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. then at the
University of California Berkeley, where it remained until being put into storage in the 1960s. In 1943, American paleontologist
Samuel Paul Welles found that the specimen was notably different from other known
plesiosaurs and declared it as the type specimen of a new genus and species which he named
Hydrotherosaurus alexandrae. The
generic name means "fisherman lizard", while the
specific name honors
Annie Montague Alexander, who has done plenty of research on the vertebrates of the western United States. ==Description==