Plesiosaurus
To see pictures of animals click the blue dot..
Plesiosaurus
To see pictures of animals click the blue dot..
Plesiosaurus inhabited the oceans 200 million years ago. "flying" underwater with four wing like limbs. Its sharp teeth and snapping jaws formed a deadly trap for small aquatic animals. The long necked Plesiosaurus gave its name to the plesiosaurs, a group of flesh eating marine reptiles that are extinct. Along with the dolphin like ichthyosaurs and other marine reptiles, plesiosaurs were the "sea dragons" that inhabited the seas from 200 to 65 million years ago, while the dinosaurs were dominant on land.
Breeding: Nothing is known about the breeding habits of Plesiosaurus, because no fossils nests, juveniles, or pregnant females have been found. It may have laid eggs in holes dug in sandy beach, ot it may have incubated its eggs in nests on land. But the foot paddles of Plesiosaurus do not seem suited to moving about on land or to digging nests.
Its seems more likely that Plesiosaurus gave birth to live young in the water, the way sea snakes do, or on the beach lion sea lions. The young may have lived in estuaries until they became big enough to move to the open sea.
Food & Hunting: Plesiosaurus had a small head on a long neck. Its teeth were long and pointed, and the teeth of the upper and lower jaws intermeshed. Plesiosaurus used its teeth to catch its food, not to chew it. It probably ate fish, squid like cephalopods, and shrimp like crustaceans. Its U shaped jaws acted as a fish trap allowing Plesiosaurus swallow food whole.Plesiosaurus probably struck at prey by lashing out with it long neck and then snatching at victims and its sharp teeth. Its neck would have acted as a long rudder when negotiating turns while chasing prey.
Characteristics: Plesiosaurus was first identified in 1821 by two amateur scientist who were studding ichthyosaurs in a museum in Great Britain. FInding that they had some odd bones, they concluded that the bones must have belonged to a new animal. they were proved right in 1824 by Mary Anning, a famous fossil collector in Dorset England. She discovered the first complete Plesiosaurus skeleton, which is now in the Natural history Museum in London. Plesiosaurus gave its name to the plesiosaurs because it was the first of its group to be discovered.
Plesiosaurus like other plesiosaurs, swam with its legs rather than its tail, using its paddle like forelimbs the way penguins and sea lions do. BUT while penguins and sea lions use only their hind limbs for steering or for moving on land, Plesiosaurus used both its fore and hind limbs to propel itself throughout water.. To help it stay underwater, the animal may have swallowed stones to prevent the air in its lungs from bringing it to the surface. Some Plesiosaurs had much longer necks than Plesiosaurus. Other had enormous heads, often on shorter necks.
Enemies: Plesiosaurus was probably preyed on by larger marine reptiles that lived in the same seas. These reptiles included the ichthyosaur Temnodontosaurus, (as big as a killer whale) and the 16 foot long plesiosaur Rhomaleosaurus.
With no armor and an exposed neck, Plesiosaurus must have been vulnerable. It was probably not a fast swimmer and may have relied on its good sight, camouflage colors and maneuverability to survive.
Key Facts: Sizes, Weight, breeding, lifestyle,
related Species
Length: 10 feet
Weight: Unknown. Possibly about one ton
Breeding:
Mating: Unknown. Probably internal fertilization
Incubation: Unknown, May have given
birth to live young.
No of young: Unknown
Lifestyle:
Diet: Small to medium sized fish,
squid like cephalopods, maybe shrimp like crustaceans.
Habit: Active hunter in the sea
maybe in estuaries.
Related Species: Other Plesiosaurus were
the longer necked Microcleidus and the even longer necked Elasmosaurus,
50 ft long with a 25 foot long neck and a small head. They probably used
their flexible necks to help catch prey.
When & Where they lived: Plesiosaurus
fossils were discovered in Great Britain in rocks that were first laid
down in the Lower jurassic period, about 200 million years ago, on what
was then the seabed. Related plesiosaurs, often incorrectly called
Plesiosaurus, have been found in marine rocks in North America and elsewhere.
Features of the Plesiosaurus:
Swimming: Both for and hind limbs were
used in flapping motion to propel Plesiosaurus through the water.
Short tail was probably not used for propulsion.
Paddles: Toes fused together to form a
mitten. Grew from the shoulder and hip girdles with large, plate like bones
supporting strong muscles to aid swimming.
Neck: Long and flexible. Allowed quick
changes of direction when
Plesiosaurus was pursing prey or being pursued
by predators.
Head: Small in relation to neck and body.
Wide jaw and intermeshing teeth were efficient at trapping prey.
Did you know:
Part of a fossil plesiosaur skeleton was found
in 1719. It was called a crocodile ot porpoise because at the time
no one knew that there had ever been animals other than modern species.
It has been suggested that the Loch Ness monster
if it exist may be a plesiosaur. But plesiosaurs became extinct about 65
million years ago. And Loch Ness was frozen solid until about 12,000 years
ago.
Plesiosaurus wa not a dinosaur. It was from a
different group of reptiles.
Return to Wildlife Menu HERE!!