Cryptic diversity of Rhinogobius rubromaculatus species complex (Gobiidae) in Taiwan: Mitogenomes reveal their evolutionary history

Cryptic diversity of Rhinogobius rubromaculatus species complex (Gobiidae) in Taiwan: Mitogenomes reveal their evolutionary history

Rhinogobius rubromaculatus species complex is a group of freshwater gobies endemic to Taiwan. To understand the cryptic species diversity of R. rubromaculatus species complex, this study collected 501 specimens of the genus Rhinogobius from 34 rivers in Taiwan and used the sequences of mitochondrial DNA cytochrome b gene (1140 bp) as a DNA barcoding tool to identify species. In total, four allopatric lineages were found within R. rubromaculatus species complex, and large genetic divergences (pdistances > 0.043) support that they are distinct species. To better understand their evolutionary history, the complete mitochondrial genomes (mitogenomes) of these four lineages were sequenced. These results showed that (1) the mitogenomes characteristics of these four lineages were similar to those of other Rhinogobius species; (2) the mitogenome genetic distances (p-distances > 0.045) also supported that these four lineages are different species; (3) the results of the Approximate Bayesian Computation analyses support that these four species colonized Taiwan through four different colonization routes; (4) the R. rubromaculatus species complex reveal an evolutionary history similar to other Taiwanese freshwater fish such as Squalidus, Cobitis sinensis and Acrossocheilus paradoxus; and (5) the complex geological history of Taiwan has shaped the colonization history and distribution patterns of R. rubromaculatus species complex. These results have important implications for the conservation, population genetics and evolution of freshwater fishes in Taiwan.