Plesiosaurs were one of the most successful groups of marine reptiles that ever lived. Their ancestors were lizard like land animals that entered the sea about 250 million years ago. They rapidly adapted to life in the water with hydrofoil shaped legs and pointed teeth for catching fish. They swam much like modern day sea lions, penguins and turtles by "flying" through the water with sweeps of their long paddles. Their bodies were stout but streamlined and their short tails steered them through the water like a rudder.
(Elasmosaurs reconstruction By Paul Stumkat)
Three types of plesiosaurs have been found near Richmond: Kronosaurus, Elasmosaurs and the Richmond Pliosaur.
See more information on Kronosaurus and the Richmond Pliosaur.
Elasmosaurs were marine reptiles with extremely long necks. The neck had between 50 to 72 vertebrae (humans only have 7!) and could be longer than the rest of the body and tail combined! Elasmosaurs were related to other plesiosaurs such as Kronosaurus and the Richmond Pliosaur.
They had short, stout bodies and long, diamond-shaped paddles for swimming through the water.
Unfortunately, good fossil skeletons of elasmosaurs are rare. After they died, their carcasses may have drifted at sea for weeks at a time. Predators and scavengers often dismembered the bodies, and slow decay scattered their bones along the seafloor. It seems that the head and neck were the parts of the skeleton most easily lost.
Elasmosaur skulls are extremely rare. Only a dozen or so have been found worldwide. One complete Elasmosaur has been found in Australia. It was found as two separate pieces. Only one complete skull has ever been found in Australia. It was found as two separate pieces several years apart.