Speciation processes in putative island endemic sister bat species: false impressions from mitochondrial DNA and microsatellite data

Cases of geographically restricted co-occurring sister taxa are rare and may point to potential divergence with gene flow. The two bat species Murina gracilis and M. recondita are both endemic to Taiwan and are putative sister species. To test for non-allopatric divergence and gene flow in these taxa, we generated sequences using Sanger and Next Generation Sequencing, and combined these with microsatellite data for coalescent-based analyses. MtDNA phylogenies supported the reciprocally monophyletic sister relationship between M. gracilis and M. recondita, however, clustering of microsatellite genotypes revealed several cases of species admixture suggesting possible introgression. Sequencing of microsatellite flanking regions revealed that admixture signatures stemmed from microsatellite allele homoplasy rather than recent introgressive hybridization, and also uncovered an unexpected sister relationship between M. recondita and the continental species M. eleryi, to the exclusion of M. gr...