A new analysis of an isolated spinosaur tooth from East Sussex shows that several distinct spinosaur lineages inhabited Britain during the Cretaceous period.
Spinosaurs are members of Spinosauridae, an aberrant family of large-bodied theropod dinosaurs that includes the giant Spinosaurus.
These dinosaurs are known from the Early to Mid Cretaceous of Africa, Europe, South America and Asia.
They are characterized by an elongate, laterally compressed snout; long, crocodile-like jaws and conical teeth; and, in a subset of species, a long neural spine sail.
“Spinosaurids are an unusual clade of large-bodied tetanuran theropods best known for the multiple lines of evidence indicating specialization for a semi-aquatic ecology and the associated controversy over their lifestyle,” said University of Southampton paleontologist Chris Barker, whose Ph.D. focuses on the spinosaurs of southern Britain.
“Spinosaurids are currently known from Cretaceous deposits and possess a wide spatial distribution, with important specimens coming from England, Brazil, northern Africa, the Iberian Peninsula and Southeast Asia.”
“The clade is generally considered to consist of the sister-clades Baryonychinae (anchored on Baryonyx walkeri from southern England) and Spinosaurinae (anchored on Spinosaurus aegyptiacus, first described from Egypt though since reported from other north African countries).”
“However, several recent analyses suggest that support for this dichotomy may not be as robust as usually supposed.”
“Spinosaurid skeletal material is rare, but tooth crowns attributed to the group are regularly discovered,” they noted.
“Numerous isolated specimens have been reported from England and other countries.”
In their study, Barker and his colleagues from the University of Southampton examined a spinosaur tooth from the collections of the Hastings Museum and Art Gallery in East Sussex.
The specimen was gifted to the museum in 1889; it was collected from the local Lower Cretaceous rocks of the Wealden Supergroup, a thick, complicated rock sequence deposited across south-eastern England between 140 and 125 million years ago.
“We used a variety of techniques to identify this specimen, in order to test whether isolated spinosaur teeth could be referred to Baryonyx,” Barker said.
“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.
“Dinosaur teeth preserve numerous anatomical details, and we can use various analytical techniques to see how similar, or different, they are to other teeth,” said University of Southampton paleontologist Darren Naish.
“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.”
“A page-turner. … Brusatte skillfully brings dead dino bones to life. … The beauty of this book lies in the details, too, and in the stories of the scientists who dig them up.”–New York Times Book Review