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

Abstract

The timing and geographic origin of the common ancestor of modern humans and Neandertals remain controversial. A poor Pleistocene hominin fossil record and the evolutionary complexities introduced by dispersals and regionalisation of lineages have fuelled taxonomic uncertainty, while new ancient genomic data have raised completely new questions. Here, we use maximum likelihood and 3D geometric morphometric methods to predict possible morphologies of the last common ancestor of modern humans and Neandertals from a simplified, fully resolved phylogeny. We describe the fully rendered 3D shapes of the predicted ancestors of humans and Neandertals, and assess their similarity to individual fossils or populations of fossils of Pleistocene age. Our results support models of an Afro-European ancestral population in the Middle Pleistocene (Homo heidelbergensis sensu lato) and further predict an African origin for this ancestral population.

Homology, homoplasy and cusp variability at the enamel–dentine junction of hominoid molars

“…The occasional presence of this trait in Pleistocene and, to a lesser extent, recent H. sapiens , also suggests that this taxon likely inherited the developmental predisposition for PPT from its LCA with H. neanderthalensis . This is supported by a recent 3D cranial reconstruction of the hypothetical LCA of H. neanderthalensis and H. sapiens by Mounier & Lahr (), who suggested that this LCA was more similar to H. neanderthalensis . Under this scenario, the presence of PPT in H. sapiens may have been gradually lost through genetic drift and periods of drastic demographic change.…”

The origin and evolution ofHomo sapiens

“…A new study using geometric morphometrics of various crania to virtually reconstruct the LCA of Neanderthals and modern humans also found that an Afro-European species (H. heidelbergensis s.l.) most closely approached the hypothetically reconstructed LCA, with the added suggestion that the LCA most likely lived in Africa [28]. An alternative model has a much older proposed LCA for the neanderthalensis and sapiens lineages, based on the 'modern' maxillary conformation of the ATD6-69 H. antecessor face from Gran Dolina, Atapuerca, dated approximately 850 ka [29].…”

Twentieth anniversary of Homo antecessor (1997‐2017): a review

“…In a pure “cladistic” approach, it is not possible to find the taxa that correspond to the ancestral nodes of a cladogram. Instead, this approach finds the taxa that are closer to it and later tests whether the morphological and chronological information is consistent with this possibility . The other key issue is that Gómez‐Robles et al have concluded that no known hominin matches the expected morphology of the LCA because there is incongruence between the fossil and the molecular data.…”

“…In particular, it would be desirable to obtain more complete cranial remains of adults in future field seasons. Then we could compare H. antecessor with real fossils and with virtual models, which try to predict the cranial morphology of the LCA of Neandertals and modern humans …”