Cryptoclidus

Lore & Background

The type species was initially described as Plesiosaurus eurymerus, with the specific name 'wide femur' referring to the forelimb, which was mistaken for a hindlimb at the time. It was moved to its own genus Cryptoclidus by Seeley in 1892. Fossils have been found in the Oxford Clay of Cambridgeshire, England. The dubious species Cryptoclidus beaugrandi is known from Kimmeridgian-age deposits in Boulogne-sur-Mer, France. Cryptoclidus vignalensis, now considered undiagnostic, comes from the Jagua Formation of western Cuba. In 2016, a fragmentary postcranial skeleton from Russia was reported, but later defined as an indeterminate cryptoclidid.

Reader's Guide

Cryptoclidus represents a medium-sized plesiosaur, with the largest individuals measuring up to 4 meters long and weighing about 737–756 kg. Its fragile head and teeth preclude grappling with prey, suggesting a diet of small, soft-bodied animals such as squid and shoaling fish. It may have used its long, intermeshing teeth to strain small prey from water or sift through sediment. The size and shape of the nares and nasal openings have led researchers to argue they were used to sample seawater for smells and chemical traces. The genus is significant for illustrating the diversity of plesiosaurs in the Middle Jurassic and for the ongoing taxonomic refinements, as seen in the reclassification of some specimens as indeterminate. Its remains across multiple continents highlight its wide distribution.

Did You Know?

• The name Cryptoclidus means 'hidden clavicles,' referring to its small, practically invisible clavicles buried in its front limb girdle.
• The type species was initially described as Plesiosaurus eurymerus because the forelimb was mistaken for a hindlimb.
• Fossils of Cryptoclidus have been found in England, France, and Cuba.
• The largest individuals measured up to 4 meters long and weighed about 737–756 kg.