Shonisaurus

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Shonisaurus
Fossil range: Late Triassic
life restoration of Shonisaurus
life restoration of Shonisaurus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Subclass: Diapsida
Superorder: Ichthyopterygia
Order: Ichthyosauria
Family: Shastasauridae
Genus: Shonisaurus
Species
  • S. popularis (type)
  • S. sikanniensis

Shonisaurus was the largest genus of ichthyosaur that has yet been found. Fossils of Shonisaurus were first found in a large deposit in Nevada in 1920. Thirty years later, they were excavated and it was found that the deposit contained the remains of 37 very large icthyosaurs which were named Shonisaurus, which means "Lizard from the Shoshone Mountains", after the formation where the fossils were found.

Shonisaurus lived during the Norian stage of the late Triassic period. It had a whale-like body and long narrow paddles. Shonisaurus had a long pointed mouth that contained teeth only at the end.

The two known species of Shonisaurus with an adult human to scale.
The two known species of Shonisaurus with an adult human to scale.

The first species discovered, S. popularis, was adopted as the State Fossil of Nevada in 1984. Excavations, begun in 1954 under the direction of Dr. Charles Camp and Dr. Samuel Welles of the University of California, Berkeley, were continued by Camp throughout the 60s. It was named by Charles Camp in 1976.

Shonisaurus popularis specimens reached a length of 15 meters (50 feet). The Nevada fossil sites can currently be viewed at the Berlin-Ichthyosaur State Park.

A discovery in British Columbia in the 1990s made S. popularis the smaller of the Shonisaurus species; a second species, S. sikanniensis, was discovered and has an estimated length of 21 meters (70 feet).

An ichthyosaur found in the Himalayan mountains called Himalayasaurus, may be the same animal as Shonisaurus.

[edit] References

  • Dixon, Dougal. "The Complete Book of Dinosaurs." Hermes House, 2006.
  • Camp, C. L. 1980. Large ichthyosaurs from the Upper Triassic of Nevada. Palaeontographica, Abteilung A, 170:139-200.
  • Camp, C.L. 1981. Child of the rocks, the story of Berlin-Ichthyosaur State Park. Nevada Bureau of Mines and Geology special publication 5.
  • Cowen, R. 1995. History of life. Cambridge, Mass.: Blackwell Scientific.
  • Hogler, J. A. 1992. Taphonomy and paleoecology of Shonisaurus popularis (Reptilia: Ichthyosauria). Palaios 7:108-17.
  • McGowan, C., and R. Motani. 1999. A reinterpretation of the Upper Triassic ichthyosaur Shonisaurus. Journal of Vertebrate Paleontology 19:42-49.
  • Motani, R., N. Minoura, and T. Ando. 1998. Ichthyosaurian relationships illuminated by new primitive skeletons from Japan. Nature 393:255-57.

[edit] External links