February 14, 2016

Archaeologists studying Monte Verde claim an age of 18 Ka BP and add some detail

Quickies

I'm going in this and upcoming short entries through my backlog. You are warned.

New archaeology from Monte Verde (Chile) suggests a date of 18 Ka BP (slightly older than the oldest known North American site) and also that it was a transiting site for highly mobile peoples and not a main base, as they were not using superior local lithics but bringing their own.

Tom D. Dillehay et al. New Archaeological Evidence for an Early Human Presence at Monte Verde, Chile. PLoS ONE 2015. Open accessLINK [doi:10.1371/journal.pone.0141923]

Abstract

Questions surrounding the chronology, place, and character of the initial human colonization of the Americas are a long-standing focus of debate. Interdisciplinary debate continues over the timing of entry, the rapidity and direction of dispersion, the variety of human responses to diverse habitats, the criteria for evaluating the validity of early sites, and the differences and similarities between colonization in North and South America. Despite recent advances in our understanding of these issues, archaeology still faces challenges in defining interdisciplinary research problems, assessing the reliability of the data, and applying new interpretative models. As the debates and challenges continue, new studies take place and previous research reexamined. Here we discuss recent exploratory excavation at and interdisciplinary data from the Monte Verde area in Chile to further our understanding of the first peopling of the Americas. New evidence of stone artifacts, faunal remains, and burned areas suggests discrete horizons of ephemeral human activity in a sandur plain setting radiocarbon and luminescence dated between at least ~18,500 and 14,500 cal BP. Based on multiple lines of evidence, including sedimentary proxies and artifact analysis, we present the probable anthropogenic origins and wider implications of this evidence. In a non-glacial cold climate environment of the south-central Andes, which is challenging for human occupation and for the preservation of hunter-gatherer sites, these horizons provide insight into an earlier context of late Pleistocene human behavior in northern Patagonia.

Notice that Monte Verde is quite towards the south and, in Ice Age contexts, it was a rather extreme environment, barely outside of the glaciers. I wonder what they looked for in such a remote place, even if they probably only went there in summer.

14 comments:

  1. Dear Maju, I too saw this paper. The date you cite from the paper is Dillehay's 'preferred' date. His team in fact discovered artifacts, other materials and debatable charcoal between ca. 33,000 and 44,000 years old. However due to the extremely controversial nature of presenting such dates he plays them down. I have written a long blog post about this at: http://www.thefuzzysasquatch.blogspot.co.uk/2015/12/monte-verde-18500-bp.html?m=1
    Hope you find the information interesting. NeilB

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    1. Well, interesting analysis the one you make, thanks, but:

      Fig. S6a could be a chopper but could also be a stone broken naturally. Unless more evidence is found the principle of caution prevails. It happens with all unusual ("out of place") artifacts and unusual datings, some evidence must pile up and be hard to dismiss as a mere random accident. Wheres is that other evidence?

      IF that's a chopper, then it's almost certainly not evidence for presence of H. sapiens, nor even the second global wave of H. erectus/ergaster (with Acheulean tech) but it should be "evidence" of H. erectus, and that's a very long shot.

      I must remind you that in America there is a non-human species of primate that does use tools: capuchin monkeys, who use small round boulders to crack nuts in a planned (intelligent) manner. Those rocks can perfectly break through use in the way of choppers. We are not that unusually bright in the realm of mammals: some primates, corvids and definitely dolphins do approach our intellectual capabilities. But even assuming (what is a lot to assume considering the paucity of evidence) that it is a chopper, then the most parsimonious explanation would be a very ancient H. habilis style population. This is anyhow extremely hard to believe and no doubt would need of more evidence of the kind we do find in Africa: human bones, signs of use of fire, accumulation of tools in specific sites, etc. The evidence you present is a very long shot from that.

      Fig. 6b does remind of some Epipaleolithic flakes, however it's clear that the rock has not been worked and only presents a single flaking cut, what is almost certainly an accident.

      So not credible, sorry.

