Residue Analysis of Stone Artifacts from the Wenquan Paleolithic Site Reveals Early Exploitation of Wild Cereals and Food Processing Functions ofAcheulean Tools in Northern China (70,000–40,000 BP)

The Wenquan Site is located in Wenquan Town, Ruzhou City, Pingdingshan City, Henan Province, China. It is a Paleolithic site dating from approximately 70,000 to 40,000 years ago, and the unearthed stone tools exhibit distinct Acheulean technical features, including handaxes, cleavers, and scrapers. This study conducted residue analysis on 11 typical artifacts from the Wenquan Site to investigate plant food resource utilization by its ancient inhabitants and the functions of stone tools. Results indicate that starch grains were found on all 11 stone tools (including flakes, large flakes, handaxes, picks, cleavers, scrapers, heavy-duty scrapers, and denticulate tools). These starch grains show a high degree of similarity with those from grasses and rhizomatous plants, such as species from the Triticeae, Paniceae, Coix , Trichosanthes , Setaria , Agropyron , Dioscorea , and Pueraria tribes or genera. The Triticeae starch grains discovered on stone tools from the Wenquan site represent the earliest recorded evidence of Triticeae starch grains in northern China. This indicates that ancient humans at the Wenquan site had already begun to collect and consume grass seeds, providing important physical evidence for the study of the exploitation and utilization of wild cereals prior to their domestication. Moreover, a higher concentration of starch grains from Poaceae and rhizomatous plants was discovered on handaxes, picks, and cleavers, clearly indicating that ancient humans at the Wenquan site between 70,000 and 40,000 years ago used these large-sized tools to process food resources. This finding provides new directions and insights for discussing the functions of large Acheulean tools.