The origin of
The origin of anatomically and genetically modern humans (
This paper aims at investigating such a new frontier for paleoanthropology. It will focus on topology, chronology, tempo, and mode of the main evolutionary nodes before the appearance of
When considering all the available data, we are confronted with a comprehensive scenario about the deep roots of our species. At the same time, it becomes possible to approach the issue from regional and/or local perspectives [
Views about the origin of our own species greatly changed during the last couple of decades, involving our interpretation of the evolution of the genus
According to this view, successive stages and/or regional variants were implied within a widespread archaic species—
The theory called “multiregional evolution” is a good example of this view. It is well known that according to the model introduced by Wolpoff and colleagues [
To a large extent, this view has now been abandoned, after a debate that lasted for more than two decades [
Evolutionary tree of the genus
One of the consequences of the middle-century paradigm on the interpretation of the fossil record was that a single species,
However, an increasing number of data—including the evidence coming from the Georgian site of Dmanisi [
Within this new approach,
Although the identification of all these different species clearly implies an overestimation of interspecific diversity—that in many cases was more probably intraspecific (see below)—this plethora of nomina is in accordance with a scenario that foresees the geometry of an “adaptive radiation,” describing the generation from a common stem of a great variability, in space as well as in time. Moreover, this confers a clearer, more intelligible significance to human varieties that were formerly hidden, being referred either to
Looking at Europe, the relatively best known regional example, at least two distinct waves of immigrants seem to be recognizable between the late Early and the early Middle Pleistocene. In terms of fossil record, the former wave is documented at present only in Spain and is referred to
Seemingly, the latter possible dispersal into Europe was more recent than 700–600 ka and related to morphologically derived hominids, with clear signs of further encephalization, which are well known from a number of sites. The most notable assemblage of fossil material is again in the Sierra de Atapuerca [
Moving to Africa, it has been shown [
More in general, late
To sum up, at present, the chronology, topology, and phylogenetic dynamics related to the geographically dispersed and rather synchronous appearance of Middle Pleistocene humans—or
A possible answer comes from the results recently obtained with the analysis of the complete mitochondrial DNA (mtDNA) sequence retrieved from the isolated human phalanx of the Denisova cave in the Altai mountains, southern Siberia. In the context of episodic occupations of this site in the Late Pleistocene, the layer where the phalanx was found has been dated to 48–30 ka, in association with an archaeological assemblage including both Middle and Upper Palaeolithic elements. The mtDNA evidence surprisingly points to humans that were different from both
Researchers opted to wait for their data to provide a clearer picture of the relationship with Neanderthals and modern humans before giving the hypothetical unknown species a formal name. Nevertheless, it is already possible to speculate that the Denisova hominins were in relation with the “non-
Further analyses on the Denisova material—including exceptionally preserved nuclear DNA from the phalanx and the discovery of an upper molar—drove the same group of researchers to publish additional data [
Evolutionary tree of
Paleogenetic data also indicate that trajectories of human evolution leading in Europe to the Neanderthals and in Africa to modern humans coalesced around 500 ka [
At present, there is a general consensus in assuming that humans spread towards western Europe during the late Early Pleistocene, probably earlier than 1,200 ka. This is demonstrated by recent findings in Spain [
Less than 20 years ago, at the beginning of the 1990s, the available data were not so clear, and a model of “short chronology” for the earliest inhabitants of Europe was put forward [
One year after the discovery at Boxgrove, hard evidence from Italy (Ceprano, March 1994) and Spain (Atapuerca TD6, July 1994) chronologically referred to more than 700–800 ka [
The Italian specimen was discovered in several fragments in a field known as Campogrande, near the town of Ceprano, in southern Lazio, less than 100 km south-east of Rome. Its discovery represents the result of systematic field activities conducted for decades in southern Lazio by the Italian Institute of Human Palaeontology (under the supervision of the Soprintendenza Archeologica del Lazio), and particularly by I. Biddittu. On March 13th 1994, Biddittu found a first cranial fragment during a survey along the trench excavated for a new road while other portions of the same cranium were still included in the nearby section created by the excavators. Subsequently, all the fragments (about fifty) were carefully extracted and sieved from the clayey sediments. The reconstruction of the cranium required more than one attempt, the intervention of a composite team, and, overall, about five years [
For the purpose of a chronological reference, the geologist A. G. Segre [
With these premises, a project of surveys and excavations started in 2001 under the direction of I. Biddittu and G. Manzi, with a threefold aim: (1) a better comprehension of the Pleistocene stratigraphy of the Ceprano basin; (2) validation of the geochronological model set by A.G. Segre; (3) improvement of the palaeontological and archaeological records. After ten years, the results obtained through a multidisciplinary approach—including stratigraphic and palynological data, combined with sedimentology, geochemistry, soil-micromorphology, taphonomy, and the archaeological evidence—showed that the Ceprano calvarium is more recent than previously believed, pointing at a time range close to about 400 ka and, more precisely, to the interval at the beginning of marine isotopic stage (MIS) 11 bracketed between 430 and 385 ka [
These unexpected results and the consequent new chronology of the fossil specimen in the mid of the Middle Pleistocene led Manzi and colleagues [
This also calls for a taxonomic re-evaluation of the Italian specimen. Originally, Ceprano was attributed to “late
On the whole, these researches largely support conclusions preliminarily reached by Manzi and colleagues [
Viewed in a wide paleoecological scenario, the earliest dispersal of human groups towards the western Mediterranean regions was likely part of the progressive faunal renewal that involved the diffusion of some large mammals of African and Asian origin during the Early Pleistocene [
The unique hominin hard evidence in Europe for this time period is represented so far at Atapuerca TE9 and TD6, but the presence of human populations is documented by a number of Mode 1 archaeological sites. It is possible that diffusion waves, presumably scattered in time and space, led to the arrival of archaic humans in western Eurasia until MIS 16, one of the worst glaciations of the last million years, with an ice sheet extension below 50° latitude in Eastern Europe [
The exact origin of these humans is still not clear, though it may be assumed that they ultimately emerged from Africa [
Subsequently, the observed pattern of evolution in Europe during the Middle Pleistocene is consistent with a long period of isolation for humans north of the Mediterranean Sea, which seems to be supported on both morphological and genetic grounds [
On the other hand, however, more recent evidence on the European fossil record of the Middle Pleistocene hardly supports the hypothesis of a linear and gradual process of change [
It is reasonable that something similar—although not identical—happened with the locally evolving populations of late
In this paper, we dealt with arguments concerning the evolution of the genus
As stated in the introduction, the aim was to investigate a new frontier for paleoanthropology. This is represented in my view by the discovery of the deep roots for the origin of modern humans in the Early and Middle Pleistocene, respectively, when the common ancestor of both
I also observed that something that was crucial for the evolution of the genus
Thus, when connecting all the elements described in this brief overview on the Early-to-Middle Pleistocene fossil evidence preceding the emergence of
These and other arguments (compare Section
In conclusion, it seems to me that the time is ripe to introduce a trinomial nomenclature for this species. Furthermore, as stated for instance by Mayr [
My proposal is to consider the single widespread species that was ancestral to both Neanderthals and modern humans (and the “Denisovans” [
The contribution of various people and institutions involved in field activities and researches in the Ceprano basin—with special reference to the