Geographical differentiation of the Euchiloglanis fish complex (Teleostei: Siluriformes) in the Hengduan Mountain Region, China: Phylogeographic evidence of altered drainage patterns.

Yanping Li,Arne Ludwig,Zuogang Peng

doi:10.1002/ece3.2715

Abstract

The uplift of the Tibetan Plateau caused significant ecogeographical changes that had a major impact on the exchange and isolation of regional fauna and flora. Furthermore, Pleistocene glacial oscillations were linked to temporal large‐scale landmass and drainage system reconfigurations near the Hengduan Mountain Region and might have facilitated speciation and promoted biodiversity in southwestern China. However, strong biotic evidence supporting this role is lacking. Here, we use the Euchiloglanis fish species complex as a model to demonstrate the compound effects of the Tibetan Plateau uplift and Pleistocene glacial oscillations on species formation in this region. The genetic structure and geographical differentiation of the Euchiloglanis complex in four river systems within the Hengduan Mountain Region were deduced using the cytochrome b (cyt b) gene and 10 microsatellite loci from 360 to 192 individuals, respectively. The results indicated that the populations were divided into four independently evolving lineages, in which the populations from the Qingyi River and Jinsha River formed two sub‐lineages. Phylogenetic relationships were structured by geographical isolation, especially near drainage systems. Divergence time estimation analyses showed that the Euchiloglanis complex diverged from its sister clade Pareuchiloglanis sinensis at around 1.3 Million years ago (Ma). Within the Euchiloglanis complex, the divergence time between the Dadu–Yalong and Jinsha–Qingyi River populations occurred at 1.0 Ma. This divergence time was in concordance with recent geological events, including the Kun‐Huang Movement (1.2–0.6 Ma) and the lag time (<2.0 Ma) of river incision in the Hengduan Mountain Region. Population expansion signals were detected from mismatched distribution analyses, and the expansion times were concurrent with Pleistocene glacier fluctuations. Therefore, current phylogeographic patterns of the Euchiloglanis fish complex in the Hengduan Mountain Region were influenced by the uplift event of the Tibetan Plateau and were subsequently altered by paleo‐river transitions during the late Pleistocene glacial oscillations.

Highlights

Climatic fluctuations and geological events in the Pleistocene induced an accelerated change in the genetic structure of species and populations (Yan et al, 2013; Yu, Chen, Tang, Li, & Liu, 2014)
We considered the Euchiloglanis species distributed in the Hengduan Mountain Region as a species complex, and we attempted to determine the phylogeographical patterns of Euchiloglanis within this region
Our goals were to: (1) infer the genetic structure and geographical differentiation of populations belonging to the Euchiloglanis species complex throughout the Hengduan Mountain Region; and (2) verify a vicariant speciation hypothesis based on geological evidence of massive scale paleo-drainage shifts that are related to the uplift of the Tibetan Plateau

Summary

| INTRODUCTION

Climatic fluctuations and geological events in the Pleistocene induced an accelerated change in the genetic structure of species and populations (Yan et al, 2013; Yu, Chen, Tang, Li, & Liu, 2014). The evolution of distribution patterns of primary freshwater fishes responded to the complex paleo-geographical structure in the Tibetan Plateau, as well as to processes leading to their isolation or interconnection during the uplift event (Hurwood & Hughes, 1998; Montoya-Burgos, 2003; Zhang et al, 2015). Our goals were to: (1) infer the genetic structure and geographical differentiation of populations belonging to the Euchiloglanis species complex throughout the Hengduan Mountain Region; and (2) verify a vicariant speciation hypothesis (i.e. whereby the geographical range is split into discontinuous parts by the formation of a physical or biotic barrier to gene flow or dispersal) based on geological evidence of massive scale paleo-drainage shifts that are related to the uplift of the Tibetan Plateau

| MATERIALS AND METHODS

Findings

| DISCUSSION