Yuanmou Man

Discovery On May 1, 1965, geologist Qian Fang recovered two archaic human upper first incisors (catalogue number V1519) from fossiliferous deposits of the Yuanmou Basin near Shangnabang village, Yuanmou County, Yunnan Province, China. The Yuanmou Basin sits just to the southeast of the Tibetan Plateau, and is the lowest basin on the central Yunnan–Guizhou Plateau at an elevation of . The Yuanmou Formation is divided into four members and 28 layers. The human teeth were discovered in the silty clay and sandy conglomerates of Member 4 (the uppermost member) near the bottom of layer 25. Age The Yuanmou Formation has been identified as a fossil-bearing site since the 1920s, and palaeontological work on the area suggest a Lower Pleistocene age. Because the formation is faulted (several rock masses have been displaced), biostratigraphy (dating an area based on animal remains) of the human-bearing layer is impossible. In 2002, Masayuki Hyodo and colleagues, using palaeomagnetism, reported a date of 0.7 million years ago near the Matuyama–Brunhes geomagnetic boundary during the Middle Pleistocene. Later that year, the boundary was re-dated to 0.79–0.78 million years ago by geophysicist Brad Singer and colleagues. In 2003, Ri Xiang Zhu and colleagues made note of the inconsistency among previous palaeomagnetic studies, and in 2008 palaeomagnetically dated it to roughly 1.7 million years ago. They believed Middle Pleistocene dates were probably caused by too small a sample size. The tibia was probably found somewhere in layers 25–28, and by Zhu's calculations would date to 1.7–1.4 million years ago. The date of 1.7 million years ago is widely cited. Yuanmou Man could also indicate humans dispersed from south to north across China, but there are too few other well-constrained early Chinese sites to test this hypothesis. Classification The teeth were formally described in 1973 by Chinese palaeoanthropologist Hu Chengzhi, who identified it as a new subspecies of Homo erectus, distinct from and much more archaic than the Middle Pleistocene Peking Man, H. ("Sinanthropus") e. pekinensis, from Beijing. He named it H. ("S.") e. yuanmouensis, and believed it represents an early stage in the evolution of Chinese H. erectus. ==Anatomy==

For the teeth, only the left and right first incisors are preserved for the Yuanmou Man. The left incisor measures in breadth and in width, and the right incisor and . The tibia is a long mid-shaft fragment. ==Culture==

Palaeohabitat A total of 35 other animals have been reported from layer 25. The mammals are: the chalicothere Nestoritherium; the deer Cervocerus ultimus, Procapreolus stenosis, Paracervulus attenuatus, Rusa yunnanensis, Cervus stehlini, Muntiacus lacustris, M. nanus, gazelle, and chital; cattle; pigs; the elephant Stegodon; rhino; the giant short-faced hyaena Pachycrocuta brevirostris licenti; pika; and small rodents. Various mollusks, turtles, crustaceans, and plants were also found. Fossil pollen deposits on the Yuanmou teeth and artefacts can largely be assigned to herbaceous plants, pine, and alder. Altogether, they suggest Yuanmou Man inhabited a mixed environment featuring open grassland, bushland, forest, marshland, and freshwater, not unlike what is suggested for the Dmanisi hominins. totaling 16 tools. They were made of quartz and quartzite probably gathered from the nearby river. Most were modified with direct hammering (using a hammerstone to flake off pieces), but a few were modified with the bipolar technique (smashing the core with the hammerstone, creating several flakes). ==References==