I could be wrong.
I think humans came from arabia, then a group migrated into ethiopia at a very early date (like 250,000 years carrying the oldest y haplogroups A and perhaps oldest x haplogroups L ), and then spread into southern and then central/west africa, and adapted to the climate, by aquiring kinky hair/darker skin(though the khoesan have a ligth brown skin).
I think the super dark skin found among south sudanese and other blacks is due to them living in the sahara over a long stretch, wheras in southern africa you don't need to be that dark.
Not sure about north africa though.
Arabia wouldn't have any remains because its a desert.
They've found tools in arabia dating way back that were prob used by homo sapiens,
but scientists think their was a migration from ethiopia into arabia,
but I think it was the reverse,
but I could be wrong