The other Megafaunal Extinction: The peopling of Australia I

In an interesting paper that came out at the end of January, Miller et al (1) provide the first unambiguous evidence that humans at least contributed to Australia’s Megafaunal extinctions. The latest evidence comes in the form of burnt eggs from the giant flightless bird Genyornis newtoni.

 

 

 Genyornis newtoni narrowly avoids another of Australia’s extinct megafauna, the 7m Megalania prisca Photo credit: Peter Trusler

Comparison of the statures of Homo sapiens and Genyornis newtoni from Murray and Vickers-Rich 2004 (2).

 

Here is the abstract:

 

Although the temporal overlap between human dispersal across Australia and the disappearance of its largest animals is well established, the lack of unambiguous evidence for human–megafauna interactions has led some to question a human role in megafaunal extinction. Here we show that diagnostic burn patterns on eggshell fragments of the megafaunal bird Genyornis newtoni, found at >200 sites across Australia, were created by humans discarding eggshell in and around transient fires, presumably made to cook the eggs. Dating by three methods restricts their occurrence to between 53.9 and 43.4 ka, and likely before 47 ka. Dromaius (emu) eggshell occur frequently in deposits from >100 ka to present; burnt Dromaius eggshell first appear in deposits the same age as those with burnt Genyornis eggshell, and then continually to modern time. Harvesting of their eggs by humans would have decreased Genyornis reproductive success, contributing to the bird’s extinction by ~47 ka.

 

A few of the selected quotes:

 

Although many elements of the Australian megafauna (those animals >45 kg body mass) lack firm extinction timelines, last appearance dates for taxa that occur most frequently in the fossil record are between 50 and 40 ka indicating a temporal overlap between humans and megafauna. The climate of Australia was drying gradually between 60 and 40 ka, but neither the rate nor magnitude of change were more severe than during earlier Pleistocene climate shifts. The lack of evidence for unprecedented climate change between 60 and 40 ka and survival of megafauna during earlier more extreme climate fluctuations implies that climate change is unlikely to be the sole cause of megafaunal extinction, leaving human agency more likely to have been the decisive factor, with modest additional stress from increasing aridity potentially a contributing factor.

 

The time interval during which Genyornis became extinct (50±5 ka)8 coincides with the interval when humans were consuming its eggs (53.9 to 43.4 ka), suggesting that predation contributed to the bird’s extinction.

 

The range of burn patterns found in clusters of Genyornis eggshell is most consistent with humans scattering eggshell fragments of consumed eggs in and around transient cooking fires, and the strong thermal gradients required to explain the observed burn patterns are incompatible with a wildfire cause.
 

 We found no in situ hearths or in situ stone artefacts directly associated with burnt Genyornis eggshell,.. This is expected because the alkaline dune sediments that preserve eggshell carbonate also degrade charcoal, and transient cooking fires in a sandy substrate leave no baked clays. Few regions provided Genyornis eggshell in stratigraphic sections where their association with artefacts could be securely evaluated; most samples were collected from the floors of deflation hollows. Lithic artefacts (commonly) and hearthstones (occasionally) are found in deflation hollows among surface scatters of burnt Genyornis eggshell, but because both occur as deflationary lags, temporal association cannot be demonstrated. However, the presence of hearthstones confirms that fire-using humans were in the same landscape, despite the lack of preserved hearths. At Garnpung [one of the sites from which burnt eggshell was collected during the study], one of the few sites with burnt Genyornis exposed in a stratigraphic section, an in situ hearthstone stratigraphically below the horizon containing burnt Genyornis eggshell demonstrates a temporal overlap with humans.
 

..none of the Genyornis eggshell collections from WA that predate 50±5 ka contain burnt fragments.

