A–ZAdd dino

Not a dinosaur — marine reptile

"Lizard of the Meuse River"

Mosasaurus

Late Cretaceous · 82–66 MyaCarnivoreNetherlands, North America

Not a dinosaur — a giant marine lizard, closer kin to monitor lizards and snakes. Mosasaurus ruled the Late Cretaceous seas as an apex predator, swallowing prey almost whole with a double-hinged jaw. Its skull was dug from a Maastricht chalk quarry in the 1770s, decades before dinosaurs were even recognized as a group.

Length
13 m
Height
2.4 m
Weight
15,000 kg
Top speed
12 km/h

Field notes

  • Named for the Meuse river near Maastricht, Netherlands, where the first skull was found.
  • French Revolutionary forces seized the original fossil skull as war spoils in 1795.
  • Fossilized skin impressions show it swam with a shark-like tail fin, not a simple tapering tail.
Meet the rest of the Mosasauridae family →