Human remains from Zhirendong, South China, and modern human emergence in East Asia

Abstract

The 2007 discovery of fragmentary human remains (two molars and an anterior mandible) at Zhirendong (Zhiren Cave) in South China provides insight in the processes involved in the establishment of modern humans in eastern Eurasia. The human remains are securely dated by U-series on overlying flowstones and a rich associated faunal sample to the initial Late Pleistocene, >100 kya. As such, they are the oldest modern human fossils in East Asia and predate by >60,000 y the oldest previously known modern human remains in the region. The Zhiren 3 mandible in particular presents derived modern human anterior symphyseal morphology, with a projecting tuber symphyseos, distinct mental fossae, modest lateral tubercles, and a vertical symphysis; it is separate from any known late archaic human mandible. However, it also exhibits a lingual symphyseal morphology and corpus robustness that place it close to later Pleistocene archaic humans. The age and morphology of the Zhiren Cave human remains support a modern human emergence scenario for East Asia involving dispersal with assimilation or populational continuity with gene flow. It also places the Late Pleistocene Asian emergence of modern humans in a pre-Upper Paleolithic context and raises issues concerning the long-term Late Pleistocene coexistence of late archaic and early modern humans across Eurasia.

Fig. 1.

The human remains from Zhiren Cave. The Zhiren 3 mandible in anterior (A), lateral left (B), and superior (C) views. The midsymphyseal cross-section of the Zhiren 3 mandible (D). The Zhiren 1 M₃ in buccal and mesial views (E), and the Zhiren 2 M₃ in the same views (F). (Scale bar, 5 cm.)

Fig. 2.

The anterior (infradental-pogonion versus alveolar plane) symphyseal angle of Zhiren 3 versus comparative samples (A), and the anterior symphyseal profile of Zhiren 2 (stars) versus consensus profiles for the comparative samples (B). MidPl: Middle Pleistocene archaic humans; LatePl: Late Pleistocene archaic humans; SAfr: later Pleistocene sub-Saharan Africans; MPMH: Middle Pleistocene modern humans; EUP: earlier Upper Paleolithic modern humans. The sample sizes for the two comparisons, in left to right sample order, are: anterior angle: 14, 26, 4, 5, and 21; anterior profile: 13, 26, 4, 4, and 20.

Fig. 3.

The major axis symphyseal angle of Zhiren 3 versus comparative samples (A), and the symphyseal contour of Zhiren 2 (stars) versus consensus contours for the comparative samples (B). Sample abbreviations as in Fig. 2. The sample sizes for the two comparisons, from left to right, are: major axis angle: 13, 26, 4, 4, and 20; profile consensus: 13, 25, 4, 4, and 20.

Fig. 4.

(A) Residuals from the RMA line of the anteroposterior versus superoinferior second moments of area, and (B) residuals from the RMA line of the corpus breadth versus height at the mental foramen, for Zhiren 3 (ZR3) and comparative samples. Scatterplots of the original data are in SI Appendix, Figs. S10 and S11. Sample abbreviations as in Fig. 2. The sample sizes for the two comparisons, from left to right, are: symphyseal second moments: 13, 25, 4, 4, and 20; lateral corpus breadth versus height: 25, 31, 5, 6, and 23.