Early Pleistocene Site Research Articles

The bears from Dmanisi and the first dispersal of early Homo out of Africa

We report on the taxonomy and paleodiet of the bear population that inhabited the emblematic palaeoanthropological Early Pleistocene (1.8 Ma) site of Dmanisi (Georgia), based on a dual approach combining morphometrics and microwear of upper and lower teeth. Given that the teeth of Ursus etruscus Cuvier, 1823 from Dmanisi show considerable size variability, their systematic position has been debated. However, a comparative study of the coefficients of variation for tooth size measurements in several modern bear species shows that the variability in tooth size of the ursid population from Dmanisi could result from sexual dimorphism. The analysis of tooth microwear indicates that these bears inhabited a mixed environment of open plain with forest patches, where they had a browsing diet with a substantial contribution of meat and/or fish. Comparative tooth morphometric analyses of modern ursids and fossil U. etruscus indicate that this extinct species had an omnivorous behavior similar to that of extant brown bears. The ecological interactions of the Dmanisi bears with other members of the large mammals community, including the first hominins that dispersed out of Africa, are discussed in the light of this new evidence.

An alternative scenario for the first human dispersal out of Africa

Recent paleoanthropological evidence from the early Pleistocene site of Dmanisi in Georgia has revealed that the first hominins out of Africa were more archaic than the coeval African Homo erectus. Therefore, anatomical or cultural innovations associated with the later species cannot be invoked as a cause for the first out of Africa. More evidence suggests that these archaic hominins were forest dwellers rather than savannah inhabitants. This is in agreement with their trophic role as passive scavengers. In contrast with open-dry savannah, passive scavenging is much easier and safer in forest, were carcasses can remain untouched for up two days. Moreover, forest-adapted sabertooths could have supply hominids with more carrion than modern savannah felids. Between 1.8 and 1.6 Ma a climate crisis caused a new spread of savannah and arid zones across large parts of Africa. As a consequence, early Homo populations splitted, with some populations becoming adapted to the new ecological conditions and others following woodland areas in their regression. For these last populations Southern Caucasus could have acted as a refugium area, with dominant forest conditions, still inhabited by sabertooths and with easy access to carcasses.

Inner structural organization of the mandibular corpus in the late Early Pleistocene human specimens Tighenif 1 and Tighenif 2

The present study investigates the inner structural organization of the two mandible specimens Tighenif 1 and Tighenif 2 from the late early Pleistocene site of Tighenif, Algeria. Using (micro)tomographic scans, we built a new protocol to investigate the cortical bone topography at the post-canine level. We selected two cross-sectional slices placed between the P3/P4 and M1/M2 on the right and left sides and assessed the cortical bone thickness topography (CBT) on each slice. Our analyses demonstrate that the mandibles from Tighenif exhibit higher CBT and a different topographic distribution pattern at the molar level than in modern humans, resulting in a proportionally more robust inner structure, while a similar signal is observed between the fossil and extant specimens at the premolar level. Further studies need to be done in order to determine if this feature is related to functional constraints during mastication or paramasticatory activities; or if it is related to any independent evolutionary process.

Site formation processes at Donggutuo: a major Early Pleistocene site in the Nihewan Basin, North China

ABSTRACTUnderstanding site formation processes is crucial for interpreting archaeological context patterns and hominin behaviour as these affect the preserved condition of a site and the integrity of archaeological remains. The fluvio‐lacustrine sequences in the Nihewan Basin of North China are rich sources of early Pleistocene archaeological sites, which offer an important opportunity to investigate human evolution and adapted behaviours in East Asia. Although many Palaeolithic sites have been reported from the Nihewan Basin, North China, few of them focus on site formation processes before interpreting the hominin behaviour patterns. Here, we present a site formation study of four archaeological layers (Layers 6D, 6C, 6B and 6A) in Trench 1 from the Donggutuo (namely DGT‐T1) site in the Nihewan Basin with an age of 1.1 Ma. Through the study of sedimentary contexts, spatial distributions of artefacts and fossils, intra‐assemblage category ratios, debitage size distributions, lithic abrasion, artifact orientation and planar dip, our results show that all the layers had been disturbed by low‐energy sheet wash across the lake shore setting, but to differing extents. The post‐depositional disturbance caused by water decreased from the lower to the upper layers, from Layer 6D to Layer 6A. This indicates that the archaeological remains in DGT‐T1 have not been subject to significant natural modifications and are thus suitable for studying early hominin behaviour in North China. Copyright © 2019 John Wiley & Sons, Ltd.

