RICERCA ITALIANA     

Palaeoenviromental and Palaeobiogeographical context of the earliest dispersal of the genus Homo in Europe: evidences from Early Pleistocene in Italy

Università degli Studi di Roma "La Sapienza"

Abstract

Enviromentals changes occurred from the Late Pliocene to the Early Pleistocene had a strong impact on several taxa of terrestrial vertebrates. The study of such variations, confirmed by palaeobotanical and micromammal data, started to give a view for the different peninsula areas.
The integration of biocronological, magnetostratigraphical and radiometric data from Early Pleistocene sites of Italy could give a better knowledge of bioevent successions, that can be correlate to coevals Eurpean sites.
Moreover such reconstructions of the Early Pleistocene could help us to define the palaeoenviroment of the earliest human occupation of Europe; evidences actually are given by lithics manufacts dated one million years B.P. and, more recently, by the important human fossil from Ceprano.
This research point out the palaeoenviromental changes occurred between the Late Pliocene and the Early Pleistocene in the Late Villafranchian Mammal Age, in particular between Olivola/Tasso FU and Farneta/Pirro FU. Such reconstruntion is the "scenario" where the earliest occupation of Italy and Europe by genus Homo occurs, as testified by lithic manufacts recently found in the Pirro Nord site.
Moreover this research would define the possible mammal faunas' migration way from the Africa and Asia that occurred in the same time of the human migration. Sedimentological, biostatigraphical and radiocronological analyses will be the tools that allow us to define the chronological sequence of these bioevents. <<<

Principal Investigator

Carmelo Petronio Università degli Studi di ROMA "La Sapienza"

Research Objectives

This project concerns palaeontological and palaeoanthropological researches, under stratigraphic control, pointing to the definition of the palaeoenvironmental, palaeobiogeographic and palaeoclimatic settings which guided the earliest human spreading to the Italian peninsula and, as a whole, in southern Europe at the beginning of the Pleistocene. The starting point is determined by the new findings of lithic artefacts in the Pirro Nord site (1.7-1.3 My) of the Gargano area, Puglia region, which testify for an anticipated phase of human migration in Europe. This datum, at first glance displaced from the palaeogegraphic point of view in comparison with the well-assessed emergencies of the Spanish sites Fuente Nueva and Barranco Leon (1.2 My), is on the way of the Dmanisi site record in Georgia (1.8 My). It anticipates the first colonization in the Mediterranean area to the middle part of the Early Pleistocene, along migration pathways which still need to be clarified. Therefore the finalities of this research are manifold.
A first target consists in the stratigraphic-depositional framing of the fossil-bearing karst deposits at Pirro Nord, as well as the analysis of fossil vertebrate assemblages and the definition of functional characters of lithic artefacts, which constitute a singularity of relevant importance. For this purpose the researches are intended to provide general aspects on the vertebrate and plant assemblages which formed the continental ecosystems of Pirro Nord, within the frame of a previously assessed geological evolution of the Gargano area at the Pliocene-Pleistocene transition. Particular attention will be devoted to taphonomic analysis of the fossil-bearing deposits, with the purpose to ascertain the isochronism of the vertebrate assemblages, which form the so-called Pirro Nord Faunal Unit, with the associated lithic artefacts. Detailed palaeomagnetic studies will allow a more precise chronological framing of such deposits and, as a consequence, will provide a dating for human colonisation in southern Italy.
The second research target is the palaeobiological comparison and the biochronological correlation of the data obtained in Gargano with those of other Italian sites referable to the Lower Pleistocene. On the whole, information on terrestrial vertebrates and plants will allow definition of two aspects: the palaeoenvironmental, palaeoclimatic and palaeobiogeographic framework supporting the spreading of Pleistocene populations; the chronological rythm of palaeobiological substitution on the Italian country. In addition, we will direct attention to identify the compatible migration routes with particular reference to the vertebrate coenosis. In this respect, the Tremiti Islands may represent a palaeogeographic step very meaningful in the picture of an Early Pleistocene migration through Adriatic landscape, with higher importance for the human peopling of clear oriental origin.
A further aspect deals with the evolution of anthropic systems which is documented by two sets of human rests. From one hand, the products of lithic industry which during time, starting from those of Mode I of Pirro Nord and Cà Longa, lead to the rich materials of Isernia La Pineta, by the Monte Poggiolo documents. On the other hand, the cranial bone of Ceprano which gives information useful for the evaluation of ontogenetic models and their evolutionary meaning. The integration of palaeoanthropological studies with more definitely palaeontological analysis, starting from the data of Pirro Nord, does materialize in the integration of the technologic analysis of lithic materials and the palaeozoological and palaeobotanical analysis aimed to reconstruct the palaeoenvironment and the modus vivendi of the first human species occupying the Italian Peninsula, which is still undefinied among Homo heidelbergensis, H. ceprarensis and H. antecessor.
As a last point we single out the cultural impact of this project, whose relevance in terms of national and local interest is immediately apparent and will be concretized throughout the organization of scientific conferences (“The Mediterranean area in the context of the first human peupling in Eurasia”) and joint programs with local institutions, for example the Natural Sciences Museum of Foggia. The synergy between the acquisition of scientific knowledge and its application to the development of the territory is a successful strategy of an interdisciplinary research project. <<<

