Showing posts with label ESHE. Show all posts
Showing posts with label ESHE. Show all posts

September 12, 2013

ESHE 2013 abstracts

219 pages worth of abstracts from the upcoming meeting of the European Society for the study of Human Evolution (pdf).

I will post some excerpts:

Evolutionary History And Biological Diversity Of Homo Sapiens In Southeast Asia: Contour Shape Analysis Of Modern Human Upper Molars:


The evolutionary history and the pattern of biological diversity of modern humans in Southeast Asia has long been regarded as resulting of two major migrations waves. In this hypothesis it is generally considered that a first wave of migration (generally referred as “Australo-Melanesians”) reached Australia around 60000 BP while the second wave (often referred as “Mongoloids”) is correlated to a demic diffusion of the Neolithic from a Southeast China homeland which started around mid-Holocene. ... Our results also bring very interesting perspectives concerning the detection of the signature of a possible Denisovan admixture in the phenotype of modern human populations. Indeed, past and recent modern human groups which are hypothetically sharing Denisovan ancestry have closer phenetic affinities with each other than with other populations.

Podium Presentation: Session 9, Sa (14:20) A fine scale survey of the worldwide similarity between humans and archaic hominids and its implication on the proposed admixture scenario 
Since the publications of Green et al. 2010 and Reich et al. 2010, several investigations have followed suit addressing the question regarding anatomically modern human and archaic hominin admixture. The genetic analyses of the Neanderthal draft genome and the Denisova genome concluded that these archaic hominins made a 1-4% contribution to non-African populations and 4-6% contribution to Melanesian populations, respectively. The argument of whether the observed genetic similarity is consistent with admixture or ancient substructure is still under debate. While observations have been consistent with an admixture scenario of Neanderthals and the ancestors of non-Africans coming into contact 50 – 80 kya in the Middle East, the lack of power in these experiments falter in providing reliable results. Here we look at the relationship between AMH and these archaic hominins on a fine-scale level by using several methods (including revised D-statistic) on the Neanderthal draft genome, Denisova high-coverage genome, and a collection of published and unpublished genotype and sequence data. We use our findings to clarify the proposed admixture scenario as well as discuss new findings in newly analyzed comparisons of African, South Asian and American populations with archaic hominins, Neanderthal and Denisova. Our results shed light on understanding the observed genetic similarity within and between humans (African and non-African) and archaic hominins, particularly in relevance to the admixture versus ancient substructure scenarios. 

How ‘modern’ are the earliest Homo sapiens? 
Previous research (reviewed in Trinkaus, 2005) has suggested that the African and western Asian contemporaries of Neandertals, generally considered to be the earliest Homo sapiens, are not particularly ‘modern’ looking in their cranial anatomy. Here we test whether the dental morphological ‘signal’ agrees with this assessment. We examined and recorded dental morphological variation in the earliest H. sapiens and asked: how ‘modern’ are they dentally? We used a Bayesian statistical approach to classifying individuals into two possible groups based on dental non-metric traits. e classification was based on dental trait frequencies and sample sizes for two ’known’ samples of 120 Neandertals and 106 Upper Paleolithic H. sapiens individuals. A cross- validation test of these individuals resulted in a correct classification rate of 95%, which is even better than the results of a previous study using the same method based on fewer individuals (Bailey et al 2009). Our early H. sapiens sample included 41 individuals from Southern Africa (Die Kelders, Klasies River Mouth and Equus Cave), Northern Africa (Temara, El Harhoura, Dar es Soltan) and the Levant (Qafzeh, Skhul). We treated our early H. sapiens individuals as ‘unknown’ and calculated the probability that each belonged to either the Upper Paleolithic or Neandertal sample. While understanding that technically these individuals did not belong to either group, we hypothesized that if the earliest H. sapiens were already dentally modern then, when forced into a group, they should fall into the Upper Paleolithic H. sapiens group. We also hypothesized that if there had been significant admixture in the Levant during the initial dispersal out of Africa - as has been sometimes proposed based on paleontological - and more recently on genetic - evidence (Green et al 2010) that these samples would have the largest proportion of individuals classified as Neandertal. Our results indicated that this was not the case. While a surprising number (27%) of early H. sapiens did classify as Neandertal, the smallest proportion of these came from the Levant (7% - one out of 14 individuals). The African sample was more of a ‘mixed bag’. None of the individuals from Die Kelders or Klaises River Mouth classified as Neandertal, while four out of five of the individuals from Equus Cave did. Moreover, 6 out of 13 (46%) of the Northern African individuals were classified as Neandertal. An inspection of the individual specimens that classified as Neandertals revealed that in most cases it is the predominance of primitive features, rather than derived Neandertal traits, that is driving the classification. We conclude (1) by the time the earliest H. sapiens dispersed from Africa they had already attained a more-or-less ‘modern’ dental pattern; (2) in the past, as is the case today, Late Pleistocene Africans were not a homogeneous group, some retained primitive dental traits in higher proportions than others. Furthermore, we acknowledge that while our method is an excellent tool for discriminating between Upper Paleolithic H. sapiens and Neandertals, it may not be appropriate for testing Neandertal – H. sapiens admixture because all traits (primitive and derived) are weighed equally. 