Verdict:
 

The authors present a fairly airtight case for human predation of Genyornis newtoni eggs as at least a contributing in the species’ extinction
 

With no samples of burn egg shells pre-dating to greater than 55,000BP this is fairly strong evidence for the peopling of Australia having begun only slightly earlier than this date

 

Rock art representation of Genyornis newtoni

In the western part of Arnhem Land in Australia’s Northern territory lies the Jawoyn site. This small rock shelter preserves a remarkable piece of rock art: the shape of an enormous bird. An analysis by palaeontologist Peter Murray, detailed in Gunn et al (3) concludes that flightless bird is Genyornis newtoni.

 

Aboriginal representation of Genyornis newtoni from western Arnhem Land.

Picture credit: R.G. Gunn (3).

 

Peter Murray made the identification based on the following points:

• a deep convex bill, very unlike any casuariiformes;

• a globular cranium;

• relatively thick neck;

• indication of a crop (emus and cassowaries lack crops);

• unusual posture of the wing (unlike the pendulous wing posture of emus);

• the proportions of the pelvic limb showing long tibiotarsi and stout tarsometatarsi;

• the short, broad toes terminating in blunt, robust claws; and

• a dorsal profile exactly paralleling that of reconstructed dromornithids and quite unlike an emu or a cassowary, in which the vertex of the back is more anterior.

The painting is tentatively dated as >25,000BP, thus raising the possibility of a late survival of this species.

Key points in the identification of Genyornis newtoni by Murray from Gunn (3) Figure 9. Original caption reads: Common distinctive traits between the painting and Genyornis.

What about other megafauna?

There is abundant rock art evidence that Aboriginals were well acquainted with, a number of other megafaunal species. The timing of the extinction has been much debated for a number of decades but according to Roberts et al (5) most occurred ca. 46,000BP. From their paper: “Twenty-three of the 24 genera of Australian land animals weighing more than 45 kg (which, along with a few smaller species, constituted the “megafauna”) were extinct by the late Quaternary.”

 

A few examples:

The Marsupial Lion, Thylacoleo carnifex. An interesting paper by Akerman and Willing identified one of the few paintings of this apex predator from the western shore of the Admiralty Gulf in the north-west Kimberley region of Western Australia.

 

Aboriginal defends himself from a Marsupial Lion Thylacoleo carnifex  from Akerman (4). Original caption: Figure 2. Panel showing hunter apparently spearing, or fending off, a large striped animal. Drysdale River, Kimberley, Western Australia (image courtesy of D. MacLeod).

 

 

Black and white rendition of painting from Akerman (4). Original caption reads:

Figure 3. Detailed black and white image taken from the original picture sent by D. MacLeod. Total width approximately 300 mm.

 

Although, not strictly part of the megafaunal extinction as it died out within recorded history in mainland Australia, the Tasmanian Devil, Sarchilus harrisii is well shown in Aboriginal art as seen here from Callaby and Lewis (6), also from Arnhem Land:

 

 

Callaby and Lewis Fig. 1

Original caption reads: Line drawing rendition of the painting in Figure 2. Note the long facial vibrissae, dog-like paws, marsupial genitalia, and long hairs on the dorsal side of the tail - a combination of features unique to the Tasmanian devil.

 

 

Callaby and Lewis Fig. 2

Original Caption reads: Red ochre painting identified as a Tasmanian Devil (Sarchilus harrisii). The left-hand ear and facial vibrissae extend around a Iedge on the ceiling and are therefore not visible in this photograph. Length = 83 cm

 

 

Other megafauna represented in Aboriginal art reported by Akerman:

 

• Tasmanian Devil (Sarcophilus harrisii: Chaloupka 1993; Lewis 1988);

• Thylacoleo, the marsupial lion (Thylacoleo carnifex: Murray and Chaloupka 1984);

• Sthenurus, a giant macropod (Sthenurus stirlingi: Murray and Chaloupka 1984);

• Zaglossus, a giant echidna (Zaglossus sp.: Murray and Chaloupka 1984); and

• Palorchestes, a marsupial tapir (Palorchestes azeal: Chaloupka 1984, 1993; Murray and Chaloupka 1984; Lewis 1986).

