Plesiosauria

Diversity of Sauropterygia. Above: Ceresiosaurus calcagnii (Nothosauroidea), Henodus chelyops (Placodontia); Below: Aristonectes parvidens, Brachauchenius lucasi (Plesiosauria).

Diversity of Sauropterygia. Above: Ceresiosaurus calcagnii (Nothosauroidea), Henodus chelyops (Placodontia); Below: Aristonectes parvidens, Brachauchenius lucasi (Plesiosauria).

Diversity of Sauropterygia. Above: Ceresiosaurus calcagnii (Nothosauroidea), Henodus chelyops (Placodontia); Below: Aristonectes parvidens, Brachauchenius lucasi (Plesiosauria).

Cervical Vertebra of Crymocetus (formerly Plesiosaurus) Bernardi, nat. size. Fig. 1. Front view. Fig. 2. Back view of spinous process. Fig. 3. Side view. Fig. 4. Under view. From the Upper Chalk of Sussex. In the Collection of the late Fred. Dixon, Esq., F.G.S., of Worthing.

Partial skull and anterior cervical vertebrae of unidentified pliosaurid plesiosaurian (MPPL 18797) from the uppermost Callovian–middle Oxfordian of Kaberlaba (Asiago, Italy), in left lateral view. Photograph (A) and explanatory drawing (B). White, preserved bone surfaces; dark grey, preserved margins of skull fenestrae; light grey, eroded bone surface; cross hatching, broken bone.

Holotype of the polycotylid[1] plesiosaur Edgarosaurus muddi DRUCKENMILLER, 2002, (MOR 751) comprising the skull, the neck, and the left front flipper, on display in the Museum of the Rockies in Bozeman, Montana. The specimen was collected in Edgar, Carbon County, Montana, from the Shell Creek member of the Thermopolis Shale Formation, Upper Albian, uppermost Lower Cretaceous.[2]

Plesiosaurus of the Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"

Muraenosaurus? Reedii, Sp. Nov. and Tricleidus? Laramiensis Knight, American Jurassic Plesiosaurs

Muraenosaurus? Reedii, Sp. Nov. and Tricleidus? Laramiensis Knight, American Jurassic Plesiosaurs

Muraenosaurus? Reedii, Sp. Nov. and Tricleidus? Laramiensis Knight, American Jurassic Plesiosaurs

Muraenosaurus? Reedii, Sp. Nov. and Tricleidus? Laramiensis Knight, American Jurassic Plesiosaurs

Muraenosaurus? Reedii, Sp. Nov. and Tricleidus? Laramiensis Knight, American Jurassic Plesiosaurs

Vertebrae and ribs of the British Jurassic pliosaurid plesiosaur Eardasaurus housed at the Oxford University Natural History Museum.

Caudal vertebrae and chevrons of the British Jurassic pliosaurid plesiosaur Eardasaurus housed at the Oxford University Natural History Museum.

Paddle of the British Jurassic pliosaurid plesiosaur Eardasaurus housed at the Oxford University Natural History Museum.

Attenborosaurus conybeari, a plesiosaur from the Early Jurassic of England, pencil drawing