Mineral assemblages and low energy sedimentary processes in the FLK-Zinj, DS, PTK and AMK complex palaeolandscape (Olduvai Gorge, Tanzania)

The mineralogical composition of the clay stratum (level 22) that contains the FLK Zinj-DS-PTK-AMK complex, the only example of pene-contemporaneous early Pleistocene sites occurring on the same palaeolandscape and simultaneously covered by the same ash fall tuff, shows significant intra-site and inter-site differences. Overall, level 22A is related to a more hydrologically closed system, with higher salinity and alkalinity than level 22B. Both levels show fresher water was entering the system from the DS area during deposition. Textural analysis of the studied samples shows great microporosity and abundant edge-to-edge and edge-to-face contacts between crystals. These results have major repercussions for the interpretation of the archaeological assemblages in the FLK Zinj-DS-PTK-AMK palaeolandscape. First, this implies that two distinct archaeological levels formed at different times with different environmental conditions in most of these localities. Second, textural analyses provide evidence that no important sedimentary compaction took place after the deposition of this layer. This affects interpretations of palaeolandscape geomorphology. Third, it shows that the sedimentary processes during all the clay sequence occurred in very low-energy conditions. This reinforces that no significant physical forces disturbed the original configurations of materials contained within these assemblages and reinforces their autochthony. Behavioural interpretations can, thus, be more solidly built upon the conception that those sites preserve most of their original in situ properties.

Magnetostratigraphic and archaeological records at the Early Pleistocene site complex of Madigou (Nihewan Basin): Implications for human adaptations in North China

The Nihewan Basin in North China contains the densest concentration of early Pleistocene Paleolithic sites outside Africa. This paper introduces a new archaeological site complex at Madigou (MDG) that was systematically excavated from 2011 to 2014 in the northeastern part of the Nihewan Basin. The site contains fossils and well-preserved stone artefacts in fluvio-lacustrine sediments. Our magnetostratigraphic results situate the MDG sedimentary sequence in the early Brunhes normal chron and the late Matuyama reverse chron, including the Jaramillo normal subchron. The MDG artifact layers are positioned within the pre-Jaramillo Matuyama chron, with an estimated age of ca. 1.2 Ma, close to the onset of Mid-Pleistocene climate transition. The MDG core and flake technology includes bipolar flaking of siliceous dolomite cobbles, and freehand flaking of chert and brecciated chert block fragments. Mammalian fauna and pollen compositions indicate that the MDG hominins lived in an open habitat varying from lightly-wooded grassland to an ecosystem dominated by sparse steppe near the shore of the Nihewan paleolake. Our combined results in the fields of archaeology, paleontology, palynology and magnetochronology suggest that innovations in technological behavior may correlate with adaptations to high environmental variability during the start of Mid-Pleistocene climate transition.

Macaque remains from the early Pliocene of the Iberian Peninsula

Macaques dispersed out of Africa into Eurasia in the framework of a broader intercontinental faunal exchange that coincided in time with the sea level drop associated with the Messinian Salinity Crisis. They are first recorded in Europe (Italy and Spain) by the latest Miocene, being subsequently recorded all over Europe, albeit sparsely, throughout the Pliocene and Pleistocene. These fossil European macaques are attributed to several (sub)species of the extant Barbary macaque (Macaca sylvanus). In Iberia, fossil macaques are best documented by Macaca sylvanus florentina from various Early Pleistocene sites, whereas their published Pliocene record is very scarce. Here we report the oldest post-Messinian occurrence of macaques in the Iberian Peninsula, based on the description and metrical comparisons of two upper teeth (a male canine and a third molar of two different individuals) from the early Pliocene (MN14, 5.0–4.9 Ma) site of Puerto de la Cadena (Murcia, SE Spain). The male C1 is fully comparable in morphology with those of extant and fossil M. sylvanus, and larger than those of Mesopithecus. The M3, in turn, displays the typical papionin morphology that characterizes the dentally-conservative genus Macaca—thereby discounting an alternate assignment to either the extinct colobine monkey Mesopithecus or the more dentally-derived papionin Theropithecus. Dental size and proportions of the M3 further support an attribution to an extinct subspecies of M. sylvanus instead of the larger papionin Paradolichopithecus. Mostly on biochronologic grounds, the two macaque teeth from Puerto de la Cadena are here assigned to Macaca sylvanus cf. prisca, albeit tentatively, given the lack of clear-cut criteria to distinguish this subspecies from the younger Macaca sylvanus florentina. The described material represents the oldest well-dated Pliocene record of macaques in Iberia, predating the record of Paradolichopithecus by almost 1.5 million years.

