It may have been three metres long – but a newly discovered dinosaur has been hiding in plain sight for three decades.
The new species has been identified after sitting in a museum collection in South Africa for 30 years.
Professor Paul Barrett, a dinosaur researcher at the Natural History Museum, is part of a team that reassessed the specimen, which is being held at the University of Witwatersrand, Johannesburg.
The new dinosaur, named Ngwevu intloko – which means grey skull in the Xhosa language – has been described from a single fairly complete specimen with a remarkably well-preserved skull.
The specimen indicates it was most likely an omnivore, walked on two legs, had a fairly chunky body, a long slender neck and a small boxy head.
Scientists say it would have measured three metres (9.84ft) from the tip of its snout to the end of its tail.
Prof Barrett said: “This is a new dinosaur that has been hiding in plain sight.
“The specimen has been in the collections in Johannesburg for about 30 years, and lots of other scientists have already looked at it. But they all thought that it was simply an odd example of Massospondylus.”
Massospondylus was one of the first dinosaurs to reign at the start of the Jurassic period.
Researchers are now looking closer at many of the supposed Massospondylus specimens, believing there to be much more variation than first thought.
PhD student Kimberley Chapelle explained: “In order to be certain that a fossil belongs to a new species, it is crucial to rule out the possibility that it is a younger or older version of an already existing species.
“This is a difficult task to accomplish with fossils because it is rare to have a complete age series of fossils from a single species.
“Luckily, the most common South African dinosaur Massospondylus has specimens ranging from embryo to adult.
“Based on this, we were able to rule out age as a possible explanation for the differences we observed in the specimen now named Ngwevu intloko.”
Scientists say the findings will help them better understand the transition between the Triassic and Jurassic period, around 200 million years ago.
Known as a time of mass extinction, it now seems more complex ecosystems were flourishing in the earliest Jurassic than previously thought.
The findings are published in the journal PeerJ.