The most complete dinosaur discovered in this country in the last 100 years, with a pubic hip bone the size of a 'dinner plate', has been described in a new paper published today.
The specimen, which is around 125 million years old, was found in the cliffs of Compton Bay on the Isle of Wight in 2013 by fossil collector Nick Chase, before he tragically died of cancer.
Jeremy Lockwood, a retired GP and University of Portsmouth PhD student, helped with the dinosaur's excavation and has spent years analysing the 149 different bones that make up the skeleton.
Jeremy determined that the skeleton represented a new genus and species, which he named Comptonatus chasei in tribute to Nick.
Jeremy Lockwood at the excavation site, Compton Bay, Isle of Wight
Jeremy said: "Nick had a phenomenal nose for finding dinosaur bones - he really was a modern-day Mary Anning. He collected fossils daily in all weathers and donated them to museums. I was hoping we'd spend our dotage collecting together as we were of similar ages, but sadly that wasn't to be the case.
"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."
When it was first discovered, the specimen was thought to be a known dinosaur called Mantellisaurus, but Jeremy's study revealed a lot more dinosaur diversity. Indeed, this is the second new genus to be described by Jeremy.
An artist's impression of the dinosaur. Image credit: John Sibbick
He said: "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!"
Jeremy doesn't know why the pubic hip bone, which is placed at the base of the abdomen was so big: "It was probably for muscle attachments, 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."
Jeremy named the dinosaur Comptonatus after Compton Bay where it was found and 'tonatus' is a latin word meaning 'thunderous'.
"This animal would have been around a ton, about as big as a large male American bison. 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."
The 'dinner plate' pubic hip bone
Dr Susannah Maidment, Senior Researcher and palaeontologist at the Natural History Museum and senior author of the paper completed whilst supervising Jeremy's PhD, commented: "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 late Nick Chase, an avid fossil collector who found Comptonatus chasei in the cliffs of Compton Bay in 2013
Despite only four new dinosaur species being described on the Isle of Wight in the whole of the 1900s, there have been eight new species named in the last five years.
Jeremy added: "This really is a remarkable find. It helps us understand more about the different types of dinosaurs that lived in England in the Early Cretaceous. This adds to recent research that shows that Wessex was one of the world's most diverse ecosystems."
The dinosaur has been added to the collections at the Dinosaur Isle Museum in Sandown on the Isle of Wight. The paper is published today in the Journal of Systematic Palaeontology.
Dr Martin Munt, Dinosaur Isle curator, said: "Ongoing research on the museum collection continues to reveal exciting new discoveries. Most of Nick's most important finds have remained on the Island, a lasting legacy.
"We can look forward to many more new types of prehistoric creatures being discovered from the Island's cliffs and collection."
Mike Greenslade, General Manager for the National Trust on the Isle of Wight, said: "This extraordinary discovery at National Trust's Compton Bay highlights the rich natural heritage of the Isle of Wight.
"Finding the most complete dinosaur in the UK in a century not only showcases the island's palaeontological significance but also underscores the importance of preserving our landscapes for future generations to explore and learn from.
"Nick Chase's remarkable find and Jeremy Lockwood's dedicated research are a testament to the incredible history waiting to be uncovered here. We are thrilled to be part of this ongoing journey of discovery and scientific advancement."
