Cryptoclidus

Cryptoclidus is an extinct genus of medium-sized plesiosaurs that lived in Jurassic seas around what is now Europe. Its fossils are especially well known from the Oxford Clay Formation of England.

Plesiosauria: Plesiosauria is an extinct group of marine reptiles characterized by limbs modified into flippers. Cryptoclidus belongs to this group, whose shared body plan frames its anatomy.
Plesiosaur feeding: Plesiosaur feeding encompassed the ways these marine reptiles captured and swallowed prey. Cryptoclidus likely used its jaws and neck to seize small aquatic animals.
Cryptoclidus eurymerus: Cryptoclidus eurymerus is a species of plesiosaur known from Middle Jurassic deposits in England. This is the type species that anchors the genus name Cryptoclidus.
Callovian: The Callovian is a stage of the Middle Jurassic, lasting roughly 166 to 163 million years ago. Many Cryptoclidus fossils come from English strata deposited during this interval.
Oxford Clay Formation: The Oxford Clay Formation is a Middle Jurassic deposit in England rich in marine fossils. Its beds preserve many of the best-known Cryptoclidus fossils.
Plesiosaur teeth: Plesiosaur teeth were conical or slender teeth suited to gripping prey rather than chewing it. Cryptoclidus had narrow teeth consistent with catching slippery marine prey.
Plesiosaurus: Plesiosaurus is an extinct genus of plesiosaurs from the Early Jurassic of Europe. Its earlier fossils help distinguish the Middle Jurassic Cryptoclidus from older European forms.
Middle Jurassic: The Middle Jurassic is the geological epoch between the Early and Late Jurassic, about 174 to 163 million years ago. Cryptoclidus lived within this broader interval of Jurassic history.
Plesiosaur locomotion: Plesiosaur locomotion used four flippers to propel the animal through water. Cryptoclidus had the four-flipper swimming anatomy characteristic of plesiosaurs.
Plesiosaur swimming: Plesiosaur swimming involved coordinated strokes of the fore and hind flippers. Its broad flippers indicate propulsion by underwater strokes rather than tail-driven swimming.

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