No abstract

Homo naledi is a previously-unknown species of extinct hominin discovered within the Dinaledi Chamber of the Rising Star cave system, Cradle of Humankind, South Africa. This species is characterized by body mass and stature similar to small-bodied human populations but a small endocranial volume similar to australopiths. Cranial morphology of H. naledi is unique, but most similar to early Homo species including Homo erectus, Homo habilis or Homo rudolfensis. While primitive, the dentition is generally small and simple in occlusal morphology. H. naledi has humanlike manipulatory adaptations of the hand and wrist. It also exhibits a humanlike foot and lower limb. These humanlike aspects are contrasted in the postcrania with a more primitive or australopith-like trunk, shoulder, pelvis and proximal femur. Representing at least 15 individuals with most skeletal elements repeated multiple times, this is the largest assemblage of a single species of hominins yet discovered in Africa.

Denisovans are members of a hominin group only known from fragmentary fossils genomically studied from a single site, Denisova Cave 1-3 in Siberia, and from their genetic legacy through gene flow into several low-altitude East Asian populations 4,5 and high-altitude modern Tibetans 6 . The lack of morphologically informative Denisovan fossils impedes our ability to connect geographically and temporally dispersed Asian fossil hominins and understand their relation to these recent populations in a coherent manner, including the Denisovan-inherited human adaptation to the high-altitude Tibetan Plateau 7,8 . Here we report a Denisovan mandible, identified by ancient protein analysis 9,10 , found in Baishiya Karst Cave, Xiahe County, Gansu Province (China), on the Tibetan Plateau. We determine the mandible to be at least 160 thousand years old through U-series dating of an adhering carbonate matrix. It is the first direct evidence of this hominin group outside the Altai Mountains, and provides unique insights into Denisovan mandibular and dental morphology. Our results indicate that archaic hominins occupied the Tibetan Plateau in the Middle Pleistocene and successfully adapted to high-altitude hypoxia environments much earlier than the regional arrival of modern Homo sapiens.