Revising the species “Mustela” ardea Gervais, 1848–1852 (Mammalia, Mustelidae): Martellictis gen. nov. and the systematics of the fossil “Galictinae” of Eurasia

A number of recent genetic and systematic reviews have changed our knowledge of the taxonomy of Mustelidae. In particular, the subfamily Galictinae Reig, 1956 has been recently grouped in the subfamily Ictonychinae Pocock, 1921. Among the Eurasian fossil taxa of this subfamily, the first to be described were Enhydrictis Major, 1901 and Pannonictis Kormos, 1931. The latter genus is well characterised from the Plio-Pleistocene deposits of central and southern Europe, whereas Enhydrictis is an endemic and enigmatic form, recovered from late Pleistocene localities of Sardinia. Other recent studies have revealed a more palaeodiverse and complex taxonomic scenario than was previously thought. Based on various evidence, this review proposes a reinterpretation of the material of the galictini from early Pleistocene sites such as St. Vallier and Olivola, historically named “Mustela” ardea Gervais, 1848–1852, and its attribution to Martellictis gen. nov. The definition of Martellictis ardea reveals a more complex systematic panorama of western Eurasian Ictonychinae, and at the same time, this re-ascription stresses the importance of understanding the possible origin of the different morphological adaptations (such as those of Enhydrictis) and clarifying the phylogenetic relationships among these taxa.

Joint vegetation and mammalian records at the early Pleistocene sequence of Bòvila Ordis (Banyoles-Besalú Basin, NE Spain) and their bearing on early hominin occupation in Europe

The early Pleistocene site at Bovila Ordis (Banyoles-Besalu Basin in NE Iberia) delivered in the past a significant pollen succession which can be assigned to the upper Matuyama geomagnetic chron owing to the identification of the Cobb Mountain magnetic subchron (1.2 Ma ago). It has been previously shown by palynology that the succession of lakes recorded at Bovila Ordis corresponds to a succession of late early Pleistocene glacial–interglacial phases, between 1.2 and 1 Ma, which can be correlated with MIS 35, 33 and 31. The present investigation focuses on lake 1 (borehole BOIV) and lake 3 (boreholes BOI, BOII and BOIII and outcrops) from this site, where both fossil pollen and rodent teeth were recovered together in the same sediment, and offers the potential to provide a vegetation and climatic context to sites that are dated by rodent teeth, such as some hominin sites in Western Europe. Here we analyse the rodent content and their biostratigraphical implications in the context of early hominin dispersal in Western Europe. In lake 1, pollen data had revealed in previous analysis a complete glacial–interglacial cycle and parts of a second one. The uppermost part of BOIV sequence yielded rodent remains that can be assigned to the arvicolid species Allophaiomys chalinei and Mimomys cf. savini. Previous palynological investigations from lake 3 had revealed a temperate deciduous forest, indicative of warm and humid conditions. At the top of the section of lake 3, a regression of the forest and the spread of open landscape elements indicated drier, more steppic conditions. The palaeobiological record of lake 3 includes pollen and large (Cervus philisi, Hippopotamus antiquus and Equus stenonis) and small mammal remains (Mimomys savini and Allophaiomys lavocati). The rodent material from lake 1 clearly indicates an early Pleistocene age somewhat older than that of lake 3. According to these new biostratigraphic data in the context of previous palynological and chronological data, it is clear that Allophaiomys chalinei entered Iberia before 1 Ma ago and A. lavocati remained until 1 Ma ago. The fact that Allophaiomys lavocati and Allophaiomys chalinei, two arvicolids currently associated with the earliest evidence of hominin presence in Western Europe, appear in Bovila Ordis at a time of mild, temperate conditions reinforce the idea that the first hominin dispersal in this region was strongly dependent on favourable climatic conditions.

