Evidence for new Neanderthal teeth in Tabun Cave (Israel) by the application of self-organizing maps (SOMs)

Morphological and metrical study suggested that seven human teeth from Tabun Cave, Israel were part of the upper dentition of a single, probably Neanderthal, individual renumbered as Tabun BC7. An enamel fragment gave ESR age estimates of 82+/-14 ka (early U-uptake) and 92+/-18 ka (linear uptake) and an age estimate of 90(+30)(-16) ka using U-series disequilibrium. Although metrical analyses suggested Neanderthal affinities, definitive assessment was difficult as the values often fell into the ranges of both Neanderthal and Levantine early modern human samples. Therefore, two further classification analyses were conducted (neural networks using self-organizing maps and homogeneity analysis). Both identify Tabun BC7 as a Neanderthal. Neural networks are a promising tool for paleoanthropological studies as they can provide reliable classifications even with incomplete data.     

New Neandertal remains from Cova Negra (Valencia, Spain)

New Neandertal fossils from the Mousterian site of Cova Negra in the Valencia region of Spain are described, and a comprehensive study of the entire human fossil sample is provided. The new specimens significantly augment the sample of human remains from this site and make Cova Negra one of the richest human paleontological sites on the Iberian Peninsula. The new specimens include cranial and postcranial elements from immature individuals and provide an opportunity to study the ontogenetic appearance of adult Neandertal characteristics in this Pleistocene population. Children younger than 10 years of age constitute four of the seven minimum number of individuals in the sample, and this relative abundance of children at Cova Negra is similar that in to other Neandertal sites in Europe and southwest Asia. The recognition of diagnostic Neandertal features in several of the specimens, as well as their western European context and late Pleistocene age, suggests that all the human remains from Cova Negra represent Neandertals. The archaeological evidence from Cova Negra indicates sporadic, short-term occupations of the site, suggesting a high degree of mobility among Neandertals.     

Metric and morphological study of the upper cervical spine from the Sima de los Huesos site (Sierra de Atapuerca, Burgos, Spain)

In this article, the upper cervical spine remains recovered from the Sima de los Huesos (SH) middle Pleistocene site in the Sierra de Atapuerca (Burgos, Spain) are described and analyzed. To date, this site has yielded more than 5000 human fossils belonging to a minimum of 28 individuals of the species Homo heidelbergensis. At least eleven individuals are represented by the upper cervical (C1 and C2) specimens: six adults and five subadults, one of which could represent an adolescent individual. The most complete adult vertebrae (three atlases and three axes) are described, measured, and compared with other fossil hominins and modern humans. These six specimens are associated with one another and represent three individuals. In addition, one of these sets of cervical vertebrae is associated with Cranium 5 (Individual XXI) from the site. The metric analysis demonstrates that the Sima de los Huesos atlases and axes are metrically more similar to Neandertals than to our modern human comparative sample. The SH atlases share with Neandertals a sagittally elongated canal. The most remarkable feature of the SH (and Neandertal) axes is that they are craniocaudally low and mediolaterally wide compared to our modern male sample. Morphologically, the SH sample shares with Neandertals a higher frequency of caudally projected anterior atlas arch, which could reflect greater development of the longus colli muscle. In other features, such as the frequency of weakly developed tubercles for the attachment of the transverse ligament of the atlas, the Sima de los Huesos fossils show intermediate frequencies between our modern comparative samples and the Neandertals, which could represent the primitive condition. Our results are consistent with the previous phylogenetic interpretation of H. heidelbergensis as an exclusively European species, ancestral only to H. neanderthalensis.     

百色六怀山旧石器遗址发掘简报

百色六怀山遗址位于右江右岸第四级基座阶地。2005年10—11月对该遗址进行抢救性发掘,揭露面积1000m^2,出土石制品136件,砾石37件。石制品类型包括石器、石核、石片、断块和砾石等。古人类选择阶地底部河卵石为原料进行剥片和加工石器;石器以大型为主,手镐和砍砸器是主要类型;古人类多在砾石一端采用锤击法打制石器。石器面貌具有中国南方旧石器主工业的鲜明特点。地貌和地层对比显示该遗址形成于中更新世早期。     

Shifting distributions and speciation: species divergence during rapid climate change

Questions about how shifting distributions contribute to species diversification remain virtually without answer, even though rapid climate change during the Pleistocene clearly impacted genetic variation within many species. One factor that has prevented this question from being adequately addressed is the lack of precision associated with estimates of species divergence made from a single genetic locus and without incorporating processes that are biologically important as populations diverge. Analysis of DNA sequences from multiple variable loci in a coalescent framework that (i) corrects for gene divergence pre-dating speciation, and (ii) derives divergence-time estimates without making a priori assumptions about the processes underlying patterns of incomplete lineage sorting between species (i.e. allows for the possibility of gene flow during speciation), is critical to overcoming the inherent logistical and analytical difficulties of inferring the timing and mode of speciation during the dynamic Pleistocene. Estimates of species divergence that ignore these processes, use single locus data, or do both can dramatically overestimate species divergence. For example, using a coalescent approach with data from six loci, the divergence between two species of montane Melanoplus grasshoppers is estimated at between 200,000 and 300,000 years before present, far more recently than divergence estimates made using single-locus data or without the incorporation of population-level processes. Melanoplus grasshoppers radiated in the sky islands of the Rocky Mountains, and the analysis of divergence between these species suggests that the isolation of populations in multiple glacial refugia was an important factor in promoting speciation. Furthermore, the low estimates of gene flow between the species indicate that reproductive isolation must have evolved rapidly for the incipient species boundaries to be maintained through the subsequent glacial periods and shifts in species distributions.     

