A new species of meat-eating dinosaur has been named from a single piece of skull that spent more than a hundred years in storage at the Natural History Museum in London.
The animal, Invictibellatrix amberina, is a two-legged theropod, the dinosaur family that includes birds. Two of the authors of the study describing it set out the find in The Conversation.
Over its nearly 150-year history the London museum has become home to over 30 million specimens, which, as the authors put it, makes it fairly easy to forget about the odd fossil or rock here and there.
In 2020 Paul Barrett, one of the museum's palaeontologists, was looking through the fossil collections and came across a small chunk of bone that he recognised as an important part of a dinosaur's skull: the braincase. Museum records showed it had been found on a beach near Sudmoor Point on the Isle of Wight.
Barrett enlisted Cassius Morrison, then a PhD student specialising in dinosaur braincases, to study the fossil in detail and work out which dinosaur it belonged to. The roughly 120-million-year-old bone proved unlike anything found on the island before.
It belongs to the Megaraptora, a family of carnivores known for slender skulls, lightly built skeletons and gigantic hand claws, with some of the larger species having claws over a foot long. Most known species come from South America, particularly Argentina.
The British animal was on the smaller side, about 5 metres from head to tail and weighing as much as a large tiger, making it the smallest known megaraptoran. It probably comes from the early days of megaraptoran evolution, before the group grew to gigantic sizes.
The work involved direct comparison with the skulls of other carnivores, CT scanning to look inside the braincase, and a computer algorithm to place the species in the theropod family tree and reduce the risk of bias.
The result matters for the group's geography. Before this find, megaraptorans were known only from the early Cretaceous, 130 to 120 million years ago, of Thailand and Japan, plus multiple larger species from the late Cretaceous, 85 to 66 million years ago, of Australia and Argentina. As the first European megaraptoran, Invictibellatrix is strong evidence that the group travelled to the southern continents from Asia by way of Europe and Africa, and suggests others may be waiting in Africa and even Antarctica.
On the Isle of Wight it probably lived alongside Neovenator, a relative of Allosaurus, Ceratosuchops, a relative of Spinosaurus, and Eotyrannus, an early relative of Tyrannosaurus rex. The four are thought to have eaten different animals, with the spinosaur specialising in fish; Invictibellatrix probably took small dinosaurs, mammals, lizards and even crocodiles. Its name translates as "unconquered warrior of the amber".
The museum's own explanation of how the fossil came to be overlooked repays a second reading. Thirty million specimens. Nearly a century and a half of accumulation. One new genus recovered in 2020 by a palaeontologist walking through the collection and looking down.
That is a description of a site, not an embarrassment. The Department of Unnecessary Research has accordingly reclassified the museum's storage as the most productive megaraptoran locality in Europe, on the straightforward grounds that it has produced all of them.
The stratigraphy is unusually well documented. Access requires no permit and no tide tables. The specimens arrive pre-sorted into drawers and labelled with the beach they came from. Fieldwork can be conducted in a cardigan.
Europe's richest dinosaur bed has been sitting under a roof in South Kensington for a hundred years, and the only excavation technique it has ever required is opening the drawer.