Plesiosaurus (which means "near lizard") gave its name to the
Plesiosaurs, a group of predatory marine reptiles, because it was the first
of its group to be discovered. This earliest Plesiosaurus had already
developed all the main features of the order.
This animal must have been very vulnerable, since it had no any
protective "armor" and what is more, it had an exposed tail. It may have
relied on its sight, maneuverability and camouflage colors to survive. It
was probably preyed on by large marine reptiles.
Plesiosaurus probably laid its eggs just like a sea turtle does, in nests that were dug out in the sand. It was an excellent fish-catcher; its long
neck was well suited to catching fish. Wide jaws and teeth were efficient at
trapping prey. It used its intermeshing teeth to catch its food. It did not
chew it, but it swallowed food whole.
It had four wide, paddle-like flippers, used to propel the Plesiosaurus through the water with great maneuverability. It flapped its paddles up and
down, so that it probably looked like it was "flying" through the waters.
This long necked animal had a streamlined, tapered body. Its long and
flexible neck allowed quick changes of direction, it could turn almost on the
spot. Plesiosaurus had a small head and rows of long, pointed and razor sharp teeth.
The teeth of the upper and lower jaws were intermeshed.
Plesiosaurus was first found in 1821; it was probably the first fossil
reptile to be seen by scientists.
- 135MYA, Late Jurassic
- Europe England and Germany, East Africa.
Some American species are known as well.
- Grew up to lengths of 16.5ft (5m).