Monday, September 26, 2016

Pagani et al., Paragraph 2

Pagani et al
Nature
Published online
(Link)

Paragraph 2:  "The paths taken by AMHs out of Africa (OoA) have been the subject of considerable debate over the past two decades. Fossil and archaeological evidence [13,14], and craniometric studies [15] of African and Asian populations, demonstrate that Homo sapiens was present outside of Africa ~ 120–70 thousand years ago (kya) [11]. However, this colonization has been viewed as a failed expansion OoA [16] since genetic analyses of living populations have been consistent with a single OoA followed by serial founder events [17]."


Pagani et al, Paragraph 2 References:

[13]  Huw S. Groucutt, Michael D. Petraglia, Geoff Bailey, Eleanor M. L. Scerri, Ash Parton, Laine Clark-Balzan, Richard P. Jennings, Laura Lewis, James Blinkhorn, Nick A. Drake, Paul S. Breeze, Robyn H. Inglis, Maud H. Devès, Matthew Meredith-Williams, Nicole Boivin, Mark G. Thomas, Aylwyn Scally, Rethinking the dispersal of Homo sapiens out of Africa, Evolutionary Anthropology:  Issues, News, Reviews, 8 July, 2015 (Link)

Abstract:  Current fossil, genetic, and archeological data indicate that Homo sapiens originated in Africa in the late Middle Pleistocene. By the end of the Late Pleistocene, our species was distributed across every continent except Antarctica, setting the foundations for the subsequent demographic and cultural changes of the Holocene. The intervening processes remain intensely debated and a key theme in hominin evolutionary studies. We review archeological, fossil, environmental, and genetic data to evaluate the current state of knowledge on the dispersal of Homo sapiens out of Africa. The emerging picture of the dispersal process suggests dynamic behavioral variability, complex interactions between populations, and an intricate genetic and cultural legacy. This evolutionary and historical complexity challenges simple narratives and suggests that hybrid models and the testing of explicit hypotheses are required to understand the expansion of Homo sapiens into Eurasia.



[14]  Wu Liu, María Martinón-Torres, Yan-jun Cai, Song Xing, Hao-wen Tong, Shu-wen Pei, Mark Jan Sier, Xiao-hong Wu, R. Lawrence Edwards, Hai Cheng, Yi-yuan Li, Xiong-xin Yang, José María Bermudez de Castro, Xiu-jie Wu, The earliest unequivocally modern humans in southern China, Nature, Volume: 526, Pages: 696–699, Date published:


 
 
[15]  Hugo Reyes-Centeno, Silvia Ghirotto, Florent Detroit, Dominique Grimaud-Hervé, Guido Barbujani, Katerina Harvati, Genomic and cranial phenotype data support multiple modern human dispersals from Africa and a southern route into Asia, PNAS, vol. 111 no. 20 (Link)

Significance:  Current consensus indicates that modern humans originated from an ancestral African population between ∼100–200 ka. The ensuing dispersal pattern is controversial, yet has important implications for the demographic history and genetic/phenotypic structure of extant human populations. We test for the first time to our knowledge the spatiotemporal dimensions of competing out-of-Africa dispersal models, analyzing in parallel genomic and craniometric data. Our results support an initial dispersal into Asia by a southern route beginning as early as ∼130 ka and a later dispersal into northern Eurasia by ∼50 ka. Our findings indicate that African Pleistocene population structure may account for observed plesiomorphic genetic/phenotypic patterns in extant Australians and Melanesians. They point to an earlier out-of-Africa dispersal than previously hypothesized.         
                                                       
Abstract:  Despite broad consensus on Africa as the main place of origin for anatomically modern humans, their dispersal pattern out of the continent continues to be intensely debated. In extant human populations, the observation of decreasing genetic and phenotypic diversity at increasing distances from sub-Saharan Africa has been interpreted as evidence for a single dispersal, accompanied by a series of founder effects. In such a scenario, modern human genetic and phenotypic variation was primarily generated through successive population bottlenecks and drift during a rapid worldwide expansion out of Africa in the Late Pleistocene. However, recent genetic studies, as well as accumulating archaeological and paleoanthropological evidence, challenge this parsimonious model. They suggest instead a “southern route” dispersal into Asia as early as the late Middle Pleistocene, followed by a separate dispersal into northern Eurasia. Here we test these competing out-of-Africa scenarios by modeling hypothetical geographical migration routes and assessing their correlation with neutral population differentiation, as measured by genetic polymorphisms and cranial shape variables of modern human populations from Africa and Asia. We show that both lines of evidence support a multiple-dispersals model in which Australo-Melanesian populations are relatively isolated descendants of an early dispersal, whereas other Asian populations are descended from, or highly admixed with, members of a subsequent migration event.


