(Left) River systems (differentiated by colors) and major lakes of East Africa. Arabic numerals indicate localities at which haplochromines examined in this study were collected. The names of the localities are: 4, Lake Babati; 10, Lake Nshere; 18, Kitilda/Rukwa; 30, Lake Singida; 32, Muze River; 34, Zimba River; 36, Lake Nabugabo, Lake Kayugi, and Lake Kayania; 37, Lake Wamala; 39, Lake Katwe/Lake Edward; 40, Katunguru Bridge/Kazinga Channel; 45, Butiaba/Lake Albert; 47, Buzumu Gulf, Kissenda Bay; 48, Mwanza Gulf, Butimba; 49, Chamagati Island; 50, Zue Island; 51, Speke Gulf; 52, Muhuru; 53, Rusinga, Gemba, Gingo; 54, Anyanga; 55, Mbassa; 56, Katonga; 57, Yetti, Nyegezi Rocks; 58, Katavi River. (Right) Representatives of the cichlid taxa used in this study. The background color indicates the different tinge and translucency of the water in Lake Victoria (Upper) and Lake Malawi (Lower). The cichlid fish are: 1, Haplochromis nyererei; 2, Astatotilapia nubilus from Lake Victoria (in front) and Lake Wamala (behind); 3, Paralabidochromis chilotes; 4, Haplochromis pyrrhocephalus; 5, Haplochromis katavi; 6, Aulonocara jacobfreibergi; 7, Melanochromis parallelus; 8, Pseudotropheus daktari.