Abstract said:The Neotropical Midas cichlid species complex (Amphilophus citrinellus Günther 1864) has become a model system for investigating the mechanisms of speciation and adaptive radiation. In several instances ancestral Midas cichlids from the great Nicaraguan lakes have colonized nearby crater lakes where they continued to evolve in isolation. Each crater lake can be seen as a natural experiment of sympatric and allopatric divergence. Several ecologically and genetically well-differentiated crater lake species have already been identified, but the species complex is not fully taxonomically resolved. Here, two new endemic Nicaraguan crater lake cichlids species are described: Amphilophus tolteca n. sp., a slender-bodied species which is endemic to the ca. 1,245 year old Lake Asososca Managua and Amphilophus viridis n. sp., an endemic benthic species from Lake Xiloá. Amphilophus tolteca morphologically resembles previously described limnetic species from the crater lakes Apoyo and Xiloá with a depressed, elongated body. However, A. tolteca is geographically isolated and genetically distinct from those species and from the putative generalist ancestral species. Amphilophus viridis resembles the Xiloá species A. amarillo in terms of body shape, but is distinct in coloration and ecology, and is genetically differentiated from all other syntopic species.
And the water muddies even more...Recknagel, Hans & H. Kusche, K.R. Elmer & A. Meyer. 2013. "Two new endemic species in the Midas cichlid species complex from Nicaraguan crater lakes: Amphilophus tolteca and Amphilophus viridis (Perciformes, Cichlidae)". Aqua: International Journal of Ichthyology. v. 19(n. 4), pp. 207-224