Phylogeography and Population Structure of the Imperiled Redtail Splitfin (Goodeidae:Xenotoca eiseni): Implications for Conservation

Abstract

The river drainages of Central Mexico have a high degree of freshwater diversity, and are subsequently a focal point for many freshwater fish conservation studies. The livebearing subfamily Goodeinae (Teleostomi: Goodeidae) is a diverse endemic group, under threat from many anthropogenic factors. Xenotoca eiseni, the Redtail Splitfin, a member of this subfamily, has a fragmented distribution in the western basins of the Pacific Coast including the Rios Grande de Santiago, Compostela, Ayuquila, Coahuayana, and the endorheic Lago de Magdalena and Etzatlan-San Marcos basins. Previous studies have noted high levels of genetic differentiation between the endorheic Lago de Magdalena and Etzatlan-San Marcos basins and surrounding areas which may be indicative of more taxonomic diversity within X. eiseni than currently recognized. The objectives of this study were to use mitochondrial (cytochrome b) and nuclear (ITS-1) DNA sequences and microsatellite data to assess phylogeography, genetic differentiation, and po...