Pleistocene refugia in an arid landscape: analysis of a widely distributed Australian passerine

While many studies have documented the effect that glacial cycles have had on northern hemisphere species, few have attempted to study the associated effect of aridification at low latitudes in the southern hemisphere. We investigated the past effects that cyclic aridification may have had on the population structure and history of a widespread endemic Australian bird species, the Australian magpie (Gymnorhina tibicen). One thousand one hundred and sixty-six samples from across its native range were analysed for mitochondrial control region sequence variation and variation at six microsatellite loci. Analysis of mitochondrial control region sequence data indicated monophyletic clades that were geographically congruent with an eastern and western region. The contemporary distribution of east and west clades is nonoverlapping but in close proximity. Populations were estimated to have diverged in the Pleistocene around 36,000 years ago. The putative Carpentarian and Nullarbor arid barriers appear to be associated with the divergence between east and west mainland populations. Nested clade analysis indicated a signature of range expansion in the eastern region suggesting movement possibly inland and northward subsequent to the last period of aridity. The island population of Tasmania was of very recent origin, possibly since sea levels rose 16,000 years ago. Given the east-west structure, there was no congruence between morphology and recent history of this species indicating a lack of support for morphological taxa. Overall mitochondrial DNA and microsatellite variation suggest that increasing aridity and Pleistocene refugia played a role in structuring populations of the Australian magpie; however, the dispersal ability and generalist habitat requirements may have facilitated the movement of magpies into an almost contiguous modern distribution across the continent. This study supports the idea that Pleistocene aridification played an important role in structuring intraspecific variation in low latitudinal southern hemisphere avian species.     

Trans-Arctic dispersals and the evolution of a circumpolar marine fish species complex, the capelin (Mallotus villosus)

Trans-Arctic dispersals and population and range expansions during the Pleistocene enhanced opportunities for evolutionary diversification and contributed to the process of speciation within the capelin, a northern marine-fish complex exhibiting a circumpolar distribution. Capelin is composed of four highly divergent and geographically discrete mitochondrial DNA (mtDNA) clades (609 bp; cytochrome b). Two clades occur in the North Atlantic, one associated with Canadian Atlantic waters, including Hudson Bay, and the second distributed from West Greenland to the Barents Sea. Two additional clades occur in the Arctic and northeast Pacific Oceans, representing the most recent divergence within the capelin phylogenetic tree. Judged from mtDNA diversity, capelin populations comprising all clades experienced at least one demographic and spatial reduction-expansion episode during recent Pleistocene glaciations that imprinted their molecular architecture. The large contemporary populations in the northeast Pacific and Arctic Oceans exhibited significant genetic structure whereas no such structure was detected in the equally extensive North Atlantic clades. All clades are characterized by one or two prevalent mtDNA haplotypes distributed over the entire range of the clade. Assuming a Pacific ancestor for capelin, we infer that capelin dispersed on two separate occasions to the North Atlantic. A more recent event resulted in the isolation of eastern Pacific and Arctic clades, with the Arctic clade positioned for a potential third Atlantic invasion, as revealed by the presence of this clade in the Labrador Sea. The Labrador Sea is a potential contact zone for three of the four capelin clades.     

Cueva Negra del Estrecho del Río Quípar: Comings and goings recorded in a late Early (Lower) Pleistocene microstratigraphical palimpsest

Preliminary conclusions from high-resolution microstratigraphical and taphonomical research suggest that Palaeolithic frequentation of the rock-shelter alternated with that of local fauna in the late Early (Lower) Pleistocene.     

On the ecological scenario of the first hominin dispersal out of Africa

The archaeopaleontological site of Dmanisi in Georgia, dated to ～1.8 Ma, provides evidence on the first hominin dispersal out of Africa, while the sites of Barranco León and Fuente Nueva-3 in Spain, dated to ～1.4 Ma, record the earliest hominin settlements in Europe. However, a number of issues related to the dispersal route, the climatic conditions and the ecological scenario of this dispersal event are subject to debate. In a recent paper in L’anthropologie, Agustí and Lordkipanidze (2019) proposed an alternative scenario for the arrival of hominins in the Caucasus, which they conceived as a forest refugium area during the Early Pleistocene, and discarded that their dispersal coincided with that of other members of the Ethiopian and Asian faunas, like the sabertooth Megantereon whitei or the giant hyena Pachycrocuta brevirostris. Our review of these issues suggests that: (i) the elongated sabers and reduced postcanine teeth of African M. whitei limited the ability of this predator to process the prey carcass, which resulted in scavengeable resources for the Dmanisi hominins; (ii) the mass estimate in excess of 100 kg obtained for the trochlear perimeter of the distal humerus of the hyena from Dmanisi shows that it can be confidently ascribed to the genus Pachycrocuta; (iii) the postcranial anatomy of the Dmanisi hominins was not advantageous for scavenging tree-stored prey; (iv) the laterally flattened upper canines of M. whitei could not withstand the loads that would result from climbing a prey carcass into a tree; (v) paleobotanical analyses suggest a temperate grassland ecosystem in Dmanisi, not dominant forest conditions, with enhanced aridity in the level of hominin occupation; (vi) similarly, the low frequency of arboreal pollen in the Levantine Corridor at ～1.8 Ma points to more arid conditions than today in this area; (vii) many archaeopaleontological sites of the Rift Valley and its extension towards the Red Sea, the Levant and the Caucasus show evidence of tectonic, volcanic and/or hydrothermal events; and (viii) the delay of 400 ka in the arrival of hominins in Western Europe did not result from a lower availability of scavengeable resources.