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    2. Dear Maju, thank you for taking the time to have a look at my post.
      A quick couple of points in an interview with National Geographic Dillehay had this to say regarding Monkey made tools: " Dr. Dillehay, the American archaeologist who discovered Monte Verde. “Fiedel does not know what he is talking about,” he said, explaining that similarities existed between the stone tools found here and at the site across South America in Chile. “To say monkeys produced the tools is stupid.”
      Secondly as you yourself have pointed out as did Dillehay, the environment in the region of Monte Verde at the time the stone tools were deposited was periglacial and therefore not suitable for Capuchins. The nearest population is in fact in the northern semi-tropical of Argentina east of the Andes. The pounding stones they use to crack nuts are almost always spherical river cobbles as discussed in Fragaszy D, et al. 2004 Wild capuchin monkeys (Cebus libidinosus) use anvils and stone pounding tools. American Journal of Primatology 64: 359-366.
      No flaked cobbles like those at Monte Verde were used.
      Therefore it is extremely unlikely Capuchins made the tools dated ca. 33000BP. One of the lithic implements of this date discovered pre-1997 had proboscidean blood traces. Why Dillehay has chosen to play down his own evidence of an early entry of man into the Americas is surely to do with his previous difficulties getting his site accepted at even 13000BP.
      The main point is that Dillehay has proven occupation at Monte Verde at least by 18500BP. The site is ca. 15000km from the presumed point of entry in Beringia.
      In your opinion given the genetic evidence available, by what route and at what date would you hypothesize man entered America? NeilB

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    3. OK, not capuchins maybe BUT rocks do break accidentally. The kind of fracture that those two rocks display has no clear signature of human facture, on the contrary: the most parsimonious explanation is random breakage by natural causes. However, if you or others think otherwise, the best you can do is to find more and better evidence, in Monte Verde or elsewhere in America that supports your claim. Just insisting on this most dubious kind of "evidence" won't be enough: no impartial court would consider your case proven and your demand would almost certainly never pass the preliminary hearing level. Get more, better evidence.

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  2. Dear Maju, I sincerely applaud you for at least entering into a discussion about the possibility of human entry into the Americas at an early date. I agree if Dillehay does not claim an early entry into the Americas based on the data he has collected why should you? Quite correctly you ask for more evidence. May I therefore direct you to the paper by Farina et al: Arroyo del Vizcaino, Uruguay: a fossil-rich 30ka-old megafaunal locality with cut-marked bones.
    http://rspb.royalsocietypublishing.org/content/281/1774/20132211 . This site has well has a large collection of all-adult, well dated giant Ground Sloth bones with unquestionable human-made butchery marks. The date is ca. 30,000BP. Let me know what you think of the quality of Farina's evidence. Incidentally you failed to answer my question: " The main point is that Dillehay has proven occupation at Monte Verde at least by 18500BP. The site is ca. 15000km from the presumed point of entry in Beringia. 
    In your opinion given the genetic evidence available, by what route and at what date would you hypothesize man entered America?"
    NeilB

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    1. Ugh, unmistakable cut marks are not so unmistakable and can easily be produced by ungulates trampling on the bones. I recall a discussion years ago about whether Australopithecus afarensis used tools, based on similar evidence from the Horn of Africa, and AFAIK the case remains open.

      Anyhow, considering the dates, I'd say it's almost impossible that those presumed early settlers could be Amerinds, because Asian archaeology has them at those dates still in Mongolia and North China: it's approx. the same date that the Upper Paleolithic technology arrives to East Asia. If anything it'd be a very early and strictly Oriental branch whose genetic track is now lost (went extinct, unless they persist in the minor Y-DNA C* of Ecuador, what may also have arrived later anyhow).

      I am very open-minded but the best evidence is lots of evidence, good quality one if possible. And, well, some isolated cutmarks don't seem enough, really. Where's the flake technology? Where the handaxes? Where the skulls and bones?

      There's a general precaution principle in archaeology which is that "out of place" artifacts or sites are generally quarantined, i.e. not taken seriously unless more evidence in the same direction piles up. For example: I recall something (decades ago) about late Acheulean persistence in Galicia, what happened with that? Nothing because nothing else in the same direction has been documented. Or, do you recall the once famous Lagar Velho boy, "evidence" of Neanderthal admixture in Portugal? Well, his skull was just flattened by post-mortem earth pressure: he was a perfectly normal "modern" guy when alive.

      Caution, please. Enthusiasm is good but precaution is also. There must be a reasonable balance.

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    2. "In your opinion given the genetic evidence available, by what route and at what date would you hypothesize man entered America?"

