Scientists have discovered a new species of dinosaur with an “eye-catching sail” along its back and tail that may have been used to attract mates.
The iguanodontian dinosaur, whose fossils were found on the Isle of Wight, was identified by Dr Jeremy Lockwood, a PhD student at the University of Portsmouth and the Natural History Museum.
The retired GP has named it Istiorachis macarthurae, a mix of “sail spine” and a reference to Ellen MacArthur, who set a world record for the fastest solo non-stop sailing voyage around the world in 2005.
The iguanodontian dinosaur was identified by Dr Jeremy Lockwood, above, of the University of Portsmouth and the Natural History Museum. Photograph: James Brown/PA
Prior to Lockwood’s analysis, the fossils, which date back 125m years, were assumed to have belonged to one of the two known dinosaur species from the Isle of Wight.
But after comparing the preserved bones with a database of similar dinosaur back bones, it became clear the fossil was unique. Lockwood said: “While the skeleton wasn’t as complete as some of the others that have been found, no one had really taken a close look at these bones before … unlike the others, this one had particularly long neural spines, which was very unusual.”
The Istiorachis macarthurae is named after Ellen MacArthur, who set a world record for the fastest solo non-stop sailing voyage around the world in 2005. Photograph: Adam Davy/PA
He said the animal would probably have had a pronounced sail-like structure along its back. “Evolution sometimes seems to favour the extravagant over the practical. While the exact purpose of such features has long been debated – with theories ranging from body heat regulation to fat storage – researchers believe that the most likely explanation in this case is visual signalling, possibly as part of a sexual display to attract a mate.
“In modern reptiles, sail structures often show up more prominently in males, suggesting that these attributes evolved to impress mates or intimidate rivals. We think Istiorachis may have been doing much the same.”
Prof Susannah Maidment, of the Natural History Museum, said: “Jeremy’s careful study of fossils that have been in museum collections for several years has brought to life the iguandontian dinosaurs of the Isle of Wight.
“His work highlights the importance of collections like those at Dinosaur Isle, where fossil specimens are preserved in perpetuity and can be studied and revised in the light of new data and new ideas about evolution.”
This article was amended on 22 August 2025. Owing to an error provided in supplied information, an earlier version misspelled Istiorachis macarthurae.
