Starch grains from dental calculus reveal ancient plant foodstuffs at Chenqimogou site, Gansu Province

Chenqimogou site, located at the south bank of Tao River, is comprised of a large group of graves dated to000 a BP. For its large scale, unique mortuary system, and abundant of typical artifacts, the site was named one of "Top Ten Archaeological Discoveries of 2008 in China". Many intact human skeletons have been excavated from the graves. Three teeth from two adult skeletons excavated from graves M187 and M194 were examined. Forty-eight starch grains were retrieved from dental calculus of three teeth. Six of those starch grains could not be identified because of damage. The others were classified into seven groups. Most of them were from wheat （Triticum aestivum） and/or barley （Hordeum vulgare）. Remains possibly from foxtail millet （Setaria italica）, buckwheat （Fagopyrum esculentum）, gingkgo （Ginkgo biloba）, acorn （Quercus spp.）, bean, roots or tubers were identified. Ancient starch grains from dental calculus indicate that human foodstuffs primarily sourced from wheat, buckwheat, and foxtail millet. Acorn, beans, tubers or roots were supplements. A variety of starch grains retrieved from dental calculus revealed that diverse crops were cultivated in the Chenqimogou site 4000 years ago, and both dry-land farming and gathering were engaged.