The dinosaur with horns on its shoulders
- Name: Sauropelta
- Diet: Herbivore
- Weight: 2 tons
- Period: Cretaceous
- Found In: United States
In this article we will talk about one of the largest Nodosauridae in the family. The Sauropelta, that ankylosaur that was endowed with a large and powerful spike.
What does the name Sauropelta mean?
The meaning of this name is “shield lizard“, a name derived from the ancient Greek σαυρος/sauros, which is understood as “lizard” and πελτε/pelte which is understood as “small shield”, referring to the armor.
The designation of the species honors the couple Nell and Tom Edwards who offered shelter to Ostrom’s team.
Because they are two people, George Olshevsky named the species in 1991 as edwardsorum, but not all researchers have accepted this.
History of the Sauropelta discovery
In 1932, Barnum Brown found what would be five skeletons of a still unknown species of dinosaur near Push Creek in Big Horn County, Montana.
Brown planned to call the animal “Peltosaurus” and used that name in some lectures, but never made the name official. In addition, the name had already been taken by a lizard: Peltosaurus (Cope 1873).
Professor John Ostrom decided to describe this animal. In 1970 he called it Sauropelta edwardsi.
The holotype is found in a layer of the Cloverly formation that dates back some 115 million years. It consists of a partial skeleton without a skull. Ostrom assigned six other large specimens to the species.
Although of these six, he assumed that two were fossil material from the other individuals, so the total of separate skeletons was limited to the five originally found by Brown.
In one of the specimens the armor is very complete, although the preserved bony parts are limited to the rear fuselage, the right foreleg and the base of the tail.
It can be said that this is the most complete nodosauridae fossil found in North America.
Another of these fossils consisted of the skull and neck, again with armored elements.
Something curious is that all the fossils were fossilized face up, probably because they died in a flood.
Besides the skeletons, Ostrom assigned hundreds of loose bones, most of them from the site where these fossil remains were found.
In 1984, Kenneth Carpenter described one of these 5 skeletons and gave a completely new interpretation of the distribution of the armor elements.
Since 1970, when it was described by John Ostrom this dinosaur was always classified as a Nodosauridae.
The family Nodosauridae, together with the family Ankylosauridae, are part of the infraorder Ankylosauria.
How and when did the Sauropelta live?
As for where and when he lived, we have to take into account that all the remains of this dinosaur were found in the Cloverly Formation in Wyoming and Montana,
This formation dates from 108.5 million years ago, in what is known as the early Cretaceous. Its habitat was characteristic of wide plains, which were easily flooded, with shallow rivers.
Recurrent flooding from these rivers frequently covered all the surrounding plains, creating mud traps and swamps.
That frequently left many dinosaurs trapped, which would be fossilized until our times.
What did the Sauropelta eat?
Like all the dinosaurs in its family, this specimen generally fed on plants, conifers, tubers, roots…
Sauropelta was one of the largest Nodosauridae that ever lived. The length was calculated at approximately 6 meters and the weight was estimated at 2 tons.
The trunk is not extremely broad; the neck and skull are relatively elongated. More than half of the body length was tail. However, the legs were quite short, which makes the construction a bit narrow.
The hind leg is longer than the front leg. The hands and feet are short and wide.
Like all known ankylosing agents, the upper body is covered from the muzzle to the tip of the tail with osteoderms, protective bony plates formed by ossification of the skin. On the outside they were covered and enlarged by a horny layer.
According to Ostrom, the Sauropelta is a medium-sized ankylosaur with an extensive armor on the back and flanks consisting of a mosaic of large flat and wavy skin plates surrounded by smaller plates and beak scales.
The lower jaws are long and have twenty-five to twenty-seven teeth, almost continuous to the front end of the jaws.
The tines have transversely flattened crowns with triangular side profiles and signs on both cutting edges.
The crowns are lost in the longitudinal ribs but sometimes have an irregularly widened base, more prominent on the outside than on the inside.