 

References

1. Miller, G. et al. 2016. Human predation contributed to the extinction of the Australian megafaunal bird Genyornis newtoni ~47 ka. Nature Communications  7, Article number: 10496 doi:10.1038/ncomms10496

Retrieved from: http://www.nature.com/ncomms/2016/160129/ncomms10496/full/ncomms10496.html

 

 

2. Murray, P.F. and P. Vickers-Rich 2004 Magnificent Mihirungs: The colossal

flightless birds of the Australian Dreamtime. Bloomington: Indian University Press.

3. Gunn, R.G. et al 2011. What Bird is that? Identifying a Probable Painting of Genyornis newtoni in Western Arnhem Land. Australian Archaeology Number 73, December 2011. Pdf retrieved from: http://connectingcountry.arts.monash.edu.au/wp-content/uploads/2011/10/2011-What-bird-is-that.pdf

4. Akerman, K. & T. Willing. 2009. An ancient rock painting of a marsupial lion, Thylacoleo carnifex, from the Kimberley, Western Australia. Antiquity 83;

Retrieved from: http://antiquity.ac.uk/projgall/akerman322/

5. Roberts R.G. et al 2001. New ages for the last Australian megafauna: continent-wide extinction about 46,000 years ago. Science. 292(5523):1888-92.

Retrieved from: http://www.ncbi.nlm.nih.gov/pubmed/11397939

6. Callaby, J.H. and D.J. Lewis. 1977. The Tasmanian Devil in Arnhem rock art.
Mankind 11(2):150-151. Downloadable from:
https://www.library.uq.edu.au/ojs/index.php/aa/article/viewFile/1467/1460
 

References from Akerman:

Callaby, J.H. and D.J. Lewis 1977 The Tasmanian Devil in Arnhem rock art.

Mankind 11(2):150-151.

Chaloupka, G. 1993 Journey in Time: The World’s Longest Continuing Art Tradition.

Chatswood, NSW: Reed.

Lewis, D. 1988 The Rock Paintings of Arnhem Land, Australia: Social, Ecological and Material Culture Change in the Post-Glacial Period. BAR International Series

415. Oxford: British Archaeological Reports.

Murray, P. and G. Chaloupka 1984 The Dreamtime animals: Extinct megafauna in

Arnhem Land rock art. Archaeology in Oceania 19(3):105-116.

Chaloupka, G. 1984 From Paleoart to Casual Paintings. Monograph Series 1.

Darwin: Northern Territory Museum of Arts and Sciences.

Lewis, D. 1986 The Dreamtime animals: A reply. Archaeology in Oceania 21(2):140-

145.







Being Human IV: Homo floresiensis: Not us

A paper published online, on Monday this week (1) brings us closer to an understanding of who the diminutive humans, Homo floresiensis were.

The tiny hominids, popularly known as the ‘Hobbits’ died out between 19,000 and 17,000 on the island of Flores in Indonesia.

Homo floresiensis female reconstruction by John Gurche. Photo by Chip Clark (3).

Here’s the abstract:

Cranial vault thickness (CVT) of Liang Bua 1, the specimen that is proposed to be the holotype of Homo floresiensis, has not yet been described in detail and compared with samples of fossil hominins, anatomically modern humans or microcephalic skulls. In addition, a complete description from a forensic and pathological point of view has not yet been carried out. It is important to evaluate scientifically if features related to CVT bring new information concerning the possible pathological status of LB1, and if it helps to recognize affinities with any hominin species and particularly if the specimen could belong to the species Homo sapiens.

