Plesiosaur

Lore & Background

Plesiosaurs had a broad flat body and a short tail. Their limbs evolved into four long flippers powered by strong muscles attached to wide bony plates, allowing them to make a flying movement through the water. They showed two main morphological types: 'plesiosauromorphs' with extremely long necks and small heads that caught small sea animals, and 'pliosauromorphs' with short necks and large heads that were apex predators hunting large prey.

In Their Own Story

In the beginning of the nineteenth century, scientists realized how distinctive their build was. The first plesiosaurian genus, Plesiosaurus, was named in 1821 by William Conybeare and Henry Thomas De la Beche. In 1835, Henri Marie Ducrotay de Blainville named the order Plesiosauria itself.

Reader's Guide

Plesiosaurs breathed air and bore live young; there are indications that they were warm-blooded. While some species inhabited freshwater environments, they had a worldwide oceanic distribution. Modern research indicates that several 'long-necked' groups might have had short-necked members or vice versa, leading to the use of descriptive terms like 'plesiosauromorph' and 'pliosauromorph' rather than strict suborder divisions.

Did You Know?

• Plesiosaurs first appeared about 203 million years ago in the latest Triassic Period.
• The term 'plesiosaur' is properly used to refer to the Plesiosauria as a whole, though informally it sometimes indicates only the long-necked forms.
• In 1824, Conybeare named the specific species Plesiosaurus dolichodeirus, meaning 'longneck'.
• Plesiosaurs were among the first fossil reptiles discovered and recognized as such.