http://www.abc.net.au/science/articles/2010/08/17/2984178.htm

Ancient turtles hunted to extinction

Ancient giant horned turtles were driven to extinction by settlers of a Pacific island, say Australian researchers.

Palaeontologist Dr Trevor Worthy from University of New South Wales in Sydney and colleagues report their findings of a turtle graveyard in Vanuatu in this week's issue of theProceedings of the National Academy of Sciences.

The turtle remains were found on top of an even older human graveyard, and this is the first time such remains have been found with human remains, says Worthy.

The findings show the turtles coexisted with humans for 300 years before being hunted to extinction.

"People arrived on Vanuatu 3100 years ago and the village middens, which are the rubbish dumps that provided these bones, date to 2800 years ago," he says.

"So there's essentially a 300-year gap between those first human arrivals and the end of these turtles in these middens."

Horns, spikes and a club

Meiolaniid or horned turtles are an extinct family of land-dwelling animals that evolved during the time of the dinosaurs in Gondwana.

Worthy says the turtles had horns on their head, spikes on the back of their shell and a big club on their tail - an armoury that evolved as a defence against predators like dinosaurs.

He says the horned turtles were thought to have all died out by at least 50,000 years ago.

In Australia the animals were most numerous on Lord Howe Island where they died out, 'probably due to climate change', says Worthy.

But now, he and colleagues have found remains of a completely new species of horned turtles that is just 2800 to 3000 years old - the youngest ever found.

Remote butchering

The turtle graveyard was found at a place called Teouma, on the south coast of Efate Island in Vanuatu.

This was home to the Lapita people, the first colonisers of eastern Melanesia and Polynesia who are well known for their decorated pottery.

So far, Worthy and colleagues have found more than 400 fragments of turtle remains, representing about 30 individuals.

Significantly, they have found mainly leg bones, but no head or tail remains, and only small fragments of shell.

"This suggests very strongly that the animals were butchered somewhere other than in the village where we excavated them," says Worthy.

"They just cut them up and brought back the bits that had most meat on them."

Vulnerable turtles

Despite all their armour, the turtles were vulnerable to being speared in the neck and being flipped over so they were defenceless, says Worthy.

"Once you spear them, you could just turn them on their back and they're stuffed," he says.

He says this is what early Dutch and Portuguese sailors did to turtles on Rodrigues, part of the Mascarenes Islands in the Indian Ocean, in the 14th and 15th centuries.

"They just grabbed the turtles, laid them upside down so they couldn't walk away and put them in the boat. Then they had fresh meat for ages," says Worthy.

He says it took the sailors two centuries to wipe out turtles on Rodrigues.