Medical examination of the skull based on a micro-CT examination clearly brings to light the presence of a sincipital T (a non-metrical variant of normal anatomy), a scar from an old frontal trauma without any evident functional consequence, and a severe bilateral hyperostosis frontalis interna that may have modified the anterior morphology of the endocranium of LB1. We also show that LB1 displays characteristics, related to the distribution of bone thickness and arrangements of cranial structures, that are plesiomorphic traits for hominins, at least for Homo erectus s.l. relative to Homo neanderthalensis and H. sapiens. All the microcephalic skulls analyzed here share the derived condition of anatomically modern H. sapiens. Cranial vault thickness does not help to clarify the definition of the species H. floresiensis but it also does not support an attribution of LB1 to H. sapiens. We conclude that there is no support for the attribution of LB1 to H. sapiens as there is no evidence of systemic pathology and because it does not have any of the apomorphic traits of our species.

 

Micro-CT scan of LB1 showing thickening of the frontal bone, from Balzeau and Charlier, et. al et al 2016 (1)

The authors Balzeau and Charlier, et. al. used high-resolution images recently generated in Japan to compute maps of bone thickness variation, study skull morphology and look for any abnormalities such as microcephaly, as postulated by Vannuccia et. al. (2).

 

Overall the authors concluded that:

 

• The species is completely distinct from humans Homo sapiens. In other words they are not a small version of us

• The individual studied and by inference, Homo floresiensis as a species is not a human suffering from microcephaly

• The individual studied (LB1) had Hyperostosis frontalis interna. This is interesting as this is a common, benign thickening of the inner side of the frontal bone of the skull. It is found predominantly in women after menopause and is usually asymptomatic. Perhaps therefore, this condition is an ancient one occurring in a number of species on the Homo line?

• The studied individual had suffered a healed scar from a frontal skull trauma that had apparently not caused any functional consequence

In an interview for Agence France-Presse, Balzeau said he could not exclude the possibility that the "hobbit" was a scaled-down version of Homo erectus, which arrived on the neighbouring island of Java some million years ago, nor could they be sure that H. floresiensis was not a species it its own right.

Comparison of Homo floresiensis (L) and modern human (R)

Photo credit: Professor Peter Brown/University of New England

 

References

1. Balzeau, A and Charlier P. 2016 What do cranial bones of LB1 tell us about Homo floresiensis? Journal of Human Evolution Volume 93, April 2016, Pages 12–24

2. Vannuccia, C. et. al. 2011. Craniometric ratios of microcephaly and LB1, Homo floresiensis, using MRI and endocasts. Proceedings of the National Academy of Sciences of the United States of America vol. 108 no. 34

Retrieved from: http://www.pnas.org/content/108/34/14043.abstract

3. Retrieved from: http://www.gurche.com/content_homo_floresiensis_657.htm

The Peopling of the British Isles I - The Happisburgh Footprints

Homo antecessor family picnic at Happisburgh Beach 1 million BC. Image credit: Daily Mail

The peopling of the British Isles can be divided into two eras: post and pre the last glaciation. Whilst the evidence for the latter is fragmentary and somewhat sparse, sometimes wondrous things come to light.

The footprints in the Pleistocene laminated silt beds on the foreshore at Happisburgh Beach uncovered by the sea in 2013 are one such marvel. As the authors point out preserved footprints pre-dating 40Ky are extremely rare. The location of the Happisburgh and other sites with human footprints of this age is shown below:

 

 

Location of Happisburgh and other sites with human footprints from Ashton 2014 (1). Original caption read: Figure 1. Map of Pleistocene footprint sites dating from prior to 40 ky in Africa and Eurasia.

Once the site’s importance was realised archaeologists moved quickly to record them before further erosion, inevitably, destroyed them forever. The abstract of resultant paper (open access and pdf download - yay!) by Ashton et. al. 2014 (1) is shown below:

Abstract

Investigations at Happisburgh, UK, have revealed the oldest known hominin footprint surface outside Africa at between ca. 1 million and 0.78 million years ago. The site has long been recognised for the preservation of sediments containing Early

