title: No known hominin species matches the expected dental morphology of the last common ancestor of Neanderthals and modern humans.
abstract: 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.
authors.affiliation: Department of Anthropology, The George Washington University, Washington, DC 20052.
authors.forename: Aida
authors.initials: A
authors.lastname: Gómez-Robles
authors.forename: José María
authors.initials: JM
authors.lastname: Bermúdez de Castro
authors.forename: Juan-Luis
authors.initials: JL
authors.lastname: Arsuaga
authors.forename: Eudald
authors.initials: E
authors.lastname: Carbonell
authors.forename: P David
authors.initials: PD
authors.lastname: Polly
mesh_terms: D000818:Animals; D005075:Biological Evolution; D005580:Fossils; D015186:Hominidae / Q000033:anatomy & histology*; D006801:Humans; D016014:Linear Models; D010802:Phylogeny; D013045:Species Specificity; D014070:Tooth / Q000033:anatomy & histology*
keywords: European Pleistocene; geometric morphometrics; morphospace; node reconstruction; phylogeny