New Late Pleistocene age for the Homo sapiens skeleton from Liujiang southern China

The emergence of Homo sapiens in Eastern Asia is a topic of significant research interest. However, well-preserved human fossils in secure, dateable contexts in this region are extremely rare, and often the subject of intense debate owing to stratigraphic and geochronological problems. Tongtianyan cave, in Liujiang District of Liuzhou City, southern China is one of the most important fossils finds of H. sapiens, though its age has been debated, with chronometric dates ranging from the late Middle Pleistocene to the early Late Pleistocene. Here we provide new age estimates and revised provenience information for the Liujiang human fossils, which represent one of the most complete fossil skeletons of H. sapiens in China. U-series dating on the human fossils and radiocarbon and optically stimulated luminescence dating on the fossil-bearing sediments provided ages ranging from ~33,000 to 23,000 years ago (ka). The revised age estimates correspond with the dates of other human fossils in northern China, at Tianyuan Cave (~40.8-38.1 ka) and Zhoukoudian Upper Cave (39.0-36.3 ka), indicating the geographically widespread presence of H. sapiens across Eastern Asia in the Late Pleistocene, which is significant for better understanding human dispersals and adaptations in the region.

Early presence of Homo sapiens in Southeast Asia by 86-68 kyr at Tam Pà Ling, Northern Laos

The timing of the first arrival of Homo sapiens in East Asia from Africa and the degree to which they interbred with or replaced local archaic populations is controversial. Previous discoveries from Tam Pà Ling cave (Laos) identified H. sapiens in Southeast Asia by at least 46 kyr. We report on a recently discovered frontal bone (TPL 6) and tibial fragment (TPL 7) found in the deepest layers of TPL. Bayesian modeling of luminescence dating of sediments and U-series and combined U-series-ESR dating of mammalian teeth reveals a depositional sequence spanning ~86 kyr. TPL 6 confirms the presence of H. sapiens by 70 ± 3 kyr, and TPL 7 extends this range to 77 ± 9 kyr, supporting an early dispersal of H. sapiens into Southeast Asia. Geometric morphometric analyses of TPL 6 suggest descent from a gracile immigrant population rather than evolution from or admixture with local archaic populations.

The influence of climate and population structure on East Asian skeletal morphology

Recent studies have shown that global variation in body proportions is more complex than previously thought as some traits formerly associated with climate adaptation are better explained by geographic proximity and neutral evolutionary forces. While the recent incorporation of quantitative genetic methodologies has improved understanding of patterns related to climate in Africa, Europe, and the Americas, Asia remains underrepresented in recent and historic studies of body form. As ecogeographic studies tend to focus on male morphology, potential sex differences in features influenced by climate remain largely unexplored. Skeletal measurements encompassing the dimensions of the skull, pelvis, limbs, hands, and feet were collected from male (n = 459) and female (n = 442) remains curated in 13 collections across seven countries in East Asia (n = 901). Osteological data were analyzed with sex and minimum temperature as covariates adjusted by autosomal single-nucleotide polymorphism population genetic distance using univariate Bayesian linear mixed models, and credible intervals were calculated for each trait. Analysis supports a relationship between specific traits and climate as well as providing the magnitude of response in both sexes. After accounting for genetic distance between populations, greater association between climate and morphology was found in postcranial traits, with the relationship between climate and the skull limited primarily to breadth measurements. Larger body size is associated with colder climates with most measurements increasing with decreased temperature. The same traits were not always associated with climate for males and females nor correlated with the same intensity for both sexes. The varied directional association with climate for different regions of the skeleton and between the sexes underscores the necessity of future ecogeographic research to holistically evaluate body form and to look for sex-specific patterns to better understand population responses to environmental stresses.