[11]  Matt Grove, Henry Lamb, Helen Roberts, Sarah Davies, Mike Marshall, Richard Bates, Hei Huws, Climatic variability, plasticity, and dispersal: A case study from Lake Tana, Ethiopia, Journal of Human Evolution, Volume 87, October 2015, Pages 32–47 (Link)

Abstract:  The numerous dispersal events that have occurred during the prehistory of hominin lineages are the subject of longstanding and increasingly active debate in evolutionary anthropology. As well as research into the dating and geographic extent of such dispersals, there is an increasing focus on the factors that may have been responsible for dispersal. The growing body of detailed regional palaeoclimatic data is invaluable in demonstrating the often close relationship between changes in prehistoric environments and the movements of hominin populations. The scenarios constructed from such data are often overly simplistic, however, concentrating on the dynamics of cyclical contraction and expansion during severe and ameliorated conditions respectively. This contribution proposes a two-stage hypothesis of hominin dispersal in which populations (1) accumulate high levels of climatic tolerance during highly variable climatic phases, and (2) express such heightened tolerance via dispersal in subsequent low-variability phases. Likely dispersal phases are thus proposed to occur during stable climatic phases that immediately follow phases of high climatic variability. Employing high resolution palaeoclimatic data from Lake Tana, Ethiopia, the hypothesis is examined in relation to the early dispersal of Homo sapiens out of East Africa and into the Levant. A dispersal phase is identified in the Lake Tana record between c. 112,550 and c. 96,975 years ago, a date bracket that accords well with the dating evidence for H. sapiens occupation at the sites of Qafzeh and Skhul. Results are discussed in relation to the complex pattern of H. sapiens dispersal out of East Africa, with particular attention paid to the implications of recent genetic chronologies for the origin of non-African modern humans.


[16]  Paul Mellars, Kevin C. Gori, Martin Carr, Pedro A. Soares, Martin B. Richards, Genetic and archaeological perspectives on the initial modern human colonization of southern Asia, PNAS, vol. 110 no. 26 (Link)

Abstract:  It has been argued recently that the initial dispersal of anatomically modern humans from Africa to southern Asia occurred before the volcanic “supereruption” of the Mount Toba volcano (Sumatra) at ∼74,000 y before present (B.P.)—possibly as early as 120,000 y B.P. We show here that this “pre-Toba” dispersal model is in serious conflict with both the most recent genetic evidence from both Africa and Asia and the archaeological evidence from South Asian sites. We present an alternative model based on a combination of genetic analyses and recent archaeological evidence from South Asia and Africa. These data support a coastally oriented dispersal of modern humans from eastern Africa to southern Asia ∼60–50 thousand years ago (ka). This was associated with distinctively African microlithic and “backed-segment” technologies analogous to the African “Howiesons Poort” and related technologies, together with a range of distinctively “modern” cultural and symbolic features (highly shaped bone tools, personal ornaments, abstract artistic motifs, microblade technology, etc.), similar to those that accompanied the replacement of “archaic” Neanderthal by anatomically modern human populations in other regions of western Eurasia at a broadly similar date.

[17]  Franck Prugnolle, Andrea Manica, François Balloux, Geography predicts neutral genetic diversity of human populations, Current Biology, Volume 15, Issue 5, pp. 159–R160, 8 March 2005 (Link)

Abstract:  A leading theory for the origin of modern humans, the ‘recent African origin’ (RAO) model [1] , postulates that the ancestors of all modern humans originated in East Africa and that, around 100,000 years ago, some modern humans left the African continent and subsequently colonised the entire world, displacing previously established human species such as Neanderthals in Europe [2,3] . This scenario is supported by the observation that human populations from Africa are genetically the most diverse [2] and that the genetic diversity of non-African populations is negatively correlated with their genetic differentiation towards populations from Africa [3] .

