It was only a couple of years ago that I learned that Peru had a black population, when I was exposed to the glorious voice of Susana Baca.
Now thanks to stumbling across Africana.com I learn that Argentina once had a black population as well. They made major contributions to Argentinean culture, including the tango, which is based on West African sources and not simply a Spanish-Italian fusion as I had always mistakenly assumed.
The disappearance of African Argentineans has been considered a demographic mystery, but one writer says there's nothing mysterious about it: it was the result of an overtly genocidal policy in the last half on the 19th century. In other words, Argentina treated its freed slave population much as they (and we norteamericanos) treated indigenous populations at around the same time.
Afro- (U.S. of) Americans, Afro-Cubans, Afro-Brazilians, Afro-Mexicans, Afro-Peruvians, Afro-Argentineans... Surely someone, somewhere has written a readable book that compares and contrasts the African diaspora throughout the Americas.