Timescale

24 months

National and international background

The global climate change that occurred at the end of Pliocene until the beginning of Pleistocene are related to different astronomical, geological and geographical factors. These changes strongly influenced the geographical distribution and the evolution of the terrestrial ecosystems, in particular in the Mediterranean region, and originated extinction, speciation and dispersal events.
Among the dispersals occurred between the Plio-Pleistocene transition and the early Middle Pleistocene, the first human occupation of Europe is of particular importance, with an increasing of evidence coming from Italy.
From the latest Pliocene to the Early Pleistocene the glacial-interglacial cycles alternating deeply influenced the distribution of vegetation and its composition; palaeobotanical assemblages including taxa indicating open environments and dry climatic conditions became very common, and the subtropical taxa, related to Pliocene warm and humid climate, from north to south progressively disappeared. In Central and Southern Italy the glacial-interglacial cycles are characterised by steppe-wood phases alternating; their floristic composition is related to the period and to the geographical area (Bertini, 2003).
The analysis of the most important Plio-Pleistocene Italian mammal faunas enabled the definition of turnover curves for genera and species. In particular, the analysis of the First Occurrences (FO) and Last Occurrences (LO) data show evident events of faunal changes respectively at approximately 1,8 and 0,8 Ma (Sardella et al., 1998; Azanza, et al., 2000; Azanza et al., 2004).
In the phases preceding the beginning of the Early Pleistocene (1,8 Ma) and Middle Pleistocene (c. 0,8 Ma) respectively, the climatic-environmental global changes caused the dispersal events of different mammal species that spread into Europe from Asia and Africa.
At the Plio-Pleistocene transition the canids Canis etruscus and Canis arnensis entered Italy from Asia, together with the Eurasian jaguar Panthera gombaszoegensis (Rook &amp; Torre, 1996; Sardella &amp; Palombo, 2006). On the other hand, the wild dog Lycaon falconeri, the giant short faced hyaena Pachycrocuta brevirostris, and the dirktoothed cat Megantereon whitei, together with the hippo Hippopotamus antiquus can be considered faunal element of African origin. The occurrence at the Early Pleistocene site of Pirro Nord (Apulia) of the African monkey Theropithecus sp. (Rook et al., 2004) is a further evidence of the dispersal event that took place between the end of the Pliocene and the beginning of the Middle Pleistocene. At the end of this period, at approximately 0,8 Ma, an important faunal renewal occurred, with the diffusion, among the others, of the cervids Praemegaceros and Cervus, of the primitive water buffalo “Bos” galerianus, and of canivores such as the spotted hyaena Crocuta crocuta, that ecologically replaced Pachycrocuta (Sardella, 2004).
The most important localities for the vertebrate fossil record in Italy are: Valdarno superiore, Bacino Tiberino, Capena, Pirro Nord, Colle Curti, Redicicoli, Ceprano, Ponte Galeria.
Besides Dmanisi (Georgia), the reference localities in Europe can be considered: Apollonia (Greece), Venta Micena, Fuente Nueva, Barranco Leon and Atapuerca (Spain), Le Vallonet (France), Untermassfeld (Germany).
The stratigraphic analyses carried on until now at the Pirro Nord site allowed to describe repeated phases of Plio-Pleistocene marine ingression and Pleistocene continentalization with karst development on the Cretaceous and Plio-Pleistocene substrate, leading to the formation of infiltrated fossil-bearing deposits. Palaeomagnetic and palaeontologic data (foraminifers and terrestrial vertebrates) permitted to frame such vertebrate assemblages to the middle-lower part of the Lower Pleistocene, 1.3 to 1.7 Ma in age (Napoleone et al., 2003).
From a biochronologic point of view the vertebrate assemblages, and particularly the mammal components, represent a reference association of the Italian and European late Villafranchian, and has been exploited to define the Pirro Faunal Unit (Gliozzi et al., 1997).
In a very recent study (Arzarello et al., 2006) all the available data have been summarised and the rich vertebrate faunal list is updated, but also the discovery of lithic artefacts, representing until now the earliest evidence of human occupation in the Early Pleistocene of Europe.
The first occurrence in Eurasia of the genus Homo after its dispersal from Eastern Africa can be placed in this paloaeoenvironmental context (Manzi, 2001). The occupation of very wide territories probably caused regional evolutionary trends, with different adaptative strategies and phyletic lineages (e.g., Manzi et al., 2000, 2003; Bruner et al. 2003, 2004).
The particular case-study of the earliest diffusion towards Europe and, more generally, across the Mediterranean regions has a crucial interest in this respect (e.g., Manzi, 2004). The earliest evidence of human presence in Mediterranean territories of Europe are nowadays referred to about 1,1-1,2 Ma, especially in Spain: either for deposits in the Orce basin (Granada) or for the inferior layers of the Sima del Elefante, (Sierra de Atapuerca, Burgos).
The relationship between man/environment/territory in this context, founds on the studies conducted for some important sites with lithic artefacts dating from the Lower Pleistocene and the initial phases of the Middle Pleistocene: Cà Belvedere di Monte Poggiolo (Peretto (edited by), 1992; Cremaschi &amp; Peretto, 1988), Quarto delle Cinfonare (Peretto et al., 1997) Isernia La Pineta (Coltorti et al, 1982; Crovetto et al., 1994; Peretto et al., 2004), Visogliano (Cattani et al., 1991), Castagnone (Giraudi et al., 2003), Ceprano.
Taking into account the fossil evidences, the cranium from Ceprano, clearly different from penecontemporaneous specimens of Eastern Africa (Manzi et al. 2003), has been indicated as a candidate to represent the adult form of the still hypothetical "last common ancestor" before the divergence of the evolutionary lineages recognised in Europe and in Africa during the Middle Pleistocene (Manzi et al. 2001). These, in turn, represents the evolutionary bases for the respective emergence of Homo neanderthalensis and Homo sapiens (anatomically modern humans). <<<