Thursday, September 22, 2016

Some comments on "Genomic analyses inform on migration events during the peopling of Eurasia"

Pagani et al
Nature
Published online
(Link)

"High-coverage whole-genome sequence studies have so far focused on a limited number[1] of geographically restricted populations [2–5], or been targeted at specific diseases, such as cancer[6]. Nevertheless,  the availability of high-resolution genomic data has led to the development of new methodologies for inferring population history[7–9] and refuelled the debate on the mutation rate in humans [10].  Here we present the Estonian Biocentre Human Genome Diversity Panel (EGDP), a dataset of 483 high-coverage human genomes from 148 populations worldwide, including 379 new genomes from 125 populations, which we group into diversity and selection sets.  We analyse this dataset to refine estimates of continent-wide patterns of heterozygosity, long- and short-distance gene flow, archaic admixture, and changes in effective population size through time as well as for signals of positive or balancing selection. We find a genetic signature in present-day Papuans that suggests that at least 2% of their genome originates from an early and largely extinct expansion of anatomically modern humans (AMHs) out of Africa. Together with evidence from the western Asian fossil record [11], and admixture between AMHs and Neanderthals predating the main Eurasian expansion [12], our results contribute to the mounting evidence for the presence of AMHs out of Africa earlier than 75,000 years ago."

My comments: 

Sounds good to me.  I would add that it is pretty backward to think that there is no "Eurasian" ancestry in Africans.  And if there is "Eurasian" ancestry in Africans, due to obvious high mobility of hominins backward and forwards across and between continents for hundreds of thousands of years, (and most large mammals for that matter) then most of these calculations regarding the degree of archaic and modern admixture in the hominin past are grossly under-estimated (since the degree of admixture in non-Africans has been inferred against Africans, and assumes that Africans [incorrectly] have no Neanderthal or Denisovan admixture.)  Furthermore, the time estimates of population splits would be different if we started to include the idea of high mobility and "soft" splits between hominin populations and continents.

Unfortunately, we rarely see sophisticated models accounting for bidirectional gene flow, high mobility, and other possible confounding phenomena.   The models reflect the same "just so" human origin genetic story, with ever so minor a variation, and are carefully crafted so as not to too directly tread on the toes of a small number of prominent and entrenched paleoanthropologists and human origin geneticists.

At least this paper managed to state the obvious that AMH was present in Eurasia earlier than 75,000 years ago (given those "80,000 year old" Daoxian AMH teeth).

:)

Yes, I'm smiling, but only because I don't work professionally in any field related to the cloying, over specialized, highly politicized and narrow field of human origin genetics.

Tuesday, September 20, 2016

Evolution of middle-late Pleistocene human cranio-facial form: A 3-D approach

Katerina Harvati, Jean-Jacque Hublin, Philipp Gunz
Journal of Human Evolution
59(5):445-64
November 2010
(Link)

Abstract


The classification and phylogenetic relationships of the middle Pleistocene human fossil record remains one of the most intractable problems in paleoanthropology. Several authors have noted broad resemblances between European and African fossils from this period, suggesting a single taxon ancestral to both modern humans and Neanderthals. Others point out 'incipient' Neanderthal features in the morphology of the European sample and have argued for their inclusion in the Neanderthal lineage exclusively, following a model of accretionary evolution of Neanderthals. We approach these questions using geometric morphometric methods which allow the intuitive visualization and quantification of features previously described qualitatively. We apply these techniques to evaluate proposed cranio-facial 'incipient' facial, vault, and basicranial traits in a middle-late Pleistocene European hominin sample when compared to a sample of the same time depth from Africa. Some of the features examined followed the predictions of the accretion model and relate the middle Pleistocene European material to the later Neanderthals. However, although our analysis showed a clear separation between Neanderthals and early/recent modern humans and morphological proximity between European specimens from OIS 7 to 3, it also shows that the European hominins from the first half of the middle Pleistocene still shared most of their cranio-facial architecture with their African contemporaries.

Monday, September 19, 2016

The earliest occupation of Europe: the Balkans

Andreas Darlas
Analecta Praehistorica Leidensia
1995
(Link) pdf

The absence of knowledge of prehistoric man in the Balkans is aciually due to the lack of prehistoric research within this area. Information on the Palaeolithic of the Balkan countries started to become available only in recent years. Data concerning the Lower Palaeolithic are very scarce and sites known from this period are not numerous. The only excavated sites which date to the earlier parts of the Middle Pleistocene are the caves of Yarimburgaz (Turkey), Petralona (Greece), Gajtan (Albania) and Sandalja (Croatia).

