The fossil of a bison-sized dinosaur discovered on the Isle of Wight in 2013 is "one of the most complete" skeletons found in the UK in the last century, say scientists. It's also a new species.
Unearthed from the cliffs of Compton Bay on the southern coast of the island, it's taken scientists more than 10 years to piece together the 149 bones and figure out exactly which animal they belong to.
Nick Chase, the fossil collector who made the discovery, sadly died of cancer just before the COVID-19 pandemic. Fellow collector Jeremy Lockwood, who helped with the dinosaur's excavation and the ensuing study, named the dinosaur Comptonatus chasei – paying homage to its finder.
"This animal would have been around a ton, about as big as a large male American bison," explains Jeremy.
"And evidence from fossil footprints found nearby shows it was likely to be a herding animal, so possibly large herds of these heavy dinosaurs may have been thundering around if spooked by predators on the floodplains over 120 million years ago."
"I've been able to show this dinosaur is different because of certain unique features in its skull, teeth and other parts of its body. For example its lower jaw has a straight bottom edge, whereas most iguanodontians have a jaw that curves downwards. It also has a very large pubic hip bone, which is much bigger than other similar dinosaurs. It's like a dinner plate!"
Why was the dinosaur's hip bone so big?
"It was probably for muscle attachments," explains Jeremey, "which might mean its mode of locomotion was a bit different, or it could have been to support the stomach contents more effectively, or even have been involved in how the animal breathed, but all of these theories are somewhat speculative."
Why is it called Comptonatus chasei?
"Nick had a phenomenal nose for finding dinosaur bones - he really was a modern-day Mary Anning," says Jeremey, who chose to name the dinosaur Comptonatus chasei. The latter part of the name 'chasei' pays homage to Nick, while 'Comptonatus' is a combination of Compton Bay, where the fossil was found, and 'tonatus', the Latin word for 'thunderous', a nod to the likely heavy-footed nature of the animal.
"Despite his many wonderful discoveries over the years, including the most complete Iguanodon skull ever found in Britain, this is the first dinosaur to be named after him," says Jeremey.
Isle of Wight dinosaurs
Eight new species of dinosaur have now been described on the Isle of Wight in the past five years, says Dr Susannah Maidment, a palaeontologist at the Natural History Museum and senior author of the paper.
"Comptonatus is a fantastic dinosaur specimen: one of the most complete to be found in the UK in a century.
"Its recognition as a new species is due to incredibly detailed work by NHM Scientific Associate Dr Jeremy Lockwood, whose research continues to reveal that the diversity of dinosaurs in southern England in the Early Cretaceous was much greater than previously realised.
"The specimen, which is younger than Brighstoneus but older than Mantellisaurus (two iguandontian dinosaurs closely related to Comptonatus) demonstrate fast rates of evolution in iguandontian dinosaurs during this time period, and could help us understand how ecosystems recovered after a putative extinction event at the end of the Jurassic Period."
The paper was published in the Journal of Systematic Palaeontology.
Main image credit: John Sibbeck
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