Ice Age - metrics

[MOESAN]

I lost my first post so I put here juste an abstract of a paper you can google to red it entirely.
Good night

NATURE COMMUNICATIONS | ARTICLE
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Craniometric analysis of European Upper Palaeolithic and Mesolithic samples supports discontinuity at the Last Glacial Maximum
· Ciarán Brewster,
· Christopher Meiklejohn,
· Noreen von Cramon-Taubadel
· & Ron Pinhasi
· Affiliations
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Nature Communications

5,

Article number:

4094

doi:10.1038/ncomms5094
Received

28 February 2014
Accepted

12 May 2014
Published

10 June 2014
Updated online
24 June 2014
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Abstract
· Abstract•
· Introduction•
· Results•
· Discussion•
· Methods•
· Additional information•
· Change history•
· References•
· Acknowledgements•
· Author information•
· Supplementary information
The Last Glacial Maximum (LGM) represents the most significant climatic event since the emergence of anatomically modern humans (AMH). In Europe, the LGM may have played a role in changing morphological features as a result of adaptive and stochastic processes. We use craniometric data to examine morphological diversity in pre- and post-LGM specimens. Craniometric variation is assessed across four periods—pre-LGM, late glacial, Early Holocene and Middle Holocene—using a large, well-dated, data set. Our results show significant differences across the four periods, using a MANOVA on size-adjusted cranial measurements. A discriminant function analysis shows separation between pre-LGM and later groups. Analyses repeated on a subsample, controlled for time and location, yield similar results. The results are largely influenced by facial measurements and are most consistent with neutral demographic processes. These findings suggest that the LGM had a major impact on AMH populations in Europe prior to the Neolithic.

[Angela]

Most interesting, Moesan. Thanks very much.

It seems that the biggest shift is pre-LGM to post LGM. It's certainly suggestive to me of a new population.

[MOESAN]

I have not had time to read the entire paper.
I only noticed: shortening of leggs (ratio to body) often associated to cold climate so seemingly coherent with environmental evolution but: a shortening of leggs would have been associated to a more robust shape and it is the opposite; and the crania shapes are very different so the environmental evolution upon unchanged population does not seem the case and as you say we can figure out new populations. By the way, Villabruna had long leggs: so newcomers from South in its case, or ancient forms remained in some places ?(the Villabruna crania, spite its face being not so broad as 'cromagnons', is by far closer to 'cromagnon' than to more recent Europeans of postLGM and Mesolithic, concerning skull shape; it's true Villabruna Y-R1b is ONE man, and we cannot say too much upon a single case). I regreat they have not more samples for every place in a so large space of land and time. &: the newcomers - except the Villabruna pattern - could have been come from far East after LGM; it was the suggestion of some old anthropologists: more adapted to cold?; there was something 'artic' in them, but not in all of them. Convergence or ancestry? Northern 'mongoloids' show also some 'artic'. Maybe hazard... these traits (on jaws of some types) could be linked more to way of life (food and Co) than to only genetic inheritage. Uneasy to tell.
&: I don't believe in a complete turn over of populations at post LGM. personal fragile feeling.
I have to read the whole paper;

[LeBrok]

I have not had time to read the entire paper.
I only noticed: shortening of leggs (ratio to body) often associated to cold climate so seemingly coherent with environmental evolution but: a shortening of leggs would have been associated to a more robust shape and it is the opposite; and the crania shapes are very different so the environmental evolution upon unchanged population does not seem the case and as you say we can figure out new populations. By the way, Villabruna had long leggs: so newcomers from South in its case, or ancient forms remained in some places ?(the Villabruna crania, spite its face being not so broad as 'cromagnons', is by far closer to 'cromagnon' than to more recent Europeans of postLGM and Mesolithic, concerning skull shape; it's true Villabruna Y-R1b is ONE man, and we cannot say too much upon a single case). I regreat they have not more samples for every place in a so large space of land and time. &: the newcomers - except the Villabruna pattern - could have been come from far East after LGM; it was the suggestion of some old anthropologists: more adapted to cold?; there was something 'artic' in them, but not in all of them. Convergence or ancestry? Northern 'mongoloids' show also some 'artic'. Maybe hazard... these traits (on jaws of some types) could be linked more to way of life (food and Co) than to only genetic inheritage. Uneasy to tell.
&: I don't believe in a complete turn over of populations at post LGM. personal fragile feeling.
I have to read the whole paper;

Good post Moesan. I believe that WHG didn't come from very far away, and started from same stock as other European Paleo HGs, so there is a big degree of relationship. Also there is substantial degree of intermixing of both. I would be surprised if they looked totally different. Interestingly, but not unexpectedly, they have some similarities to EEF (living closer to them and in warmer zone) like longer legs, more vertical forehead and longer skull in general. I'm not sure though if it is through mixing with similar looking (to EEF) hunter gatherers or just from same environmental forcings on evolution of their phenotype?

[epoch]

I have not had time to read the entire paper.
I only noticed: shortening of leggs (ratio to body) often associated to cold climate so seemingly coherent with environmental evolution but: a shortening of leggs would have been associated to a more robust shape and it is the opposite; and the crania shapes are very different so the environmental evolution upon unchanged population does not seem the case and as you say we can figure out new populations. By the way, Villabruna had long leggs: so newcomers from South in its case, or ancient forms remained in some places ?(the Villabruna crania, spite its face being not so broad as 'cromagnons', is by far closer to 'cromagnon' than to more recent Europeans of postLGM and Mesolithic, concerning skull shape; it's true Villabruna Y-R1b is ONE man, and we cannot say too much upon a single case). I regreat they have not more samples for every place in a so large space of land and time. &: the newcomers - except the Villabruna pattern - could have been come from far East after LGM; it was the suggestion of some old anthropologists: more adapted to cold?; there was something 'artic' in them, but not in all of them. Convergence or ancestry? Northern 'mongoloids' show also some 'artic'. Maybe hazard... these traits (on jaws of some types) could be linked more to way of life (food and Co) than to only genetic inheritage. Uneasy to tell.
&: I don't believe in a complete turn over of populations at post LGM. personal fragile feeling.
I have to read the whole paper;

Me neither. LGM was a huge bottleneck, which means that a lesser abundant phenotype could become dominant all of a sudden. If there is one thing Fu 2016 shows is that there was quite a diverse population before LGM. Diverse yet clearly related.