New megaraptoran dinosaur named from Isle of Wight fossil held since 1924

Centre · 2Researchers have named a new species of predatory dinosaur, Invictibellatrix amberina, from a partial skull found on the Isle of Wight that had gone unstudied in the Natural History Museum for about a century. 1 2 Centre · 2The fossil, a fragmentary braincase, was acquired by the museum in London in 1924 and was found in the Lower Cretaceous Wessex Formation on the island's south-west coast, in rocks about 120 million years old. 2 3 Centre · 2The study, published in the journal Royal Society Open Science, was led by Cassius Morrison, described as now at the University of Leeds; the Evening Standard describes the team as led by University College London, and co-author Charlie Scherer is a UCL doctoral student. 3 1

Centre · 1The researchers used CT scans to build a 3D model of the fossil and compared it with other dinosaurs; the closest match was the Argentinian megaraptoran Murusraptor, so they place the animal in the Megaraptora, which they say makes it the first megaraptoran found in Europe. 2 Centre · 2The genus name means "unconquered female warrior". Megaraptorans were two-legged theropods with slender heads, lightly built skeletons and long, strong arms with large hand claws, and may be related to tyrannosaurs, though where they sit on the theropod family tree is debated. 3 1 Centre · 2Size estimates differ between reports: New Scientist and the Evening Standard give a length of 3 to 4 metres, about 1.5 metres tall, with claws 10 to 20 cm long, and New Scientist gives a weight of 200 to 300 kg, while CNA says about 5 metres (16 feet) with the weight of a large tiger. 2 3

Centre · 2It is thought to have had feathers and to have hunted small dinosaurs, lizards and mammals; it was not the island's top predator, and CNA says it may have filled a role like that of a hyena today. 1 3 Centre · 2Morrison said humans would have been about a third of its body weight, making them suitable prey, and that it would have been more dangerous to people than a T. rex, which would have been too massive to bother with something so small. 1 3 Centre · 2A leading hypothesis holds that megaraptorans originated in Asia and spread through Europe into Africa and then South America, and the researchers say the new species supplies fossil evidence for the European step; New Scientist says the Isle of Wight was then attached to mainland Europe with a subtropical climate. 3 2

Centre · 1Jake Kotevski of Monash University told New Scientist that the finding, if the classification holds, would fill a gap in knowledge of the group, but that more fossils are needed to support or reject the hypothesis; he also regretted that the fossil could not be compared in more detail with the earlier Wessex Formation theropod Eotyrannus, whose remains do not overlap with it. 2 Centre · 2The reports differ on the original finder: New Scientist says the fossil was acquired from a Reverend Reginald Hooley, while the Evening Standard credits amateur palaeontologist Reginald Walter Tooley with finding it at the foot of a cliff. The Standard says the research was funded by the Palaeontographical Society, the Royal Society and UK Research and Innovation. 2 1