The potential for catastrophic impact of the Campanian Ignimbrite (CI) tephra on human evolution: new data from the Lower Danube loess steppe:
Here we investigate an unexpectedly thick CI tephra deposit at Urluia in the southeast Romanian loess steppe, 1200 km from the super-eruption vent in Italy. Existing models suggest that the CI tephra thickness might reach a maximum 5-10 cm in Eastern Europe; the Urluia ash deposit is up to 100 cm thick. Additional, recently discovered Lower Danube sites also reveal substantially thicker than modelled CI ash beds. 
Radiocarbon dating the extinction of European Neanderthals

The transitional industries and their makers:
The demonstration of modern settlements pre-dating the earliest Aurignacian in Europe has important implications (Hublin 2012). It is consistent with a patchy pattern of modern colonization, with some significant chronological overlap between Neandertals and modern humans on a continental scale. In this model innovations observed in the Neandertal world around or after 50 ka cal BP may have resulted from cultural diffusion triggered by these influxes of populations into western Eurasia.
The Upper Paleolithic of the Ikh Tulberin Gol (Northern Mongolia): new excavations at the Tolbor 16 open-air site:
Numerous questions remain regarding the timing and the context of Upper Paleolithic emergence in Northeast Asia. Available data allow the recognition of a form of Initial Upper Paleolithic (IUP) (Brantingham et al, 2001) documented in the Altai circa 45-40 ka uncal BP (Goebel et al., 1993, Derevianko et al, 2000, Zwyns et al., 2012), in the Cis- and Transbaikal around 40 ka uncal BP (Lbova, 2008) ...
New data on the radiocarbon chronology of the Stretleskayan at Kostenki (Voronezh, Central Russia) :
It concerns cultural layer III at Kostenki 12 and cultural layer V at Kostenki I, respectively previously dated 36,280±360 and 34,900 ±350 BP in Groningen (Damblon et al., 1996). ... Remaining material of the charcoal sample from cultural layer III at Kostenki 12, previously dated 36,280 ±250 BP, was also submitted for dating to Oxford with ABOx-SC pretreatment. the results show that the two Groningen dates and the three Oxford dates are in good agreement and fit within a time interval of 1 millennium, but provide ages several millennia older than the ages obtained previously. Taking into account this new chronology, the appearance of the Stretleskayan at Kostenki will be compared with the chronological background of the Early Aurignacian, Szeletian and Bohunician occurrences in the MiddleDanube sequence, also based on ABA and ABOx-SC cross-dating (Haesaerts et al., 2013). 

Two Waves of Paleolithic Settlers Migrations to North West Beringia in Pleistocene End (End of Karginsky Interstadial) :
Way of 1st wave is marked by sites Afontova Gora V, Ust-Kova on Angara, than along Lena river up to Central Ykut plain, turn Aldan (Ikhine I etc), than round Kolyma plain to Chukotka, where they left abt 30 Ka Orlovka II site in North of West and Kymyneykey site in North of East Chukotka. In Aldan basin migration slowly down. Its reason could be glaciation of Verkhoyansk and Chersky ranges. During this delay “technical re-equipment” happened of migrations. Orlovka II and Kymyney artefacts are clear Aldan. 2nd wave migration was abt 29-28 Ka during final karginsky (middle: würm, wisconsin) warming, when paleoclimate along all northern outskirts of Asia was like to recent or more warm (Drozdov and Laukhin, 2010). Migrants of 2nd wave went to Yana mouth and left here site. Artifacts of this site don’t have Aldanian traditions, but are very close to Yeniseisk. There were little of favorable niches to North of South Mountain Belt; and their demographic capacity were nor big. 
Modern human dispersal into Eurasia: Preliminary results of the multi-disciplinary project on the replacement of Neanderthals by modern humans (RNMH)
Both the chronometric dating and the geographic distribution of archaeological entities indicate that modern human populations equipped themselves with blade products based on the Levallois method, a technology that emerged in North Africa (Taramsan) around 60 ka and then dispersed into the Eastern Mediterranean Levant (Emiran) between 49 and 48 ka. Blade technology further expanded into Eastern and Central Europe (Bachokirian and Bohunician) between 48 and 45 ka and into Southern Siberia (Kara-Bom horizons 6 and 5) at around 47 ka. The rapid expansion of modern humans into Western and Eastern Eurasia followed by the demise of archaic populations in these regions may imply technological and cognitive advantages of modern humans. 