Sunday, September 18, 2016

Letter from the Society for American Archaeology (SAA) regarding the Dakota Access Pipeline

Diane Gifford-Gonzalez
Society for American Archaeology
September 13, 2016
(Link) pdf

Tribes open new front in fight over pipelines

Devin Henry
The Hill
09/18/16 08:30 AM EDT
(Link)

Pre-Sapiens Man in Greece

View from above Petralona Cave, looking south toward the Aegean Sea 














Aris N. Poulianos
Current Anthropology
Volume 22, Number 3, June 1981
(Link)

Until only 15 years ago, the Palaeolithic was almost unknown in Greece.  Some important Middle and Upper Palaeolithic sites and materials were discovered in Epirus and Thessaly in the 1960s, but apart from a few handaxes Greece remained terra incognita for the Lower Palaeolithic and the pre-sapiens stages of human development.  In recent years, however, discoveries by members of the Anthropological Association of Greece have radically transformed the situation.

In 1959, at Petralona, a village in Khalkidiki province, south of Thessaloniki, some local men searching for a spring in the mountainside happened upon a hole through which they were able to enter a huge cave full of stalagmites and stalactites.  The following year a primitive human skull was found adhering to a rock in the cave and was removed.  An early examination of this skull and of animal bones from the cave floor led to an estimated age of ca. 70,000 years; a search for the rest of the skeleton involved breaking up of the stalagmite layer and led to the destruction of the human bones.  My systematic excavations in the cave since 1968 have established a detailed stratigraphy, salvaged some human fragments, and proved conclusively that the skeleton and the cave's occupation belong to the Lower and Middle Pleistocene.  No fewer than 27 layers, with thicknesses ranging from 2 cm to 2 m and a total depth of over 15m, have so far been differentiated in the cave's fill.  The original entrance is blocked by a huge cone of sediment.  The layers decrease in thickness as one moves from this entrance to the interior of the cave.  Almost all the layers show traces of human occupation.

The Petralona hominid, known as Archanthropus europaeus petraloniensis, was located in a sort of compartment formed by a large fallen rock which had become wedged against the cave wall, thus constituting a 2 meter squared natural "mausoleum."  The body was in a crouched position with the head slightly elevated and resting on a rock;  it was surrounded by bone awls, burnt animal bones, and stone implements.  All of these finds are from Layer 11, which is the thickest and contains the most tools and other traces of habitation.  It is not surprising that the use of the cave at this time was intensive, since the sediments and fauna indicate a cold, humid climate.  Subsequently it became more humid, and a stalagmitic breccia (Layer 10) covered the floor and walls of the "mausoleum" and made a bridge between the skull and the rock.  During a later, drier phase, the sediments shrank and dropped to 24 cm, but the skull remained suspended, fixed by the stalagmite and thus separated from the rest of the skeleton.

Fauna, sediments, and stratigraphy all point to a late stage of the Lower Pleistocene for Layer 11.  The new dating technique of electron spin resonance gave a figure of 670,000 years, probably the Günz-Mindel interglacial, for Layer 10 and dated the stalagmite of Layer 1 to between 250,000 and 350,000 years.  Before the formation of this top stalagmite, probably by the end of the Mindel glacial, the cave had been abandoned and had closed up.  The uranium/thorium method dated the stalagmite of Layer 10 to a minimum of 400,000 B.P. (the upper limit of this method) and suggested a true age of ca. 600,000.  Palaeomagnetic studies of the sediments have shown an inversion of the earth's magnetic field in layers below 11, but such studies are fraught with problems.  In short, the cave's stratigraphy spans at least half a million years, corresponding to the late Lower and early Middle Pleistocene, Archanthropus having died more than 700,000 years ago, is the most ancient European yet known.

The fragments of post cranial skeleton salvaged from the "mausoleum" suggest that this hominid was a short (about 157 cm), muscular, mature individual.  Thought it is classified as Homo erectus, many features of the skull and skeleton fall within the modern human range.  Fragments of up to 15 other individuals have so far been found in different parts of the cave.

The first ten layers contain bone tools, pebble tools, and handaxes;  this stone industry has been dubbed Petralonian.  A cruder industry, the Crenian, is found in Layer 11 and below.  The type of tool technology used here was not known in Europe until these finds; . . .

