We don’t.
However the violet-coloured skin is unlikely, since violet is quite a difficult colour to achieve using mammalian pigments.
Hmm; however blue might not be so difficult - these reasonably close relatives of humans have patches of strikingly blue skin;
paintings of early humans by early humans are generally brownish, blackish or reddish, but this might just be due to the pigments they used to paint with.
The overall shape of the face and skull can be inferred from the bones and so can the length of the arms and the height. Skin and eye color are unknowable, but simply guessed since Homo evolved in Africa and all native Africans have brown eyes and brown skin. Lighter colors apparently evolved further north, presumed to be an adaptation to less sunlight so less vitamin D.
Just to change the subject slightly, I recently read that there is some evidence that there is more to sunlight than just vitamin D since not all the supposed benefits come from vitamin supplements.
More to the point, the non-fur-covered parts of exposed skin of our close evolutionary cousins the great apes (orangs, gorillas, chimps, bonobos) are brown, black or pinkish, so it’s reasonable to assume that our lineage of hominids would follow the same pattern, rather than somehow resurrect (only to lose again) the bright pigment markings of more distant monkey lineages from which the hominoidea diverged long before.
Bone structures and muscle attachment points tend to give us a good sense of the facial features, as mentioned. While at it, notice that no higher primates have pixie ears either so the reasonable assumption is they did not just show up and then go away either, unless we find fossilized evidence thereof.
For species living in open sunny habitats, we can probably infer dark skin, although this may depend on whether they had much body hair.
[QUOTE=AK84]
All native Africans don’t have brown skin and hair.Especially in the North.
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I assume that Hari Seldon was referring to sub-Saharan Africans, all of whom have relatively dark skin and brown to black hair. (However, the San and Khoikhoi of southern Africa have paler skin than most others.)
Wasn’t there recently a DNA analysis done on some skeletons found in Spain and something like 15 000 years old, that seemed to indicate these people were probably dark-skinned and clear-eyed?