Three new archaeological finds have provided evidence questioning anthropologists’ previous theory that primates originated in Africa and pushing back accepted dates on migration to Asia and the origins of stone tool-making.
The questions start with a new study published in Nature describing newly discovered anthropoid fossils in Dur At-Talah in Libya. Anthropoids are the primate group including humans, apes and monkeys; the fossils, composed only of teeth but providing immense data for anthropologists, date to 39 million years ago and indicate the early anthropoids weighed between one-quarter and one pound. Furthermore, the fossils indicate at least three anthropoid species had already diverged from a common ancestor through evolution, corresponding to earlier described anthropoid species from Asia.
These new fossils appear suddenly in the archaeological record, researchers say, prompting one of two explanations. The first, and less likely, is a massive gap in Africa’s fossil record; scientists believe it to be unlikely because Eocene epoch sites in northern Africa have been thoroughly sampled and no diverse anthropoid fossils have been found predating these new fossils. Most likely, the study’s authors argued, is that these new anthropoids “colonized” Africa from another continent, most likely Asia approximately 39 million years ago, in the middle of the Eocene.
“If our ideas are correct, this early colonization of Africa by anthropoids was a truly pivotal event — one of the key points in our evolutionary history,” says Christopher Beard, Curator of Vertebrate Paleontology at Carnegie Museum of Natural History and an author on the paper. “At the time, Africa was an island continent; when these anthropoids appeared, there was nothing on that island that could compete with them. It led to a period of flourishing evolutionary divergence amongst anthropoids, and one of those lineages resulted in humans. If our early anthropoid ancestors had not succeeded in migrating from Asia to Africa, we simply wouldn’t exist.”
Meanwhile, researchers working in south China have uncovered fossils pushing back the emergence of anatomically modern humans by almost 60,000 years. A partial jawbone and several teeth found in Zhirendong in 2007 have been dated to 100,000 years ago, well before archaeologists believed modern humans had made it from Africa to Asia.
Researchers say the fossils have a mix of modern and Neanderthal features. While the Daily Mail notes Chinese scientists may pounce on the fossils as evidence for a controversial theory that humans in China descend from a species called Homo Pekinensis rather than from the African-borne Homo Sapiens. The researchers say the Zhirendong fossils really indicate that modern humans and Neanderthals coexisted for some time in that region, mating and creating a hybrid species.
“There was mating between these ‘archaic’ and ‘modern’ groups across Asia, and not just in Europe and the remainder of Africa,” researcher and Neanderthal expert Erik Trinkaus said. “Of more interest than who had sex with whom is the fact that modern humans had spread across southern Eurasia by 100,000 years ago, and yet archaic humans remained across the more northern areas, and even displaced the modern humans in Southwest Asia for an additional 50,000 to 70,000 years. … It argues for very little adaptive advantage on the part of these modern humans.”
Although the find is exciting, anthropologists caution against reading too much into it as there is so far only one sample.
Back in Africa, a new expedition has found relatively sophisticated stone artifacts in a cave in South Africa dating back 75,000 years, 50,000 years earlier than prehistoric peoples’ tool use was thought. The tools, found in the Blombos Cave near the southern tip of South Africa, were created with a technique known as pressure flaking, which, according to Wired, “consists of trimming the edges of a finished tool by pressing with a bone point hard enough to remove thin slices of rock. This process creates the narrow, evenly spaced grooves found on flint tools from Europe’s 20,000-year-old Solutrean culture and prehistoric Native American groups.” The technique better controls the sharpness, thickness and shape of spearheads and stone knives.
The researchers analyzed 159 silcrete points and fragments, 179 other retouched pieces and more than 700 flakes from the cave. They also experimented with replicating the procedure for comparative purposes; pressure flaking can be taught to a novice in about half an hour, according to archaeologist John Shea. “It is, literally, so easy a caveman can do it,” he said.
Again, archaeologists caution, while this is an interesting discovery, it merely indicates the technique appeared earlier than previous thought and is not a game-changer on questions of origins or cognitive development.
Finally, some quick summaries of other recent anthropological developments:
- A new paper will likely spark debate for arguing that the so-called Homo floresiensis, a 3.5-foot-tall, 15,000-year-old “hobbit”-like human species discovered in Indonesia in 2003, is actually an idodine-deprived Homo sapiens. The lack of iodine combined with endemic dwarf cretinism derived from congenital hypothyroidism gave the nine skeletons their short stature, the researchers argue.
- Archaeologists from the Smithsonian, Southern Methodist University and the University of Oregon are concerned about rising ocean levels threatening seaside archaeological sites. In the Journal of Coastal Conservation they argue for using “quantifiable factors such as historical rates of shoreline change, wave action, coastal slope and shoreline geomorphology” to create an index of threatened sites in order to inform decision-making about preservation and salvageability.
- Israeli archaeologist Ehud Netzer, famous for excavating King Herod’s winter palace and discovering Herod’s tomb, died at 76 years of age after accidentally falling at the site this week. Prime Minister Benjamin Netanyahu called his death “a loss for his family, scholars of Israel’s history and the science of archaeology.”
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