New iguanodon relative revealed

A new species of iguanodontian dinosaur has been discovered on the Isle of Wight.

Researchers from the Natural History Museum and University of Portsmouth, UK, described the new genus as part of the iguanodontian group, which includes iguanodon and Mantellisaurus – but this is the first of this genus described on the 390 square kilometre island off England’s south coast.

The dinosaur was named Brighstoneus simmondsi – after the village of Brighstone, near the excavation site, and Keith Simmonds who found the fossil in 1978. The fossil had key differences from its iguanodontian cousins that made it stand out, leading to the realisation that it was actually a different species.

Brighstoneus simmondsi left dentary jaw in medial view credit dr jeremy lockwood samll
Brighstoneus simmondsi left dentary (jaw) in medial view. Credit: Dr Jeremy Lockwood

“For me, the number of teeth was a sign,” says Dr Jeremey Lockwood, who examined the specimen.

Mantellisaurus has 23 or 24, but this has 28. It also had a bulbous nose, whereas the other species have very straight noses. Altogether, these and other small differences made it very obviously a new species.”

The herbivorous dinosaur was likely eight metres in length and weighted around 900 kilograms.

This discovery suggests that there were far more iguanodontian dinosaurs in the present-day UK during the early Cretaceous than previously thought, so extra scrutiny is required to properly categorise them.

Nasal and maxilla credit dr jeremy lockwood samll
Nasal and Maxilla fossils. Credit: Dr Jeremy Lockwood

“We’re looking at six, maybe seven million years of deposits, and I think the genus lengths have been overestimated in the past,” says Lockwood.

“If that’s the case on the island, we could be seeing many more new species. It seems so unlikely to just have two animals being exactly the same for millions of years without change.

“British dinosaurs are certainly not something that’s done and dusted at all.

“I think we could be on to a bit of a renaissance.”

Brighstoneus simmondsi was described in the Journal of Systematic Palaeontology.

Brighstoneus and mantellisaurs credit john sibbick small 1
Brighstoneus (above) and Mantellisaurs (below). Credit John Sibbick.
Dr jeremy lockwood in compton bay isle of wight samll
Dr Jeremy Lockwood in Compton Bay, Isle of Wight. Credit: DrJeremy Lockwood.

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