viernes, 14 de agosto de 2015

Marks on 3.4-million-year-old bones not due to trampling, analysis confirms

Figure 2: Stone-tool-inflicted marks on DIK55-2, a rib of a probably size 4 or larger ungulate... Nature 2010.

Analysis supports a previous finding, that the best match for the marks is butchery by stone tools

Marks on two 3.4 million-year-old animal bones found at the site of Dikika, Ethiopia, were not caused by trampling, an extensive statistical analysis confirms. The Journal of Human Evolution is publishing the results of the study, which developed new methods of fieldwork and analysis for researchers exploring the origins of tool making and meat eating in our ancestors.

"Our analysis clearly shows that the marks on these bones are not characteristic of trampling," says Jessica Thompson, an assistant professor of anthropology at Emory University and lead author of the study. "The best match we have for the marks, using currently available data, would still be butchery with stone tools."

The 12 marks on the two specimens -- a long bone from a creature the size of a medium antelope and a rib bone from an animal closer in size to a buffalo -- most closely resemble a combination of purposeful cutting and percussion marks, Thompson says. "When these bones were hit, they were hit with enormous force and multiple times."

The paper supports the original interpretation that the damage to the two bones is characteristic of stone tool butchery, published in Nature in 2010. That finding was sensational, since it potentially pushed back evidence for the use of stone tools, as well as the butchering of large animals, by about 800,000 years. [...]