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

Abstract

The origin ofH. sapienshas deep roots, which include two crucial nodes: (1) the emergence and diffusion of the last common ancestor of laterHomo(in the Early Pleistocene) and (2) the tempo and mode of the appearance of distinct evolutionary lineages (in the Middle Pleistocene). The window between 1,000 and 500 thousand years before present appears of crucial importance, including the generation of a new and more encephalised kind of humanity, referred to by many authors asH. heidelbergensis. This species greatly diversified during the Middle Pleistocene up to the formation of new variants (i.e., incipient species) that, eventually, led to the allopatric speciation ofH. neanderthalensisandH. sapiens. The special case furnished by the calvarium found near Ceprano (Italy), dated to 430–385 ka, offers the opportunity to investigate this matter from an original perspective. It is proposed to separate the hypodigm of a single, widespread, and polymorphic human taxon of the Middle Pleistocene into distinct subspecies (i.e., incipient species). The ancestral one should beH. heidelbergensis, including specimens such as Ceprano and the mandible from Mauer.