Pleistocene fauna and flora, but since 2005 has also yielded humanly made flint artefacts, extending the record of human occupation of northern Europe by at least 350,000 years. The sediments consist of sands, gravels and laminated silts laid down by a large river within the upper reaches of its estuary. In May 2013 extensive areas of the laminated sediments were exposed on the foreshore. On the surface of one of the laminated silt horizons a series of hollows was revealed in an area of

ca. 12m². The surface was recorded using multi-image photogrammetry which showed that the hollows are distinctly elongated and the majority fall within the range of juvenile to adult hominin foot sizes. In many cases the arch and front/back of the foot can be identified and in one case the impression of toes can be seen. Using foot length to stature ratios, the hominins are estimated to have been between ca. 0.93 and 1.73 m in height, suggestive of a group of mixed ages. The orientation of the prints indicates movement in a southerly direction on mud-flats along the river edge. Early Pleistocene human fossils are extremely rare in Europe, with no evidence from the UK. The only known species in western Europe of a similar age is Homo antecessor, whose fossil remains have been found at Atapuerca, Spain. The foot sizes and estimated stature of the hominins from Happisburgh fall within the range derived from the fossil evidence of Homo antecessor.

Based on previous research, on the sedimentary sequence of the region, the team assigned the age of the deposits to between ca. 1 million and 0.78 million years ago. They did so by noting that the bounding layers were the Happisburgh Formation of date ca. 450ky. These overlay the estuarine sediments of the Hill House Formation (HHF) of Early Pleistocene in age, dating to between 1 and 0.78 My. This in turn overlies the Norwich Crag formation of earlier Pliocene-Pleistocene date.

Next the authors considered what natural processes could have caused the extensive area of foot-shaped depressions. They concluded, by reference to published literature that the depressions were in fact fossil footprints made by mid-Pleistocene hominins.

 

So let’s look at these at these ancient footprints!

 

Close-up of a single footprint at Happisburgh, adapted from Ashton 2014 (1). Original caption reads: Figure 5b. Detail of footprint surface. Photo: Martin Bates.

 

Of all the footprints uncovered only one showed toes properly and that isn’t shown with any clarity in the paper!

However as the team used the laser-scanning technique multi-image photogrammetry (MIP) to record the surface over the two weeks before it eroded. Dr Sarah Duffy of York University part of the team that carried out the 3D image analysis, has provided some of the images to Simon Parfitt of UCL (2), who was also part of the team that studied the site. I have adjusted the contrast to show the toes:

 

At first I found it hard to figure out what was going on.. the shape of the foot was just.. well.. wrong! Then I recalled that I, and every other person in the western world have “wrong feet”. It’s the wearing of shoes from an extremely early age that does it. A study from the American Journal of Orthopaedic Surgery from 1905 show what our feet should look like. The upper photographs show native barefoot populations from the Philippines and Central Africa whilst the lower ones show a U.S. businessman.

 

 

In the two photographs above, the big and little toes spread naturally and fan out to provide a wide, stable base for walking or standing. A line can be drawn that runs through the heel, ball, and big toe of a habitually bare foot.

Below the habitually shod feet of the businessman, also from 1905 show that no such line can be drawn, and the big and little toes crowd to a point.

 

Comparing the Happisburgh photo to the habitually unshod feet shows that the ancient footprint is a right foot with wide spread big and little toes and a well-defined arch at the bottom of the picture and big toe bottom left. I think the second and third toes left the ill-defined wider mark next to the big toe in the photo of the ancient footprint as these two tend to be slightly closer together in habitually unshod humans as evidenced by top 1905 photos.

As depth of prints was unavailable the authors chose to concentrate on the length and width of the prints in their analysis. The foot lengths ranged from 50mm to ca. 325mm and widths from ca. 50mm to ca. 150mm.

Using the multi-image photogrammetry (MIP) data, the authors were able to deduce a number of interesting facts from the 155 footprints on the surface. They were able to infer routes of individuals across the area, the number of individuals as being a minimum of 5, that male and female adults were present and that children were amongst the group. Therefore they surmised that it was a family group and not a hunting party.

