Plesiosauria

Illustration of an Elasmosaurus platyurus devouring a juvenile Tylosaurus while a Hesperornis swims by in the background, based on recent research on Elasmosaurid paleobiology which shows that they were far more raptorial than previously thought: https://sobekswimmingpool.wordpress.com/2021/05/30/what-sea-dragons-ate-plesiosaur-diets-revised/

Elasmosaurus platyurus, plesiosaurian from Late Cretaceous (Campanian) of North America

Elasmosaurus platyurus, plesiosaurian from Late Cretaceous (Campanian) of North America

Geographic and geologic map showing the location and involved strata of the studied fossil sites in the Xinhe Formation. (A, B) location of the fossiliferous localities in the Gansu Province. (C) Geological map of the involved strata of the studied fossil site (from State Bureau of Surveying and Mapping, GS (2016)2884). White star=Jinchuanloong niedu. Black star=plesiosaur fossils. (D) Stratigraphic chart of the Jurassic at the localities.

Basal cryptoclidid plesiosaur restoration.

Basal cryptoclidid plesiosaur restoration.

Leptocleidus capensis, a plesiosaur from the Early Cretaceous of South Africa, pencil drawing, digital coloring

Paleo Hall at HMNS

Paleo Hall at HMNS

Paleo Hall at HMNS

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]