A team from the University of Cambridge has managed to construct the first complete skeleton of a dinosaur known as "Scelidosauru," after more than a century and a half on its discovery. This achievement has been announced in the latest issue of the Zoological Journal of the Linnean Society of London.
The skeleton of this dinosaur was collected more than 160 years ago on west Dorset's (a county to the southwest of England) Jurassic Coast. The rocks in which it was fossilized are around 193 million years old, close to the dawn of the Age of Dinosaurs.
This remarkable specimen was sent to Richard Owen at the British Museum, the man who invented the word dinosaur. He published two short papers on its anatomy, but many details were left unrecorded. Owen did not reconstruct the animal as it might have appeared in life and made no attempt to understand its relationship to other known dinosaurs of the time. In short, he "re-buried" it in the literature of the time, and so it has remained ever since: known, yet obscure and misunderstood.
Over the past three years, Dr. David Norman from Cambridge's Department of Earth Sciences has been working to finish the work which Owen started, preparing a detailed description and biological analysis of the skeleton of Scelidosaurus.
The results of Norman's work, published as four separate studies in the Zoological Journal of the Linnean Society of London, not only reconstruct what Scelidosaurus looked like in life, but reveal that it was an early ancestor of ankylosaurs, the armor-plated 'tanks' of the Late Cretaceous Period.
The new study also revealed that the skull of the Scelidosaurus had horns on its back edge, in addition to several bones that have never been recognized in any other dinosaur. It's also clear from the rough texturing of the skull bones that it was, in life, covered by hardened horny scutes, a little bit like the scutes on the surface of the skulls of living turtles. In fact, its entire body was protected by skin that anchored an array of stud-like bony spikes and plates.
Now that its anatomy is understood, it is possible to examine where Scelidosaurus sits in the dinosaur family tree, said Norman in a report by the University of Cambridge.
It had been regarded for many decades as an early member of the group that included the stegosaurs, but that was based on a poor understanding of its anatomy. Now it seems that Scelidosaurus is an ancestor of the ankylosaurs alone.
"It is unfortunate that such an important dinosaur, discovered at such a critical time in the early study of dinosaurs, was never properly described. But, as they say, better late than never," he concluded.
