Probing diversity in freshwater fishes from Mexico and Guatemala with DNA barcodes
Abstract:The freshwater fish fauna of Mexico and Guatemala is exceptionally diverse with >600 species, many endemic. In this study, patterns of sequence divergence were analysed in representatives of this fauna using cytochrome c oxidase subunit 1 (COI) DNA barcodes for 61 species in 36 genera. The average divergence among conspecific individuals was 0·45%, while congeneric taxa showed 5·1% divergence. Three species of Poblana, each occupying a different crater lake in the arid regions of Central Mexico, have had a controversial taxonomic history but are usually regarded as endemics to a single lake. They possess identical COI barcodes, suggesting a very recent history of isolation. Representatives of the Cichlidae, a complex and poorly understood family, were well discriminated by barcodes. Many species of Characidae seem to be young, with low divergence values (<2%), but nevertheless, clear barcode clusters were apparent in the Bramocharax–Astyanax complex. The symbranchid, Opisthernon aenigmaticum, has been regarded as a single species ranging from Guatemala to Mexico, but it includes two deeply divergent barcode lineages, one a possible new endemic species. Aside from these special cases, the results confirm that DNA barcodes will be highly effective in discriminating freshwater fishes from Central America and that a comprehensive analysis will provide new important insights for understanding diversity of this fauna.
Document Type: Regular Paper
Affiliations: 1: Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, N1G 2W1 Canada 2: El Colegio de la Frontera Sur, Av. Centenario km 5.5, Chetumal 77014, Quintana Roo, México 3: Bioconservación A. C., A.P. 504, San Nicolás de los Garza 66450, Nuevo León, México
Publication date: February 1, 2009