6 Dinosaurs that Lived in South Dakota (And Where to See Fossils Today)

Written by Jeremiah Wright
Updated: July 15, 2023
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South Dakota’s fossil record starts in the Paleozoic period when, unfortunately, the state’s area was submerged underwater. This means that no dinosaurs could have ever lived there at the time, as dinosaurs are specifically extinct animals with upright limbs that lived on land.

The Cambrian period, the first geological period of the Paleozoic, is now considered responsible for a significantly rich fossil record in South Dakota. However, until the Late Cretaceous period, no dinosaurs lived in the region. Instead, it was populated by organisms such as ammonites, crinoids, marine reptiles, plesiosaurs, and prehistoric sea turtles.

Ultimately, due to a process known as geologic uplift, the Late Cretaceous period was the one that brought actual dinosaurs to the territories of South Dakota. Stick around, and you’ll find out more about six of them!

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6 Dinosaurs That Lived in South Dakota

6 Dinosaurs That Lived in South Dakota

As mentioned, the Late Cretaceous period was when dinosaurs roamed the region of South Dakota. At the time, some of the most famous dinosaurs of all time, such as the Tyrannosaurus and the Triceratops, could be seen here.

Without further ado, here are six dinosaurs that lived in South Dakota!

1. Triceratops

Triceratops horridus, screaming dinosaur isolated with shadow on white background (3d illustration)

The

triceratops

is actually an entire genus consisting of herbivorous quadrupedal dinosaurs.

©Dotted Yeti/Shutterstock.com

Also known as the “three-horned face” dinosaur, thanks to its scientific name, the triceratops is actually an entire genus consisting of herbivorous quadrupedal dinosaurs. They lived during the Late Cretaceous period (specifically the Maastrichtian stage), 68 to 66 million years ago.

The genus’ distinctive features are the three horns located on top of the skull, a large bony frill, and a four-legged body with characteristics similar to rhinoceros and bovine bodies. Alongside the Tyrannosaurus, the Triceratops is one of the most well-known dinosaurs in the entire world.

Moreover, specimens of the Triceratops genus were also some of the largest dinosaurs at the time, growing up to 26-30 feet (8-9 m) long and weighing around 5.5-9.9 short tons (5-9 metric tons).

The Triceratops served as prey for the Tyrannosaurus. Contrary to popular belief, the three-horned face dinosaur wouldn’t rely on its horns and frills to scare away or fight predators. Instead, recent research suggests that these features were used during courtship and to show dominance. Essentially, they functioned as modern antlers.

2. Edmontonia

Edmontonia

Edmontonia is a genus within the Ankylosauria suborder of armored dinosaurs.

©Artush/Shutterstock.com

This genus bears the name of the rock unit found in Canada, namely the Edmonton Formation. Edmontonia is a genus within the Ankylosauria suborder of armored dinosaurs. They lived during the Late Cretaceous period, 76.5 to 69 million years ago.

The two species in the genus (E. longiceps and E. rugosidens) were not taller than humans. They were about 22 feet (6.6 m) in length. Edmontonia dinosaurs are known as bulky and broad, weighing about 3.31 short tonnes (according to Gregory S. Paul, a paleontological researcher).

When it comes to distinctive features, the dinosaurs in this genus were equipped with sharp spikes along the sides and oval, ridged bony plates on their heads and backs. At the same time, keeled plates protected their necks.

Unlike Triceratops, it is believed that Edmontonia made good use of its armor and spikes. Some sources suggest that the dinosaur would crouch down to the ground to protect its underbelly and allow its spikes to impale any predator that would be foolish enough to charge directly at its lateral spikes.

3. Edmontosaurus

Edmontosaurus model
Edmontosaurus

were part of the

Saurolophinae

subfamily.

©MVolodymyr/Shutterstock.com

This lizard from Edmonton (literal translation of the scientific name) is a genus within the Hadrosauridae family of duck-billed dinosaurs. The two species of the genus, E. regalis and E. annectens, lived during the Late Cretaceous period (specifically from Campanian to Maastricthian), 73 to 66 million years ago.

Edmontosaurus most likely shared its territory with the Triceratops and Tyrannosaurus, as they all lived during the same period.

The dinosaurs in this genus would grow up to 39 feet (12 m) long and weigh about 6.2 short tons (5.6 metric tons). Unlike most hadrosaurid species, Edmontosaurus were part of the Saurolophinae subfamily, meaning they lacked the distinctive hollow crests of hadrosaurids and sported fleshy combs or even solid crests (although smaller in size).

Edmontosaurus was one of the few herbivore genera that could move freely on two legs and on all four, depending on the situation. Bone beds suggest that the genus lived in groups and preferred coastal plains and coastal areas.

4. Ornithomimus

Ornithomimus had long arms and hands with curved necks. Their beaks were positioned towards the front of the head with ridges that look much like the inside of a goose or duck’s mouth.

The three weight-bearing toes are the most distinctive features of the

Ornithomimus

dinosaurs.

