The Dinosaurs and Prehistoric Animals of Nevada

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Which Dinosaurs and Prehistoric Animals Lived in Nevada?

Shonisaurus, a prehistoric animal of Nevada. Nobu Tamura

Surprisingly, given its proximity to dinosaur-rich states like Utah and New Mexico, only scattered, incomplete dinosaur fossils have ever been discovered in Nevada (but we do know, given this state's scattered footprints, that at least some types of dinosaurs called Nevada home during the Mesozoic Era, including raptors, sauropods and tyrannosaurs). Fortunately, the Silver State wasn't entirely lacking in other kinds of prehistoric life, as you can learn by perusing the following slides. (See a list of dinosaurs and prehistoric animals discovered in each U.S. state.)

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Shonisaurus, a prehistoric reptile of Nevada. Nobu Tamura

How, you may ask, did a 50-foot-long, 50-ton marine reptile like Shonisaurus wind up as the state fossil of land-locked Nevada, of all places? The answer is that, 200 million years ago, much of the American southwest was submerged under water, and ichthyosaurs like Shonisaurus were the dominant marine predators of the late Triassic period. Shonisaurus was named after the Shoshone Mountains in western Nevada, where the bones of this giant reptile were discovered in 1920.

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The skull of Aleosteus, a prehistoric fish of Nevada. Wikimedia Commons

Discovered in sediments dating to about 400 million years ago--smack in the middle of  the Devonian period--Aleosteus was a type of armored, jawless prehistoric fish known as a placoderm (the largest genus of which was the truly gigantic Dunkleosteus). Part of the reason placoderms went extinct by the start of the Carboniferous period was the evolution of giant ichthyosaurs like Shonisaurus (see slide #2), also discovered in Nevada sediments.

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The Columbian Mammoth

columbian mammoth
The Columbian Mammoth, a prehistoric mammal of Nevada. Wikimedia Commons

In 1979, an explorer in Nevada's Black Rock Desert discovered a strange, fossilized tooth--which prompted a researcher from UCLA to later excavate what became known as the Wallman Mammoth, now on display at the Carson State Museum in Carson City, Nevada.  Researchers have determined that the Wallman specimen was a Columbian Mammoth rather than a Woolly Mammoth, and died about 20,000 years ago, right at the cusp of the modern era.

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A typical ammonoid shell. Wikimedia Commons

Ammonoids--small, shelled creatures distantly related to modern squids and cuttlefish--were some of the most common marine animals of the Mesozoic Era, and constituted an essential part of the undersea food chain. The state of Nevada (which was completely underwater for much of its ancient history) is especially rich in ammonoid fossils dating from the Triassic period, when these creatures were on the lunch menu of huge ichthyosaurs like Shonisaurus (slide #2).

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Various Megafauna Mammals

A prehistoric camel, of the type that lived in late Pleistocene Nevada. Heinrich Harder

During the late Pleistocene epoch, Nevada was pretty much as high and dry as it is today--which explains its profusion of megafauna mammals, including not only the Columbian Mammoth (see slide #4), but prehistoric horses, giant sloths, ancestral camels (which evolved in North America before spreading to their current home of Eurasia) and even giant, meat-eating birds. Sadly, all this remarkable fauna went extinct shortly after the end of the last Ice Age, about 10,000 years ago.