No known hominin species matches the expected dental morphology of the last common ancestor of Neanderthals and modern humans.

Bibliographic Collection: 
Publication Type: Journal Article
Authors: Gómez-Robles, Aida; Bermudez De Castro, Jose Maria; Arsuaga, Juan-Luis; Carbonell, Eudald; Polly, P David
Year of Publication: 2013
Journal: Proc Natl Acad Sci U S A
Volume: 110
Issue: 45
Pagination: 18196-201
Date Published: 2013 Nov 5
Publication Language: eng
ISSN: 1091-6490
Keywords: Animals, Biological Evolution, Fossils, Hominidae, Humans, Linear Models, Phylogeny, Species Specificity, Tooth

A central problem in paleoanthropology is the identity of the last common ancestor of Neanderthals and modern humans ([N-MH]LCA). Recently developed analytical techniques now allow this problem to be addressed using a probabilistic morphological framework. This study provides a quantitative reconstruction of the expected dental morphology of the [N-MH]LCA and an assessment of whether known fossil species are compatible with this ancestral position. We show that no known fossil species is a suitable candidate for being the [N-MH]LCA and that all late Early and Middle Pleistocene taxa from Europe have Neanderthal dental affinities, pointing to the existence of a European clade originated around 1 Ma. These results are incongruent with younger molecular divergence estimates and suggest at least one of the following must be true: (i) European fossils and the [N-MH]LCA selectively retained primitive dental traits; (ii) molecular estimates of the divergence between Neanderthals and modern humans are underestimated; or (iii) phenotypic divergence and speciation between both species were decoupled such that phenotypic differentiation, at least in dental morphology, predated speciation.

DOI: 10.1073/pnas.1302653110
Alternate Journal: Proc. Natl. Acad. Sci. U.S.A.