Speciation and differentiation of the genus Opsariichthys (Teleostei: Cyprinidae) in East Asia

Abstract

The genus Opsariichthys is an endemic and widespread cyprinid genus in East Asia, but the speciation and differentiations are still unknown. This study examined the phylogeography of the genus Opsariichthys using mitochondrial DNA cytochrome b sequences (1140 bp) with extensive sampling throughout its distribution range. In total, 444 specimens belonging to seven Opsariichthys species were collected from 43 populations. The time coalescing to the genus Opsariichthys could be traced back to the late Miocene [TMRCA = 6.43 mya (million years ago)]. The interspecies differentiations occurred in two phases, Pliocene (>2 mya, Opsariichthys uncirostris, Opsariichthys bidens, Opsariichthys evolans, Opsariichthys kaopingensis and Opsariichthys pachycephalus) and Pleistocene (<2 mya, Opsariichthys minutus and Opsariichthys hainanensis). The results of a statistical dispersal-vicariance analysis suggested that the ancestral populations of the genus Opsariichthys were widely distributed over East Asia before diversification. Our study showed that the cyclic tectonic movements and climate changes may have shaped speciation, migrations and population differentiations. Moreover, our study considered the colonization times and migrating potentiality that could affect the Opsariichthys species’ distribution ranges and intraspecific genetic variation patterns.