The first complete dinosaur skeleton ever identified was eventually scrutinized and found its place in the dinosaur family tree. This completed a project that began more than a century and a half ago. Photo credit: John Sibbick
The first complete dinosaur skeleton ever identified was eventually scrutinized and found its place in the dinosaur family tree. This completed a project that began more than a century and a half ago.
The skeleton of this dinosaur, called Scelidosaurus, was collected in West Dorsets more than 160 years ago law Coast. The rocks in which it was petrified are about 193 million years old, just before the beginning of the age of the dinosaurs.
This remarkable specimen – the first complete dinosaur skeleton ever recovered – was sent to Richard Owen at the British Museum, the man who invented the word dinosaur.
So what did Owen do with this find? He published two short articles on his anatomy, but many details were not recorded. Owen did not reconstruct the animal as it might have appeared in life, and made no attempt to understand its relationship with other known dinosaurs of the time. In short, he “buried it again” in the literature of the time, and it has remained so since then: known, but obscure and misunderstood.
For the past three years, Dr. David Norman of the Cambridge Department of Earth Sciences worked to complete the work Owen began. He has made a detailed description and biological analysis of the skeleton of Scelidosaurus, the original of which is kept in the Natural History Museum in London, with other specimens in the Bristol City Museum and the Sedgwick Museum, Cambridge.
The results of Norman’s work, published as four separate studies in the Zoological Journal of the Linnean Society from London, you not only reconstruct what Scelidosaurus looked like in life, but also reveal that it was an early ankylosaur ancestor, the armored “armor” of the late period chalk Period.
For more than a century, dinosaurs have been classified primarily by the shape of their hip bones: they were either dinosaurs (lizard-hopping) or ornithischians (bird-hopping).
However, in 2017, Norman and his former PhD students Matthew Baron and Paul Barrett argued that these groupings of dinosaur families needed to be rearranged, redefined, and renamed. In a study published in Nature, the researchers suggested that bird-hip dinosaurs and lizard-hip dinosaurs such as Tyrannosaurus evolved from a common ancestor, possibly turning more than a century of theory about the evolutionary history of dinosaurs on its head.
Another fact that emerged from their work on dinosaur relationships was that the earliest known ornithischians first appeared in the early Jurassic period. “Scelidosaurus is one such dinosaur and represents a species that appeared at or near the evolutionary” birth “of ornithischia,” said Norman, a fellow at Christ’s College, Cambridge. “What was actually known about Scelidosaurus in this context? The answer is remarkably little! ”
Norman has now completed a study of all known materials attributable to Scelidosaurus and his research has revealed many innovations.
“Nobody knew the skull had horns on the trailing edge,” said Norman. “It had several bones that were not recognized in any other dinosaur. The rough texturing of the skull bones also suggests that in life it was covered by hardened horn grooves, a bit like the grooves on the surface of the skull of living turtles. In fact, his entire body was protected by skin that anchored a series of bud-like bony spines and plates. ”
Once the anatomy is understood, one can study where Scelidosaurus is in the dinosaur tree. It has been considered an early member of the group that the stegosaurs belonged to for many decades, including Stegosaurus, with its huge plates of bone running along the spine and a spiky tail, and ankylosaurs, the armored “carapace” of the dinosaur era that was based on a poor understanding of the Anatomy of Scelidosaurus. Now Scelidosaurus seems to be an ankylosaur alone.
“It is unfortunate that such an important dinosaur, discovered at such a critical point in the early study of dinosaurs, has never been properly described,” said Norman. “It has now – finally! – Has been extensively described and provides many new and unexpected insights into the biology of early dinosaurs and their underlying relationships. It’s a shame the job wasn’t done earlier, but, as they say, better late than never. ”
Reference: “Scelidosaurus harrisonii (Dinosauria: Ornithischia) Early Jurassic from Dorset, England: Biology and Phylogenetic Relations “by David B. Norman, FLS, August 18, 2020, Zoological Journal of the Linnean Society.
DOI: 10.1093 / zoolinnean / zlaa061
