Mosasaurs are an extinct group of large aquatic reptiles within the family Mosasauridae that lived during the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. They belong to the order Squamata, which includes lizards and snakes.
Fossil shell of ammonite Placenticeras whitfieldi showing punctures caused by the bite of a mosasaur, Peabody Museum of Natural History, Yale
Scales of Tylosaurus proriger (KUVP-1075)
Fibrous tissues and microstructures recovered from Prognathodon specimen IRSNB 1624
Ichthyosauria is an order of large extinct marine reptiles sometimes referred to as "ichthyosaurs", although the term is also used for wider clades in which the order resides.
An ichthyosaur and plesiosaur by Édouard Riou, 1863. This old representation of a plesiosaur lifting its head is not accurate and physically impossible.
The skull of specimen NHMUK PV R1158 found by Joseph Anning in 1811
The torso of specimen NHMUK PV R1158 found by Mary Anning in 1812