The Scutellosaurus (or little shielded lizard) was an early thyreophoran ornithischian dinosaur that existed about 205–202 million years ago. The scutellosaurus ate plants only (meaning it was a herbivore). It existed during the early Jurassic period in North America. Its fossil remains were discovered in Arizona.
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Some Quick Facts About the Scutellosaurus
| Name | Scutellosaurus (meaning “little shielded lizard”) |
| Type of dinosaur | Ornithischian |
| Territory | Forests and floodplains (based on the order Ornithischia), North America (Arizona) |
| Size | 4.25 feet long, 12-20 inches tall |
| Color | Brownish, possibly scaled with stripes |
| Interesting Characteristics | Bony plates on the back (scutes), armored body |
| Diet | Herbivore |
| Major Threats | Climate change, competition from larger dinosaurs |
The Scutellosaurus was one of the earliest armored thyreophoran dinosaurs. This small dinosaur lived in the United States during the early Jurassic period, approximately 205–202 million years ago.
Unlike most of the other thyreophorans, a Scutellosaurus was a small dinosaur, measuring about 5 feet long and weighing just 25 pounds (a bit bigger than a Compsognathus). This dinosaur had a long, slender tail to help balance the weight of the armored body. They were also characterized by double rows of tiny bony plates on their backs.
What Kind of Dinosaur Is a Scutellosaurus?
The Scutellosaurus was an early ornithischian dinosaur from the ornithischia order, which means “bird-hipped.” It is considered a primitive ornithischian, which means that it has many ancestral characteristics that are not present in more advanced dinosaurs.
These prehistoric animals lived during the Early Jurassic period and are related to dinosaurs such as the Ankylosaurus and the Stegosaurus through their Thyreophora suborder of classification.
Who Found the Scutellosaurus?
In 1971, a paleontologist named Douglas Lawler found the first fossil remains of a Scutellosaurus in the Kayenta Formation of Arizona. Back then, Lawler was a student at the University of California. These early remains produced the holotype specimen of Scutellosaurus lawleri. In other words, this one fossil was our primary source of information about the Scutellosaurus.
According to the Museum of Northern Arizona Bulletin, Lawler took these remains to another paleontologist named Edwin Colbert for analysis.
After a thorough examination, Colbert gave the creatures the name Scutellosaurus Lawleri. Another famous paleontologist named James Clark later recovered six more specimens in other areas in Arizona in 1983, providing scientists with a clearer picture of an almost complete dinosaur.
Where Did the Scutellosaurus Live?
The Scutellosaurus was a herbivore that lived in the Kayenta Formation of Arizona, which extends from Arizona to Utah through the Colorado plateau. The Kayenta Formation of Arizona is one of the many formations that form the Upper Triassic and Lower Jurassic Glen Canyon Group. These formations make up a huge collection of terrestrial sediments on the western border of North America.
The Scutellosaurus thrived in these terrestrial habitats that included forests and floodplains. These regions were abundant in vegetation, providing the perfect environment for this small herbivorous dinosaur to thrive.
What Is a Unique Trait of the Scutellosaurus?
One unique characteristic of this little shielded lizard is the presence of numerous scutes (bony plates) on the skin, covering the back, tail, ribs, and neck. These double rows of small scutes on the sides and back helped to protect it from potential predators. These scutes were made of small bony plates that overlapped and provided additional defense.
These small bony plates resembled the scutes of crocodiles and alligators. On a Scutellosaurus, these scutes were very small. Besides the armored body, the Scutellosaurus was most likely bipedal, as its long hind feet and hind limbs suggest.
The Scutellosaurus was most likely very common, which explains the significant number of armored dinosaurs discovered in a small region.
What Did the Scutellosaurus Eat?
Despite its small size, the Scutellosaurus was an important dinosaur for understanding the evolution of ornithischian dinosaurs. Its leaf-shaped teeth are indicative of its herbivorous diet, which is a common feature of this group of dinosaurs.
Studying the dental structures of Scutellosaurus has provided valuable insights into the diets of other primitive ornithischian dinosaurs that lived during the Late Jurassic and Cretaceous periods, such as jaws and teeth designed for grinding vegetation and guts specialized for digesting plant matter.
For instance, the Scutellosaurus used its leaf-shaped teeth to grind leaves, but because it lacked cheeks to retain the food, it simply swallowed it.