Okay, every year (or so) there is a "BIG STORY" in paleoanthropology that usually revolves around a fossil (sometimes it's a genetic study) and increasingly it's the publication of a paper (finally!) that analyzes a fossil that was actually found years ago.
This week people started talking about a skull that was found 8 years ago at the site of Dmanisi (Pronounced "Dee-man-EE-see) in the Republic of Georgia (in the Caucusus Mountains- a former member of the Soviet Union, not the state in the American South). Really, the story is about how one skull fits in with several other skulls that had been discovered there, and the answer is "not very well." Taken together, the five hominid skulls found at one site all look very different from each other although they are all found in the same place in pretty much the same geological instant, so the interpretation is that there was a LOT more variability in species during the paleolithic than many at first thought.
For years there has been a battle between "Lumpers" (people who emphasize similarities and therefore lump fossils together as part of the same species) and "splitters" (people who emphasize discontinuities in the fossil record and split them into many different species). Taken together, the Dmanisi fossils give a lot of creedence to the lumpers, but to the splitters... eh- not so much.
On top of that there is the question of the "Multiregional hypothesis" that competes with the "Out of Africa hypothesis." The Out of Africa hypothesis states that modern humans evolved in Africa and spread out subsequently, replacing populations of archaic Homo in Asia and Europe. The multiregional hypothesis (sometimes called "regional continuity") claims that ancestral Homo species were one giant gene pool and advantageous genes in one geographic area would spread to others via gene flow, but local populations might retain regional variations.
The takeaway (from MY perspective): Lumpers look pretty good here, although it would be a dream come true to find a similar site in Africa to show such variability. I'm still not convinced that there was only one species in east Africa 2 million years ago. I've (mostly) been a lumper since I started studying this stuff though. I have to admit that the miltiregional hypothesis seems to come out on top with this find, although I think the genetic evidence has really given the edge to the African origin hypothesis over the past ten years or so.
Never a dull moment in this field! Here are stories about the find from some of the major players in the mainstream media.
The New York Times' take:
http://www.nytimes.com/2013/10/18/science/fossil-skull-may-rewrite-humans-evolutionary-story.html?_r=1&hp&adxnnl=1&adxnnlx=1382036967-uVGQOLIVXjaActXANk%2Fc2g
The BBC's take:
http://www.bbc.co.uk/news/science-environment-24564375
Nat Geo's Take:
http://news.nationalgeographic.com/news/2013/10/131017-skull-human-origins-dmanisi-georgia-erectus/
2 comments:
Good post, Marc. I just finished covering this in one of my classes. I've also always thought the "lumpers" argument made more sense despite the mounting evidence against it. It will be interesting to see how this find shakes things up.
Thanks Anton. And yes, it's always a good idea to wait and see how the dust settles on these things! I wonder how many biological anthropologists will stop talking to each other after the AAA meetings!
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