Hydrotherosaurus

Hydrotherosaurus (meaning "fisherman lizard") is an extinct genus of elasmosaurid plesiosaur from the Upper Cretaceous (Maastrichtian stage) Moreno Formation of Fresno County, California, USA. The only known species, H. alexandrae, was named for Annie Montague Alexander in 1943 by Samuel Paul Welles.

==Discovery and naming== The first remains of Hydrotherosaurus to be found were several vertebrae discovered by Frank C. Paiva on his own property in the Panoche Hills of Fresno County, California, which were taken to Berkeley in the spring of 1937 by W. M. Tucker, who was the Chairman of the Department of Geology of Fresno State College. Afterwards, Fresno State College and the University of California Museum of Paleontology organized a joint expedition which would uncover a nearly complete fossilized skeleton of the animal, with only parts of the skull, shoulder girdle, flippers and certain vertebral elements missing. This specimen, designated UCMP 33912, was collected in a ravine on the property of the Sun Ray Gypsum Mine, about 22 miles west of Mendota, California, and the deposits from which it originates are part of the Moreno Formation. After being excavated, UCMP 33912 was mounted for display, first at the Golden Gate International Exposition, then at the University of California Berkeley, where it remained until being put into storage in the 1960s.