Part of the authors’ quantitative analysis looked at the 12 most clearly defined prints. These they plotted on a length verses age graph, thus proving that at least 5 individuals of different ages were present. See below:

 

Diagrams showing image of 12 clearest prints and the resultant length to age conversion from Ashton 2014 (1). Original caption reads:

Figure 8. Vertical image of Area A at Happisburgh. a. Model of footprint surface generated from photogrammetric survey showing the 12 prints used in the metrical analyses of footprint size; b. Plot of length and width measurements of 12 prints showing possible individuals. Means and standard deviations for foot length and age for modern populations are also shown. doi:10.1371/journal.pone.0088329.g008

 

Based on a large body of research that links foot length to height (the authors cited 7 papers from which they drew their inferences), the authors were able to calculate the that the hominins that made the footprints were between 0.93m and 1.73m tall, therefore further confirming the presence of adults and children in the group.

Using both footprint area and footprint length the authors were able to estimate the body mass of the adults in the group. These ranged from as ca. 48-52kg using footprint area and 48-52kg using footprint length.

By comparing such metric details as staure, foot index and body mass available for the fossils from Sima de los Huesos (the site of the type specimen of H. antecessor), Neanderthal fossils from around European and anatomically modern humans, the authors conclude that the closest match to species level was Homo antecessor.

The data on the foot index is most instructive. According to Klenerman and Wood (3), the foot of H. antecessor is quite narrow and gracile with longer toe phalanges than later hominins such as H. heidelburgensis, H.neanderthalensis and some modern H. sapiens populations. This could account for some of the longer narrower footprints observed at Happisburgh. It is particularly pleasing that this feature is accurately shown in the recreation of H. antecessor created by a Spanish museum.

 

 

H. antecessor showing gracile foot. Image Credit: Ibeas Museum, Burgos, Spain.

I expect you’ve noticed the other notably feature of the picture.. that would be the cannibalism.

 

A 2010 study of the massive array of bones from Atapuerca found indisputable evidence of H. antecessor eating it’s own kind:

“Human cannibalism is currently recorded in abundant archaeological assemblages of different chronologies. The TD6 level of Gran Dolina (Sierra de Atapuerca, Burgos), at more than 800 ka, is the oldest case known at present. The analysis of cranial and postcranial remains of Homo antecessor has established the presence of various alterations of anthropic origin (cut marks and bone breakage) related with exploitation of carcasses. The human remains do not show a specific distribution, and they appeared mixed with lithic tools and bones of other taxa. Both nonhuman and human remains show similar evidence of butchering processes. The stratigraphic evidence and the new increment of the collection of remains of Homo antecessor have led us to identify a succession of cannibalism events in a dilated temporal sequence. These data suggest that hunting strategies and human meat consumption were frequent and habitual actions. The numerous evidences of cannibalism, the number of individuals, their age profile, and the archaeostratigraphic distribution suggest that cannibalism in TD6 was nutritional.”

It therefore seems that the rosy picture painted by the artist of the picture at the top of this post, may not have been a reflection of the true nature of Homo antecessor.

Yes it seems the British Press (the source from which the artist’s impression is drawn) would have British Homo antecessor was a kinder, more family orientated species than elsewhere in Europe.

A good short video about the discovery can be found here.

 

mtDNA Haplogroups M and N stated as Native American!!!

An “In Press Corrected Proof” of a paper by Cosimo Posth et. al (1), released last week had an enormously shocking (to me at least!) statement in its summary.

Here is that summary with the true shocker in bold - the emphasis is of course mine.

