ヒトの進化：東アジアでオーカーの加工が行われていたことを示す最も古い証拠

The earliest known evidence of ochre processing in east Asia is reported in a study in Nature this week. Use of this pigment is associated with symbolic behaviours that are in present-day human culture. The findings, including miniaturized tools, from a site in northern China are unique for Eastern Asia and provide new insights into the expansion of Homo sapiens.

Current archaeological evidence suggests that H. sapiens was present in northern Asia by at least 40,000 years ago. However, the cultural adaptations present at the time have remained unknown.

Shi-Xia Yang and colleagues report the discovery of ochre-processing materials along with an assembly of innovative tools dated to around 40,000 years ago at Xiamabei, a newly excavated and well-preserved site in the Nihewan Basin of northern China. Ochre pieces found in the area show that different types of ochre were processed using abrasion and pounding to produce powders of different colours and grain sizes. The assemblage of stone tools, comprising 382 artefacts, demonstrates novel and complex technological capacities, such as miniaturization (almost all of the pieces are smaller than 40 mm, and most are smaller than 20 mm) and hafting (a process by which an artefact is attached to a handle or strap).

The authors note that the assemblage of cultural traits at Xiamabei is unique and does not correspond with those found at other archaeological sites inhabited by archaic populations, such as Neanderthals and Denisovans, or to those generally associated with the expansion of H. sapiens. They suggest that this may reflect an initial colonization by modern humans, potentially involving cultural and genetic mixing with local Denisovans, who were perhaps replaced by a later second arrival. Yang and co-authors argue that the findings support a complex evolutionary scenario for the expansion of H. sapiens, involving repeated but differential episodes of genetic and cultural exchange over large geographical areas.