Fossil amphibians and reptiles from Tegelen (Province of Limburg) and the early Pleistocene palaeoclimate of The Netherlands

Few Quaternary herpetofaunas have been recovered from The Netherlands. Among these, the one coming from the early Pleistocene site of the Russel-Tiglia-Egypte pit near Tegelen is of particular interest, because it is the type locality of the recently described, last western European palaeobatrachid anuran, Palaeobatrachus eurydices. The large number of fossil remains of amphibians and reptiles found in the pit are representative of a very diverse fauna, including at least 17 taxa: Triturus gr. T. cristatus, Lissotriton sp., Pelobates fuscus, Bufo bufo, Bombina sp., Pelophylax sp., Rana sp., Hyla gr. H. arborea, Pelodytes sp., Mauremys sp., Lacerta sp., Lacertidae indet., Anguis gr. A. fragilis, cf. Pseudopus sp., “colubrines” indet., Natrix natrix and Vipera sp. Emys orbicularis, previously reported from a different Tegelen pit, is not present in this assemblage. Palaeoclimatic conditions reconstructed based on the herpetofaunistic association indicate a humid subtropical climate (Cfa according to the Köppen-Geiger classification of climates) for Tegelen during the TC5 section of the Tiglian, with low, but fairly regular rainfalls during the year. Mean annual temperature was 13.4 ± 0.3 °C and mean annual precipitation was 542 ± 50 mm. Moreover, three dry months were present during summer and early autumn, resulting in a much drier climate than the one present at Tegelen today. Nevertheless, the occurrence of the water-dwelling P. eurydices suggests the persistence of suitable permanent water bodies during the whole year, and the survival of this taxon in this part of Europe might have been allowed by the generally humid climate.

Discovery of circa 115,000-year-old bone retouchers at Lingjing, Henan, China.

Most Chinese lithic industries dated between 300,000 and 40,000 are characterized by the absence of Levallois debitage, the persistence of core-and-flake knapping, the rarity of prepared cores, their reduction with direct hard hammer percussion, and the rarity of retouched flakes. Here we report the discovery of seven bone soft hammers at the early hominin Lingjing site (Xuchang County, Henan) dated to 125,000–105,000. These artefacts represent the first instance of the use of bone as raw material to modify stone tools found at an East Asian early Late Pleistocene site. Three types of soft hammers are identified. The first consists of large bone flakes resulting from butchery of large herbivores that were utilized as such for expedient stone tools retouching or resharpening. The second involved the fracture of weathered bone from medium size herbivores to obtain elongated splinters shaped by percussion into sub-rectangular artefacts. Traces observed on these objects indicate intensive and possibly recurrent utilization, which implies their curation over time. The last consists of antler, occasionally used. Lingjing bone tools complement what we know about archaic hominin cultural adaptations in East Asia and highlight behavioural consistencies that could not be inferred from other cultural proxies. This discovery provides a new dimension to the debate surrounding the existence of the Middle Palaeolithic in the region. The attribution of East Asian sites to the Middle Palaeolithic assumes that cultural traits such as the Levallois method represent evolutionary hallmarks applicable to regions of the world different from those in which they were originally found. Here, we promote an approach that consists in identifying, possibly from different categories of material culture, the original features of each regional cultural trajectory and understanding the behavioural and cognitive implications they may have had for past hominin populations.

Раскопки раннеплейстоценовой стоянки Кермек в Южном Приазовье в 2017 г.

Раскопки раннеплейстоценовой стоянки Кермек в Южном Приазовье в 2017 г.

Equid prey acquisition and Archaic Homo adaptability at the early Late Pleistocene site of Xujiayao, China

AbstractBesides active hunting by hominins, there are two methods of scavenging that can provide primary access to intact ungulate carcasses: first‐access scavenging from nonpredator‐related accidents and early‐access aggressive scavenging from carnivore kills. Patterns in mortality profiles of prey animals at archaeological sites provide evidence of prey acquisition strategies, which is an important factor in reconstructing hominin adaptability. The Xujiayao site is an early Late Pleistocene site in the Nihewan Basin, China. Its faunal assemblage is dominated by Equus przewalskii and Equus hemionus. Evidence from previous taphonomic analysis has implied that Archaic Homo was the dominant taphonomic agent in the accumulation of the animal remains. This research applies mortality profile analysis to determine a follow‐up question: how were the equid carcasses acquired? The results of this study indicate that Archaic Homo at Xujiayao probably used both active hunting and scavenging to acquire equids in the early period (lower cultural layer) but mainly used active hunting in the later period (upper cultural layer) due to the fact that the climate changed to much colder conditions in the later period. This research provides new information on the subsistence adaptations of Archaic Homo in northern latitudinal climates of China in the early Late Pleistocene.

