Human remains from the Pleistocene-Holocene transition of southwest China suggest a complex evolutionary history for East Asians.

BACKGROUND: Later Pleistocene human evolution in East Asia remains poorly understood owing to a scarcity of well described, reliably classified and accurately dated fossils. Southwest China has been identified from genetic research as a hotspot of human diversity, containing ancient mtDNA and Y-DNA lineages, and has yielded a number of human remains thought to derive from Pleistocene deposits. We have prepared, reconstructed, described and dated a new partial skull from a consolidated sediment block collected in 1979 from the site of Longlin Cave (Guangxi Province). We also undertook new excavations at Maludong (Yunnan Province) to clarify the stratigraphy and dating of a large sample of mostly undescribed human remains from the site. METHODOLOGY/PRINCIPAL FINDINGS: We undertook a detailed comparison of cranial, including a virtual endocast for the Maludong calotte, mandibular and dental remains from these two localities. Both samples probably derive from the same population, exhibiting an unusual mixture of modern human traits, characters probably plesiomorphic for later Homo, and some unusual features. We dated charcoal with AMS radiocarbon dating and speleothem with the Uranium-series technique and the results show both samples to be from the Pleistocene-Holocene transition: ∼14.3-11.5 ka. CONCLUSIONS/SIGNIFICANCE: Our analysis suggests two plausible explanations for the morphology sampled at Longlin Cave and Maludong. First, it may represent a late-surviving archaic population, perhaps paralleling the situation seen in North Africa as indicated by remains from Dar-es-Soltane and Temara, and maybe also in southern China at Zhirendong. Alternatively, East Asia may have been colonised during multiple waves during the Pleistocene, with the Longlin-Maludong morphology possibly reflecting deep population substructure in Africa prior to modern humans dispersing into Eurasia.

On the systematic status of the late Neogene hominoids from Yunnan Province, China.

Late Miocene and Pliocene hominoids from Yunnan Province in southern China have been recovered from four sites or site complexes: Xiaolongtan, Yangyi, Shihuiba and Yuanmou. Of these, Shihuiba and Yuanmou are among the most prolific fossil hominoid sites in Eurasia, and they have yielded important evidence that is critical for documenting the evolutionary history, biogeography and paleobiology of later Neogene hominids. The aim of this paper is to clarify their taxonomy and nomenclature, and to present a preliminary synthesis of their phylogenetic relationships and biogeography. The morphological pattern and degree of variation observed in the fossil samples is consistent with there being a single, sexually dimorphic species represented at each site. Provisionally, we consider the Shihuiba, Xiaolongtan and Yuanmou samples to belong to two separate species within a single genus. The valid names for these species are Lufengpithecus lufengensis (from Shihuiba) and L. keiyuanensis (from Xiaolongtan and Yuanmou). From a phylogenetic perspective, the currently available evidence suggests that Lufengpithecus is either a primitive hominid that represents the sister taxon of the Ponginae+Homininae or a primitive sister taxon to the Ponginae. We tend to favor the second alternative, but acknowledge that a more comprehensive comparative analysis is needed to substantiate the phylogenetic and taxonomic affinities of Lufengpithecus. Importantly, the Yunnan fossil apes provide a unique temporal perspective on the evolutionary history of hominoids. Their continued occurrence during the late Miocene and Pliocene (approximately 8-2Ma), when hominoids became extinct throughout the rest of Eurasia, suggests that southern China (and presumably southeast Asia in general) was an important refugium for hominoids, including the ancestors of the orang-utans and gibbons. The uplift of the Tibetan plateau and its impact on regional climatic conditions may have been an important contributing factor in isolating the hominoids geographically and ecologically. We speculate that changed climatic condition in the mid-Pliocene, and possibly the arrival of Homo soon after, may have precipitated the regional extinction of large hominoids in southern China and in mainland southeast Asia.