Définition du taxon Homo heidelbergensis Schoetensack, 1908 : analyse phénétique du massif facial supérieur des fossiles du genre Homo du Pléistocène moyen

Abstract

Parution en ligne, article non paginé.La découverte de nouveaux fossiles au Pléistocène moyen a entraîné la reconsidération de l'espèce Homo heidelbergensis. La morphologie particulière de la mandibule de Mauer (holotype) et l'inclusion de nombreux fossiles ne présentant pas de mandibule dans le taxon ne permettent pas l'émergence d'un consensus. L'espèce est considérée comme un taxon afro-européen ancêtre des Homo sapiens et des H. neanderthalensis ou comme un taxon européen ancêtre des Néandertaliens. La validité de l'espèce est souvent contestée, et la diagnose de 1908 ne permet pas l'attribution de nouveaux spécimens au taxon. Nous testons la validité d'H. heidelbergensis grâce à une approche phénétique menée sur le massif facial supérieur de 27 fossiles et 94 Hommes de l'Holocène. Trente-trois caractères morphologiques codés sont analysés pour obtenir des groupes de spécimens et quantifier leur description par des caractères morphologiques statistiquement significatifs. Les résultats soutiennent l'existence d'une espèce valide, distincte des autres taxons du genre Homo et définie par une liste de caractères sur le massif facial supérieur. Ce taxon inclut des fossiles africains et européens du Pléistocène moyen et pourrait représenter l'espèce ancestrale d'H. neanderthalensis et d'H. sapiens. La mandibule de Mauer peut être intégrée à l'hypodigme de ce taxon, H. heidelbergensis est donc le nomen approprié pour le désigner. Nous proposons une liste de traits morphologiques diagnostiques sur le massif facial supérieur. Pou

Virtual ancestor reconstruction: Revealing the ancestor of modern humans and Neandertals

“…The morphological similarities between the African MP fossils Jebel Irhoud 1, Ndutu and Florisbad and modern humans has been suggested before (Clarke, 1990;Hublin, 2001;Bräuer, 2008;Mounier, 2009) and are thus not surprising. While more controversial for the Asian fossils Dali and Jinniu Shan, such affinities have also been noted before (Mounier, 2009(Mounier, , 2011Pope, 1992). The other specimens Arago 21, Atapuerca SH5 and Petralona are linked to the Neandertals, which is consistent with the presence of features considered Neandertal apomorphies among the MP European fossil record (Condemi, 1989;Dean et al, 1998).…”

“…3D and Appendix B): in norma lateralis the vault is low and elongated, the zygomatic is slightly curved backward with a tuberculum marginale, the external auditory meatus shows an intermediate position in relation to the zygomatic process and the mastoids are weakly-developed; the frontal shows a well-developed supraorbital region with associated well-developed sinuses; the occipital has a slight occipital bun, it is rounded in norma occipitalis, presents an incipient supra-iniac fossa and the maximum width of the calvarium is at the supramastoid crest; the upper face is long and projecting, the maxilla is not pneumatised as observed in Neandertals (Maureille, 1994), but its anterior surface shows the presence of a slight incurvatio horizontalis, sagittalis, and in norma facialis a weakly-marked incurvatio inframalaris frontalis is observed. The morphology of the 3 vLCAs' calvaria has been described in some MP specimens such as Kabwe and Petralona (Mounier, 2009), while aspects of the face (such as the incurvatio inframalaris frontalis) are reminiscent of the morphology of African and European MP fossils such as Kabwe, Bodo, Arago 21 and Petralona (Mounier, 2009(Mounier, , 2011.…”

“…600ka (Clark et al, 1994) -and the much more derived morphology of Jebel Irhoud 1 (Hublin, 2001;Mounier, 2011). This peculiar affinity pattern must be discussed within the framework of overall strong morphological similarity of vLCA3 with the Neandertals as shown by the mean and individual procrustes distances (Tables 3, 4, C.4 and C.5): both Jebel Irhoud 1 (Ennouchi, 1963) and Bodo (Mounier, 2012) have been described as presenting affinities with the Neandertals, even though they do not share apomorphies with H. neanderthalensis (Hublin, 1992;Mounier, 2011;Rightmire, 1996). On the contrary, the general morphological pattern of vLCA1 and vLCA2 seems more accurate within a framework of an Afro-European Middle Pleistocene population as the ancestor of modern humans and Neandertals (Mounier, 2009;Rightmire, 1998).…”

Before the Emergence ofHomo sapiens: Overview on the Early-to-Middle Pleistocene Fossil Record (with a Proposal aboutHomo heidelbergensisat the subspecific level)

“…Moreover, it should be added that the hypodigm of H. heidelbergensis shows a considerable amount of variability, in which regional features may be recognised [47, 69] while phenotypic variations are observed also locally such as within the European fossil record [49]. This supports the conclusion that Ceprano would document at present, better than other specimens, a possible ancestral stock of H. heidelbergensis , close in time [6] to the evolutionary divergence between Neanderthals and modern humans.…”

Long anterior mandibular tooth roots in Neanderthals are not the result of their large jaws

“…If Mauer is considered as a representative of the common ancestor between Neanderthals and recent modern humans (Mounier et al, 2009;Mounier, 2011; however see; Rosas and Bermúdez De Castro, 1998), and given the position of early modern human specimen Qafzeh 9 in the area of overlap of both taxa for all measured variables, long anterior tooth roots are probably the ancestral condition. This would suggest a negative allometry in root size in recent modern humans.…”