Nakonanectes is a small elasmosaurid plesiosaur from the Bearpaw Shale of Montana, USA. It is known from a single moderately complete specimen including a particularly fine skull. It has a relatively short neck for an elasmosaur consisting of 'only' 39-42 neck vertebrae. However, 16–19 of the neck vertebrae were lost in a…
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…
Kaiwhekea, also known as the 'Shag Point Plesiosaur', was classified as a cryptoclidid by Cruickshank and Fordyce (2002). More recent classifications regard it as an aristonectid. It has an unusually large number of small needle-like teeth and a shortened snout, much like the closely related Aristonectes. Kaiwhekea katiki is the type and…
Hydrotherosaurus is a long-necked elasmosaurid from California, USA. It is represented by one of the most complete elasmosaurid skeletons ever discovered, so Hydrotherosaurus is one of the best known members of this family. The almost complete type skeleton of Hydrotherosaurus was discovered in the Panoche Hills by Mr. Frank C. Paiva in…
The mysterious plesiosaur Aristonectes is notable for its mouthful of pin-like teeth. A special feeding guild, the 'trap guild', has been proposed to accommodate Aristonectes and other plesiosaurs with similar dentition (Chatterjee and Small 1989) such as Cryptoclidus, Kimmerosaurus, and Kaiwhekea. These plesiosaurs may have fed in a similar manner to the…