Review Article

Before the Emergence of Homo sapiens: Overview on the Early-to-Middle Pleistocene Fossil Record (with a Proposal about Homo heidelbergensis at the subspecific level)

Figure 2

Evolutionary tree of H. heidelbergensis distinguished in subspecies, as suggested in this paper: (1) H. h. heidelbergensis; (2) H. h. steinheimensis; (3) H. h. rhodesiensis; (4) H. h. daliensis. The main evolutionary trajectories (dashed-bold lines) and the maintenance of gene flow between populations of distinct lineages (GF) are in accordance with a combination of paleogenetic data reported by Krause and colleagues [42] and by Reich and colleagues [44]. According to this scenario, Ceprano would represent one of the latest representatives of the most archaic variant of H. heidelbergensis (1) whereas more derived subspecies, respectively, in Europe (2) and in Africa (3), led to the allopatric speciation of H. neanderthalensis and H. sapiens (both schematically represented in the graph by triangles). Eventually, H. h. daliensis (4) would include all the “non-erectus” archaic humans distributed in mainland Asia before the diffusion of H. sapiens. Localised interspecific hybridization between H. heidelbergensis or H. neanderthalensis versus H. sapiens is admitted by the model (according to [4446]). Penecontemporaneous human lineages and/or species—such as H. erectus and H. floresiensis (compare Figure 1)—are not represented in this diagram.
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