Old hidden-face: An artist's impression of the scavenger Kryptops a new meat-eater unearthed in Niger.

Credit: Todd Marshall/Project Exploration

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SYDNEY: The remains of two new predatory dinosaurs, one with a penchant for gnawing on carcasses, the other for severing body parts, have been unearthed in Africa.

Dubbed Kryptops palaios, meaning 'old hidden face', and Eocarchia dinops, meaning 'fierce-eyed dawn shark', the 110-million-year-old dinosaurs give fresh insight into an odd group of Cretaceous-era meat-eaters.

Fearsome looking creatures

The beasts were discovered in Niger by palaeontologists Paul Sereno of the University of Chicago in the U.S., and Stephen Brusatte of the University of Bristol in England.

Their report, detailed today in the journal Acta Palaeontologica Polonica, found the ferocious Kryptops to be the oldest indisputable member of a group of dinosaurs called abelisaurids, while Eocarchia is an early member of a group called the carcharodontosaurids.

Both were fearsome looking creatures, with Kryptops around seven metres in length and Eocarchia even larger - possibly 10 to 12 metres head to tail (its close South American relative, Giganotosaurus, was thought to have been larger than Tyrannosaurus rex).

Living up to its menacing namesake, Eocarchia had a mouth full of incredibly sharp, shark-like teeth, together with a "massive ornamented brow" that would have lent it a rather intimidating glare, the researchers said. It is likely the oversized bony protrusion was used as a 'battering ram' by the dinosaur while fighting off rivals, while its blade-like teeth were suited to smoothly severing body parts and incapacitating live prey.

Kryptops, on the other hand, had short, serrated teeth more suited to taking apart an already dead meal. Brusatte likened the creature at dinner-time to a "fast, two-legged hyena gnawing and pulling apart a carcass." Its short-shouted face was almost completely masked in a horny covering, leading to its much-suited moniker, "old hidden face".

Precious fragments

Though the excavated remains of the fossils are relatively meagre fragments, the information that can be learnt from them is not, said Steve Salisbury, a dinosaur palaeontologist at the Queensland Museum in Brisbane, Australia.

"They provide important information about the nature of Africa's dinosaur fauna during the mid-Cretaceous period (112 to 95 million years ago)," he said. And it is by learning more about the distribution and evolutionary relationships of creatures at this point in time, he continued, that we can learn important information about the fragmentation of the giant landmass Gondwana.

Gondwana was the 'supercontinent' that eventually gave rise to most of the southern continents, including Australia, South American and Africa – but it still isn't clear how its fragmentation process progressed and at what times the different landmasses broke off from one another.

By looking at the distribution of Kryptops and Eocarchia's relatives on other Gondwanan landmasses (South America and India, for example) we might learn more about the time when Africa became isolated from them, painting a clearer picture of the development of the continents we know today.