Uneven Data Quality and the Earliest Occupation of Europe\u2014the Case of Untermassfeld (Germany)

The database regarding the earliest occupation of Europe has increased significantly in quantity and quality of data points over the last two decades, mainly through the addition of new sites as a result of long-term systematic excavations and large-scale prospections of Early and early Middle Pleistocene exposures. The site distribution pattern suggests an ephemeral presence of hominins in the south of Europe from around 1 million years ago onward, with occasional short northward expansions along the western coastal areas when temperate conditions permitted. From around 600,000–700,000 years ago, Acheulean artefacts appear in Europe and somewhat later hominin presence seems to pick up, with more sites and now some also present in colder climatic settings. It is again only later, around 350,000 years ago, that the first sites show up in more continental, central parts of Europe, east of the Rhine. A series of recent papers on the Early Pleistocene palaeontological site of Untermassfeld (Thuringia, Germany) makes claims that are of great interest for studies of earliest Europe and are at odds with the described pattern: the papers suggest that Untermassfeld has yielded stone tools and humanly modified faunal remains, evidence for a 1 million years old hominin presence in European continental mid-latitudes, and additional evidence that hominins were well-established in Europe already around that time period. Here, we evaluate these claims and demonstrate that these studies are severely flawed in terms of data on provenance of the materials studied and in the interpretation of faunal remains and lithics as testifying to a hominin presence at the site. In actual fact, any reference to the Untermassfeld site as an archaeological one is unwarranted. Furthermore, it is not the only European Early Pleistocene site where inferred evidence for hominin presence is problematic. The strength of the spatiotemporal patterns of hominin presence and absence depends on the quality of the data points we work with, and database maintenance, including critical evaluation of new sites, is crucial to advance our knowledge of the expansions and contractions of hominin ranges during the Pleistocene.

Before and after the earliest Homo dispersal in Europe: Evidence from the early Pleistocene sites of the Italian Peninsula

Fossil mammal assemblages found in various localities of the Italian Peninsula provide significant information to create a detailed biochronological framework for the middle–late Villafranchian and Epivillafranchian of Europe and to reconstruct the evolution of early Pleistocene terrestrial ecosystems, when the earliest dispersal of Homo in Europe occurred. Here, we provide an updated critical overview on three Italian sites that in the last few years have provided the most interesting information on this crucial time interval: Coste San Giacomo (Latium; about 2.1 million years, Ma), Pantalla (Umbria; about 1.9–1.7Ma), and Pirro Nord (Apulia; about 1.6–1.3Ma).

Criteria for identifying the African origin of early Pleistocene mammalian fauna in Eurasia

The “Migratory Wave Hypothesis” suggests that early Pleistocene Homo dispersed from Africa together with a suite of other large mammals. Support for this hypothesis has been found primarily at the sites of ‘Ubeidiya, (Israel) and Venta Micena (Spain) where a high number of African taxa have been identified. This paper presents a critical evaluation of how we can identify these taxa and suggest criteria for the identification of taxa of African origin present in Eurasia during the early Pleistocene. Biogeography, taxonomy and chronology are used to develop criteria that have an effect on how we defined or identify African taxa. By critically evaluating the number of African taxa in Eurasia through the lens of these criteria, the number of African taxa may be reduced from a maximum of 30 to a minimum of six. The actual number may be either one of these two numbers, or any number in between, depending on how rigorous we are in applying the criteria. Thus, while the criteria presented in this paper have face value, they are not in any way more “correct” than other criteria, but are heuristic in presenting the difficulties in assigning an African origin to fauna found in early Pleistocene sites. This points to the need to be cautious when making inferences about the relationship between the dispersal of Homo with that of other African taxa.

