The Dinosaurs and Prehistoric Animals of Oklahoma

01
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Which Dinosaurs and Prehistoric Animals Lived in Oklahoma?

saurophaganax
Wikimedia Commons

During much of the Paleozoic, Mesozoic and Cenozoic eras--that is, from 300 million years ago to today--Oklahoma had the good fortune to be high and dry, allowing for the preservation of a wide variety of fossils. (The only gap in this pristine record occurred during the Cretaceous period, when much of the state was submerged beneath the Western Interior Sea.) On the following slides, you'll discover the most important dinosaurs, prehistoric reptiles and megafauna mammals that have called the Sooner State their home. (See a list of dinosaurs and prehistoric animals discovered in each U.S. state.)

02
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Saurophaganax

saurophaganax
Saurophaganax, a dinosaur of Oklahoma. Sergey Krasovskiy

The official state dinosaur of Oklahoma, the late Jurassic Saurophaganax was a close relative of the better-known Allosaurus--and, in fact, it may have been a species of Allosaurus, which would consign Saurophaganax ("greatest lizard-eater") to the trash heap of paleontology. True Sooners may not want to hear this, but the Saurophaganax skeleton on display at the Oklahoma Museum of Natural History is padded out with a few Allosaurus bones!  

03
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Acrocanthosaurus

acrocanthosaurus
Acrocanthosaurus, a dinosaur of Oklahoma. Dmitry Bogdanov

One of the largest carnivorous dinosaurs of the early Cretaceous period (about 125 million years ago), the "type fossil" of Acrocanthosaurus was discovered in Oklahoma shortly after the Second World War. This theropod's name, Greek for "high-spined lizard," refers to the distinctive neural spines on its back, which may have supported a Spinosaurus-like sail. At 35 feet long and five or six tons, Acrocanthosaurus was almost the size of the much later Tyrannosaurus Rex.

04
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Sauroposeidon

sauroposeidon
Sauroposeidon, a dinosaur of Oklahoma. Wikimedia Commons

Like many sauropod dinosaurs of the middle Cretaceous period, Sauroposeidon was "diagnosed" based on a handful of vertebrae found on the Oklahoma side of the Texas-Oklahoma border in 1994. The difference is, these vertebrae were truly enormous, putting Sauroposeidon in the 100-ton weight class (and possibly making it one of the biggest dinosaurs that ever lived, perhaps even rivaling the South American Argentinosaurus).

05
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Dimetrodon

dimetrodon
Dimetrodon, a prehistoric reptile of Oklahoma. Fort Worth Museum of Natural History

Often mistaken for a true dinosaur, Dimetrodon was actually a type of prehistoric reptile known as a pelycosaur, and lived well before the classic age of dinosaurs (during the Permian period). No one knows the exact function of Dimetrodon's distinctive sail; it was probably a sexually selected characteristic, and may have helped this reptile absorb (and dissipate) heat. Most Dimetrodon fossils hail from the "Red Beds" formation shared by Oklahoma and Texas.

06
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Cotylorhynchus

cotylorhynchus
Cotylorhynchus, a prehistoric reptile of Oklahoma. Wikimedia Commons

A close relative of Dimetrodon (see previous slide), Cotylorhynchus adhered to the classic pelycosaur body plan: a huge, bloated trunk (which held the yards and yards of intestines this prehistoric reptile needed to digest tough vegetable matter), a tiny head, and stubby, splayed legs. Three species of Cotylorhynchus (the name is Greek for "cup snout") have been discovered in Oklahoma and its southern neighbor, Texas.

07
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Cacops

cacops
Cacops, a prehistoric amphibian of Oklahoma. Dmitry Bogdanov

One of the most reptile-like amphibians of the early Permian period, about 290 million years ago, Cacops ("blind face") was a squat, cat-sized creature with stubby legs, a short tail, and a lightly armored back. There's some evidence that Cacops was also equipped with relatively advanced eardrums, a necessary adaptation for life on the dry Oklahoma plains, and that it hunted at night, the better to avoid the larger amphibian predators of its Oklahoma habitat.

08
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Diplocaulus

diplocaulus
Diplocaulus, a prehistoric reptile of Oklahoma. Wikimedia Commons

The remains of the bizarre, boomerang-headed Diplocaulus ("double stalk") have been discovered all over the state of Oklahoma, which was much hotter and swampier 280 million years ago than it is today. Diplocaulus' V-shaped noggin may have helped this prehistoric amphibian to navigate strong river currents, but its more likely function was to deter larger predators from swallowing it whole!

09
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Varanops

varanops
Varanops, a prehistoric reptile of Oklahoma. Wikimedia Commons

Yet another genus of pelycosaur--and thus closely related to Dimetrodon and Cotylorhynchus (see previous slides)--Varanops was important for being one of the last of its family on the earth, dating all the way to the late Permian period (about 260 million years ago). By the start of the ensuing Triassic period, ten million years later, all the pelycosaurs on earth had gone extinct, muscled out of the scene by better-adapted archosaurs and therapsids.

10
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Various Megafauna Mammals

mastodon
The American Mastodon, a prehistoric animal of Oklahoma. Wikimedia Commons

Oklahoma was teeming with life during the Cenozoic Era, but the fossil record is relatively sparse until the Pleistocene epoch, stretching from about two million to 50,000 years ago. From the discoveries of paleontologists, we know that the vast plains of the Sooner State were traversed by Woolly Mammoths and American Mastodons, as well as prehistoric horses, prehistoric camels, and even one genus of giant prehistoric armadillo, Glyptotherium.