Is the Loomis Hypothesis wrong?

I remember an old vitamin D book – I believe it was Feldman’s Vitamin D – that going down the Transsahara Route (Algier-Lagos) human skin color gets always darker towards Tamanrasset due to increased solar power (also known as Loomis Hypothese).

Let’s look at three maps now.

1. Solar power. Source: https://upload.wikimedia.org/wikipedia/commons/1/1e/Global_Map_of_Global_Horizontal_Radiation.png

The above map does not match the skin tones.

2. Skin tone. Source https://science.sciencemag.org/content/358/6365/867.full For full details see the original paper

Neither does a new vitamin D map published last week in the Lancet

3. Vitamin D map. Source: https://linkinghub.elsevier.com/retrieve/pii/S2214109X19304577 For full details see the original paper

Although the maps are still patchy, I think the Loomis hypothesis is wrong.