Late Jurassic plesiosaurs

Megalneusaurus is a genus of large pliosaurid plesiosaur from the Late Jurassic of North America. It was provisionally described as a species of Cimoliosaurus by the geologist Wilbur Clinton Knight in 1895, before being given its own genus by the same author in 1898. The only known species is M. rex, known from several specimens mainly found in the Redwater Shale Member, within the Sundance Formation, Wyoming, United States. A specimen discovered in the Naknek Formation in southern Alaska was referred to the genus in 1994. The loss of most fossils has led some paleontologists to consider the g

Gallardosaurus is a genus of pliosaurid plesiosaur from the Caribbean seaway. It contains the single species Gallardosaurus iturraldei. Gallardosaurus was found in middle-late Oxfordian-age (Late Jurassic) rocks of the Jagua Formation of western Cuba. Gallardosaurus is believed to be evolutionarily connected to Peloneustes, a pliosaurid commonly found in the Oxfordian-aged sediment.

Pantosaurus ("all lizard") is an extinct genus of plesiosaur from the Late Jurassic (Oxfordian) of what is now Wyoming. It lived in what used to be the Sundance Sea. It was originally named Parasaurus ("near lizard") by Othniel Charles Marsh in reference to Plesiosaurus, but that name was preoccupied, and Marsh changed it. The species Muraenosaurus reedii is in fact a junior synonym of Pantosaurus. The holotype YPM 543 is a partial articulated skeleton, partially prepared to yield a distal humerus, four articulated carpals, a fragment of the coracoid, and several isolated cervical vertebrae fr

Tatenectes is a genus of cryptoclidid plesiosaur known from the Upper Jurassic of Wyoming. Its remains were recovered from the Redwater Shale Member of the Sundance Formation, and initially described as a new species of Cimoliosaurus by Wilbur Clinton Knight in 1900. It was reassigned to Tricleidus by Maurice G. Mehl in 1912 before being given its own genus by O'Keefe and Wahl in 2003. Tatenectes laramiensis is the type and only species of Tatenectes. While the original specimen was lost, subsequent discoveries have revealed that Tatenectes was a very unusual plesiosaur. Its torso had a flatte

Vinialesaurus is a genus of plesiosaur from the Late Jurassic (Oxfordian) Jagua Formation of Pinar del Río, Cuba. The combinatio nova of the type species is Vinialesaurus caroli, first described as the subspecies Cryptocleidus? cuervoi caroli by Ricardo De la Torre and Luis Rojas in 1949 under the holotype MNHNCu P 3008, and redescribed by Zulma Gasparini, Bardet and Iturralde in 2002. The authors of the 2002 paper considered Vinialesaurus distinct enough from Cryptocleidus to warrant its own genus, but it was a cryptoclidid.