A 140-million-year-old tooth reveals the diversity of spinosaurs in ancient Britain

University of Southampton palaeontologists have discovered evidence of various spinosaurs[{” attribute=””>species in southern England 100 million years ago, based on analysis of a 140 million year old dinosaur tooth. The tooth doesn’t match any known species, suggesting greater spinosaur diversity in the region during the Early Cretaceous period.

Paleontologists at the University of Southampton (UK) studying a British dinosaur tooth have concluded that several distinct groups of spinosaurs – dinosaurs with fearsome crocodile-like skulls – inhabited southern England over 100 million years ago.

The team, from the University’s EvoPalaeoLab, carried out a series of tests on the 140 million-year-old tooth, discovered in the early 20th century, in a thick, complicated rock structure named the Wealden Supergroup. The Wealden lies across south-eastern England and was formed around 140-125 million years ago.

The scientists conducted statistical analysis on the tooth, which is stored at the Hastings Museum and Art Gallery in East Sussex. They meticulously compared its characteristics with other species in the spinosaur ‘family’ of dinosaurs to which it belongs. Their findings, published in the journal PeerJ, confirm the tooth doesn’t match that of any identified spinosaur species.

Project supervisor, Dr. Neil Gostling explains: “While we can’t formally identify a new species from one tooth, we can say this spinosaur tooth doesn’t match any of the existing species we know about. Given how many individual teeth exist in collections, this could be just the tip of the iceberg and it’s quite possible that Britain may have once teemed with a diverse range of these semi-aquatic, fish-eating dinosaurs.”

The spinosaur tooth from the Wealden in south east England seen from two different angles. Credit: Hastings Museum and Art Gallery

The Wealden is famous for its spinosaur fossils. Baryonyx – discovered in Surrey in 1983 – is one of the world’s most significant spinosaur specimens, since it was the first to reveal the true appearance of this crocodile-headed group. Less impressive spinosaur remains – isolated teeth – are common throughout the Wealden, and have often been identified as belonging to Baryonyx. However, some experts have long suspected that this is incorrect.

“We used a variety of techniques to identify this specimen, in order to test whether isolated spinosaur teeth could be referred to Baryonyx,” said lead author Chris Barker, whose PhD focuses on the spinosaurs of southern Britain. “The tooth did not group with Baryonyx in any of our data runs. It must belong to a different type of spinosaur.”

The results show that distinct and distantly related spinosaur types lived in the region during Early Cretaceous times. This backs up research by the EvoPalaeoLab team, who argued in previous studies that the spinosaurs of southern England are more diverse than previously thought.

In 2021, they named the ‘Hell Heron’ Ceratosuchops from the Isle of Wight, and in 2022 announced the discovery of what might be Europe’s largest ever land predator, a giant known only as the ‘White Rock’ spinosaur. These several spinosaurs did not all live at the same time, but inhabited the region over the course of more than 15 million years.

“Museums themselves are places to make exciting discoveries as our understanding of specimens changes from the time they were deposited,” said Dr. Neil Gostling. “What this work highlights is the importance of keeping collections alive, and developing our understanding of them. Curators are essential to help us navigate the cupboards and displays, helping us to unpick the often-incomplete records – either never fully recorded, or lost to time. The diversity of palaeoenvironments is not always hidden in rocks, it is often waiting in a museum, its importance waiting to be rediscovered!”

Co-author Darren Naish said “Dinosaur teeth preserve numerous anatomical details, and we can use various analytical techniques to see how similar, or different, they are to other teeth. Our new study shows that previously unrecognized spinosaur species exist in poorly known sections of the Wealden’s history, and we hope that better remains will be discovered that improves our knowledge. Here’s another reminder that even well-studied places like southern England have the potential to yield new dinosaur species.”

Reference: “Isolated tooth reveals hidden spinosaurid dinosaur diversity in the British Wealden Supergroup (Lower Cretaceous)” by Chris T. Barker, Darren Naish and Neil J. Gostling, 31 May 2023, PeerJ.
DOI: 10.7717/peerj.15453