The name Mosasaur derived from the Meuse River in the Netherlands where the first discovery was made "Mosa" is the Latin form of "Meuse" and "saur" is from the Greek "saurus" meaning "lizard".

DISCOVERY
The first mosasaur was found in 1780 by quarrymen working in a shaft 90 feet below the surface of St. Peters Mount at Maestricht, the Netherlands, in rocks of Cretaceous age. Dr. Hoffman, a surgeon of Maestricht was called to examine the remains of what proved to be the skull and vertebral column. However, the specimen was found beneath ground owned by a clergyman named Goddin who claimed it. He forced Hoffman to yield the specimen as well as pay the costs of the resulting lawsuit.

In 1815 the troops of the French Republic, repulsed by the Austrians, laid siege to the city of Maestricht and bombarded Fort St. Peter. The commanding general of the French army ordered his artillerymen to avoid Goddin's country house where the now famous fossil was kept. Goddin guessed the reason behind this and had the specimen removed and kept in the city.

After Maestricht fell, a reward of 600 bottles of wine was offered for its recovery. The following day the specimen was borne into French hands by a dozen grenadiers. It was sent to Paris, where it remains in the collections of the Museum National d'Histoire Naturelle.

PHYSIOLOGY
People are inclined to think of animals from the "Age of Reptiles" as primitive, and so many of them were, but if by primitive we mean to imply simple, or unspecialized, then the term cannot be applied to the mosasaur, for this voracious fish-eater was beautifully adapted to its underwater environment. For example, the design of the jaws of the mosasaur permitted great expansion, enabling the beast to swallow bulky prey. A joint in the middle of each mandible permitted the jaws to bow outward when opened. Mosasaur teeth were more or less round in cross section and were used for seizing prey. Two rows of recurved pterygoid teeth in the roof of the mouth were used to hold the prey while swallowing.

In size and head-shape the mosasaurs somewhat suggest modern alligators or crocodiles, though no creature living today bears more than a superficial resemblance to this extinct hunter of the seas. Its nearest surviving relatives are the monitor lizards of Africa and Asia. Snakes are also close relatives, having many similarities in the construction of the skull and the body plan in general.

The limbs of mosasaurs were modified into paddles and some species developed a tail fin to assist movement in the water. The long backbone was made up of as many as 130 cup-and-ball vertebrae, indicating great flexibility. The tail which was long and muscular was moved in an undulating manner from side-to-side to provide the motive power for the big lizard. The relatively small flippers acted as stabilizers.

From its body construction, it appears that the mosasaur was a sub-surface feeder, pursuing its prey in much the same manner as seals do today. In all likelihood mosasaurs were viviparous, bearing their young live, since certain other reptiles are known to do this. It is unlikely that they dragged themselves onto land to lay eggs as the limb girdles were no longer connected with the vertebral column and could not support the weight of the animal out of water. Mosasaurs were fish-eaters, although some skeletal remains indicate they may have fed on smaller mosasaurs as well.

Some types of mosasaurs grew to lengths of 45 feet or more, the majority measured from 10 to 20 feet in length. Darting through the water in pursuit of smaller dwellers of the deep, the mosasaur must have proved a fearsome predator, extremely capable of holding his own against all comers.