez de Bertodano Formation of Seymour Island, Antarctica. Morturneria was regarded by Gasparini et al. (2003) as a junior synonym of Aristonectes. Chatterjee and Small (1989) regarded Morturneria as a cryptoclidid.
Maastrichtian, Late Cretaceous
Seymour Island, Antarctica