Anthropology.net

Hans-Peter Uerpmann of the University of Tubingen has lead a team excavating the Jebel Faya site in the United Arab Emirates, right near the Straits of Hormuz. They’ve found 125,000 year old stone tools that look like early modern human tools from East Africa around the same time. They’ve published their findings in today’s Science, under the title, “The Southern Route “Out of Africa”: Evidence for an Early Expansion of Modern Humans into Arabia.”

The current understanding is what we know as anatomically modern humans (AMH) originated in Africa about 250,000 years ago. The oldest Home sapiens, known as H. sapiens idaltu, was found to be 160,000 years old, found at the Middle Awash site in Ethiopia. Then between 80k-100k years ago, modern humans began appearing in the middle east, as remains from sites like the Qafzeh cave in Israel have yielded. Most agree that AMH stayed in Africa and about 140,000 years ago they began migrating out. There was an exception, a colonization remained or failed in Israel about 100,000 years ago.

One of the hand axes from Jebel Faya, UAE (Photograph courtesy Science/AAAS)

These hand axes, pictured above, show a pattern of flaking distinct from that made by Neandertals and also dissimilar to those by ~100,000 year old Israeli tools. They are two sided and very similar to stone tools seen only in early Africa.

What this means is early humans left Africa 20,000 years earlier than thought. Just how did they do it? 130,000 years ago, there was a window of climate change. They figured this out by using luminescence dating to determine the age of sand grains buried with the stone tools. Luminescence dating is a technique that measures naturally occurring radiation stored in the sand. The data showed that 130,000 years ago, the Arabian Peninsula was relatively more warm which caused more rainfall, turning it into a series of lush habitable land. During this period the southern Red Sea’s levels dropped and was only 2.5 miles or 4 km wide. This offered a brief window of time for humans to easily cross the sea and cross the Peninsula to opposing sites like Jebel Faya.

Does this study tell us that modern humans left Africa, into Arabia and out from there? It is most certainly a possibility. However, these axes could be of an abandoned migration like the site in Israel I’ve mentioned. I say that because no genetic clade, be it from mitochondrial, Y-chromosome, or somatic genome, shows an earlier divergence of modern humans from Africa earlier than 60,000 years ago. At the very minimum a find like this tells us humans left Africa a bit sooner than we thought, but does not really tell us that these were the humans that helped seed the Eurasia.

Armitage, S., Jasim, S., Marks, A., Parker, A., Usik, V., & Uerpmann, H. (2011). The Southern Route “Out of Africa”: Evidence for an Early Expansion of Modern Humans into Arabia Science, 331 (6016), 453-456 DOI: 10.1126/science.1199113

The following post doesn’t directly have much to do with anthropology. Indirectly, it sure does, especially to those out there that study human population expansions and the Pleistocene-Holocene transition or even anthropologists interested in prehistoric paleoenvironments and the context of how people were living and what they were doing during that time.

Anyways, this post is about a PLoS Biology paper. PLoS Biology is an open access journal that has just published a paper which investigates woolly mammoth extinction. The authors of the paper, “Climate Change, Humans, and the Extinction of the Woolly Mammoth,” ultimately conclude that both climate change and human hunting were critical factors in woolly mammoth extinction. Not a really Earth shattering conclusion, I know… but there has been some discussion whether or not climate change or human hunting was more impactful.

Right before the Holocene, the global climate was warming up. And most woolly mammoths died out during this time, the end of the Pleistocene (12,000 years ago). That’s what got many people to consider that warm temperatures may have driven the extinction of this cold-adapted species. But, the species had survived previous warming periods, and in places like St. Paul Island, Alaska and Wrangel Island they lasted up until 3,700 years ago. This is what got other people to think that the extinction of the woolly mammoth was due to the effects of human population expansion.

