10 jaw-dropping dinosaurs discovered in America

Anchisaurus is one of the first dinosaurs discovered in American territory, although it was not correctly identified at the beginning. The first fossil of this herbivore was found in East Windsor, Connecticut, in 1818, but it was then believed to be part of a human skeleton. In subsequent years, other specimens of this species were uncovered in the area.

It measured 8 to 20 ft in length and lived 210 million years ago in the Portland Formation, Northeastern United States. In the late Triassic and early Jurassic periods, the Connecticut Valley was a dry, steep depression, and it was possible to pass from here to the east and the center of what is now Africa. This explains why some dinosaurs lived both in America and other continents.

Image: Simon Infanger

One of the most iconic dinosaurs found in America is the Triceratops, a herbivore that lived 70 to 65 million years ago, right at the end of the Age of Dinosaurs, in the Late Cretaceous. Its name derives from Greek and means "face with three horns". One of the largest horned dinosaurs**,** it stood around 7.5 ft tall and weighed about 5 rhinoceroses, the equivalent of 10 tons.

Fossils of this dinosaur have been found in abundance in the Hell Creek Formation in Montana and South Dakota. No fossils of this dinosaur have been found on any other continent. Triceratops has been the state dinosaur of Wyoming since March 1994.

Image: photo_steff

Allosaurus was one of the largest carnivores of the Jurassic period and its remains in the United States have been found mainly in the Morrison Formation, which covers states such as Colorado, Utah, and Wyoming. It lived 155 to 145 million years ago in North America, Africa, Australia, and possibly China. Also, did you know that the Allosaurus fragilis is the state fossil of Utah?

This bipedal dinosaur was an agile hunter with powerful jaws and sharp teeth. It was a theropod, not as huge as the largest carnivore, Tyrannosaurus rex, but just as fearsome. Allosaurus was bigger than an elephant and heavier than a rhino. Its name means "different lizard" due to its rare concave vertebrae.

Image: WikiImages

Another inhabitant of the Morrison Formation was the Stegosaurus, famous for its dorsal plates and spines on its tail, which it used for defense. Stegosaurus used to walk on all fours, grazing on low vegetation. Its head was perfectly adapted to this way of feeding. It was first described in 1877 by Yale paleontologist Othniel Charles Marsh, and its name means "roof(ed) lizard".

This Jurassic herbivore has been discovered in several states in the western United States. Scientists have found many fossils, showing that it was a very common creature for 10 million years, despite its tiny brain, small head, and useless teeth. The discovery of the Stegosaurus has helped them better understand the anatomy and behavior of armored dinosaurs.

Image: ariesa66

Is Tyrannosaurus rex the most famous dinosaur on the planet? Portrayed by pop culture to the hilt, this formidable predator is known for its gigantic size, razor-sharp teeth, and bipedal posture. However, its popularity has a logical explanation. T. rex is also one of the best-represented dinosaurs in the fossil record, with several complete specimens discovered, particularly in the states of Montana, South Dakota, and Wyoming.

Based on bones found in the late 19th century, paleontologist Henry Fairfield Osborn recreated the first drawing of this gigantic creature. He named it Tyrannosaurus rex, meaning "tyrant lizard king," because it is believed to have been the most dangerous dinosaur and the largest land carnivore of all time. Although it is estimated that up to 1.7 billion T. rex dinosaurs lived on Earth, only about 30 nearly complete skeletons have been found. Think about that!

Image: Elly Enn

This small but ferocious theropod lived during the Cretaceous period about 115-108 million years ago. Deinonychus is known for its sickle-shaped claws on its feet, used for hunting. Its name, unsurprisingly, means "terrible claw". Like all bipeds, it moved only on its hind legs and is believed to have been able to run at 25 miles per hour: more than the average Olympic champion.

Deinonychus fossils were found in Utah, Oklahoma, Montana, and Wyoming, in rocks of the Cloverly Formation and Antlers Formation. The study of this species, beginning in the 1960s, revolutionized the way scientists thought about dinosaurs, providing fascinating new insight into smaller predators.

Image: Steve Wrzeszczynski

Ankylosaurus is one of the best-known armored dinosaurs, which lived at the end of the Cretaceous period. It had bony protrusions on its head and all over its body as protection against the teeth and claws of predators. The armor was made up of small plates of bone welded together, constituting a shell as effective as that of turtles.

This gigantic herbivore roamed the jungles of North America about 68-66 million years ago, almost as well protected as a modern tank. The first specimen of Ankylosaurus was found in 1906 in the Hell Creek Formation, near Gilbert Creek, Montana. Other fossils of this species were discovered in other parts of Montana and Alberta, Canada, in the following years. However, to this day, it has not been possible to obtain a complete skeleton.

Image: mdherren

The first Hadrosaurus fossils were discovered by William Parker Folke, an amateur paleontologist, in 1838 in Haddonfield, New Jersey. The excavation site, known as the Hadrosaurus foulkii Leidy site, is now a National Historic Landmark. Hadrosaurids are known for their duck-billed mouth, with a powerful jaw containing several rows of teeth for chewing all kinds of leaves.

In 2004, scientists found a mummified Hadrosaurus specimen in North Dakota. This fossil is extremely unusual and valuable, as dinosaur soft tissue including skin and muscle is rare. This find allows us to learn more about this species and how they lived 67 million years ago.

Image: Jordyn St. John

Diplodocus means "double beam" and is so named because of the double bones in its tail. This was one of the longest animals on earth. It was about 79-85 ft long, 15 ft high, and weighed 15 tons. It could reach the tops of towering trees for food, and its small head allowed it to forage in vegetation where few other dinosaurs could reach.

Although some Diplodocus fossils were discovered earlier near Cañon City, Colorado, the most notable find came a few years later. In 1899, Funded by Scottish-American steel tycoon Andrew Carnegie, members of the Carnegie Museum of Natural History found a well-preserved Diplodocus skeleton in the Morrison Formation of Sheep Creek, Wyoming. With these fossils, the museum created a composite mount that became very popular and even got to tour the world.

Image: michaelwedermann

Apatosaurus is one of the best-known sauropods that inhabited North America during the Jurassic period. These herbivorous giants, with their long necks and tails, have also been discovered in the Morrison Formation, mainly in Colorado and Utah. It is believed to have lived 150 million years ago, at the end of the Jurassic period.

Apatosaurus could reach 69-75 ft in length, 20 tons in weight, and was one of the largest sauropods. It had a long neck containing 15 huge bones supported by powerful muscles that allowed it to feed on the leaves of the tallest trees. Perhaps this dinosaur sounds familiar. It has been the inspiration for numerous beloved animated characters: Littlefoot from The Land Before Time and Arlo and Poppa Henry from Pixar's The Good Dinosaur are Apatosauruses.

Image: Cup of Couple