      I didn't address this question. Anyhow the answer is nowadays very clear (browse this blog for the tag "Native Americans" for specific data):

      1. A patrilocal population with Upper Paleolithic technology and dogs was established in Altai since c. 47 Ka BP.

      2. Some of them migrated east to Mongolia and North China c. 30 Ka BP, the ones remaining East of Lake Baikal probably admixed with other peoples of West Eurasia in the Gravettian period, being Mal'ta 1 and Afontova Gora their best known representatives, carrying genetics that are akin to Native Americans but also to Europeans (Eastern ones especially) and not akin to mainline East Asians.

      3. In NE Asia these migrants must have incorporated heavily local women to their population, that's why I imagine them patrilocal. A similar but inverse phenomenon happened later, after the LGM, with the (proto-)Uralic migration Westwards. The result is a population with lots of "Western" Y-DNA (Q1) but very little mtDNA from that origin (X2). Inversely it has very little Eastern Y-DNA (C2, former C3) and lots of of Oriental mtDNA (A, B, C and D).

      4. Once in coastal NE Asia, they reached Beringia easily and kept canoing ahead, on their convenience, along the coast until they reached Chile. Of course the coastal route is not incompatible with other slower routes on foot (or along rivers) in diverse directions. This part probably happened soon after the LGM, considering the solid archaeological evidence, which is of c. 17-18 Ka BP.

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  3. Dear Maju, sorry for the delay in replying. The Farina et al paper addressed the issues of the taphonomic modification of the bones at Arroyo de Vizcaino in some detail. Firstly they looked at the age profile of the ground sloths. This matched those of other human kill sites. Secondly they sorted the bones into those modified by trampling from those that had putative cut marks. That figure was 5% again comparing well with other well documented human kill sites. Next the authors analyzed whether animal trampling was the cause of the scratches on bones or whether human modification was provable. They used the latest criteria and analysis techniques as laid out in Domínguez-Rodrigo et al. 2009 (A new protocol to differentiate trampling marks from butchery cut marks. J. Archaeol. Sci. 36, 2643–2654.) to prove their case. A quote that paper: "Here we present a multivariate analysis of more than a dozen variables and show that butchery and trampling marks have very distinctive microscopic morphology." Hence I believe they showed conclusively that some of the bones were modified by humans. They also found lithic implements in the bone bed. Overall the authors seem to have been very thorough in discounting any cause other than human modification to the cut marks on the bones. Therefore it seems likely humans entered the Americas some time between ca. 75,000 and ca. 33,000 years ago depending on which migration rate one uses. This could therefore mean tthese people were archaic homo sapiens or Homo erectus sensu lato. If you discount this evidence and only use Dillehay's 18,500BP date you still arrive at a date for man's entry into the Americas of 63,000 to 21,000BP. NeilB

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    1. Can you differentiate between what is irrefutable evidence and what is merely an indication? I begin to suspect that your insistence on taking isolated indications as if it'd be proof disqualifies you for jury service.

      The accused is not guilty for lack of enough evidence, in quantity or quality. It remains suspect if you wish and, unlike in most legal systems, the trial can be held again at any moment - but bring more and more clear evidence, please, else thee will be no hearing.

      Also the window of time you are offering 63-21 Ka BP is not a reasonable time window: it's almost as saying nothing. These are in fact two windows: the 60+ one, which you're trying to prove with too limited success, and the 18+ LGM one, well attested today.

      One thing is "it seems" (looks probable) and another thing is the phrase I'd use for the older window, which is "it might". But "everything that has a name may exist", says the Basque adagio. What it doesn't say is that it does exist, for that we need strong evidence. Where are the Levallois stone flakes, handaxes, rock art and/or human bone remains, for example? Where is the oh-so-ancient genetic line? Q1 is clearly not old enough, no matter how you calibrate it, the East Asian mtDNA lines are not either! See here for the latter, and you'll realize that, considering the timeline of Asia, it is almost impossible that any modern humans were in the Arctic areas (like the necessary Beringia) as early as in your older time frame. For example the coalescence of mtDNA M8 (ancestor of M8a and CZ, this one ancestor of C, this one ancestor of some of the Native American lines but also many Eurasian ones) must be roughly coincident with the beginning of the West Eurasian Upper Paleolithic c. 50 Ka BP. And M8 did not coalesce in America, nope, but in North China. Similarly mtDNA X (precursor of X2, precursor of X2a, the Native American subclade that can be coupled all the way to Central/West Asia with Y-DNA Q1) had not yet coalesced by that time (I estimate 50-40 Ka window for the X node). So the arrival of modern humans to Beringia and America fits well with the Upper Paleolithic timeline: c. 47 Ka in Altai, c. 30 Ka in NE Asia (Mongolia, North China), by inference c. 25-20 Ka in Beringia and, finally c. 18-17 Ka in America proper.

