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Authentic Mosasaurs Bones, Vertebra or Back Bones

These authentic Mosasaurs bones are vertebra or back bones found in Morocco. They are still in the plaster jacket used to safely collect and preserve the fossilized bones. The top of the plaster jacket has been removed to reveal the bones just as they were found. This makes a very nice display or if you have the tools and skills you could prepare the bones out of the matrix and make your own display. (click on each photo to enlarge the images)

Mosasaurs were a group of predatory marine reptiles that were very successful during the Late Cretaceous Period 101-66 million years ago. The first mosasaur fossils were found in the 1764 in a mine in the Netherlands, more than 50 years before the first dinosaur bones were found. Mosasaurs were among the first fossils recognized and scientifically described. "Mosasaur" means "reptile of the Meuse," a river near the quarry where mosasaurs were first found.

The smallest-known mosasaur was less than 1 m (3.3 ft) long. Larger mosasaurs were more typical, with many species growing longer than 4 m (13 ft). The largest known species, may have reached up to 17 m (56 ft) in length. Currently, the largest publicly exhibited mosasaur skeleton in the world is on display at the Canadian Fossil Discovery Centre in Morden, Manitoba. The specimen, nicknamed "Bruce", is just over 13 m (43 ft) long.

Mosasaurs were highly adapted for living in the sea. Their four legs were modified into paddles which aided in steering. The tail was the primary means of locomotion. Being a highly successful predator, mosasaurs possessed many adaptations for capturing prey. A mosasaur's jaw could "unhinge," much like a modern snake's to swallow larger prey whole. Its mouth was armed with an array of teeth designed for piercing and holding onto its prey. Mosasaurs were even equipped with an extra set of teeth in the pterygoid bones in the roof of the palate. These extended back into the throat and further prevented prey from escaping while being swallowed. It is likely that mosasaurs became extinct along with the dinosaurs during the extinction event at the end of the Cretaceous Period. Modern relatives of mosasaurs include varanid lizards (Komodo dragons, monitor lizards, etc.) and possibly snakes.

Mosasaurs breathed air, were powerful swimmers, and were well-adapted to living in the warm, shallow inland seas prevalent during the Late Cretaceous period. Mosasaurs were so well adapted to this environment that they most likely gave birth to live young, rather than returning to the shore to lay eggs as sea turtles do.

During the Late Cretaceous, North America was divided by a great inland sea (known as the Western Interior Seaway) which stretched from the Gulf of Mexico to the Arctic Circle. Vast layers of chalk were deposited in this shallow sea, leading to remarkable preservation of its inhabitants. The chalk beds of western Kansas, known as the Niobrara Formation, are world famous for yielding some of the finest fossils of Late Cretaceous marine and flying reptiles, birds, fish, sharks, and invertebrates.