Scutellosaurus (pronounced skoo-tel-oh-sore-us) was a small plant eating dinosaur that generally inhabited North America during the early Jurassic Period sometime around two hundred million years ago. It is among the earliest known dinosaurs belonging to the armored clan. General fossil studies indicated that the Scutellosaurus measured four feet long and was about one foot eight inches tall at the hip region. They generally weighed around ten kilograms.
Scutellosaurus was characterized by the presence of hundreds of small bony plates. They had two large plates running down its spine. There were generally six different types of plates. These plates covered the animals' back and tail. Anatomical studies revealed that these bony outgrowths generally were derived from their epidermal region. These plates served as a protection against the larger meat eating and predatory animals. The name Scutellosaurus means Little Shielded Lizard. They were characterized by the presence of numerous scutes on their back. The general appearance resembled very much of a lizard but however their size was quite small.
However detailed anatomical studies of the fossil suggested that the Scutellosaurus was a very good runner in spite of having large plates on their back. It should however be understood that in spite of having those plates, the best protection for a dinosaur from the massive predators were their fast pace. The Scutellosaurus had a long tail and a long body. Their hind legs were quite thin and much longer and they were generally helpful for fast running. However they have probably walked on all their four legs as it could have been easier to balance the heavily plated body.
The fossils of Scutellosaurus were found in North Arizona and they were believed to be living in hot and dry places. Their teeth were leaf shaped that were useful to snap off leaves. Anatomical studies of their skulls reveal that these animals did not have any cheek. Hence it can be inferred from this that the Scutellosaurus probably did not chew its food. It is presumed that they swallowed their food as a whole.
The genus Scutellosaurus was named by Edwin Harris Colbert (Ned). He was born on 28th September 1905 and passed away at the age of ninety six on 15th November 2001. Edwin was a distinguished vertebral paleontologist in America. He was regarded as a prolific researcher in the field of paleontology and had authored many books.
Edwin was born in Clarinda, Iowa and spent his childhood in Maryville, Missouri. Colbert did his graduation from the University of Nebraska and completed his post graduation and doctorate from Columbia University in 1935. He was married to Margaret Matthew who happened to be the daughter of eminent paleontologist William Diller Matthew.
- Colbert held the position of Curator of Vertebrate at the American Museum of Natursl History for quite a long duration. Colbert held the position of Professor Emeritus of vertebrate paleontology at Columbia University. He also held the prestigious protege position Henry Fairfield Osborn as a foremost authority of Dinosauria.
- Colbert has been held in high regards for his work on Siwalik Mammals in the American Museum of Natural History. For his highly regarded work Colbert was awarded the Daniel Giraud Elliot medal on behalf of the National Academy of Sciences in the year 1935. Colbert has played an instrumental role in describing dozens of new taxa and authoring major systematic reviews. Apart from Scutellosaurus he has been responsible for the discovery of more than a dozen complete skeletons of small primitive dinosaurs belonging to the Triassic area. His discovery of Coelophysis at the Ghost Ranch in New Mexico in 1947 has been notable. It should also be mentioned that Ghost Ranch has been recorded as one of the largest fossil concentrated excavation site known till date. Colbert has played an influential role in the description of these fossils. He has also reviewed Ceratopsian phylogeny.
The first fossil of Scutellosaurus was discovered in the Kayenta formation of Arizona by Douglas Lawler in the year 1971. At that time lawler was pursuing his graduation from the University of California located at Berkley. He then took the fossil to E.H. Colbert who was then at the Museum of Northern Arizona at Flagstaff. After this a second specimen was also collected by a Harvard University field party in the year 1977. It was not until 1981 that after a thorough study and in depth analysis of Edwin Colbert that he concluded that this species belonged to Scutellosaurus. And he named these specimens as Scutellosaurus lawleri. Post his naming it should be mentioned that six more specimen fossils were discovered from the Kayenta formation by another noted American paleontologist James M. Clark in the year 1983.
While studying and identifying this species, Colbert made an inference that these species had a close resemblance to Lesothosaurus diagnosticus which was bird hipped or more technically termed Ornithischian. Hence he placed it in the family Fabrosauridae. But the Scutellosaurus possessed scutes, a feature that was absent in the Fabrosaurids. Not only had the absence of scutes, the Scutellosaurus had skeletal features which included a curved lower jaw. This again was a Stegosaurid feature.
However with the advent of better diagnostic studies, most paleontologists now believe that Scutellosaurus is a very primitive member of the suborder Thyreophora. In fact it is primitive enough to not fall into subgroup Ankylosaurus. Ankylosaurus had a much improved body armor which made it look like a tank. Thanks to the massive robust and sculpted body armor they possessed.
On the other hand on the way to evolution, stegosaurs on the other hand lost all their armor except the single row of parasaggital scutes which ran alternately along the spinal column. Later with the passing of time they had evolved into a diverse combination of plates and spikes. These combinations helped the Stegosaurs to identify each other. However in this regards it should also be mentioned that there have been some schools where it has been believed that these structures had defensive and thermoregulatory functions.
Concluding this article it should be noted that Scutellosaurus has been an interesting study as they have proven to landmark an evolutionary divergence as fossil studies suggest that it served as an ancestor to the later clans of armored dinosaurs. Details of their anatomical studies have also revealed that these reptiles were ambidextrous in nature which means they had the ability to use both their hands effectively.