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  4. Dear Maju you are of course right on many counts. However simply putting every small piece of evidence for an early entry into the bucket marked 'doesn't fit our model IGNORE' doesn't move the debate forwards.
    On stone tools: toolkits older than biface technology have been recorded frequently in the Americas and quietly ignored. Even older tools of the 'Chopper/chopping' occasionally published are seen as a form of heresy.
    Genetics: Many modern data sets ignore or completely screen out any mtdnas not from haplogroups A, B, C, D or X - the accepted ones. Therefore the true diversity is unknown. If we are looking for older clades in the Americas we should be looking at mtdna M and N. In mtdna M was found in two ancient burials from China Lake, British Columbia (Malhi 2007). A substantial list of papers have a section for 'other' mtdna types in Native American populations outside the five founder haplogroups. I have a long list of these and can provide references.
    On the ydna side haplogroup R has long been suspected of being Native American, again I can provide some references.
    Rock art: Extremely hard to date, but some Mojave desert images are confirmed at 17,000BP and others tentatively at 20,000BP+
    Each individual piece of evidence has been quietly ignored because it doesn't fit the entrenched model.
    So I chose to strongly defend a modern paper impeccably written BECAUSE so many papers in the past have been quietly ignored.
    Lastly humans were at Monte Verde 18500BP. What date do you think that has us entering the continent? NeilB

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    1. That "ignore" or "out-of-place" category is common in Archaeology and I bet that in other sciences, like Astronomy, as well: you find one of a kind and you're not even sure of how to judge it, so keep researching and do not jump to conclusions without further evidence. There's no need to hurry any "debate": science does not work that way, without clear evidence the answer can only be a languid shrugging of shoulders in indifferent uncertainty or maybe the slightly more dramatic raising of eyebrows in disbelief.

      Said that, I'll address your specifics:

      1. mtDNA: I recall that some ancient NA, sequenced a decade ago or so, was said to be M*, however I don't know if this was later corrected. As for modern mtDNA: any abundance of Asian-specific lineages would have been spotted, because the "screening" you mention is to leave aside any European or West Eurasian signature due to admixture. This screening anyhow I'm only aware of in Y-DNA, as recent European or other exogenous matrilineal admixture is unheard of in NA groups.

      2. Y-DNA: you're right although the issue remains AFAIK in wait of further research. Some North American Native Y-DNA R* lineages could be of Mongol relatedness. That would not change much in the scheme of things mentioned before, because Mal'ta was R* and Q1 is a close cousin of R: it would fit well with the Altai UP chronology. It would be interesting to solve in any case.

      3. Rock art: 17 Ka BP is the kind of date we are considering "normal" here, although cool because it's very early within this paradigm. 20 Ka BP even would be considered "normal" within the post-LGM colonization paradigm: I personally would not be surprised if new dates push back the date of entry to c. 20 Ka BP, probably earlier in Beringia; it's older than 25 or 30 Ka BP what would be a game changer and what I think "impossible" is older than 50 Ka BP, because IMO no H. sapiens lived in the Far North so early, so no Beringian inhabitation and no migration to America by any plausible route.

      For me the only possible "Amerind" time frame is after 30 Ka BP, probably many millennia later, like 20 Ka BP onwards (what so far fits with the solid evidence). A colonization in the 50-30 Ka BP window would correspond to a hypothetical pioneer East Asian specific population (no Q1, could be C, D, NO on the Y-DNA side, conjecturally speaking) that I cannot fully discard but for which I don't see any clear evidence in support. A colonization in before 50 or 60 Ka BP would be a total game-changer because it would imply a very early adaption of Asian H. sapiens to near-Arctic conditions, something for which absolutely no evidence exists, be it archaeological or genetic. On the other hand it could be Neanderthals or "Denisovans" (H. erectus?), which were indeed inhabiting cold areas much earlier than our species. In fact, the kind of (dubious) evidence you presented could fit best with something like H. erectus, rather than H. sapiens (if they reached Flores, they could perfectly have reached Beringia and beyond - or maybe not).

