Scientists have discovered fossil remains of a new carnivorous mammal in Turkey, one of the biggest marsupial relatives ever discovered in the northern hemisphere.

The findings, by Dr Robin Beck from the University of Salford in the UK and Dr Murat Maga, of the University of Washington who discovered the fossil, are published today in the journal PLoS ONE.

The new fossil is a 43 million year old cat-sized mammal that had powerful teeth and jaws for crushing hard food, like the modern Tasmanian Devil. It is related to the pouched mammals, or marsupials, of Australia and South America, and it shows that marsupial relatives, or metatherians, were far more diverse in the northern hemisphere than previously believed.

Dr Maga found the fossil at a site near the town of Kazan, northwest of the Turkish capital, Ankara. It has been named Anatoliadelphys maasae, after the ancient name for Turkey, and Dr Mary Maas, a Turkish-American palaeontologist. The fossil is remarkably well preserved, and includes parts of the skull and most of the skeleton.

It shows that Anatoliadelphys weighed 3-4 kilograms, about the size of a domestic cat, and that it was capable of climbing. It had powerful teeth and jaws, for eating animals and possibly crushing bones. Features of the teeth and bones of Anatoliadelphys show that is closely related to marsupials, but it is not known whether it had a pouch or not.

Dr Beck, who is a world expert in the evolution of marsupials and their fossil relatives, said: "This was definitely an odd little beast -- imagine something a bit like a mini-Tasmanian devil that could climb trees.

"It could probably have eaten pretty much anything it could catch -- beetles, snails, frogs, lizards, small mammals, bones, and probably some plant material as well. This find changes what we thought we knew about the evolution of marsupial relatives in the northern hemisphere -- they were clearly a far more diverse bunch than we ever suspected."

Most fossil metatherians from the northern hemisphere were insect-eating creatures no bigger than mice or rats, whereas Anatoliadelphys was ten times larger and could have eaten vertebrate prey.

"It might seem odd to find a fossil of a marsupial relative in Turkey, but the ancestors of marsupials actually originated in the northern hemisphere, and they survived there until about 12 million years ago," said Dr Beck.

The region of Turkey where Anatoliadelphys was found was probably an island 43 million years ago, which may have enabled Anatoliadelphys to survive without competition from carnivorous placental mammals, such as fossil relatives of cats, dogs and weasels.

Today, many marsupials in Australia have been driven to extinction due to the introduction of the dingo, cats and foxes, suggesting that marsupials may be competitively inferior to placentals.