Are they black? In which case that should tell us something about how long it takes for “races” to develop. I believe we’ve been told it takes millions of years.
Sure they're black. And the situation tells us precisely nothing about "the development of races". A small group of Semites migrates into an area of Negroids, and intermarries. Does it surprise anyone that their descendants have the characteristics of the majority population??
Dude, if they have a smidgeon of semitic ancestry that’s all well and good, but the whole “intermarrying with the native black folk” thing would require that the output of their unions, 3,00 years later, would most likely appear to be 100% african folks, albeit with little skullcaps on their heads and Stars of David on their tombstones.