(read more)

Saturday, September 3, 2016

Revisiting Kokkinopilos: Middle Pleistocene radiometric dates for stratified archaeological remains in Greece










Vangelis Tourloukis, Panagiotis Karkanas, Jakob Wallinga
Journal of Archaeological Science
March 2015
(Link)

Abstract

The red-bed site of Kokkinopilos is an emblematic and yet also most enigmatic open-air Palaeolithic site in Greece, stimulating controversy ever since its discovery in 1962. While early research raised claims for stratigraphically in situ artifacts, later scholars considered the material reworked and of low archaeological value, a theory that was soon to be challenged again by the discovery of in situ lithics, including handaxes. Here we present results of a latest and long-term research that includes geoarchaeological assessments, geomorphological mapping and luminescence dating. We show that the site preserves an overall undisturbed sedimentary sequence related to an ephemeral lake, marked by palaeosols and stratigraphic units with Palaeolithic material that is geologically in situ and hence datable. Our study resolves the issues that have been the source of controversy: the depositional environment, stratigraphic integrity, chronological placement and archaeological potential of the site. Moreover, the minimum ages obtained through luminescence dating demonstrate that the lithic component with bifacial specimens considerably pre-dates the last interglacial and therefore comprises the earliest stratigraphically defined and radiometrically-assessed archaeological material in Greece. Kokkinopilos has served as a reference site for the interpretation of all other red-bed sites in north-west Greece, therefore our results have significantly wider implications: by analogy to Kokkinopilos, the open-air sites of Epirus should not anymore be considered ‘by default’ as inscrutable palimpsests with limited archaeological potential; rather, these sites can be excavated and chronologically constrained. This realization opens up new prospects for future research in Epirus, an area that is the most prolific in Palaeolithic remains in Greece.

Saturday, August 20, 2016

The Pre-Mousterian industrial complex in Europe between 400 and 300 ka: Interpreting its origin and spatiotemporal variability

Vladimir Doronichev
Quaternary International
Volume 409, Part B,
21 July 2016, Pages 222–240
Special Issue: The Hoslteinian period in Europe (MIS 11-9)
(Link)
 
Abstract

The author discuss data indicating that the non-handaxe (non-Acheulean) tradition of small tools and core-choppers was present in parts of West Eurasia during the early Middle Pleistocene – the period marked by a wide spread of Acheulean in West Asia and West Europe – and survived until 400–300 ka and perhaps later in some areas, beyond the area of the maximum Acheulean distribution, in the Danube basin and the Balkans, and to a limited extent north of the Danube basin in Central Europe, and in the south of Russian plain and Northern Caucasus in Eastern Europe. The author defines these Middle Pleistocene assemblages, which are totally lacking true Acheulean handaxes and debitage resulted from large flake or Levallois knapping technologies, as the “Pre-Mousterian industrial complex”. The assemblages of Pre-Mousterian complex are variable due to their functional differentiation and other reasons, but generally comprise the next three components: (1) simple (mostly primary and orthogonal, and also rare unipolar and centripetal) cores with short reduction sequences, consisting of flaking of 1–3 flakes from one platform, followed by the core rotation or discard; (2) flake-tools, which are made mostly (but not exclusively) on small-sized flakes with beveled platforms and include varieties of simple side-scrapers, denticulates, notches, thick end-scrapers, awls, and convergent pieces, as well as small numbers of tools with flat ventral retouch or bifacial retouched edges; and (3) large-sized tools are always present and include mostly unifacial choppers, and more rare chopping-tools and proto-bifaces (or pointed choppers) with partial bifacial processing. The author discuss that the hominids that produced lithic industries of Pre-Mousterian complex acquired a high behavioural plasticity to settle in most uncomfortable (within Western Eurasia) forested and forest-steppe environments with cold winters in Central and Eastern Europe. The hominids developed tool inventories well suited for bone- and woodworking, made real wooden throwing spears and composite tools with wooden hafts that are found in Schöningen. In contrast to the Acheulean complex in West Europe and West Asia, assemblages of Pre-Mousterian complex do not show a transition (temporally being placed now during MIS 8–MIS 7, between c. 300–200 ka in both the regions) toward the Middle Palaeolithic or Mousterian technology. In contrast to the Acheulean to Middle Palaeolithic transition, which is associated with final neanderthalization of H. heidelbergensis and the origin of H. neanderthalensis, the assemblages of Pre-Mousterian complex disappear with the spread of Early Middle Paleolithic Neanderthals.

