Fossil overlooked for a century reveals new megaraptoran dinosaur from Isle of Wight

A fossil left in a drawer for a century

Researchers have described a new species of meat-eating dinosaur from a fossil that sat largely unstudied at the Natural History Museum in London for almost a century. The specimen is part of the back of a skull, found at the foot of a cliff on the south-west coast of the Isle of Wight by an amateur palaeontologist. The museum acquired it in 1924, but its significance went unrecognised until the research team examined it. The animal has been named Invictibellatrix amberina, a name meaning "unconquered female warrior". The study appeared in the journal Royal Society Open Science. Lead author Cassius Morrison of University College London said it was a "real mystery" why the fragment went unnoticed for so long.

Size and build

The animal measured between three and four metres in length and stood about 1.5 metres tall, roughly the height of an average adult human. Its claws could reach between 10 and 20 centimetres, and it was most likely covered in feathers. Megaraptorans were closely related to tyrannosaurs, including Tyrannosaurus rex, but had slender heads and were more lightly built. Rather than relying on their jaws, they seized prey with large forelimbs and giant curved claws. The team scanned the fragment with computed tomography and built a three-dimensional model of the skull piece. An oval opening for the spinal cord and an hourglass-shaped crest on the bone pointed to a new species, and the researchers compared the fossil with skulls and brain cavities of tyrannosaurids, spinosaurs, velociraptors and other bipedal meat-eaters.

Age, diet and rarity

The fossil dates to the Early Cretaceous, about 120 million years ago in most reports, although AP put the age at around 125 million years. The animal fed on smaller dinosaurs, lizards and mammals, occupying a place in the food chain similar to that of modern hyenas. Megaraptorans are regarded as among the most mysterious large meat-eating dinosaurs, because very few of their fossils have been found. Paul Barrett of the Natural History Museum, who co-authored the study, said the Isle of Wight has been collected for more than 200 years yet keeps yielding new dinosaur species. Finds of meat-eating species on the island are rare, he added.

Megaraptorans in Europe

Megaraptorans are thought to have originated in Asia and spread across what is now Europe and into Gondwana, the southern supercontinent, where later members became apex predators with claws up to 35 centimetres long, according to the research team. Before this study, no megaraptoran had been found in Europe, so the Isle of Wight specimen is the first evidence of the group in the region. The authors say the find adds to clues about how the group dispersed, and that Europe may have played a significant role in its expansion across the Cretaceous. The work also shows that old museum collections can still produce discoveries when examined with modern methods and updated evolutionary frameworks. Morrison has said the island's many bones raise the question of what else is still waiting to be found.