Plesiosaur Tooth in Matrix
- Early Jurassic Era Aquatic Dinosaur
- Age: 199-173 Million Years Old
* The Plesiosaur *
Plesiosaurus is a genus of extinct, large marine sauropterygian reptiles that lived during the early part of the Jurassic Period, and is known by nearly complete skeletons from the Lias of England. It is distinguishable by its small head, long and slender neck, broad turtle-like body, a short tail, and two pairs of large, elongated paddles. It lends its name to the order Plesiosauria, of which it is early, but a fairly typical member. It contains only one species, the type, Plesiosaurus dolichodeirus.
* More Information *
Plesiosaurus fed mainly on clams and snails, and are thought to have eaten belemnites, fish, and other prey as well. Its U-shaped jaw and sharp teeth would have been like a fish trap. It propelled itself by the paddles, the tail is too short to be of much use. Its neck would have been used as a rudder when navigating during a chase.
Plesiosaurus gave live birth to live young in the water like sea snakes. The young might have lived in estuaries before moving out into the open ocean.
It has been postulated that the long neck of Plesiosaurus would have been a hindrance when trying to speed up, any bend in the neck creating turbulences. If that is the case then Plesiosaurus would have had to keep its neck straight to achieve good acceleration, something that would make hunting difficult. For this reason, it may be possible that these animals would lie in wait for prey to come close instead of trying to pursue them.
* The Jurassic Era *
The Jurassic is a geologic period and system that spanned 56 million years from the end of the Triassic Period 201.3 million years ago to the beginning of the Cretaceous Period 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era. The Jurassic is named after the Jura Mountains in the European Alps, where limestone strata from the period were first identified.