Is Erik Trinkaus on a wild Neandertal witch hunt or is he onto something?
After yesterday’s post, I’ve become curious and began digging up some more on Erik Trinkaus’ claims of hybridization of humans and Neandertals. I came across an article he published in 2003 where he rexamined Eyasi 1,
a later Middle Pleistocene east African neurocranium, reveals the presence of a suite of midoccipital features, including a modest nuchal torus that is limited to the middle half of the bone, the absence of an external occipital protuberance, and a distinct transversely oval suprainiac fossa. These features, and especially the suprainiac fossa, were considered to be uniquely derived for the European and western Asian Neandertals. These observations therefore indicate that these features are not limited to Neandertal lineage specimens, and should be assessed in terms of frequency distributions among later archaic humans.
I’ve bolded the second to last sentence of the abstract because the suprainiac fossa is the same feature that Trinkaus has honed in on with the Cioclovina crania. And he drew the same conclusions from it! His Eyasi 1 paper has two crappy photos of the crania, where I can’t quite distinguish the suprainiac fossa as Neandertal like, and unfortunately there aren’t many photographs of Eyasi 1 online for me to show to you. What I could find is a cartoon of the cranial anatomy of a Neandertal:
Without any other pictures than the drawing above to illustrate my point, you’re gonna have to imagine that the suprainiac fossa, a groove above the inion in the back of the skull is considerably more robust or pronounced in Neandertals and less so in modern humans. So when one comes across a human with a pronounced suprainiac fossa, are we to assume its hybridization? What I also wonder, is Trinkaus looking high and low in the fossil record for evidence that fits his theory?
There are over 9 billion modern humans, each a unique experiment in genetic mutation. To find a percentage with pronounced suprainiac fossa is likely. The question is whether the proportion of modern humans with one, two or many Neanderthal-like skeletal dimensions is an indicator of hybridization or of random genetic drift. It is difficult for me to differentiate various bison, lion and horse species and subspecies from their hybrids. When related species live within the same enclosures, they inevitably hybridize. To possibly prove hybridization, we must find locations where both hominids coexisted in proximity.
Mark A. Hiselman
August 6, 2007 at 12:47 pm
We seperate people into different groups based on a collection of characteristics . When we find characteristics from one group appearing in another group it’s often explained that it’s within the normal range. So why have groups if the characteristics are within each group’s range? Sort of like we can’t define a Neanderthal but we know one when we see one.
Jones
December 2, 2007 at 2:03 pm