From the author’s summary,

“In this study, we combined paleo-climate simulations, climate envelope models (which describe the climate associated with the known distribution of a species—its envelope—and estimate that envelope’s position under different climate change scenarios), and a population model that includes an explicit treatment of woolly mammoth–human interactions to measure the extent to which climate changes, increased human pressures, or a combination of both factors might have been responsible. Results show a dramatic decline in suitable climate conditions for the mammoth between the Late Pleistocene and the Holocene, with hospitable areas in the mid-Holocene being restricted mainly to Arctic Siberia, where the latest records of woolly mammoths in continental Asia have been found. The population model results also support the view that the collapse of the climatically suitable area caused a significant drop in mammoth population size, making the animals more vulnerable to increasing hunting pressure from expanding human populations. The coincidence of the collapse of climatically suitable areas and the increase in anthropogenic impacts in the Holocene are most likely to have been the “coup de grâce,” which set the place and time for the extinction of the woolly mammoth.”

I’m really not clear about how the authors established their population models. I’ll do my best to review them, though. The authors compared and contrasted the population sizes to the climatic conditions. Curiously, their results differ as they increase the n, but they were able to calculate,

“that the most suitable geographic area available to woolly mammoths increased by 7.7 million km² from the last interglacial, 126 ky BP, to 42 ky BP (from 0.3 to 8.1 million km²). There was a 0.5 million km² decrease in the most suitable area between 42 ky BP and 30 ky BP periods, and then a 3.7 million km² decrease between 30 ky BP and 21 ky BP (from 7.5 to 3.8 million km²). Finally, between 21 ky BP and 6 ky BP, there was a 2.9 million km² decrease. By the 6 ky BP period, only 0.8 million km² of the most suitable climatic conditions remained.”

This shows that with time, the available suitable habitats for the species reduced and did thus contributed to a reduction in woolly mammoth population sizes. Now the authors didn’t directly test the zooarchaeological record to directly correlate if human hunting or the side effects of human population expansion affected mammoth populations. But they did infer that their results of the incremental decrease in population sizes over time showed a “synergy” to the northward increase in human population densities during the Holocene.

So what about the mammoth groups in Alaska and the Arctic Ocean that persisted late after all the others died off? Their results actually show that these areas were largely unchanged by both climate and human impact. In fact, that climate change and human impacts were focused on mammoths in the northernmost land masses of Arctic Siberia and some arctic islands, “leaving them with nowhere to run away from extinction.”

Nogués-Bravo, D., Rodríguez, J., Hortal, J., Batra, P., Araújo, M.B. (2008). Climate Change, Humans, and the Extinction of the Woolly Mammoth. PLoS Biology, 6(4), e79. DOI: 10.1371/journal.pbio.0060079

National Geographic News has just published an article about the recent symposium in Alaska regarding a possible connection between Yeniseic languages in Siberia and Na-Dene languages in the Americas. John Roach’s article, Siberian, Native American Languages Linked — A First, highlights the recent work of Edward Vajda, who defended his connection during the February symposium. Vajda goes deeper than cognate lists in his parallels, providing several corresponding grammatical systems, particularly verb prefix structure. Ket, his primary Siberian source, is the only living Yeniseic language (which remains highly endangered) and bears some striking grammatical similarities to Navajo. Yeniseic languages have a unique verb prefix system: unique enough that Vajda could not find a corresponding system throughout Northern Asia. Na-Dene was the closest family geographically with a similar system. Johanna Nichols, a groundbreaking Historical Linguist and Linguistic Anthropologist, attended the symposium and made comment. Roach quotes:

With the exception of the Eskimo-Aleut family that straddles the Bering Strait and Aleutian Islands, this is “the first successful demonstration of any connection between a New World language and an Old World language,” Nichols said.

Vajda has not yet published his findings, so the extent of his linguistic claims is not yet clear. However, based on Roach’s summary of his discussion, there are two major points of controversy. First, Roach states that Vajda found “several dozen” cognates. Whether or not the comparative method for linguistic reconstruction was used remains to be seen. Regardless, a cognate list under 50 seems a bit thin to solidify a connection at all, let alone begin reconstruction. Furthermore, the public at this point has no access to the words to assess their status as true cognates. Without a doubt, a consistent and corresponding element of grammatical structure is a strong argument for a common ancestor, but we must consider the systems of linguistic change, particularly sound change (which requires cognates), as a central factor.

