What is "platecarpus"

Platecarpus ("flat wrist") is an extinct genus of aquatic lizard belonging to the mosasaur family, living around 84–81 million years ago during the middle Santonian to early Campanian, of the Late Cretaceous period. Fossils have been found in the United States as well as a possible specimen in Belgium and Africa. Platecarpus probably fed on fish, squid, and ammonites. Like other mosasaurs, it was initially thought to have swum in an eel-like fashion, although a recent study suggests that it swam more like modern sharks. An exceptionally well-preserved specimen of P. tympaniticus known as LACM 128319 shows skin impressions, pigments around the nostrils, bronchial tubes and the presence of a high profile tail fluke, showing that it and other mosasaurs did not necessarily have an eel-like swimming method but were more powerful fast swimmers. It is held in the Natural History Museum of Los Angeles County.