Opallionectes is a large, around 5 m long, derived cryptoclidid plesiosauroid from the Early Cretaceous of South Australia. It is known from a partial opalised skeleton, which is mounted for display in the South Australian Museum. The holotype specimen lacks a skull. It is diagnosed by the following unique combination of characters:…
Umoonasaurus is a small (~2.5 m long) leptocleidid that lived during the Early Cretaceous in Southern Australia. The holotype specimen (AM F99374), a spectacular opalised skeleton including the skull, is nicknamed 'Eric'. It is the most complete opalised plesiosaur skeleton (and fossil vertebrate) known. It was originally described briefly as Leptocleidus sp.…
Due to its large size and ferocious appearance, Kronosaurus is one of the most famous plesiosaurs. The iconic skeleton referred to Kronosaurus on display in the Museum of Comparative Zoology in Harvard is nicknamed 'plasterosaurus' because so much of it is reconstructed in plaster. About a third of the skeleton is plaster…
Edgarosaurus is a basal polycotylid (Druckenmiller 2002) from the Thermopolis Shale