Cthulhu Mythos Obscurities

In the story "The Shadow out of Time" H.P. Lovecraft mentions "a general of the great-headed brown people who held South Africa in B.C. 50,000" as one the Yithian's mental abductees.
Perhaps HPL's inspiration for this was Boskop Man aka Homo Capensis, a separate species of ancient humans theorized to have a much greater brain capacity based on some big skulls found in South Africa in 1913 (the idea has since been discredited). Was HPL imagining them in his mythos as a prehistoric empire since they had a general smart enough to get mind switched with a Yithian cone creature?

Not much online about Boskop Man since it's now considered just some unusually big skulls and not a separate race of early man but here's an image and a couple of articles.

https://en.wikipedia.org/wiki/Boskop_Man

https://steemit.com/history/@getonthetrain/boskop-man-ancient-humans-with-extraordinarily-large-skulls-how-smart-were-they