The world's first complete dinosaur skeleton, found 160 years ago, has finally been examined and its position in the Jurassic family tree confirmed.
Cambridge University researchers have provided a detailed description and biological analysis of the Scelidosaurus skeleton for the past three years.
This completes the work that Richard Owen of the British Museum – the man who invented the name dinosaur – began 160 years ago after receiving the skeleton.
It was found on the Jurassic Coast of West Dorset, and the rocks in which it was petrified are about 193 million years old, just before the beginning of the Age of the Dinosaurs.
The Cambridge team, led by Dr. David Norman revealed that the dinosaur was an ancestor of the ankylosaur – the armored "shell" of the late Cretaceous period.
Cambridge University researchers have made a detailed description and biological analysis of the Scelidosaurus skeleton for the past three years (artistic impression).
His work also revealed that the skull had horns on its trailing edge, several bones not seen in any other dinosaur, and a skull covered in hardened, horny, turtle-like grooves.
After Richard Owen received the full Scelidosaurus fossil in 1858, he published two brief articles on its anatomy – but many important 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 to other known dinosaurs of the time.
In short, he "buried it again" in the literature of the time, and it has stayed that way ever since: known, but obscure and misunderstood, says Norman.
For the past three years, Dr. Norman worked to finish the work Owen started and produce a detailed description and biological analysis.
harmouth is a coastal village about a kilometer east of Lyme Regis. The Spittles-Black Ven is an eroding cliff from which the remains of Scelidosaurus have been recovered since the late 1850s
The original skeleton is kept in the Natural History Museum in London, other specimens in the Bristol City Museum and the Sedgwick Museum in Cambridge.
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 also show that it was an early ankylosaur ancestor.
For more than a century, dinosaurs have been classified by hip bone shape – they were either dinosaurs (lizard hips) or ornithischians (bird hips).
However, in 2017, Norman and colleagues argued that these groupings of dinosaur families needed to be rearranged, redefined, and renamed.
The researchers suggested that bird hopping dinosaurs and lizard-hipped 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," Norman said.
What was actually known about Scelidosaurus in this context? The answer is remarkably little! & # 39;
A number of Scelidosaurus fossils exist, and Norman used examples from other samples to create a detailed picture of those found in the 19th century
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 it was covered in hardened horn grooves in life, a bit like the grooves on the surface of the skull of living turtles," Norman said.
"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 family tree.
The encased skeleton has been restored as it might have appeared when it was first discovered and exposed on a series of more or less contiguous blocks of areno-clay limestone
It has been considered an early member of the group that stegosaurs belonged to for many decades, including stegosaurus, with its huge bony plates running along the spine and a spiky tail, and ankylosaurs, the armored "tanks" of the dinosaur era.
This was due to a poor understanding of Scelidosaurus anatomy. Now, Scelidosaurus seems to be an ankylosaur alone.
"It is unfortunate that such an important dinosaur, discovered at such a critical time in the early study of dinosaurs, has never been properly described," said Norman.
"It has finally been fully described and offers many new and unexpected insights into the biology of early dinosaurs and their underlying relationships."
WHAT WERE THE ANKYLOSAURID DINOSAURS AND WHAT DO WE KNOW ABOUT THEM?
One of the most formidable weapons to appear during the Cretaceous Dinosaur Arms Race was the Bony Tail Club run by some members of a group of armor-like herbivores.
The special feature – a stick used in combat that could have given cause for concern even to the wild Tyrannosaurus Rex – belonged to the heavily armored dinosaur Ankylosaurus and its cousins.
Researchers have examined fossils of a group known as ankylosaurs, including primitive species without a tail lobe and those with a fully developed defensive bone on the tail, which emerged later.
According to a 2015 study, ankylosaurs began developing tail clubs much earlier than previously thought, and the clubs evolved in two steps over tens of millions of years.
Ankylosaurs lived at a time when the greatest land robbers in Earth history, including T. rex, roamed the countryside, carving up other dinosaurs with powerful jaws and jagged teeth
First, the vertebrae in the back of the tail changed so that the tail became stiff.
Next, bones that form in the skin to provide body protection known as osteoderms became very large at the tip of the tail and completely enveloped the end of the tail to form a club that swung against an enemy could be.
Ankylosaurs were four-legged, broad-bodied dinosaurs covered with bony plates and spines.
The oldest known ankylosaur dates back to about 160 million years ago during the Jurassic period.
Ankylosaurs from China were critical to understanding the origin of the tail club, including Gobisaurus about 92 million years ago and Liaoningosaurus about 122 million years ago.
Asian ankylosaurids had stronger spines on their skulls compared to the smooth-boned armor of their North American counterparts.
The first fully formed ankylosaur tail club appeared about 75 million years ago during the Cretaceous Period.
At six meters tall, the ankylosaurus was the largest and last of the ankylosaurs that lived around 65 million years ago at the end of dinosaur history.
(tagsToTranslate) dailymail (t) sciencetech