Prehistoric Planet Store - Replica fossils including dinosaurs like T. rex, Triceratops, and more!

This is a Prehistoric Planet original discovery. Our paleontologist discovered, escavated, prepared and mounted this virtually complete Cladastes, Mososaur, skeleton in 2001. It was discovered in the Pierre Shale Formation, late Cretaceous (74-83 million years) near Chadron, Nebraska.

This specimen is missing only three to four vertebra from the distal portion of the tail and three phalanges from one paddle. It is otherwise a very rare complete specimen. The original specimen was donated to and is on exhibit at the Elachee Nature Center, Gainesville, GA.

Clidastes is an extinct genus of marine lizard belonging to the mosasaur family. Clidastes means "locked vertebrae”. This refers to how the vertebral processes allow the proximal heads of the vertebrae to interlock for stability and strength during swimming. Clidastes was the one of the smallest of the mosasaurs (the smallest known being Dallasaurus), averaging 2–4 meters (6.6–13.1 ft) in length, with the largest specimens reaching 6.2 meters (20 feet) long. The skull offered here was from a 15 foot specimen.. Even though the vertebrae lock together, the living animal would have still had a range of motion in the horizontal plane that is sufficient to allow for the high quality of swimming in shallow waters. Additionally the strengthening of the tail, and entire backbone, allowed for muscle attachments to help it swimming. It possessed a delicate and slim form with an expansion of the neural spines and chevrons near the tip of the tail and this enabled it to chase down the fastest of prey.

Photo 3 shows the complete skeleton from which this skull was made.