Fossil hunters have discovered a new species of dinosaur that has been hidden in plain sight in a South African museum collection for 30 years.
The fossilised bones had been misidentified as a peculiar specimen of Massospondylus, one of the first named dinosaurs.
But a detailed analysis of the 200m-year-old skeleton, which includes an almost complete skull, led researchers to conclude that the remains not only represented a new species but belonged to an entirely new genus too.
Named Ngwevu intloko, which is Xhosa for “grey skull”, the creature measured about 4m from the tip of its snout to the end of its tail and may have weighed as much as 300kg (660lb).
It walked on its hind legs and had a barrel-shaped body, a long, slender neck and a small, boxy skull. Though predominantly a plant-eater, Ngwevu may have taken small animals too when the opportunity arose.
Paul Barrett and his PhD student Kimberley Chapelle at the Natural History Museum in London identified the new species after comparing the bones with a haul of other museum specimens. Details of the discovery are published in the journal PeerJ.
The near-complete fossil was collected from a farm in the Fouriesburg area in Free State, South Africa, in 1978 and has been in the collection at the Evolutionary Studies Institute (ESI), part of the University of the Witwatersrand in Johannesburg, ever since.
“A few of us harboured suspicions that it might be something new and different,” Barrett said. “In particular, the skull of Ngwevu is much broader and boxier than that of Massospondylus, which is much narrower and taller in proportions.”
Because Massospondylus was so common in South Africa, the researchers had a number of specimens of different ages with which to compare the Ngwevu bones. “Based on this, we were able to rule out age as a possible explanation for the differences we see,” Chapelle said.
The dinosaur appears to have been fully grown when it died at about 10 years old, and was smaller than the 5m to 6m-long adult Massospondylus.
Ngwevu belonged to a diverse population of early dinosaurs that were related to the massive plant-eating sauropods such as diplodocus. Ngwevu lived in a world of ferns, horsetails and conifers watered by a few large permanent rivers. Of all the predators it had to watch out for, the carnivore Dracovenator probably came top.
“This is a dinosaur that’s been hiding in plain sight,” Barrett said of Ngwevu. “We recognised it by going back through museum collections and doing detailed comparisons between the available specimens. It makes the point that museum collections, even those that are heavily studied, often have the potential to surprise us with finds of brand new species.”