Resource and niche differentiation mechanisms by sympatric Early Pleistocene ungulates: the case study of Coste San Giacomo

Resource competition and niche partitioning among the exceptionally high number of sympatric ungulates of the Early Pleistocene site of Coste San Giacomo (Central Italy) is here examined through the study of their dietary proclivities and body size. The main aim of this study is to investigate the niche differentiation mechanisms that let the fossil ungulates coexist in the same region. We also provide information about the complementarity of two different methodologies that observe diet variation at a different time scales (inner and outer mesowear) in the study of dental wear patterns of fossil ungulates. Results from analyses of dental wear degree and body masses predictions show that a wide range of feeding behaviours were adopted by the taxonomical groups (i.e., cervids, bovids and equids) in order to avoid competition. Among larger ungulates diet ranges from strict browsing (Eucladoceros sp., Gazellospira torticornis), to mixed feeding (Gallogoral meneghinii, Leptobos sp.) to pure grazing (Equus stenonis), whereas smaller taxa are more selective feeders (Axis cf. lyra, Croizetoceros cf. ramosus) with only one exception (Gazella borbonica). When taxa with the same feeding behaviour occurred in the same habitat, competition was minimised by differences in body size.

NEW MATERIAL OF LUTRA SIMPLICIDENS (CARNIVORA, MUSTELIDAE, LUTRINAE), A KEY TAXON FOR UNDERSTANDING THE EVOLUTION OF EUROPEAN OTTERS

Lutra lutra (Linnaeus, 1758) is the only otter living in Europe today, but the palaeodiversity of this group during the Pleistocene was much higher. Lutra simplicidens Thenius, 1965 is one of the best-known taxa from the European Quaternary fossil record, having been reported in at least eight localities in Central Europe, Britain, Italy and the Azov Sea area, with a stratigraphic occurrence spanning the mid Early to the Middle Pleistocene. However, no cranial remains of this species have been described so far. Here I analyse some unpublished material of L. simplicidens from the early Middle Pleistocene site of Voigtstedt (Germany), which consists of the right and left P4-M1 of the same individual and a complete left humerus. The comparative study of these findings highlights a number of morphological and biometrical similarities between L. simplicidens and some Mediterranean Quaternary otters, such as Lutraeximia umbra Cherin et al., 2016 from central Italy, Lutraeximia trinacriae (Burgio & Fiore, 1988) from Sicily, Sardolutra ichnusae (Malatesta, 1977) from Sardinia and Lutrogale cretensis (Symeonides & Sondaar, 1975) from Crete. These species - together with the living Lutrogale perspicillata (Geoffroy Saint-Hilaire, 1826) - form a monophyletic clade, which most probably includes also L. simplicidens , as well as several other Eurasian extinct taxa only known by fragmentary remains. These results confirm the pivotal importance of L. simplicidens for the evolution of European otters and lead to doubts about its taxonomic status, which will be solved with the discovery of new material.

Canis othmanii sp. nov. (Carnivora, Canidae) from the early Middle Pleistocene site of Wadi Sarrat (Tunisia)

The North African fossil record of the family Canidae is scarce and scattered and for this reason poorly known. This is particularly true for the genus Canis, fossils of which only come from a few sites of Morocco and Algeria. Here, we provide the description of the first material of Canis from the early Middle Pleistocene site of Wadi Sarrat (Tunisia), recovered in association with other fossil mammal taxa and Acheulian lithic artifacts. A cranial specimen is described and compared to other fossil and extant canid species by anatomical and morphometric analyses. The specimen shows cranio-dental morphologies and proportions considerably different from other fossil and extant African canids. Remarkably, its proportions resemble more closely those of Eurasian Early-Middle Pleistocene taxa, e.g., Canis mosbachensis Soergel, 1925, although its principal morphological features cannot be referred to any of the known Eurasian taxa. Therefore, we suggest to ascribe this material to a new species of canid, Canis othmanii sp. nov. The presence of new species of Canis with Eurasian affinities in the northern part of the African continent has a high significance for the fossil record of this region, as well as strong implications on the paleobiogeography of canids during the Middle Pleistocene.

Out of Africa: An alternative scenario for the first human dispersal

Recent paleoanthropological evidence from the early Pleistocene site of Dmanisi in Georgia has revealed that the first hominins out of Africa were more archaic than the coeval African and Asian Homo erectus . More evidence suggests that these archaic hominins were forest dwellers rather than savannah inhabitants. Between 1.8 and 1.6 million years ago a climate crisis caused a new spread of savannah and arid zones across large parts of Africa. As a consequence, early Homo populations splitted, with some populations becoming adapted to the new ecological conditions and others following woodland areas in their regression.