Le statut phylogénétique d’Homo heidelbergensis – étude cladistique des homininés du Pléistocène moyen

Abstract

Two views prevail concerning the significance of H. heidelbergensis in Middle Pleistocene human evolution. H. heidelbergensis sensu stricto refers to a European chronospecies of H. neanderthalensis while H. heidelbergensis sensu lato is considered to be an Afro-European species ancestral to modern humans and Neandertals. Here, we test the phylogenetic validity of H. heidelbergensis using a cladistic analysis based on cranial morphological data of Pleistocene fossils. We perform a low-level analysis to ascertain the information content of the morphological features, a high-level analysis with reweighted characters resulting in a single most parsimonious cladogram and a bootstrap analysis to assess the robustness of this cladogram. Our results show that (i) the identification of a coherent H. heidelbergensis s.l. species is not well supported and is equivocal; (ii) the hypothetical last common ancestor of H. sapiens and H. neanderthalensis has more affinities with African specimens than European; (iii) two Middle Pleistocene European fossils (Atapuerca SH5 and Steinheim) should be classified as H. neanderthalensis.