At Bianfu Cave in southwestern China, researchers found 4 teeth, two skull fragments and the first known forearm bone belonging to Denisovans. Qiaomei Fu of the Chinese Academy of Sciences and her team were unable to detect ancient DNA in the remains among 60 thousand mammal bones; however, amino acid variants showed that the specimens belonged to Denisovans. The findings were announced in two papers published in Nature on 9 September.
The approximately 4.5-centimeter bone was part of the radius. Analyses revealed that the attachment point of the biceps muscle was farther back than in modern humans and that Denisovans could generate more force when bending their arms with their palms facing upward.
More than 1300 stone tools were also found in the cave. The bones were dated to between 167 thousand and 134 thousand years ago, while the tools were dated to between 190 thousand and 70 thousand years ago. The tools were described as not complex and as having been produced flexibly without spending much time on them. Denisovans are thought to have hunted large animals such as buffalo, gaur, red deer and sika deer.
The findings show that this group lived far beyond the northern regions and may have encountered modern humans farther south than previously thought. Scientists believe they lived alone in the cave for a long time. Denisovans are thought to have emerged at least 200 thousand years ago and disappeared approximately 30 thousand years ago.
Why it matters
The fossils expand the framework for the group’s habitat by extending the known geographic distribution of Denisovans beyond the northern regions. Although ancient DNA could not be recovered, identification based on amino acid variants shows that specimens in which genetic material has not been preserved can also be evaluated in research on human evolution. Examining the muscle attachment on the forearm bone together with the tools and animal remains in the cave allows for a more comprehensive picture not only of the Denisovans’ identity, but also of their mobility, production methods and subsistence practices. However, it remains unclear whether the relationship between the assessment that they lived alone in the cave for a long time and the possibility that they may have encountered modern humans farther south can be directly demonstrated.