Some hundred and twenty million years ago, a slender meat-eater roamed what is now the southern coast of England, a creature whose kin would spread across the ancient world before the great extinction closed the age of dinosaurs. Its scattered remains waited a century in a museum drawer until researchers recognised them as something new. The find gives the human story of this lineage its first European chapter, linking Asia to Africa and South America. Where the animal sits upon the family tree, however, remains an open question that future bones may yet answer.
Isle of Wight Fossil Reveals Europe's First Known Megaraptoran, a Small Clawed Predator
Left in a drawer for a century, until someone finally looked
Mark
Why does a skull fragment from a drawer matter so much?
Mimi
Because Europe was the missing link in a proposed route. Megaraptorans were thought to travel from Asia through Europe into Africa and South America, and until now no European fossil backed that up.
Luke
Careful, though. One fossil supports the hypothesis; it doesn't prove the route.
Mark
Fair. What do we actually know about the animal?
Mimi
Only a fragmented braincase survives. The 5 metre length and tiger-like weight are estimates based on close relatives.
Luke
And the feathers are a maybe. The researchers say its body may have been covered in filament-like feathers, not that it was.
Mark
How did it live alongside bigger predators?
Mimi
It wasn't the island's top hunter. Larger theropods were around, and the researchers suggest a hyena-like role.
Luke
That's a suggestion by the team, an analogy, not something the fossil shows directly.
Mark
And the tyrannosaur link?
Mimi
Still debated. One hypothesis places megaraptorans close to tyrannosaurs, but the source says paleontologists disagree.
Luke
Right, and this fossil doesn't settle it. The human-threat comparison is Morrison's reasoning, not a finding.
Der Puls
- A fragmented skull unnoticed for a hundred years suddenly reveals an unknown predator from Europe.
- The newly named Invictibellatrix challenges assumptions about how megaraptorans hunted, pitting agile claws against the brute force of tyrannosaurs.
- Scientists are tracing the group's migration route from Asia through Europe to Africa and South America, filling a long-missing gap.
- The placement of this predator on the theropod family tree remains disputed, with further discoveries needed to settle the question.
Some hundred and twenty million years ago, a slender meat-eater roamed what is now the southern coast of England, a creature whose kin would spread across the ancient world before the great extinction closed the age of dinosaurs. Its scattered remains waited a century in a museum drawer until researchers recognised them as something new. The find gives the human story of this lineage its first European chapter, linking Asia to Africa and South America. Where the animal sits upon the family tree, however, remains an open question that future bones may yet answer.
For about a century, a fragmented braincase lay in a drawer at the Natural History Museum in London. It had been found on the Isle of Wight and acquired in 1924, and for most of that time nobody gave it much notice. Only a couple of years ago did Charlie Scherer, a doctoral student at University College London, and his colleagues recognise that it belonged to a previously unknown predator, the first megaraptoran ever identified in Europe.
The animal, named Invictibellatrix amberina, meaning "unconquered female warrior," lived around 120 million years ago. The researchers, led by Cassius Morrison of the University of Leeds, estimate it stretched about 5 metres and weighed roughly as much as a large tiger, based on related megaraptorans rather than a complete skeleton. Its body may have been covered in filament-like feathers.
Megaraptorans were agile hunters with slender heads, long arms ending in massive claws, and light skeletons. Morrison suggests they chased prey down and disembowelled it, a sharp contrast to the powerful, bone-crushing bite of Tyrannosaurus rex. Invictibellatrix was not the top predator of its island home, and may have played a role something like a modern hyena.
The discovery matters for the group's story. The leading hypothesis holds that megaraptorans began in Asia, passed through Europe into Africa, and eventually thrived in South America until the asteroid strike 66 million years ago. Until now, the European leg of that journey had no fossil evidence. Where megaraptorans belong on the theropod family tree, including possible ties to tyrannosaurs, is still debated, and further fossils may settle it.
For about a century, a fragmented braincase sat in a drawer at the Natural History Museum in London. It had been found on the Isle of Wight, off England's southern coast, and the museum acquired it in 1924. Nobody paid it much attention until a couple of years ago, according to Charlie Scherer, a doctoral student at University College London. Now researchers say the fossil belongs to a previously unknown predator, and that it is the first megaraptoran ever identified in Europe.
The animal has been named Invictibellatrix amberina. The name means "unconquered female warrior." It lived roughly 120 million years ago, in the Cretaceous Period, and the researchers describe it as an early member of the megaraptorans, a lineage of meat-eating dinosaurs. The findings appear in the journal Royal Society Open Science, and the lead author is Cassius Morrison, a postdoctoral researcher at the University of Leeds.
By the researchers' estimate, Invictibellatrix was about 5 metres long and weighed about as much as a large tiger. That estimate rests on fossils of closely related megaraptorans, not on a complete skeleton of this animal. It makes Invictibellatrix one of the smallest megaraptorans known. The researchers say its body may have been covered in filament-like feathers.
Megaraptorans belong to the theropods, the broad group that includes all the meat-eating dinosaurs. Morrison says they stand out within it. They had relatively small, slender heads, long and strong arms ending in massive hand claws, and very lightly built skeletons. He reads these traits as signs of agile hunters that chased prey down, then caught and disembowelled it with their claws. That is the opposite of how Tyrannosaurus rex hunted, using a large, stoutly built head, enormous teeth and great bite strength, with arms too puny to matter.
The size range within the group is wide. The largest known megaraptoran, Maip, reached about 10 metres and lived in Patagonia near the end of the dinosaur age, some 50 million years after Invictibellatrix. Small ones like Invictibellatrix may have taken mammals, smaller reptiles and baby dinosaurs. Larger ones may have gone after bigger plant-eaters such as duckbilled hadrosaurs and long-necked sauropods, though probably not the biggest. On the Isle of Wight, Invictibellatrix was not the top predator. Larger theropods lived there too, alongside various herbivorous dinosaurs, and the researchers suggest it may have filled a role like that of a hyena today.
The find matters for where megaraptorans came from. A leading hypothesis holds that the group began in Asia, moved through Europe into Africa, and then reached South America, where it thrived until an asteroid strike 66 million years ago doomed the dinosaurs. That route lacked fossil evidence from Europe until now. Morrison says megaraptorans, after humble beginnings, became apex predators in South America, Australia and Antarctica, the "ruling queens," while tyrannosaurs became the "tyrant kings" of North America and Asia. Scherer said the findings help uncover the evolution of one of the most mysterious theropod groups.
The family tree remains contested. Paleontologists debate where megaraptorans fit among theropods. One hypothesis, despite the differences in build and hunting style, ties them closely to the tyrannosaurs.
Morrison also offered a comparison for human readers, prompted by the recent film The End Of Oak Street. A person sent back in time would be a poor meal for T. rex, he said, being too small to be worth the energy of the chase. For Invictibellatrix, humans would be about a third to a quarter of its weight, a hearty meal, and it had the agility to catch one. Further fossils may help settle the family-tree question.
Bemerkenswerte Zitate
Megaraptorans were agile hunters capable of chasing down prey and using their large arms and claws to catch and disembowel them.— Cassius Morrison, University of Leeds
The fossil was left in one of the collection's drawers and no one noticed it until a couple of years ago.— Charlie Scherer, University College London
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