A recently completed analysis of a 2007 discovery of human remains in Zhirendong (Zhiren Cave), South China, has revealed that modern humans (the first true homo sapiens) emerged outside of Africa far earlier than was previously thought. In fact, 60, 000 years earlier!
The fossil finds were rather modest: two molars and one partial, anterior mandible (front jaw fragment). The team (Wu Liu et al), using an improved U-Series (uranium isotope) dating technique, as well as comparisons to nearby animal fossil samples, were able to date the fossil fragments to >100, 000 bp (before the present).
Post-excavation views of Zhirendong (Zhiren Cave):
The earliest date for all previous homo sapiens remains (in Eastern Asia) was about <40,000 bp (dating by radiocarbon method). No remains of anatomically modern humans had been found that pre-dated this mark, until now.
Over the past decades, two competing questions have emerged amongst anthropologists: did all modern humans emerge solely in Africa, followed by a wave of emigrations out of Africa (which over-took earlier waves)? Or, did modern humans emerge from archaic forms in more than one place, multi-regionally, throughout the Old World, including Eurasia?
An additional question amongst some anthropologists has been whether or not archaic forms of the genus homo (such as Neandertal; some have even suggested the more ancient Homo erectus) co-existed in the same regions with early modern humans (in Europe, these were the Cro-Magnon, or, European Early Modern Humans, EEMH). The question of interbreeding between EEMH and other species of Homo was hotly debated for many decades until the recent sequencing of the Neandertal genome, revealing genetic material in common (“hybridization”) with modern humans (but with key gene mutations at sites that control skeletal formation and hair pigment, amongst others).
The overlap in dating of these Zhiren Cave finds with the older ones indicates that these two forms of hominid co-existed for thousands of years. Giving further support to this scenario, analysis showed that the jaw bone and teeth possessed a mixture of modern and archaic homo characteristics. The mandible is claimed to be distinct from that of any late, archaic human mandible, and that its morphology and “corpus robustness” place it closer to the late Pleistocene archaic humans.
The Pleistocene epoch lasted from 2.5 million years ago up to the last glaciation, about 12, 000 year bp. It includes the Paleolithic (Old Stone Age) which ended at roughly the same time period. The Pleistocene was preceded by the Pliocene epoch. We currently live in the Holocene epoch.
Quoting from the paper’s abstract: “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.
The “assimilation” here may indicate interbreeding at some point.
This discovery of upper Paleolithic, modern human remains in East Asia indicates that modern human biology far-preceded the cultural (speaking, rituals, cave drawings) and technological innovations (hand axes, etc.) of the Stone Age. Further the find “raises issues concerning the long-term Late Pleistocene coexistence of late archaic and early modern humans across Eurasia.” (emphasis added)
The research (‘Human remains from Zhirendong, South China, and modern human emergence in East Asia‘) was published ahead of print on Oct. 25 in the online edition of the Proceedings of the National Academy of Sciences.
top photo: The original “Old man of Crô-Magnon”, Musée de l’Homme, Paris; 120; cc – by – sa 3.0
cave photos: supporting on-line material (PNAS paper), Liu et al.
dig diagram: supporting on-line material (PNAS paper), Liu et al.