I was led to wondering why didn't the Australian aborigines also develop lighter skin if the UV thesis is valid. But checking my globe I see Oz is located between the 10th and 40th parallels in the South, while most of Europe is above the 40th parallel in the North.

I now am curious if the DNA samples from Neanderthal and Denisovan sites provide enough information to examine the genes/alleles associated with skin color. Those species of course preceded homo sapiens by several 100 thousand years.