Cymbospondylus is an extinct genus of large ichthyosaurs, of which it is among the oldest representatives, that lived during the Anisian stage of the Middle Triassic in what are now North America and Europe. The first known fossils of this taxon are a set of more or less complete vertebrae which were discovered in the 19th century in various mountain ranges of Nevada, in the United States, before being named and described by Joseph Leidy in 1868. It is in the beginning of the 20th century that more complete fossils were discovered through several expeditions launched by the University of California, and described in more detail by John Campbell Merriam in 1908, thus visualizing the overall anatomy of the animal. While many species have been assigned to the genus, only five are recognized as valid, the others being considered synonymous, doubtful or belonging to other genera. Cymbospondylus was formerly classified as a representative of the Shastasauridae, but more recent studies consider it to be more basal, view as the type genus of the Cymbospondylidae.
Cymbospondylus
Holotype block of C. piscosus.
Partial holotype skeleton of C. nichollsi (FMNH PR 2251), on display at the Field Museum, Chicago
Holotype skull of C. youngorum (LACM DI 157871), on display at the Humboldt Museum in Winnemucca, Nevada.
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.
Ichthyosauria
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