September 22, 2012

ESHE 2012 abstracts

Some abstracts of interest from the European Society for the study of Human Evolution 2012 meeting (pdf). To avoid making this too long, I will just post the titles and the most relevant quotes. You can read the abstracts in the linked pdf for authors names and more information.


Neandertal and Denisovan Genomes from the Altai 
Susanna Sawyer  et al.
In 2010 a draft genome sequence was determined from a small finger bone found in Denisova Cave in southern Siberia. Its analysis revealed that it derives from an individual who belonged to a population related to, but distinct from, Neandertals. A molar has also been described from Denisova Cave and has shown to carry an mtDNA genome closely related to that of the finger bone.  We have recently determined the DNA sequence of the Denisova genome to a quality similar to present-day human genomes. We have also retrieved a complete mitochondrial genome and nuclear DNA sequences from an additional molar found in Denisova Cave. Furthermore, we have determined a high-quality nuclear genome from a pedal phalanx found in Denisova Cave in 2010. We show that the pedal phalanx derived from a Neandertal and thus that Neandertals as well as Denisovans have been present in the cave. We will discuss the genetic history of Denisovans as well as Neandertals in light of these new genome sequences. 

The discovery of a Neandertal genome from Denisova cave is certainly interesting. I have previously commented that:
If Vindija and Denisova, two caves less than 5,000km apart were home to people more divergent from each other than any two humans are today, it's strange to think that only "modern humans" inhabited Africa at the same time.
Now, it appears that Neandertals and Denisovans were present (when?) not only 5Mm apart, but literally on the same spot. Much later, during the Neolithic we see very differentiated humans co-existing in Europe. And, we get archaic hominins in Africa long after the appearance of anatomically modern humans there. I think the evidence is looking good for my hypothesis that regional human populations have recently gotten more similar over time through extensive admixture between divergent hominin groups, rather than that they became more dissimilar over time  through tree-like divergence.

On the same topic, here is more evidence for Neandertal presence in the Altai:

A Neanderthal mandible fragment from Chagyrskaya Cave (Altai Mountains, Russian Federation)
Both the mandible and the dentition preserve numerous derived Neanderthal traits: among else a posteriorly placed mandibular foramen, an oblique mylohyoid line, an asymmetrical P4 and continuous mid-trigonid crests on the M1 and M2. ... Ongoing ancient DNA analyses of the hominin remains from Chagyrskaya cave and absolute dates for the site will hopefully help to clarify the origin of the Altai Neanderthals, and their relationship with the Denisovans.

An hypothesis for the phylogenetic position of Homo floresiensis
Our cladistic analysis places H. floresiensis unequivocally as part of a clade with H. habilis
Who are you calling ”modern”? An assessment of the dental morphology and metrics of Homo sapiens

Although dental reduction has long been cited as a derived feature of H. sapiens, our data indicate this claim may be no longer tenable ... the single metrical assessment that groups all H. sapiens (early, Upper Paleolithic and recent) apart from other taxa is the ratio between mandibular:maxillary crown areas.  the results of our study are important for assessing recent claims of great antiquity for H. sapiens outside of Africa
Neanderthal in Malthusian demographic trap

It can be hypothesized that the demography of the Neanderthal metapopulation, living under conditions where extreme environmental instability with short periods was the norm, was primarily stagnant,
with frequent bottlenecks and episodes of decline.
 A New Framework for the Upper Paleolithic of Eastern Europe