Modern human teeth unearthed from below the ∼128,000-year-old level at Punung, Java: A case highlighting the problem of recent intrusion in cave sediments

The emergence of modern humans in the eastern edge of the Eurasian Continent is debated between two major models: early (∼130-70 ka) and late (∼50 ka) dispersal models. The former view is grounded mainly on the claims that several cave sites in Southeast Asia and southern China yielded modern human fossils of those early ages, but such reports have been disputed for the lack of direct dating of the human remains and insufficient documentation of stratigraphy and taphonomy. By tracing possible burial process and conducting direct dating for an early Late Pleistocene paleontological site of Punung III, East Java, we here report a case that demonstrates how unexpected intrusion of recent human remains into older stratigraphic levels could occur in cave sediments. This further highlights the need of direct dating and taphonomic assessment before accepting either model. We also emphasize that the state of fossilization of bones and teeth is a useful guide for initial screening of recent intrusion and should be reported particularly when direct dating is unavailable. Additionally, we provide a revised stratigraphy and faunal list of Punung III, a key site that defines the tropical rainforest Punung Fauna during the early Late Pleistocene of the region.

Trophic ecology of a Late Pleistocene early modern human from tropical Southeast Asia inferred from zinc isotopes

Tam Pà Ling, a cave site in northeastern Laos, has yielded the earliest skeletal evidence of Homo sapiens in mainland Southeast Asia. The reliance of Pleistocene humans in rainforest settings on plant or animal resources is still largely unstudied, mainly due to poor collagen preservation in fossils from tropical environments precluding stable nitrogen isotope analysis, the classical trophic level proxy. However, isotopic ratios of zinc (Zn) in bioapatite constitute a promising proxy to infer trophic and dietary information from fossil vertebrates, even under adverse tropical taphonomic conditions. Here, we analyzed the zinc isotope composition (⁶⁶Zn/⁶⁴Zn expressed as δ⁶⁶Zn value) in the enamel of two teeth of the Late Pleistocene (63-46 ka) H. sapiens individual (TPL1) from Tam Pà Ling, as well as 76 mammal teeth from the same site and the nearby Nam Lot cave. The human individual exhibits relatively low enamel δ⁶⁶Zn values (+0.24‰) consistent with an omnivorous diet, suggesting a dietary reliance on both plant and animal matter. These findings offer direct evidence of the broad utilization of resources from tropical rainforests by one of the earliest known anatomically modern humans in Southeast Asia.

Extensive Ethnolinguistic Diversity in Vietnam Reflects Multiple Sources of Genetic Diversity

Vietnam features extensive ethnolinguistic diversity and occupies a key position in Mainland Southeast Asia. Yet, the genetic diversity of Vietnam remains relatively unexplored, especially with genome-wide data, because previous studies have focused mainly on the majority Kinh group. Here, we analyze newly generated genome-wide single-nucleotide polymorphism data for the Kinh and 21 additional ethnic groups in Vietnam, encompassing all five major language families in Mainland Southeast Asia. In addition to analyzing the allele and haplotype sharing within the Vietnamese groups, we incorporate published data from both nearby modern populations and ancient samples for comparison. In contrast to previous studies that suggested a largely indigenous origin for Vietnamese genetic diversity, we find that Vietnamese ethnolinguistic groups harbor multiple sources of genetic diversity that likely reflect different sources for the ancestry associated with each language family. However, linguistic diversity does not completely match genetic diversity: There have been extensive interactions between the Hmong-Mien and Tai-Kadai groups; different Austro-Asiatic groups show different affinities with other ethnolinguistic groups; and we identified a likely case of cultural diffusion in which some Austro-Asiatic groups shifted to Austronesian languages during the past 2,500 years. Overall, our results highlight the importance of genome-wide data from dense sampling of ethnolinguistic groups in providing new insights into the genetic diversity and history of an ethnolinguistically diverse region, such as Vietnam.

