Well our eurasian ancestors mated with neanderthal. Some SE asians mated with Denisovan. It appears there was plenty of race mixing to go around . However it seems the the male lineage of most blacks is not paleo african (khoisan and pygmy) but eurasian. The Y chromosome haplogroup E is increasingly accepted to have originated outside africa. That male ancestry back migrated to africa probably some time within the last 50 thousand years and mated with Pygmies, Khoisan, and this archaic group of non-homosapiens. 11% is really quite a lot of admixture. It could be that this archaic population was extremely violent as a breed.