State Fossil of Nevada
Shonisaurus (common name)
Shonisaurus sikanniensis(scientific name)
Shonisaurus is the largest ichthyosaur ever found. Ichthyosaurs were giant, air-breathing marine reptiles that resembled modern fish and dolphins, only much bigger. A skeleton of Shonisaurus sikanniensis, discovered in British Columbia in 1991, is even larger than the first species of this genus discovered, Shonisaurus popularis. Shonisaurus popularis lived approximately 204 to 217 million years ago during the Norian and Carnian ages of the late Triassic period. Its fossils have been found on all continents except Antarctica.
A STATE SYMBOL
Several undisturbed Shonisaurus popularis fossils can be viewed today at Berlin–Ichthyosaur State Park in Nye County, Nevada. The park was established in 1957 to protect North America’s largest occurrence of ichthyosaur fossils, which were well preserved in the geological formation called the Luning Formation. In the Triassic period, Nevada lay on the west coast of North America and bordered a vast, shallow sea, which was home to this giant reptile. Today, this site is in the desert, 7,000 feet above sea level. The area was designated a National Natural Landmark in 1973. In 1977,Shonisaurus popularis was declared the official fossil of the state of Nevada.
Charles Lewis Camp, a paleontologist and zoologist from the University of California, Berkeley, named this dinosaur in 1976. The genus name for this ichthyosaur, Shonisaurus, honors the central Nevada mountains where its fossils were first discovered in 1920, the Shoshone mountain range. The suffix -saurus comes from the Greek word σαύρος (sauros), which means "lizard." The species name popularis denotes its abundance at the discovery site. The word ichthyosaur is also derived from Greek and means "fish lizard."
The largest animal of its time, Shonisaurus popularis had a whale-like body up to 50 feet (15 m) long. It had a long, narrow, pointed mouth with teeth only at the end. Shonisaurus popularis probably fed on slow-swimming fish, ammonites, and smaller marine reptiles. This huge prehistoric animal weighed up to 40 tons (36,290 kg) and had longer, narrower flippers than did other ichthyosaurs.
Ichthyosaurs lived about 90 to 245 million years ago. Shonisaurusevolved from land reptiles that moved back into the water in the middle Triassic period. It is not certain what caused these large reptiles to die and be buried in such a small area, or what caused them to go extinct.
Ichthyosaurs were among the first marine reptiles ever discovered. The first fossilized Shonisaurus popularis bones were discovered in about 1868 or 1869, and the first nearly complete skeleton of this ichthyosaur was found in 1928 near Berlin, Nevada. Around the turn of the last century, Berlin was a small mining town; today it is a true ghost town. The fossil site was excavated by paleontologists throughout the 1950s and 1960s and was established as Berlin–Ichthyosaur State Park in the late 1950s. The fossilized remains of 37 ichthyosaurs have been unearthed there.
Himalayasaurus tibetensis, an ichthyosaur found in the Himalayan Mountains of Tibet in 1979, may be the same animal as Shonisaurus.
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|Author: World Trade Press|