Evolution in Your FaceLake Victoria, Africa's largest lake, is home to more than 300 species of cichlids. These fish, which are popular in aquariums, are deep-bodied and have one nostril, rather than the usual two, on each side of the head. Seismic profiles and cores of the lake taken by a team headed by Thomas C. Johnson of the University of Minnesota, reveal that the lake dried up completely about 12,400 years ago. This means that the rate of speciation of cichlid fishes has been extremely rapid: something on average of one new species every 40 years!
by Patrick Huyghe
Omni
Wayback Machine versions
Alternatively, it could mean there was a residual reservoir of cichlid fishes, of which the researches are currrently unaware.
Especialy so, since that would help explain where the fish came from in the first place, if the lake actually "completely" dried up. 300 species don't come from no ancestral population, but could easily come for a remnant pool of 300 ancestral species.
Or that fishy Gramma had been drinking wacky juice and squirted out ALL these critters herself!
(This assumin' is FUN! I'll have to do it more often!)