A second point of controversy is the matter of depth: how long ago does the proposed connection date back? Vajda makes no direct claims, but states that this would be the oldest known language link if it corresponds to the late Pleistocene migrations evident in the archaeological record. Unfortunately, the field of linguistics currently has no reliable absolute dating techniques, and relative dating such as glottochronology, has been widely discredited. In this case, it seems the lack of cognates would help secure this relationship as an old one. If that were indeed the case, a volume of cognates would become evident in the reconstructions of Proto-Yeniseic and Proto-Na-Dene. Whether or not Vajda has taken this into consideration remains to be seen. At any rate, Nichols is not convinced of a 10,000 year-old connection:

“I don’t think there is any reason to assume the connection is [10,000 years] old … this must surely be one late episode in a much longer and more complicated history of settlement,” she said.

At this point it is very difficult to make any generalizations. Vajda has not yet published his findings, but merely opened the door to discussion on the topic. Until he does, the foundation of our support or criticism is unknown.

EurekAlert is running a very interesting press release on the discovery of a 500,000 year old Homo erectus fossil recovered from Turkey. Apparently the fossil, a fragment of skull bone, shows lesions that the individual had tuberculosis.

Tuberculosis is a deadly infectious disease caused by multiple strains of mycobacteria. Because the mycobacteria have lost numerous coding and non-coding regions in its genome, it is hard to retrace the genetic differences that would tell us of the origins, relationships, and movement of the disease causing pathogen. But through analyzing relatively modern human skeletal remains (I’m talking thousands of years modern) from Egypt and Peru, we know that tuberculosis was taking a big toll on humans relatively recently in our evolutionary history.

If this Homo erectus really did have tuberculosis, then that means he probably, and other hominids, got sick because his body produced less vitamin D due to darker skin and had a less vigilant immune system, hundreds of thousands of years ago. From what’s reported in the press release, I don’t buy it. And neither does John Hawks. I think it is over analyzed and sensationalized science to make big headlines.

I really don’t understand why a Homo erectus from Turkey isn’t enough of a killer headline. To my knowledge this is the first hominid found in Turkey and it fills a big spatial gap in understanding human evolution. Of course, I really don’t know enough about the tuberculosis evidence in this individual to make a solid judgment… we’ll have to wait until we get the paper…

Speaking of which, paper should be out anytime soon in the American Journal of Physical Anthropology, so the entire details of the fossil aren’t known to us until the AJPA decides to give the green light and publish the paper. I have, however, discussed this press release with several colleagues and they are all skeptical.

The first thing they are curious about is the date. We speculate that dating was established using faunal evidence. The problem with that is the faunal composition of Turkey during the Pleistocene isn’t well known. Sure, the late Miocene is, and that’s cause there are a lot of Miocene sites… but at 500,000 years ago it is hard to correlate a date to what organisms were around at the time.

I also got word that John Kappelman, and his team damaged the fossil. I don’t know if it was during excavation, transportation, or curation/research, but having rumors run around that your team damaged the first ever Turkish hominid isn’t something the bolsters ones reputation in the field. But again, take this with a grain of salt… it is a rumor. There aren’t any official reports that his team actually broke the fossil, and if Kappelman’s not really liked, I can see how people will start up these things. Physical anthropologists are a catty bunch. But to be really honest, I can’t help but think the tuberculosis is a smokescreen to distract attention from this broken specimen.

Anyways, just reporting on this new paleoanthropology paper… be sure to keep checking the AJPA for the paper, and check out Razib’s post as well.

The BBC reports on the discovery of a very abundant collection of fossils unearthed at an ancient hyena den in the Granada region of south-east Spain. The site is named Fonelas P-1, and it is very important. How so? It falls right in between the Pleiocene and Pleistocene which is when early Homo is thoght to have made one of the first migrations out of Africa.

Currently, the site has yielded over 4,000 very diverse fossils including, gazelles, wolves, wild boar, lynx, sabretoothed cats, giraffes and zebras… as well as hyenas.

The official date hasn’t come back yet, but Fonelas P-1 is thought to be about 1.8 million years old. No hominins have been found yet but I wouldn’t be surprised if they do find one. With such a diverse and abundant list of fauna, Fonelas P-1 would have been the perfect place to attract hominins. Also, there are many similar fauna represented in Fonelas collection and those found early tool making sites in East Africa.

So keep your eyes out for Fonelas P-1. It should be a really interesting European site for paleoanthropology and paleontology.