Shonisaurus

Taxobox
name = "Shonisaurus"
fossil_range = Late Triassic

---

image_width = 250px
image_caption = life restoration of "Shonisaurus"
regnum = Animalia
phylum = Chordata
classis = Sauropsida
ordo = Ichthyosauria
familia = Shastasauridae
genus = "Shonisaurus"
genus_authority = Camp, 1976
subdivision_ranks = Species
subdivision =
* "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 front end.

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".

BioOne Quote

"The ichthyosaur Shonisaurus sikanniensis sp. nov. is described from the Pardonet Formation (Norian, Late Triassic) of northeastern British Columbia. The type specimen is considerably larger than Shonisaurus popularis, with an estimated length of 21 m. It also differs from S. popularis in having a fan-shaped scapula, and relatively longer vertebral centra. Studies of this new species, along with re-examination of S. popularis, suggests that Shonisaurus was not as deep-bodied as previously reconstructed. Teeth are set in sockets, but are known only in a few, small individuals. This implies that teeth were present only in juveniles, and that adults were edentulous. The new species extends the geographical and stratigraphical range of Shonisaurus to the middle Norian of British Columbia." [cite news | first=Elizabeth | last=Nicholls | coauthors= Makoto Manabe | title=Journal of Vertebrate Paleontology | date=June 21, 2004 | publisher=BioOne | url =http://www.bioone.org/perlserv/?request=get-abstract&doi=10.1671%2F0272-4634(2004)024%5B0838%3AGIOTTN%5D2.0.CO%3B2 | work =BioOne | pages =pp. 838–849 | accessdate = 2008-10-01 | language = ]

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.

External links

* [http://parks.nv.gov/bi.htm Nevada Division of State Parks]
* [http://www.encyclopedia.com/doc/1G1-58243235.html THE ICHTHYOSAUR Nevada's State Fossil.]