Plesiosauria

Plesiosauria is an order or clade of extinct, large marine reptiles that lived during the Mesozoic Era. Plesiosaurs first appeared in the Late Triassic period and thrived until the end of the Cretaceous period. They are known for their distinctive body shape, which includes a broad, flat body, a short tail, and limbs that evolved into long flippers.

Description

Plesiosaurs are characterized by their unique body structure. They had a broad, flat body and a short tail. Their limbs were modified into flippers, which made them powerful swimmers. Plesiosaurs are divided into two main suborders: Pliosauroidea and Plesiosauroidea. Pliosauroids typically had shorter necks and larger heads, while plesiosauroids had long necks and smaller heads.

Classification

Plesiosaurs belong to the order Plesiosauria, which is further divided into several families and genera. Some of the well-known genera include Plesiosaurus, Elasmosaurus, and Kronosaurus. The classification of plesiosaurs is based on various skeletal features, particularly the structure of the skull and limbs.

Paleobiology

Plesiosaurs were carnivorous and primarily fed on fish and other marine organisms. Their long necks allowed them to strike at prey with great precision. Plesiosaurs are believed to have been viviparous, giving birth to live young rather than laying eggs.

Fossil Record

Plesiosaur fossils have been found on every continent, indicating that they were widespread during the Mesozoic Era. Notable fossil sites include the Solnhofen Limestone in Germany and the Oxford Clay in England. These fossils provide valuable insights into the anatomy and evolution of these ancient marine reptiles.

Extinction

Plesiosaurs, along with many other marine reptiles, went extinct at the end of the Cretaceous period, approximately 66 million years ago. This mass extinction event is believed to have been caused by a combination of volcanic activity, climate change, and the impact of a large asteroid.

Related Pages

• Pliosauroidea
• Plesiosauroidea
• Mesozoic Era
• Marine reptiles
• Cretaceous–Paleogene extinction event