Across the highest mountain on Earth: discordant phylogeographic patterns and recent dispersal of Tibetan stone loaches (Triplophysa) in the Himalayas.

Phylogeographic congruence among co-distributed taxa is regarded as an inherent inference to vicariance events. However, incongruent patterns of contemporary lineage divergence among taxa indicated that species differ in their response to common past events. To investigate the role of past events, ecological traits and lineage diversification time in shaping the contemporary phylogeographic patterns, comparative analyses were conducted for Tibetan stone loaches in the Himalayas region using three gene markers and two ecological traits (depth of caudal peduncle in its length and posterior of air bladder presence/absence). By a thorough sampling in two flanks of the Himalayas, we detected that phylogenetic breaks were spatially discordant and divergences of populations were also temporally asynchronous in co-distributed loaches. Estimated divergence time using fossils calibrated node dating indicated that the Tibetan stone loaches colonized into the south flank of the Himalayas until the Pleistocene. The demographic expansions were also disconcerted between populations in north and south flanks, or east and west Himalayas. Ongoing gene flows between populations in north and south sides implied that the Himalayas do not strictly impede dispersal for cold-adaption species. Our results highlight that the Quaternary climatic oscillation in conjunction with ecological traits and lineage diversification time, sculpted contemporary phylogenetic patterns of stone loaches in the Himalayas, and provide new insights into the biodiversity and composition of species in the Himalayas and surrounding region. This article is protected by copyright. All rights reserved.