New Dinosaur Species Discovered from Overlooked Fossil

A new species of dinosaur, described as a long-clawed predator about the size of a large tiger, has been identified from a fossil discovered on the Isle of Wight more than 100 years ago. The dinosaur, named Invictibellatrix amberina, is the first of its kind found in Europe and belongs to the megaraptoran group of agile, two-legged carnivores.

Megaraptorans were closely related to tyrannosaurs but distinguished themselves by using their large arms and giant curved claws for attacking prey, rather than their jaws. The fossil, which is a fragment of the back of a skull, was found by amateur paleontologist Reginald Walter Tooley at the foot of a cliff on the Isle of Wight and acquired by the Natural History Museum in 1924. Researchers suggest it is a "real mystery" how the specimen remained unclassified for so long.

Invictibellatrix, meaning "unconquered female warrior," is believed to have lived approximately 120 million years ago during the Early Cretaceous period. It is one of the smallest and earliest megaraptorans discovered. Researchers estimate the dinosaur was between three and four meters long and stood just over 1.5 meters tall. It may have had feathers and possessed claws estimated to be 10 to 20 centimeters long. Its diet likely consisted of small dinosaurs, lizards, and mammals, positioning it in a similar ecological niche to modern hyenas.

The study, published in the journal Royal Society Open Science, involved a CT scan of the fossil to create a 3D model of the skull fragment. The researchers compared this model with skull and brain case data from various dinosaur groups, including tyrannosaurs, spinosaurs, and raptors.

Megaraptors are considered among the most enigmatic of the large carnivorous dinosaurs due to the scarcity of fossils found to date. The discovery on the Isle of Wight fills a significant gap in the geographical distribution of these creatures.

The research team also employed mathematical modeling to explore the historical spread of megaraptors globally, using existing fossil records, evolutionary trees, geographical data, and climate information. Professor Paul Barrett of the Natural History Museum highlighted the ongoing value of historical museum collections, stating that despite extensive collecting over two centuries, the Isle of Wight continues to yield new dinosaur species.

While the study did not definitively pinpoint the reasons for the extinction of megaraptors in the north, potential factors suggested include climatic or environmental shifts, or competition from other predators like tyrannosaurs.