August 17, 2010

Humans May Be Responsible For Megafauna Extinction

Mankind most likely had a hand in the extinction of the giant animals known as "megafauna" according to a new study published Monday in the Proceedings of the National Academy of Sciences (PNAS).

A team of Australian researchers, led by Australian National University School of Archaeology and Anthropology Professor Matthew Spriggs, found the leg bones of meiolaniid, or horned turtles, on the island of Efate.

However, they did not find any shells or skulls, and since the bones were dated back to just two centuries following the arrival of humanity, they suggested that the creatures were hunted for food.

According to BBC News, "It is one of the first cases that clearly shows that humans played a role in the demise" of megafauna, including wooly mammoths and the elephant-sized megatherium sloth.

"The turtles lived far longer than other megafauna," the British news agency added. According to them, most Australian megafauna were believed to have died out nearly 50,000 years ago, but "it appears that these turtles survived for far longer--until the arrival of a people known as the Lapita."

The remains were discovered in a boneyard at a known Lapita settlement on the island, and were said to be from the edible parts of the legs of a newly discovered species in the genus Meiolania. The researchers believe that the turtles were approximately 8-foot long and had large horns on its cranium.

"The remains are mainly leg bones; shell fragments are scant and there are no cranial or caudal elements, attesting to off-site butchering of the turtles," the researchers confirm in the abstract of their report. "The new taxon differs markedly from other named insular terrestrial horned turtles. It is the only member of the family demonstrated to have survived into the Holocene and the first known to have become extinct after encountering humans."

Joining Spriggs as authors of the report were Arthur W. White and Trevor H. Worthy of the University of New South Wales School of Biological, Earth and Environmental Sciences and Stuart Hawkins and Stuart Bedford of Australian National University's Archaeology and Natural History Department.


Image Caption: An exemplary section through the Teouma deposits as revealed in the southern section of the Teouma excavation in 2009. The basal rock of uplifted reef is overlain by a layer of yellow ash. Above this lie the midden deposits from which the turtle bones described here were obtained. Credit: PNAS


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