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Monday, June 30, 2008

Archaic skulls (just notes)

First series: longfaced skulls around the World that remind somewhat of Combe-Capelle (Aurignacian):

· Skhul types: very archaic, different among them
· Predmosti: very similar to Combe-Capelle but less dolicocephalic and more prognathous
· Roonka: a recent Australian skull that, while having some unique Australoid traits in the vault, also resembles a lot the archaic European types in the face, nose and jaw.

Second series: more robust skulls around the World that remind somewhat of Crô-Magnon 1 and Taforalt:

Notes: These are even more different among them - acknowledged.
· Crô-Magnon 1: actually he's more recent than 30,000 BP, as it's been reviewed as belonging to a Gravettian layer, not Aurignacian. Noticed after creating the image, sorry.
· Taforalt: much more refined and "modern" than Crô-Magnon 1. More longfaced and gracile.
· Keilor: the one that most resembles Crô-Magnon 1 in my opinion.
· UC-101: included mostly because of the robust jaw. It has a much higher face than the rest but it's dolicocephalous, unlike modern Mongoloids.
· Kennewick Man: reminds somewhat of Taforalt but he's brachicephalous (the only one in the series) and has a very sloped forehead.

Finally, just to complete the European UP series, Chancelade man (Magdalenian, c. 15,000 BP, Franco-Cantabrian Region):

Notes: modern mesocephalic European skull in all aspects, in my opinion. The very narrow jaw and total lack of prognathism is particularly remarkable. It is worth noticing that recently it was discovered that the first known impacted tooth belonged to another Magdalenian skull. The small size of the jaw (in comparison to archaic types) clearly explains why.

Credits for the images to:
· Modern Human Origins
· Peter Brown
· Other forgotten sites

Please, if you know of other skulls (with available image) worth adding to the list, let me know.


Tod said...

Do you have any ideas about the selective pressure for reduced size of the jaw that resulted in the impacted tooth.

Could it have been sexual selection of women caused by high mortality of hunters leading to a shortage of men. (Peter Frost's theory)

Maju said...

I don't know: dietary reasons appear likely to have been influential, not just in this epysode but along all the evolution of H. sapiens.

Sexual selection may have played a role too, if smaller jaws are prefered in either gender (ir both). I know that at least for women narrower mandibles are percieved generally as more attractive. In general it is very posible that many traits that have been eventually favored in the evolution of H. sapiens have been influenced by mere aesthetic preference for softer lines and stuff like that. Nevertheless, such aesthetic preferences may vary somewhat through cultures too and be ethnic-specific in some aspects.

Another reason may be energy economy in developement: the less energy we as children invest in unnecesary traits (unnecesary, as cooking was more and more common and refined) such strong jaws and related stuff like browridges, the more we can invest in other surely more necesary aspects.

I really dont see how shortage of men would affect this anyhow. Nor I can think of any reason why hunters would die significatively more often than other members of their communities (most death causes could be more dependent on food supply or disease than anything else - and these would be shared by all).

Also, a possible dietary influence may be in higher dependence on seafood in Magdalenian times (when harpoons are extremely common and other data does suggest increased dependence on sea mammals, and probably fish too).

Another possible reason I've found here and there is mere general reduction of size during and after the LGM, possibly as defense against cold and reduced food supply.

But all this is somewhat speculative anyhow. We may never know which factors were actually the most decisive ones.

Tod said...

Going by the information on the impacted tooth you take notice of skeletal details so I would be grateful for any light your expertise could shed on the matter of rickets or osteomalacia. If and when you have the time:-

How old is the earliest evidence for rickets or osteomalacia in Europe?

Maju said...

No expert here, ok? Just an interested amateur.

I really don't know when rickets appeared first in Europe, sorry. Nevertheless it was probably a real adaptative issue because even in the Franco-Cantabrian Region, in SW Europe, at least in the Atlantic part, you don't get that much sunlight along the year, so light pygmentation must have been favored from old (unless a fish-rich diet compensates). Rickets and other illnesses caused by low vit. D must have pushed in Europe (and I'd say specially in Atlantic Europe, where clouds are nearly permanent) the developement or at least the possitive selection of lighter pygmented types. Anyhow the extreme types were maybe only selected when the far north became inhabitable after the Ice Age (and there's some genetic evidence that certain "blond" gene was only, or mostly, selected then).

Tod said...

European skull form seems to have a lot of continuity

Maju said...

Well, I've seen people using that same paper to argue that modern Europeans are not direct or pure descendants of Cro-Magnons, which are the only UP Europeans singled out in the study.

One issue I find here is that "UP Europeans" is a too loose tag. I think at least three timeline categories should be considered:

1. Archaic or early European types, like Combe-Capelle, Predmosti, Brno. Most related with Aurignacian or other early cultures.

2. Cro-Magnon or middle UP Europeans, specifically related with Gravettian (and in South/East Iberia also with their peculiar Gravetto-Solutrean), as well as with Oranian (Ibermaurusian) in North Africa.

3. Late UP Europeans, like Chancelade, specially related with Magadalenian culture (at least in West and Central regions), who are almost totally modern (but also show some affinities with their predecessors, IMO, of which they are probably an "in situ" developement).

Additionally in all periods you can see regional (and individual, of course) differences.

Talking of "European UP" in general is misleading, I think: we should rather consider separate groups for each space-time. But, well, the study is actually focused on Neolithic and Bronze Age people, so that oversight is somehow justified.

Tod said...

What do you think of
Grimaldi Man could he be the original Out of Africa type before being transformed

Maju said...

Too late in time to be "the original OOA type". Certainly he shows that marked prognathism existed in that time. In any case, he is just one among many remains, even for the Grimaldi cave itself: not really relevant, I'd say.

Btw, I'd say that prognathism is marked in this specimen but other traits are not "negroid" as some have suggested (nose shape and maybe eye orbits appear Eurasian for instance). Maybe he's more comparable with other Eurasians like Papuans or whatever, who also show an extreme prognathism but with clearly non-negroid traits otherwise.

Tod said...

shape regression on 2D : 4D ratioTo me the narrower jaw looks more feminine. Digit ratio is a index of prenatal testosteronization and narrower jawed faces are more feminine judging by the higher digit ratio. I think impacted wisdom teeth could well be a result of selection for feminine looks i.e. a smaller jaw. (I believe Europeans had a edge to edge bite at this time.) The female shapes -

Maju said...

The right face has much thicker lips, maybe that's why it looks more femenine.

Admittedly broad faces in women may be not very sexy but I don't think they are attractive in guys either. That may just be because I'm used to relatively narrow faces and/or because broad faces look "fat".