Evolution: The tooth about human face evolution

An analysis of dental enamel from Homo antecessor — an early hominin species — suggests that it was closely related to the last common ancestor of Homo sapiens, Neanderthals and Denisovans. This placement of H. antecessor in hominin evolution implies that the modern-like facial features seen in this species have deep roots in the ancestry of the genus Homo. These findings are published in Nature this week.

The relationship between Early Pleistocene (approximately 2.5 to 0.77 million years ago) hominin species, such as H. antecessor, and later hominins is debated. Owing to some of the modern-like features of the face of H. antecessor, it has been proposed that it could be the last common ancestor of Neanderthals and modern humans. However, the fragmentary nature of the fossil record and the failure to recover ancient DNA from Early and Middle Pleistocene hominins in Eurasia means that this issue remains unresolved.

Frido Welker, Enrico Cappellini and colleagues obtained sets of proteins from the dental enamel of molars of H. antecessor from Atapuerca, Spain (dated to 949,000–772,000 years ago) and Homo erectus from Dmanisi, Georgia (approximately 1.77 million years old). By conducting a phylogenetic analysis based on the ancient protein sequences obtained from H. antecessor, they determined that it is a closely-related sister lineage to subsequent Middle and Late Pleistocene hominins such as modern humans. Based on their findings, the authors suggest that the shape of the Neanderthal cranium represents a derived, rather than primitive, form.

The results provide new insights into the evolutionary relationships of H. antecessor to other hominin groups.