Forgotten Fossil Reveals Never Seen Before Dinosaur Species

A dinosaur fossil, overlooked in a museum collection for nearly a century, has been identified as an entirely new species of meat-eating dinosaur. Dubbed Invictibellatrix amberina, the creature roamed what is now Britain around 120 million years ago and weighed roughly as much as a large tiger. Researchers from University College London (UCL) analyzed the fossil, originally discovered on the Isle of Wight, and published their findings in Royal Society Open Science.

The Invictibellatrix marks the first known European member of the megaraptorans, a group of two-legged, carnivorous dinosaurs related to tyrannosaurs. Unlike the powerful jaws of Tyrannosaurus rex, megaraptorans possessed narrower heads, muscular arms, and distinctive large curved claws used to capture prey. Although smaller and less formidable than later megaraptorans, it still likely preyed on small dinosaurs, mammals, and lizards, functioning similarly to a modern hyena within its ecosystem.

The fossil, discovered by amateur paleontologist Reginald Walter Tooley in 1924, had been collecting dust in the Natural History Museum's storage for almost 100 years before being reassessed. Estimated to be three to four meters long and over 1.5 meters tall, the Invictibellatrix likely sported feathers and claws 10cm to 20cm long. The researchers believe it could have posed a more significant threat to human-sized prey than T. rex, given its smaller size and formidable claws.

Megaraptorans' rarity has left scientists uncertain about their origin and distribution. Until now, no fossils had been found in Europe. The discovery supports the theory that megaraptorans spread from Asia, moving through Europe and eventually reaching Gondwana, which included modern-day Africa, South America, and Antarctica. Co-author and UCL PhD student Charlie Scherer noted the find provides the first evidence of megaraptorans in Europe, reinforcing the idea of their arrival via the Gondwana route.

Using computed tomography scans, researchers created a detailed 3D reconstruction of the skull fragment and compared its anatomy to that of other known dinosaurs. Unusual features such as an oval opening for the spinal cord and an hourglass-shaped crest distinguished the Invictibellatrix from existing species. These comparisons consistently placed the fossil within the megaraptoran group.

Surprisingly, megaraptorans evolved into colossal predators in Gondwana, with some reaching lengths of nine to 10 meters and weighing as much as an elephant. The reasons for their disappearance from northern regions remain unclear, with possibilities including climate changes, environmental shifts, and competition from other large predators like tyrannosaurs. This discovery underscores the potential of museum specimens to yield significant scientific insights, even after decades of storage.