Denisovans probably were once widely distributed in East Asia, and it also provides a valuable basis for Homo sapiens physical anthropological comparisons between Denisovans and the current known archaic found Homo sapiens in East Asia. Morphological similarities between the Xiahe mandible and archaic specimens in China, such as Penghu 1 and Xujiayao (Fig. 1a) [7], reveal that at least some of the Denisovan anatomical Homo sapiens features occurred in known archaic specimens in China, implying that some of them may have been Denisovans. Furthermore, the Xiahe mandible, as Denisovan with a 3-rooted lower molar (a specific characteristic commonly occurring in modern Asian populations (more than 40%) and in some Asian human fossils), implies substantial genetic contributions to modern Asian populations by Denisovans [11], consistent with previous genetic studies which traced different degrees of gene flows from Denisovans to modern Asian populations [3], [4], [5]. Therefore, the Xiahe mandible also provides important clues for addressing questions about the origins of Modern Humans in East Asia. In all, these three studies reveal several important details about the enigmatic Denisovans: that Denisovans could have been present in Asia since at least 160 ka or even 200 or 300 ka, during the Middle Pleistocene, co - Homo sapiens existing with Neanderthals in western Eurasia and with unknown species of archaic in eastern Eurasia, and that they persisted in parts of Asia until about 50 ka, contemporary with Modern Humans. There has been a large extension of the spatial distribution of the Denisovans in Asia - from Altai to the Tibetan Plateau - as a result of the discovery of the Xiahe Mandible. More excitingly, the faces of Denisovans are finally possible to be physically reconstructed (Fig. 1 d), aided by the Xiahe Mandible, ten years after the identification of this new human species. A study does paint a possible portrait of a female Denisovan based on skeletal traits derived from ancient DNA [12]. However, many questions about the Denisovans still remain or are emerging. Because of the complexity of cave sediments and the limits of each dating method applied, there are several uncertainties regarding the chronological framework of Denisova Cave as established by Jacobs et al. [6] and Douka et al. [8], especially for human remains beyond the limit of the radiocarbon dating method. Moreover, due to the long coexistence of different human groups and the fact that human remains are not present within each layer at Denisova Cave, it is very difficult to determine who produced the near 300-thousand year record of archaeological remains in the cave. Although Jacobs et al. [6] assert that the earliest human occupation in Denisova Cave may have been Denisovans, and Douka et al. [8] claim that the Denisovans may have produced the tooth pendants and bone points in Denisova Cave, hard evidence is needed to confirm these hypotheses. Moreover, for the Xiahe mandible, a direct stratigraphic and archaeological context is still lacking [7], while the current U-series age of the carbonate matrix outside the mandible only provides a minimum age for the fossil. The lack of success in extracting ancient DNA from the Xiahe mandible also makes it difficult to evaluate the relationship among Xiahe Denisovans, Siberian Denisovans, and even modern Tibetans. In addition, the available physical morphological and genetic data are still insufficient to clearly interpret the complex relationships between Homo sapiens Denisovans and other archaic in East Asia. Further excavations and studies in Baishiya Karst Cave, where the Xiahe mandible was discovered, are likely to provide further information about the Xiahe Denisovans. In addition, more Denisovan fossils may be discovered or identified in East Asia in the future, especially in China, given the availability of new technologies including ancient DNA and palaeoproteomic analysis, as well as via physical anthropological morphological comparisons with the Xiahe mandible. These studies will not only help to provide a more detailed portrait of the Denisovans, but they will also contribute substantially to our understanding of human evolution, especially of the origins of Modern Humans in East Asia. References [1] M. Meyer, M. Kircher, M. Gansauge, et al. A high-coverage genome sequence from an archaic Denisovan individual. Science, 338 (2012), pp. 222-226 [2] V. Slon, F. Mafessoni, B. Vernot, et al. The genome of the offspring of a Neanderthal mother and a Denisovan father. Nature, 560 (2018), pp. 417-418 [3] E. Huerta-Sánchez, X. Jin, B.Z. Asan, et al. Altitude adaptation in Tibetans caused by introgression of Denisovan-like DNA. Nature, 512 (2014), pp. 194-197 [4] S.R. Browning, B.L. Browning, Y. Zhou, et al. Analysis of human sequence data reveals two pulses of archaic Denisovan admixture. Cell, 173 (2018), pp. 53-61