The results of field and laboratory research during the past decade require a new classificatory framework for the Upper Paleolithic in Eastern Europe. It is now apparent that people making artifacts assigned to the Ahmarian industry occupied both the southern and northern slopes of the Caucasus Mountains (i.e., Ortvale Klde, Layer 4d; Mezmaiskaya Cave, Layer 1C). Their sites probably indicate a separate movement of anatomically modern humans (AMH) from the Near East directly into Eastern Europe, establishing an independent line of development during the earlier Upper Paleolithic that parallels the Proto-Aurignacian and Aurignacian sequence in Western and Central Europe. this East European industry is most fully represented at the Kostenki-Borshchevo sites on the Don River before 40,000 cal BP (e.g., Kostenki 14, Layer IVb). It is followed by a closely related industry, also characterized by bladelet production, that is dated to the interval between 40,000 and 30,000 cal BP in Crimea and the East European Plain. The proposed new framework reflects recognition of these distinctive East European entities and of two environmental events that had significant impacts on human settlement in Eastern Europe: (1) the Campanian Ignimbrite (CI) volcanic eruption (40,000 cal BP); and (2) the Last Glacial Maximum (LGM) ( 25,000 cal BP). It has been suggested that the early Upper Paleolithic (EUP) industry present in Eastern Europe before 40,000 cal BP should be labeled an eastern variant of the contemporaneous Proto-Aurignacian of Mediterranean Europe. However, given the separate movement of people from the Near East via the Caucasus Mountains, and independent development of the East European EUP, this industry is more appropriately termed “Proto-Gravettian.” The younger bladelet industry, which includes assemblages at Buran-Kaya III (Layer 6-1), Mira (Layer II/2), Kostenki 8 (Layer II), and probably Shlyakh (Layers 4C, 6), may be termed “Early Gravettian” to distinguish it from the classic Gravettian industry that dates to less than 30,000 cal BP (e.g., Avdeevo, Zaraisk).The upper temporal boundary of the Proto-Gravettian corresponds to the CI eruption (40,000 cal BP), while the classic Gravettian of the East European Plain appears to have been effectively terminated by the LGM ( 25,000 cal BP). Several sites that date to the 40,000–30,000 cal BP interval (e.g., Kostenki 1, Layer III) contain elements that suggest a connection with the Aurignacian technocomplex of Western-Central Europe. These assemblages may be placed into the category of “Eastern Aurignacian,” which reflects differences in content with the West and Central European sites. The apparent spread of this industry into Eastern Europe from Central Europe may be related to the impact of the CI eruption on portions of the East European Plain. 
 Conflicting dates for the Late Aterian
First at the huge Ifri n’Ammar sites, TL dates have indicated 80,000 years for the Late Middle Palaeolithic/Aterian levels. Our new C14 dates yield 35,000 BP for exactly the same levels. At the “grotte des Contrebandiers”, formerly dated at 28,000 BP by Debenath and his team, is now dated at 100,000 years by new TL dates. As starting points, this kind of methodological contradiction should be confronted, understood and resolved.
 The Rio Secco Cave in the North Adriatic Region, Italy. A new context for investigating the Neanderthal demise and the settllement of Anatomically Modern Humans
A sequence of several thin layers dated to 46.0–42.1ky Cal BP represents the final Mousterian.
The Dhofar Nubian Tradition: an enduring Middle Stone Age technocomplex in southern Arabia

Between 2010 and 2012, the Dhofar Archaeological Project has located and mapped 260 Nubian Complex occurrences across the Nejd Plateau of southern Oman. Diagnostic Nubian artifacts werefound cemented in fluvial sediments at the site of Aybut Al Auwal in Dhofar, with two OSL dates around 106 ka BP; hence, roughly contemporaneous with the African Nubian Complex (Rose et al. 2011). Many of these lithic assemblages, such as that from Aybut al Auwal, are technologically homologous to the Late Nubian Industry found in northeast Africa, sensu stricto, while others may represent local facies of the greater “Afro-Arabian Nubian Technocomplex.” This presentation describes the various reduction strategies encountered at a sample of Nubian Complex sites from Oman, explores inter-assemblage variability, and begins to articulate technological units within the “Dhofar Nubian Tradition.” To achieve this aim, we have developed an analytical scheme with which to describe technological variability among Nubian Levallois reduction strategies in both Africa and Arabia. Our analysis indicates at least two distinct Nubian industries. The first, which we refer to as the “Classic Dhofar Nubian,” is virtually identical to Late Nubian Industry from the Lower Nile Valley and Red Sea Hills in Egypt. Thee subsequent group of assemblages in Dhofar, called the “Mudayyan,” exhibits a technological shift toward diminutive Nubian Levallois cores and that, recurrent bidirectional cores with opposed, faceted striking platforms. We interpret this evidence to indicate an enduring, local Nubian tradition in Dhofar that is ultimately rooted in the African Nubian Complex. 
From Late Mousterian to Evolved Aurignacian: New evidence for the Middle-to-Upper Paleolithic transition in Mediterranean Spain
Combined, the evidence from CA and FDM indicates that, in chronostratigraphic terms, the Middle-to-Upper Paleolithic transition in Murcia consists of the replacement of a Late Mousterian by an Evolved Aurignacian and occurred some time during the 38th millennium cal BP