Thursday 22 August 2013

Taxonomists Take Note: If the Geneticists Are Correct, You'll Have to Choose Between Rassenkreis and Parapatry, and Whether Or Not We Get to Keep Calling Ourselves Homo sapiens. Good Luck With That!

The one on the left is probably the most convincing effigy ever created of what some think Neanderthal males looked like. (Source © Neanderthal Museum (Mettmann, Germany)

As you know I've been critical of claims that we and the Neanderthals interbred. By "we" I mean people with the cognitive capacity that you and I possess. Even if it could be unequivocally demonstrated that the Neanderthals bred with another kind of bipedal ape, it wouldn't have been us. It would have been with the contemporaneous anatomically modern Homo sapiens [AmHs] that left a remarkably similar archaeological record. Ipso facto, not like you and me.

A member of the AmHs kind of bipedal ape: Homo sapiens idaltu. (Apologies to copywriter holder. I ripped this from Google images and there was no source ascription.)
However, if, when all the data are in, it happens that Neanderthal and AmHs interbred, and if I and a few others are correct in saying that you and I aren't the same species as AmHs, there will be at least two days of reckoning for human palaeontologists.

Here's why.

First, the role of genomics. A human palaeontologist's job it is to find and describe fossils and erect taxonomies. Until recently all they had to go on were a) the fossils themselves, b) a rough estimate of the time they lived, and c) the geological context. On those bases, there was much back and forth over the taxonomic status of the Neanderthals. However, by the time it became possible to sequence the Neanderthal genome, human palaeontologists had pretty much agreed that Neanderthals were a separate species. Big whoops, by the look of it.

Geographic distribution of Pleistocene bipedal apes. 
Source(After J.R. Stewart and C.B. Stringer,
"Human Evolution Out of Africa: The Role of Refugia and
Climate Change." Science 335(6074):1317-1321, 2012.
DOI: 10.1126/science.1215627.)
As long as the Neanderthals were considered a separate species it was easy enough to rationalize the occurrence of AmHs in the Levant at around 100 ka with that of Homo neanderthalensis at around 60 ka. Given the temporal separation, it was possible to maintain the view that they were two species, inhabiting the same place at very different times under different climatic regimes. The AmHs form was part of an African faunal community that reached into southwest Asia; the Neanderthals were part of the European, ice-age, fauna that at one time reached as far south as southwestern Asia.

If the recent claims of the genome scientists hold up, the most likely scenario would be that the two populations interbred during the time they were contemporaneous and geographically adjacent. And there's the rub. If the two bipedal ape kinds were able to produce viable offspring it would put serious pressure on the biological definition of species. H. n. and H. s. would be seen either as a mini-rassenkreis or as parapatric species. And, if the claims of people like me hold up, and AmHs was the cognitive equivalent of a Neanderthal—neither of which could match wits with you and me—there would be an even bigger problem of what to call the newly distinguished types of AmHs—them and us.

In the world of taxonomy there are strict rules about who gets to name stuff and who gets to decide who names stuff, and in the event of a tie the race goes to the temporally precedent nomen. In the hypothetical case I've just sketched for you of Homo sapiens (Linnaeus 1758), the International Commission of Zoological Nomenclature [founded in 1895] would likely end up having to rule, and would [as near as I can figure it] do so by retaining the nomen Homo sapiens for AmHs. What then?

What to call us if AmHs gets to go on being H. sapiens? Well, according to the rules of zoological nomenclature one is not permitted to name a taxon before its discovery. I suppose we could play around with some possibilities, but nothing written here could ever have valence with the gods of taxonomic nomenclature. It's possible that we got to keep the H. s. tag. After all, we would end up being the sapient ones [whatever sapient means].

I'd like to think that we'd be given a new genus name, so fundamentally different are we from all that came before. Can you imagine? I'd push for Humanum sp. That's the un-gendered form of the Latin for human, in the sense of being humane [or kind]. We'd still have a long way to go before the whole world lived up to the name, given the state we're in. But at least we'd no longer have to put up with the tittering of homophobia-inspired, grade-school, potty humour involving our current genus name! [Did I just say "tittering?" English is full of pitfalls like that. Isn't it? *sigh*]

How about Humanum naturalis? [translation: human from nature; naturally human]. Wouldn't that just stick in the craw of the Christian Supremacists?

Final word. If, as I believe, Neanderthals and AmHs interbred, leaving remnants of Neanderthal DNA in the lineage of AmHs, and if, as I also believe AmHs was fundamentally different from you and me, and cognitively identical with the Neanderthals, archaeology would undoubtedly be the means by which the distinction is made between the two anatomically modern species. I like that idea. Some minds will need to be changed before such an event occurs, but that's why I'm here!


SA announces new posts on the Subversive Archaeologist's facebook page (mirrored on Rob Gargett's news feed), on Robert H. Gargett's page, Rob Gargett's twitter account, and his Google+ page. A few of you have already signed up to receive email when I post. Others have subscribed to the blog's RSS feeds. You can also become a 'member' of the blog through Google Friend Connect. Thank you for your continued patronage. You're the reason I do this.

No comments:

Post a Comment

Thanks for visiting!

Note: only a member of this blog may post a comment.