More than 160 years after its discovery on England’s Jurassic Coast, thefirst complete dinosaur skeleton ever found has finally been examined in detail. The research reveals previously unknown features of Scelidosaurus and helps clarify where the species fits in the dinosaur family tree.
When paleontologists talk about major fossil discoveries, few specimens have a history as unusual as Scelidosaurus. Found in rocks around 193 million years old, the dinosaur was collected during the early days of dinosaur science and quickly attracted attention because of its remarkable state of preservation.
The fossil ended up in the hands of Richard Owen, the scientist who coined the word “dinosaur.” Yet despite the importance of the find, Owen never produced a complete description of the animal. He published only two short papers, leaving many details unexplored and allowing the fossil to slip into relative obscurity for more than a century.
After 160 Years, Scientists Have an Answer
That situation has now changed thanks to the work of Dr. David Norman from the University of Cambridge. Over the last three years, he has examined all known material belonging to Scelidosaurus, including the original specimen housed at London’s Natural History Museum.
His findings were published in four studies in theZoological Journal of the Linnean Society. These ones provide the most complete picture yet of a dinosaur that lived near the start of the Jurassic Period.
For Norman, one of the biggest surprises was how little researchers actually knew about such a famous fossil.
“Given that context, what was actually known of Scelidosaurus? The answer is remarkably little!” he said in a statement published by The University of Cambridge.
It is a strange twist in paleontological history: thefirst complete dinosaur skeleton ever discovered remained one of the least thoroughly studied major one fossils.
“This is a hugely significant discovery,” stated Dr. Mike Simms, a curator and paleontologist in the Department of Natural Sciences at National Museums Northern Ireland. “The great rarity of such fossils here is because most of Ireland’s rocks are the wrong age for dinosaurs, either too old or too young, making it nearly impossible to confirm dinosaurs existed on these shores.”
Hidden Features Reveal a Completely Different Animal
The new research uncoveredseveral anatomical details that had never been recognized before. One of the most notable discoveries involves the skull. Norman found evidence that Scelidosaurus had horn-like structures along its back edge. The study also identified several bones that have not been recognized in other ones.
“Nobody knew that the skull had horns on its back edge,” Norman noted. “It also had several bones that have never before been recognized in any other dinosaur.”
The skull itself provided additional clues. Its rough surface suggests it was covered by hardened horny scutes during life, similar to those found on modern turtles. The rest of the body appears to have been heavily protected as well.
Researchers found evidence that the skin supported numerous bony plates and stud-like spikes. These structures formed a natural armor system that covered much of the animal’s body. Nearly 200 million years later, scientists have their clearest look yet at Scelidosaurus.
A Key Ancestor Of Armored Dinosaurs
The study, published in theProceedings of the Geologists’ Association, also helps settle a debate that has been going on for decades about where Scelidosaurus fits in the dinosaur family tree. For years, scientists believed it was an early relative of both stegosaurs and ankylosaurs. That view was largely based on an incomplete understanding of the animal’s anatomy.
David Norman’s research tells a different story. The evidence suggests that Scelidosaurus was actually an early ancestor of ankylosaurs, the heavily armored dinosaurs that became much more common during the Cretaceous Period. Its age makes it especially important. Norman noted that Scelidosaurus appeared at or very close to the evolutionary “birth” of the Ornithischia, one of the major groups of dinosaurs.
“It is unfortunate that such an important dinosaur, discovered at such a critical time in the early study of dinosaurs, was never properly described,” Norman said. “It has now – at last! – been described in detail and provides many new and unexpected insights concerning the biology of early dinosaurs and their underlying relationships. It seems a shame that the work was not done earlier but, as they say, better late than never.”