      "What date do you think that has us entering the continent?"

      I just said it but just to underline it: post-LGM, 20 Ka BP maybe. Other older possibilities do exist but so far only in raw theory and before c. 30 Ka BP would mean that they were not mainline ancestors of modern Native Americans (their necessary "Oriental" Y-DNA got lost, unless it's that C* that has been detected at low frequencies in Ecuador), older than ~50 Ka would be almost necessarily not H. sapiens.

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  5. Dear Maju, your summary of current evidence is indisputable. However your comment from point 1 " I'm only aware of in Y-DNA, as recent European or other exogenous matrilineal admixture is unheard of in NA groups." can be questioned by new data from ancient genomes. I refer to the AMH dna stretches have been found in an Altai Neanderthal (Kuhlwilm et al. Nature (2016) doi:10.1038/nature16544 
    Ancient gene flow from early modern humans into Eastern Neanderthals). Given the age of the purported dna we have to ask what mtdna haplogroup was it? Something like L3 perhaps? This Mtdna has been found in NA populations especially in South America but is always coconsidered as post Colombian admixture from African slaves. I think our current model of the peopling of the Americas prevents us from viewing the data objectively.
    On timing of entry into the Americas by Homo sapiens I wrote a 'back of the envolope calculation showing AMH could have reached America any time after ca. 100,000 years ago (see post here: http://www.thefuzzysasquatch.blogspot.co.uk/2016/02/the-peopling-of-americas-iii-human.html?m=1). Lastly rumours in the Archaeological community of a Mammoth kill site dated ca. 50,000 BP and excavated with excruciating care and at a very slow pace have been leaking out over the last few months. I think that, on current evidence you are correct, but only further discoveries will settle the matter. If there are no ancient burials pre-dating 25,000BP over the next decade or so I'd have to completely agree with you. NeilB

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  6. AFAIK the Kuhlim paper only talks of autosomal DNA, not of any haploid lineage. These Eastern Neanderthals of Altai surely existed in situ since approx. 70 Ka and 33 Ka BP, although since c. 47 Ka BP they were constrained to the northern areas of the region, as our kin had taken their former caves of the south and center. It's plausible that Ust-Ishim had some extra admixture from them but otherwise we don't see any clear signal of significant secondary hybridization events in modern humans (John Hawks would argue for it but IMO his "evidence" is very weak, wishful thinking, as he's adamant of "multiregionalism").

    Regarding the presence of L3 among Native Americans, all I can say is that L3 is an already evolved lineage and cannot be attributed, like nothing in the modern human mtDNA tree, to introgression from any other species (in the Y-DNA and X-DNA perspectives we do find however some lines that are almost certainly introgressed: Y-DNA A00 and A0 from some African close cousin and X-DNA B006 from Neanderthals).

    Anyhow, if it has to be pre-Columbian, it should have arrived from Africa. I can't totally discard pre-Columbian trans-Atlantic travel, it's just not proven in most cases and the most likely candidates suggest Mediterranean connections such as Iberia, where L3(xM,N) does exist but is quite rare, rather than Tropical Africa. If there would have been a Mediterranean input to Native Americans, we should see lineages like H more commonly than L3, and AFAIK those are absent.

    Re. the mammoth kill site: intriguing but let's await the data. If it is 50 Ka years old, I'm sure that the researchers want to have it very well demonstrated before going public: exceptional claims demand exceptional evidence.

    The issue is that we cannot jump to conclusions without evidence, preferably good hardly questionable evidence. In fact, when the kind of breakthroughs you advocate happen, they always find resistances. Just remember how the Piltdow man fiasco delayed for decades the acknowledgement of our African evolutionary scenario. The piling up of evidence is the best way to get sure, and it requires patience and phlegm, not anxiety and preconceptions.

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    1. PS- Also, to this date, we have no evidence at all that L3(xM,N) existed in Asia (except plausibly in Arabia-Palestine maybe, also some L0 branches may be ancient there) in the Middle and Upper Paleolithic. If you are looking for early, now lost, Asian lineages in Native Americans, I suggest you look for M(xC,D) or N(xA,B,X). However these would still fit the post-LGM Beringian paradigm.

      Neanderthal or "Denisovan" mtDNA would be easy to discern because it falls outside of the modern human tree (pre-L or whatever you want to call it).

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