“Summary

How modern humans dispersed into Eurasia and Australasia, including the number of separate expansions and their timings, is highly debated [ 1, 2 ]. Two categories of models are proposed for the dispersal of non-Africans: (1) single dispersal, i.e., a single major diffusion of modern humans across Eurasia and Australasia [ 3–5 ]; and (2) multiple dispersal, i.e., additional earlier population expansions that may have contributed to the genetic diversity of some present-day humans outside of Africa [ 6–9 ]. Many variants of these models focus largely on Asia and Australasia, neglecting human dispersal into Europe, thus explaining only a subset of the entire colonization process outside of Africa [ 3–5, 8, 9 ]. The genetic diversity of the first modern humans who spread into Europe during the Late Pleistocene and the impact of subsequent climatic events on their demography are largely unknown. Here we analyze 55 complete human mitochondrial genomes (mtDNAs) of hunter-gatherers spanning ∼35,000 years of European prehistory. We unexpectedly find mtDNA lineage M in individuals prior to the Last Glacial Maximum (LGM). This lineage is absent in contemporary Europeans, although it is found at high frequency in modern Asians, Australasians, and Native Americans. Dating the most recent common ancestor of each of the modern non-African mtDNA clades reveals their single, late, and rapid dispersal less than 55,000 years ago. Demographic modeling not only indicates an LGM genetic bottleneck, but also provides surprising evidence of a major population turnover in Europe around 14,500 years ago during the Late Glacial, a period of climatic instability at the end of the Pleistocene.”

But it doesn’t end there.. oh no! Or should I rather shout yes, yes, YES!

From the Results and Discussion section we also have:

“However, whereas present-day Asians, Australasians, and Native Americans carry both M and N mtDNA hgs.”

 

Now I haven’t had time to fully digest the paper yet, but I am fairly certain that I have read this correctly and am not going out of my mind.

As most bloggers interested in the peopling of the Americas will know, the accepted mtDNA haplogroups found in the pre-Colombian population have been limited to A, B, C, D and X and one case of mtDNA M in a mid-Holocene burial from China Lake, British Columbia (Malhi et. al. 2007 (2)), so this would be BIG news.

I’ll update this post when I have closely read every sentence of the paper and supporting materials.

Let’s hope it’s not me going off my trolley or the authors making a huge error!

Below is lovely phylogenic-tree from the paper for your delectation:

Update 24th of February

Apologies for nearly for wetting myself with excitement over the wording of Posth et. als  paper.

Let me explain, after reading it several times I had doubts that it meant what I thought it meant: Haplogroups M and N are found in America.. I thought I had missed some major paper.

However just to check I posted on several genetics forums that had discussions on the paper. The replies I had were polite and explained what I had suspected Posth et al meant the lineages descended from haplogroups M and N i.e. the A, B, C, D and X of Native Americans.

Here are some of my postings and the thoughtful replies:

Here's the one from the Molecular Ecologist

Here's the one from Dienekes:

For a totally hilarious exchange see here! All I can say regarding this one is that it just goes to prove that the arrogant, opinionated and unreasonable of the 'real' world are found in fairly rarefied world of genetics discussion boards.. Go on click.. it really REALLY is worth a read.
 

References

1. Posth, C. 2016. Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe.
In Press Corrected Proof Current Biology. Retrieved from:
http://www.cell.com/current-biology/fulltext/S0960-9822(16)00087-7

 2. Malhi, R. S. et. al. 2007. Mitochondrial haplogroup M discovered in prehistoric

North Americans. Journal of Archaeological Science 34 (2007) 642-648
Pdf download at:

https://public.wsu.edu/~bmkemp/publications/pubs/Malhi_et_al_2007.pdf

The Peopling of the Americas III - Human Migration Rate and the possible arrival time of Anatomically Modern Humans in South America

Did Paleoamericans cross the Bering Strait 100,000 years ago? Image Credit: Adapted from LeFever 2012 (5).

In two previous posts (here and here), I examined the formation of the Bering Land Bridges. The dates generated for the existence of these Land Bridges has profound implications for the peopling of the Americas.

