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Sympatric speciation in Nicaraguan crater lake cichlid fish

2006; Nature Portfolio; Volume: 439; Issue: 7077 Linguagem: Inglês

10.1038/nature04325

1476-4687

Marta Barluenga, Kai N. Stölting, Walter Salzburger, Moritz Muschick, Axel Meyer,

Ichthyology and Marine Biology

One of the hottest controversies in evolutionary biology is sympatric speciation, the formation of new species in the absence of geographical boundaries. The controversy is about whether it happens or not: it ‘should’ in theory but it is difficult to prove it. Two new examples of the phenomenon are reported this week, one in fish and one (online) in plants, convincing evidence that as Darwin suggested, sympatric speciation is likely to be common. The fishy example is the formation of Amphilophus zaliosus from A. citrinellus in a volcanic crater lake in Nicaragua. And in plants, the curly palm Howea belmoreana and the thatch palm H. forsteriana diverged on Lord Howe Island, a volcanic island 480 km east of Australia in the Tasman Sea. Sympatric speciation, the formation of species in the absence of geographical barriers, remains one of the most contentious concepts in evolutionary biology. Although speciation under sympatric conditions seems theoretically possible1,2,3,4,5, empirical studies are scarce and only a few credible examples of sympatric speciation exist6. Here we present a convincing case of sympatric speciation in the Midas cichlid species complex (Amphilophus sp.) in a young and small volcanic crater lake in Nicaragua. Our study includes phylogeographic, population-genetic (based on mitochondrial DNA, microsatellites and amplified fragment length polymorphisms), morphometric and ecological analyses. We find, first, that crater Lake Apoyo was seeded only once by the ancestral high-bodied benthic species Amphilophus citrinellus, the most common cichlid species in the area; second, that a new elongated limnetic species (Amphilophus zaliosus) evolved in Lake Apoyo from the ancestral species (A. citrinellus) within less than ∼10,000 yr; third, that the two species in Lake Apoyo are reproductively isolated; and fourth, that the two species are eco-morphologically distinct.