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A new dinosaur kindsComptonatus chasei, discovered on the Isle of Wight, represents a major advance in understanding chalkvariety of dinosaurs from the England era, with ongoing research suggesting that more significant discoveries are likely.

A new paper describes the most complete dinosaur discovered in this country in the last century. The specimen, about 125 million years old and featuring a pubic femur the size of a dinner plate, was found in 2013 in the rocks of Compton Bay on the Isle of Wight. The discovery was made by fossil collector Nick Chase before he tragically died of cancer.

Jeremy Lockwood, retired GP and University of Portsmouth A PhD student who helped excavate the dinosaur and spent years analyzing 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 said: “Nick had a phenomenal nose for finding dinosaur bones – he really was a modern day Mary Anning. He collects fossils daily in all weather conditions and donates them to museums. I had hoped that we would spend our collecting years together since we were the same age, but unfortunately that was not to be. Despite its many wonderful discoveries over the years, including the most complete Iguanodon skull ever found in Britain, it is the first dinosaur to be named after him.

Scientific insights and theories

When it was first discovered, the specimen was thought to be a famous dinosaur called Mantelosaurus, but Jeremy’s research reveals much more dinosaur diversity. In fact, this is the second new genus described by Jeremy.

He said: “I was able to show that this dinosaur was different because of certain unique features in its skull, teeth and other parts of its body. For example, its lower jaw has a straight lower edge, while most iguanodonts have a jaw that curves downward. It also has a very large pubic femur, which is much larger than other similar dinosaurs. It’s like a dinner plate!”

Jeremy Lockwood at the excavation site, Compton Bay, Isle of Wight. Credit: University of Portsmouth

Jeremy doesn’t know why the pubic bone, which is located at the base of the abdomen, was so large: “It was probably for muscle attachments, which might mean that the way it moved was a little different, or it might have been support stomach contents more efficiently, or were even involved in the animal’s respiration, but all these theories are somewhat speculative.

Jeremy named the dinosaur Comptonate after Compton Bay where it was discovered and “tonatus” is a Latin word meaning “thunderous”.

“This animal would have been about a ton, about the size of a large male American bison. And evidence from fossil footprints found nearby suggests it was probably a pastoral animal, so it’s possible that large herds of these heavy dinosaurs would have rumbled around if they’d been scared off by predators on the floodplains more than 120 million years ago.

Research contribution and museum involvement

Dr Suzanne Maidment, Senior Research Fellow and Palaeontologist at the Natural History Museum and senior author of the paper completed while supervising Jeremy’s PhD, commented: “Comptonate 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 the incredibly detailed work of NHM research fellow Dr Jeremy Lockwood, whose research continues to reveal that dinosaur diversity in southern England during the Early Cretaceous was much greater than previously thought before.

“The specimen that is younger than Brystone but older than Mantelosaurus (two iguanodont dinosaurs closely related to Comptonate) demonstrates rapid rates of evolution in Iguandonian dinosaurs during this time period and may help us understand how ecosystems recovered after a putative extinction event at the end of Jurassic Period.”

The “dinner plate” femur. Credit: University of Portsmouth

Although only four new dinosaur species were described on the Isle of Wight in the whole of 1900, there have been eight new species in the last five years.

Jeremy added: “This is a truly remarkable find. It helps us understand more about the different types of dinosaurs that lived in England during the Early Cretaceous. This adds to recent research showing that Wessex is one of the most diverse ecosystems in the world.

The dinosaur has been added to the collections at the Dinosaur Island Museum in Sandown on the Isle of Wight. The paper was recently published in Journal of Systematic Paleontology.

Dr Martin Munt, curator of Dinosaur Island, said: “Ongoing research into 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 species of prehistoric creatures being discovered from the Island’s rocks and collection.

Mike Greenslide, General Manager of the Isle of Wight National Trust, said: “This exceptional discovery at the National Trust’s Compton Bay highlights the Isle of Wight’s rich natural heritage. Finding the UK’s most complete dinosaur in a century not only demonstrates the palaeontological importance of the island, but also highlights 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 testament to the amazing story waiting to be revealed here. We are excited to be a part of this ongoing journey of discovery and scientific advancement.”

Reference: “Comptonatus chasei, a new iguanodont dinosaur from the Lower Cretaceous Wessex Formation of the Isle of Wight, southern England” by Jeremy A.F. Lockwood, David M. Martill and Susanna C.R. Maidment, 9 July 2024, Journal of Systematic Paleontology.
DOI: 10.1080/14772019.2024.2346573