Thursday, August 4, 2016

Decolonizing the Past and Present of the Western Hemisphere (Americas)

Paulette F. Steeves
Decolonizing the Past and Present of the Western Hemisphere (Americas)
Archaeologies: Journal of the World Archaeological Congress (2015)
DOI 10.1007/s11759-015-9270-2
(Link)

p. 52

I have found in my research that there are hundreds of reports on Pre-13,200 calBP or Pre-Clovis sites which have been dismissed a priori by American archaeologists, yet there are very few published critiques of those same sites. In considering the possibilities of earlier initial migrations, I have found that scholars who reject Pre-Clovis sites do not often discuss the environmental possibilities of east-west migrations during the Pleistocene.

Studies based on sites in the Eastern Hemisphere indicate that early modern humans were adapted to living in diverse environments prior to 100,000 years ago and were present on the mainland and islands of Asia, Europe, and Africa. There is also a well-known history of mammalian migrations between the Eastern and Western continents spanning across millions of years (Prothero 2005:1; Rybczynski et al. 2013:1550; Wallace and Hulbert 2013:1). Archaeologists who denounce the possibilities and evidence for Pre-Clovis migrations have historically ignored the evidence of the global history of human migrations, paleoenvironments, and intercontinental mammalian migrations that shed light on the very questions they ask. Environmental records strongly infer that the worst time to cross the Bering Land Bridge was after 24,000 ybp during the post-Last Glacial Maximum period.

Initial migrations, whether 13,200 calBP or earlier, took place during a time when the continents were divided into nations and not identified by the specific cultural and political units which are common today. When archaeologists use contemporary nation’s names to discuss migrations of ancient peoples, they infer that thousands of years prior to the existence of Asia and America, Asians walked across Beringa and instantly became Americans. Such claims made in the name of Western Science and often accepted as fact by the general population are not exposed for the absurdity of their claims (Deloria 1997:73).

Tom Dillehay who excavated the Monte Verde site in Chile stated that when radiocarbon tests came back as older than 12,000 ybp, he was startled, since he had been taught that such dates were impossible (Dillehay 2000:xv).  He stated he had been taught the Clovis culture represented the first people whose initial migrations took place around 11,200 years ago (Dillehay 2000:xv).  James Adovasio who excavated the Meadowcroft site in Pennsylvania stated that on receiving the facts that his site dated to older than Clovis, he was not that surprised, but he knew that his ‘‘career was about to veer off into the archaeological badlands’’ (Adovasio and Page 2002:xiii).

What he was referring to was that the dates for the Meadowcroft site ‘‘put people in Pennsylvania some four thousand years before any human being was supposed to have set foot in this hemisphere’’ (Adovasio and Page 2002:xiv). The guarded Clovis First time frame was not in any way logical but was argued to represent a ‘‘cherished dogma’’ (Adovasio and Page 2002:xiii). Archaeologists’ experiences of having their sites overly scrutinized and of being academically bashed for reporting Pre-Clovis sites makes no sense, at least not in a world where science is expected to rule over opinion and bias.

In recent years due to mounting evidence of Pre-Clovis of pre-13,200 calBP sites such as Monte Verde in Chile (Dillehay 2000:15), archaeologists are now more accepting of the possibilities of earlier sites (Waguespack 2007:63). However, even with the presence of hundreds of sites providing evidence for earlier Pleistocene initial migrations, contemporary academics remain skeptical of sites which date to more than a few thousand years earlier than Clovis time frames. This is the same agenda as the Clovis First hypothesis regarding diminishing the time frames of initial migrations, just allowing that humans arrived in the Western Hemisphere a few thousand years earlier than Clovis time frames (Meiri et al. 2014:7; Goebel et al. 2008). Such theories, which propose a recent boundary of time for the earliest date of initial migrations, continue to ignore a vast body of data on earlier Pre-Clovis sites located throughout areas of North and South America.

When discussing initial migration possibilities, it is important to remember that we do not have a clear understanding of earliest sites in either the eastern hemisphere regions of Asia or the northern hemisphere regions of North America. Discussions of earliest human migrations are based on what we know from recorded sites, and gaps in the archaeological record suggest there is a lot we do not yet know. Further research and discovery of new sites and evidence is paramount to furthering discussions of links between sites in the Eastern and Western Hemispheres. However when early humans have been present in the Eastern Hemisphere for over 1.8 million years and a land bridge between the east and the west has been available for much of that time, why would it have been impossible for people to arrive in the Western Hemisphere at earlier than Clovis dates?

The environmental record provides strong evidence that it would not have been impossible at all. The record of early human sites in the Eastern Hemisphere informs us that early human were very capable of traveling great distances through diverse ecological zones.