©N-sky/Shutterstock.com

This is a genus of dinosaurs known as a “bird mimic” (literal translation of the scientific name). The specimens were bipedal theropods that featured feathers as well as a beak (without any teeth, however). The genus lived between 76.5 and 66 million years ago, during the Late Cretaceous period (specifically, from Campanian to Maastrichtian).

The three weight-bearing toes are the most distinctive features of the Ornithomimus dinosaurs. Besides that, they are also identified by their long necks, long and slender arms, and beaked skulls. Essentially, they are the prehistoric version of the ostrich. Thanks to their long limbs and hollow bones, the representatives of the Ornithomimus genus are believed to be extremely swift runners.

When it comes to size, it is variable, depending on the species taken into account. O. edmontonicus is estimated to have grown as long as 12 feet (3.8 m) and weighed as much as 370 lbs (170 kg). In terms of height, the species was not taller than humans, with O. velox being smaller than O. edmontonicus.

5. Pachycephalosaurus

Pachycephalosaurus
Pachycephalosaurus

would grow up to 14.8 feet (4.5 m) long.

©Daniel Eskridge/Shutterstock.com

This thick-headed lizard roamed the plains of South Dakota during the Late Cretaceous period (specifically during the Maastrichtian), about 68 to 66 million years ago. The genus consists of only one species, P. wyomingensis (although a second species, P. spinifer, is believed to exist). Pachycephalosaurus fossils have been unearthed in Alberta, Wyoming, Montana, and South Dakota.

The dinosaurs of the genus were bipedal herbivores, mainly characterized by their thick skull roof, which some believed might have been used to fight other species (behavior uncommon for most herbivores of the time). The dome atop the skull was approximately 10 inches (25 cm) thick. In most dangerous prehistoric scenarios, this dinosaur’s brain was safe and sound.

Pachycephalosaurus would grow up to 14.8 feet (4.5 m) long and weigh about 820-990 lbs (370-450 kg). According to restoration pieces, they were not taller than humans and resembled a predator.

6. Tyrannosaurus

t-rex

The

tyrannosaurus

could grow as heavy as 9.78 short tons (8.87 metric tons).

©Herschel Hoffmeyer/Shutterstock.com

The Tyrannosaurus genus is probably the best known genus of dinosaurs, main thanks to its type species, Tyrannosaurus rex. They were theropods characterized by their impressive size – some specimens could grow up to 40.7 feet (12.4 m) long and about 12-13 feet (3.66-3.96 m) tall at the hips. In terms of weight, a Tyrannosaurus could grow as heavy as 9.78 short tons (8.87 metric tons).

Even though there were plenty of other dinosaurs that were heavier and bigger than Tyrannosaurus rex, the latter stood out due to its incredibly powerful bite force. According to research, no terrestrial animal surpasses the T-Rex in terms of bite force (about 35,000 newtons).

The Tyrannosaurus has one of the shortest temporal ranges on our list of dinosaurs that lived in South Dakota. It is, however, quite impressive how this genus’ type species managed to assert dominance over the dinosaur kingdom in only two million years (the Late Cretaceous, during the Maastrichtian stage, about 68 to 66 million years ago).

Where to Find Fossils in South Dakota Today

South Dakota has three natural history museums – The Journey Museum of Rapid City, the Mammoth Site Museum of Hot Springs, and the Museum of Geology of Rapid City. However, more impressive is the state’s list of archaeological sites.

Even though most of them are rock art sites (meaning they might not exhibit fossils), there’s plenty to see at over 195 officially registered archeological sites.

Moreover, if you wish to try your luck as a fossil hunter, you should head to the Badlands National Park. According to statistics, most fossils discovered in South Dakota originate from the famous Badlands. Make sure to be accompanied by a group!

Another important thing to remember is that collecting the actual fossils that you find is typically illegal. You can brag that you found one and even take a photo, but taking the exhibit out of the Badlands National Park is forbidden by law.

However, you should definitely check out the Dinosaur Park of Rapid City if you want to see massive dinosaur replicas.

Summary of 6 Dinosaurs that Lived in South Dakota

NumberDinosaur
1Triceratops
2Edmontonia
3Edmontosaurus
4Ornithomimus
5Pachycephalosaurus
6Tyrannosaurus

The photo featured at the top of this post is © Dotted Yeti/Shutterstock.com


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About the Author

I hold seven years of professional experience in the content world, focusing on nature, and wildlife. Asides from writing, I enjoy surfing the internet and listening to music.

FAQs (Frequently Asked Questions) 

Does South Dakota have a natural history museum?

South Dakota has three natural history museums – The Journey Museum of Rapid City, the Mammoth Site Museum of Hot Springs, and the Museum of Geology of Rapid City. However, more impressive is the state’s list of archaeological sites.

Where are most fossils discovered in South Dakota?

If you wish to try your luck as a fossil hunter, you should head to the Badlands National Park. According to statistics, most fossils discovered in South Dakota originate from the famous Badlands. Make sure to be accompanied by a group!

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