Neanderthals and Denisovans

During the Middle Pleistocene (780,000 to 128,000 BC), new hominin forms appeared. They can be distinguished from the preceding Homo erectus by the increasing size of their brains and the rearrangement of their craniums. This phenomenon of brain enlargement seems to appear independently in several lineages, in Africa, Europe and Asia, no doubt as a result of similar selection pressures. In Eurasia, two sister groups with a common ancestor developed: Neanderthals in the western part of the continent and Denisovans in the eastern part. The demography and geographic distribution of these two groups were profoundly affected by the far-reaching environmental changes that took place throughout their evolution. Neanderthals are the best represented in the fossil record. Numerous archaeological sites discovered in Europe since the ^{mid-nineteenth} century have enabled us to analyze their material culture and their way of exploiting the environment. The advances in paleogenetics that have revolutionized our knowledge are making it possible to specify the phylogeny and demography of these forms. They highlight their genetic heritage within modern populations.