The position of Neandertal and Homo erectus within the hominid clade based on craniodental morphology and whole mtDNA genomes.

Abstract

To evaluate the taxonomic position of the Neandertal and Homo erectus within the hominid clade, the variation among and within the hominid taxa was assessed based on the craniodental morphology and integrated with molecular analyses of the whole mtDNA genomes. Ordination and clustering of the Procrustes craniodental landmarks have showed a notable shape transformation from the earliest hominid species to the modern humans. Although levels of distinction between the analyzed taxa (Homo, Pan, Gorilla, and Pongo) are generally corresponding to probable expectations based on their taxonomic rank, few exceptions were found. Notably, the craniodental morphology of Homo erectus showed a greater dissimilarity to other Homo species, where it consistently overlapped or grouped with Pan species on all ordination plots and clustering. In addition, the direct link between European humans and Neandertals, which is well-characterized on all of the phylogenetic trees based on maximum parsimony and maximum likelihood methods, was not outlined in the morphologic-based clustering. Both morphological and molecular distances between Neandertal and modern humans were consistently greater than the distances among modern humans, however, the distances are still smaller than those between any two distinct species (so they are subspecies). The topology of the phylogenetic trees based on the whole mtDNA has shown a minor discrepancy with the results obtained from the craniodental morphologies.