Scientists have unearthed 100 million-year-old fossil remains of an African creature that resembled a cross between a croc and a cat.
Pakasuchus kapilimai had the scaly amoured body of a crocodile but also cat-like features including canine teeth, slender limbs, and a flexible backbone that would have helped it move with agility and grace.
Discovery: This artists impression shows a Cretaceous crocodile that had a scaly armoured body and cat-like features. At 3 inches long it had a similar size to modern cats
Unlike modern crocodiles, it probably hunted on land at a time when the world was dominated by the dinosaurs.
Experts believe it occupied an ecological niche in the southern hemisphere that was chiefly filled by small mammals in the north during the mid-Cretaceous period.
The house cat-sized fossil skull and skeleton of Pakasuchus was discovered encased in sandstone on a river bank in the Rukwa Rift Basin of Tanzania.
It's skull, at 3 inches (7cm) long was similar to the size of modern cats.
Paka is Swahili for cat, while suchus is derived from the Greek word for crocodile.
The creature's most distinctive feature was its jaw and teeth, said scientists writing in the journal Nature.
A CT (computed tomography) X-ray scan, of the kind commonly seen in hospitals, was used to peer through the stone and reveal hidden details of the teeth and skull.
Modern crocodiles have simple, pointed conical teeth adapted for seizing prey and tearing off large chunks of flesh which are swallowed whole.
In contrast, Pakasuchus had teeth like those of a predatory mammal, including fangs and slicing molars with shearing edges.
Dr Patrick O'Connor, from the University of Ohio, US, who led the international team of scientists, said: 'At first glance this croc is trying very hard to be a mammal.
'A number of characteristics of this new species, including a reduction in its total number of teeth and a dentition specialised into ones similar to canines, premolars and occluding molars, are very similar to features that were critical during the course of mammalian evolution.'
This artistic impression shows an ancient crocodile Pakasuchus kapilimai that roamed Tanzania 105 million years ago
Like other crocodiles, Pakasuchus had a heavily armoured tail protected by bony plates.
However the plates were far less pronounced around the animal's back and sides. Combined with an extremely flexible backbone, this would have aided mobility.
When the creature was alive the area where its remains were found, near Lake Rukwa in south-western Tanzania, was criss-crossed by waterways and covered in low-lying vegetation.
Other fossil finds from the region dating to the same period include plant and meat-eating dinosaurs, as well as different types of crocodile.
Pakasuchus belonged to an extinct family of Cretaceous crocodilians called notosuchians.
Evidence suggests they were far more diverse than crocodiles and alligators are today and evolved to fill numerous specialised niches.
This was especially true in the southern hemisphere, where they appear to have taken the place of small mammals which were more common in northern regions.
The creature's most distinctive feature was its jaw and teeth,seen here, say scientists
'The presence of morphologically bizarre and highly specialised notosuchian crocodyliforms like Pakasuchus in the southern landmasses, along with an apparently low diversity of mammals in the same areas, has potentially profound ecological implications,' said co-author Dr Joseph Sertich, from Stony Brook University, New York.
'This entire group of crocodiles deviates radically from the 'typical' crocodile, most notably in their bizarre dentitions, demonstrating a diversification not seen in the northern hemisphere during this time interval.'
During much of the Cretaceous period, Afro-Arabia, India, Madagascar, Antarctica, Australia and South America together formed a southern 'supercontinent' called Gondwana.
Relatively few Cretaceous-age mammals have been recovered from this part of the world.
Those whose fossils have been found do not appear to be related to modern mammals. ( dailymail.co.uk )
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