 I deliberately choose to cover the last 2 million years of the Pleistocene, this is essentially because the current ‘Out of Africa’ model favours 3 waves of migration:

1. Homo erectus senso lato around 2Mya.

2. Ancestors of Homo heidelbergensis and/or Homo ergastor about 0.5Mya.

3. Homo sapiens or their archaic forebears perhaps as early as 0.15Mya.

Therefore as ALL of these species have been present in East Asia over hundreds of thousands of years, it seems possible, given the opportunity presented by the Bering Land Bridges, that any, or all of them could have crossed from Asia and populated the Americas.

To decide on the who, we kind of need to know the when.

Looking on the web for difficult to answer questions can be a frustrating business for instance try “What is the earliest man could have arrived in the Americas”. The top 10 results were 16,300BP (Athena publishing), 14,500BP (Smithsonian), 15,000BP (Wikipedia), 15,500BP (Guardian), 15,000BP (Daily Mail), 13,300BP (PBS Newshour), 14,000BP (Nature), 12,000BP (National Geographic), 22,000BP (New York Times) and 16,500BP (Centre for the First Americas). The average date is therefore about 15,400BP. This is despite the fact that Dillehay (4) recently published a paper stating that the Monte Verde site near the southern tip of Chile was occupied by 18,500BP.

I find this deeply frustrating. With very little effort one can find NUMEROUS sites that have good evidence that pre-date these stated dates by a WIDE margin.

Current evidence of man in the Americas can be summarised in the following table:

 

 

 

If we assume that these dates are correct, could anatomically modern humans account for these occupations?

To decide whether the full range of occupation dates listed above, can be accounted for by Anatomically Modern Humans (AMH) we therefore need some estimate of the rate of Human Migration. I could at this point try to refer you to a range of estimates from learned papers on the internet, however these are even more sparse and contradictory than dates for the first peopling of the Americas as outlined above.

Therefore I have carried out a simple calculation based on some of the published, dated fossils from along man’s migration route.

 

Taking the fastest migration rate of 0.27Km/year we can do a simple calculation about the arrival time at Monte Verde in southern Chile:
 

Wales Alaska to Monte Verde Chile = ca. 14726km

Migration time 14726/0.27 = 54540 years
 

Therefore arrival time in southern Chile would be 94400-54540 = 39860 years BP
 

Conclusions:
 

1. Anatomically modern humans could have arrived in Beringia ca. 100,000 years ago.
 

2. Given a migration rate of 0.27Km/year all sites in the Americas, with the exception of Valsequillo and Calico could have, therefore, potentially been occupied by Anatomically Modern Humans (AMHs).
 

3. Arguments regarding the opening and shutting of the Ice-Free corridor are irrelevant as land-based migrations could have taken place BEFORE it closed. Coastal migrations are not ruled out.

4. A quick check against my previous post here shows that  Bering Land Bridge 4 96-93 Kya, 5 104-102 Kya and 6 114.5-111.5 Kya existed at approximately the right time for this human migration.
 

5. Valsequillo and Calico, if real sites of human occupation MUST, therefore represent an archaic human population such as Homo erectus.

 

References

1. Ian McDougall, Francis H. Brown & John G. Fleagle.2005. Stratigraphic placement and age of modern humans from Kibish, Ethiopia. Nature 433, 733-736 doi:10.1038/nature03258

2. R. Grun et al. 2005. U-series and ESR analyses of bones and teeth relating to the human burials from Skhul. Journal of Human Evolution 49 316-334

3. Wu Liu, et. al. 2015. The earliest unequivocally modern humans in southern China. Nature  526, 696–699. doi:10.1038/nature15696

4. Dillehay TD, Ocampo C, Saavedra J, Sawakuchi AO, Vega RM, Pino M, et al. (2015) New Archaeological Evidence for an Early Human Presence at Monte Verde, Chile. PLoS ONE 10(11): e0141923. doi:10.1371/journal.pone.0141923

5. Greg LeFever Ancient Tides blog 2012. Retrieved from:

http://ancient-tides.blogspot.co.uk/2012/12/native-american-genetic-source-is.html