For millions of years northern areas of the Eastern and Western Hemispheres were connected by a wide low laying land mass that was periodically inundated with seawater. The area which is now known as the Bering Land Bridge was available for intercontinental migrations for much of the last 100,000 years (Wright 1991:138) and throughout much of the Pleistocene (Adovasio and Page 2002:620). During the last 1.6 million years, glaciers advanced and retreated facilitating mammalian migrations across the land bridge between the Eastern and Western Hemispheres in both directions (Adovasio and Page 2002:62). The environmental evidence suggests that the most difficult time to migrate across the Bering Land Bridge was during or after the LGM 24,000–14,000 years ago. The majority of proponents of the Clovis First hypothesis have conveniently left this discussion out of their arguments as it is a point that supports the possibilities of earlier initial migrations to Western Hemisphere.

The facts as discussed remain, and the Clovis First hypothesis of initial migrations after 13,200 calBP was never based on any proven scientific facts or data (Bryan 1986:2). The Pan Hemispheric Clovis culture was created from over-simplified theories based on fluted tools, which were ‘‘uncritically lumped together’’ (Dillehay 2000:27). The fluted Clovis tool and the boundary of time for its initial appearance became, and most often remains, a dangerous border to cross in American archaeology.

Evidence for Great Antiquity

When I had reviewed published literature which discussed over 300 pre-Clovis sites in the Western Hemisphere, I realized that there were far more than just a few well-recorded and documented sites. I also realized that this area of research had much to offer in illuminating the past and in work to decolonize historical initial migration paradigms and Indigenous histories. Pre-13,200 calBP or Pre-Clovis sites in the Western Hemisphere number in the hundreds and are located throughout the Northern and Southern continents.

There are far too many to list in this article; however, a sample is included in Table 1. This list of sites represents a small fraction of the possibilities for future Paleolithic research in the Western Hemisphere.  Many of the site collections may be available for further study and new excavations may be feasible at some site areas. The inclusion of a site in this list does not represent a site that is not controversial or that does not warrant further work. Many of the sites in this list meet or exceed the required reasonable scientific criteria. Scientific criteria are described by Adovasio and Page (2002:99) as follows:

• Undeniable artifacts or osteological remains that were unmistakably human.

• An indisputable context (such as direct stratigraphic association with extinct Pleistocene animal remains).

• A valid and reliable control over chronology… which meant an undisturbed stratigraphy (Adovasio and Page 2002:99).

Many of the sites on this list have been discussed by archaeologists as problematic based on one or more arguments. However, the majority of the sites have not benefited for a published critique based on first-hand knowledge, site visits, or collection studies. Tom Dillehay (2000) argued that many discussions which dismissed pre-Clovis sites as illegitimate were often based on invented mistakes.

‘‘In their haste to defend the Clovis First model, they fantasized floods and other natural events to explain the association of the different cultural traits often found at non-Clovis sites, or, worse they invent mistakes in the analysis of those sites to give them cause for dismissing them. What this all boils down to is the politics of science and the replacement of one paradigm by another’’ (Dillehay 2000:xviii).

I am not saying that all Pre-Clovis sites are not problematic; many would benefit from further testing and research. I do however agree with Herbert Alexander (1978) who argued that ‘‘we have had the evidence of human antiquity in the Americans for a long time, and we should insist that it be used’’ (22). A great deal of energy has been spent on arguments denying a pre-13,200 calBP human presence in The Western Hemisphere. The energy and resources spent on denial may be better utilized by training students in Paloelithic studies. 

Sunday, July 31, 2016

Progressive Westward Expansion of North American Continental Ice Sheets During The Quaternery and Implications for the Timing of Initial Human Overland Migration Into the Americas

Chief Mountain (Ninaistakis), viewed from never glaciated Del Bonita, Alberta.
 
















Western limit (Taber, Alberta) of pre-OIS 2 glaciation along the Oldman River.

 























Figure illustrating southern limit of glaciations (Illinoian and Wisconsinan).
Note that Del Bonita, Alberta lies at the southern boundary of
maximum glaciation.
 


























