Researchers have identified a century-old fossil from the Isle of Wight as a new species of meat-eating dinosaur named Invictibellatrix amberina. The tiger-sized predator lived about 120 million years ago and represents the first megaraptoran discovered in Europe, filling a major gap in the evolutionary history of these elusive hunters.
A partial fossil braincase acquired by the Natural History Museum in London in 1924 sat in a collection drawer unstudied for nearly a century before modern imaging revealed its true identity. Discovered originally on the south-west coast of the Isle of Wight, the specimen lay unnoticed until researchers applied modern investigative techniques. The Invictibellatrix fossil was originally found at the foot of a cliff on the south-west coast of the Isle of Wight by amateur palaeontologist Reginald Walter Hooley.
Lots of bones emerge from the Isle of Wight, leaving researchers wondering what else might remain hidden in museum archives.
CT Scans and Skull Anatomy of Invictibellatrix amberina
To uncover the animal’s identity, scientists took CT X-ray scans of the back of the fossil skull, building a three-dimensional digital model of the braincase and its interior cavity. Comparing this model with the skulls of tyrannosaurs, spinosaurs, and raptors revealed a unique anatomical profile.
The analysis identified a distinctive oval opening where the spinal cord entered the brain alongside an hourglass-shaped crest. These features placed the specimen within Megaraptora, a group of agile, two-legged carnivorous theropods related to Tyrannosaurus rex.
Those physical traits meant megaraptorans hunted differently from massive apex predators like Tyrannosaurus rex. While T. rex relied on a stout skull and immense bite strength, Invictibellatrix used its long arms and giant curved claws to catch and process prey.
Invictibellatrix Amberina Hunted Small Dinosaurs and Mammals
Estimates place Invictibellatrix amberina at three to four meters in length and roughly one and a half meters tall, matching the size of a large tiger. The animal likely possessed filament-like feathers and claws measuring 10 to 20 centimeters long, hunting smaller dinosaurs, lizards, and mammals in an ecological role comparable to a modern hyena.
The genus name translates to unconquered female warrior,
chosen by the researchers to give hope to those facing adversity, while the species name amberina refers to the amber found within the rocks of the Wessex Formation where the fossil was dug up.
Before this discovery, megaraptorans were considered mysterious because so few fossils had turned up globally. Theories suggested the group originated in Asia and migrated through Europe to reach southern landmasses like Australia, Africa, and South America, but Invictibellatrix provides the first definitive fossil evidence of their presence in Europe to bridge that geographic gap. In the late Cretaceous, megaraptors apparently disappeared from the northern regions, possibly because of the rise of apex predators such as T-Rex.
Humans Would Be Perfectly Sized Prey for Invictibellatrix
Researchers noted that if a human were transported back to the Early Cretaceous, this agile hunter would present a much more immediate threat than a massive tyrannosaur.
A smaller theropod like Invictibellatrix would likely have been a much bigger threat to a human than something like T. rex because we would likely be too small for T.
Cassius Morrison, now at the University of Leeds
Lead author Dr. Cassius Morrison explained that humans would have been perfectly sized prey, coming in at about a third to a quarter of the dinosaur’s body weight, making us a good hearty meal rather than just a snack. Study senior author Prof Paul Barrett from the Natural History Museum emphasized that historical archives continue to yield major breakthroughs despite centuries of fossil collection on the Isle of Wight, proving that archival drawers hold just as much potential as field expeditions.