The paternal and maternal genetic history of Vietnamese populations

Vietnam exhibits great cultural and linguistic diversity, yet the genetic history of Vietnamese populations remains poorly understood. Previous studies focused mostly on the majority Kinh group, and thus the genetic diversity of the many other groups has not yet been investigated. Here we analyze complete mtDNA genome sequences and ~2.3 Mb sequences of the male-specific portion of the Y chromosome from the Kinh and 16 minority populations, encompassing all five language families present in Vietnam. We find highly variable levels of diversity within and between groups that do not correlate with either geography or language family. In particular, the Mang and Sila have undergone recent, independent bottlenecks, while the majority group, Kinh, exhibits low levels of differentiation with other groups. The two Austronesian-speaking groups, Giarai and Ede, show a potential impact of matrilocality on their patterns of variation. Overall, we find that isolation, coupled with limited contact involving some groups, has been the major factor influencing the genetic structure of Vietnamese populations, and that there is substantial genetic diversity that is not represented by the Kinh.

When did Homo sapiens first reach Southeast Asia and Sahul?

Anatomically modern humans (Homo sapiens, AMH) began spreading across Eurasia from Africa and adjacent Southwest Asia about 50,000-55,000 years ago (ca 50-55 ka). Some have argued that human genetic, fossil, and archaeological data indicate one or more prior dispersals, possibly as early as 120 ka. A recently reported age estimate of 65 ka for Madjedbebe, an archaeological site in northern Sahul (Pleistocene Australia-New Guinea), if correct, offers what might be the strongest support yet presented for a pre-55-ka African AMH exodus. We review evidence for AMH arrival on an arc spanning South China through Sahul and then evaluate data from Madjedbebe. We find that an age estimate of >50 ka for this site is unlikely to be valid. While AMH may have moved far beyond Africa well before 50-55 ka, data from the region of interest offered in support of this idea are not compelling.

The prehistoric peopling of Southeast Asia

The human occupation history of Southeast Asia (SEA) remains heavily debated. Current evidence suggests that SEA was occupied by Hòabìnhian hunter-gatherers until ~4000 years ago, when farming economies developed and expanded, restricting foraging groups to remote habitats. Some argue that agricultural development was indigenous; others favor the “two-layer” hypothesis that posits a southward expansion of farmers giving rise to present-day Southeast Asian genetic diversity. By sequencing 26 ancient human genomes (25 from SEA, 1 Japanese Jōmon), we show that neither interpretation fits the complexity of Southeast Asian history: Both Hòabìnhian hunter-gatherers and East Asian farmers contributed to current Southeast Asian diversity, with further migrations affecting island SEA and Vietnam. Our results help resolve one of the long-standing controversies in Southeast Asian prehistory.

Homo sapiens in Arabia by 85,000 years ago

Understanding the timing and character of the expansion of Homo sapiens out of Africa is critical for inferring the colonization and admixture processes that underpin global population history. It has been argued that dispersal out of Africa had an early phase, particularly ~130-90 thousand years ago (ka), that reached only the East Mediterranean Levant, and a later phase, ~60-50 ka, that extended across the diverse environments of Eurasia to Sahul. However, recent findings from East Asia and Sahul challenge this model. Here we show that H. sapiens was in the Arabian Peninsula before 85 ka. We describe the Al Wusta-1 (AW-1) intermediate phalanx from the site of Al Wusta in the Nefud desert, Saudi Arabia. AW-1 is the oldest directly dated fossil of our species outside Africa and the Levant. The palaeoenvironmental context of Al Wusta demonstrates that H. sapiens using Middle Palaeolithic stone tools dispersed into Arabia during a phase of increased precipitation driven by orbital forcing, in association with a primarily African fauna. A Bayesian model incorporating independent chronometric age estimates indicates a chronology for Al Wusta of ~95-86 ka, which we correlate with a humid episode in the later part of Marine Isotope Stage 5 known from various regional records. Al Wusta shows that early dispersals were more spatially and temporally extensive than previously thought. Early H. sapiens dispersals out of Africa were not limited to winter rainfall-fed Levantine Mediterranean woodlands immediately adjacent to Africa, but extended deep into the semi-arid grasslands of Arabia, facilitated by periods of enhanced monsoonal rainfall.