Progressive Westward Expansion of North American Continental Ice Sheets During The Quaternery and Implications for the Timing of Initial Human Overland Migration Into the Americas
Jackson Jr, Lionel E.,
2014 Annual Meeting,
The Geological Society of America
19-22 October, 2014
Paper No. 137-3
(Link)

Abstract:

There is extensive and robust stratigraphic and geomorphic evidence of progressive enlargement of North American (NA) continental ice sheets in a westerly direction during successive glaciations of the Quaternary Period. This culminated in a one-time coalescence of the Laurentide Ice sheet and valley glaciers from the Rocky and Mackenzie mountains and outlet glaciers from the Cordilleran Ice Sheet during marine isotope stage (MIS) 2. This singular coast-to-coast ice (CCI) event ended the pattern of broad ice-free corridors between Cordilleran and continental glaciers that was the norm during all previous Quaternary glacial maxima in North America. Recent discoveries of human settlements above the Arctic Circle in eastern Siberia during MIS 3 (~30 C14 ky BP) and an accumulation of archaeological sites in NA south of the limit of glaciation dating to MIS 3 (specifically <30 C14 ky BP to ~22 C14 ky BP) or contemporaneous with the CCI event during MIS 2 (specifically ~22 C14 ky BP to ~14 C14 ky BP) suggest that the limiting event for initial overland human migration into the Americas was the closing of the ice-free corridor rather than its opening as has been the orthodoxy.

Thursday, July 14, 2016

Mammuthus Population Dynamics in Late Pleistocene North America: Divergence, Phylogeography, and Introgression

Jacob Enk, Alison Devault, Christopher Widga, Jeffrey Saunders, Paul Szpak, John Southon, Jean-Marie Rouillard, Beth Shapiro, G. Brian Golding, Grant Zazula, Duane Froese, Daniel C. Fisher, Ross D. E. MacPhee, and Hendrik Poinar
Frontiers in Ecology and Evolution
published 26 April, 2016
doi: 10.3389/fevo.2016.00042
(Link) open access pdf

Abstract.

After evolving in Africa at the close of the Miocene, mammoths (Mammuthus sp.) spread through much of the northern hemisphere, diversifying morphologically as they entered various habitats.  Paleontologically, these morphs are conventionally recognized as species.  In Pleistocene North America alone, several mammoth species have been recognized, inhabiting environments as different as cold tundra-steppe in the north and the arid grasslands or temperate savanna-parklands of the south. Yet mammoth phylogeographic studies have overwhelmingly focused on permafrost-preserved remains of only one of these species, Mammuthus primigenius (woolly mammoth).  Here we challenge this bias by performing a geographically and taxonomically wide survey of mammoth genetic diversity across North America.  Using a targeted enrichment technique, we sequenced 67 complete mitochondrial genomes including non-primigenius specimens representing Mammuthus columbi (Columbian mammoth), Mammuthus jeffersoni (Jeffersonian mammoth), and Mammuthus exilis (pygmy mammoth), including specimens from contexts not generally associated with good DNA preservation.  While we uncovered clear phylogeographic structure in mammoth matrilines, their phylogeny as recovered from mitochondrial DNA is not compatible with existing systematic interpretations of their paleontological record.  Instead, our results strongly suggest that various nominal mammoth species interbred, perhaps extensively. We hypothesize that at least two distinct stages of interbreeding between conventional paleontological species are likely responsible for this pattern—one between Siberian woolly mammoths and resident American populations that introduced woolly mammoth phenotypes to the continent, and another between ecomorphologically distinct populations of woolly and Columbian mammoths in North America south of the ice.

Sunday, June 26, 2016

The Evolution of Cultural Complexity: Not by the Treadmill Alone

and
Current Anthropology
Volume 57, Number 3 (June 2016)
(Link to abstract) [Full article available with a credit card purchase of $10.00]

Abstract

Among the drivers and constraints on the evolution of complex hominin culture that have been proposed throughout the years, demographic factors have been particularly persistent, and they have recently again come to gain traction in the literature in the shape of the so-called treadmill model. The treadmill model connects cultural complexity to group size via a need to constantly “outrun a treadmill of cultural loss,” whose backward motion is caused by errors in culture transmission. The entrenchment of the treadmill explanation of cultural complexity, however, takes place against a background of critiques of the model and the presence of other explanatory propositions. This creates a need for deentrenchment: wider integration, elaboration, and critique of the premises of the treadmill model and the evidence advanced to validate it. We begin by reviewing the treadmill model, making an assessment of its current status, and then moving on to a more synthetic proposition by placing the model into the context of other models addressing the elaboration of cultural complexity. We end by considering the broader implications for the study of the evolution of culture and of human behavior to be gained from more integrated modeling of the various factors affecting cultural complexity.