Comparative multi-locus assessment of modern Asian newts (Cynops, Paramesotriton, and Pachytriton: Salamandridae) in southern China suggests a shared biogeographic history

Evolutionary  biologists  are  always  interested  in deciphering the geographic context of diversification, therefore they introduced the concept of comparative phylogeography,  which  helps  to  identify  common mechanisms  that  contribute  to  shared  genetic structures  among  organisms  from  the  same  region. Here,  we  used  multi-locus  genetic  data  along  with environmental  data  to  investigate  shared phylogeographic  patterns  among  three  Asianendemic  newt  genera, Cynops, Paramesotriton and Pachytriton, which occurred in montane/submontane streams  or  ponds  in  southern  China.   Our  222 samples from 78 localities covered the entire range of  the  three  genera  and  represented  the  largest dataset  of  this  group  to  date.   We  reconstructed matrilineal  genealogies  from  two  protein-coding, mitochondrial  genes,  and  gene  network  from  two nuclear genes.  We also estimated divergence times of  major  cladogenetic  events  and  used  occurrence data  to  evaluate  niche  difference  and  similarity between  lineages.   Our  results  revealed  a  common basal split in all three genera that corresponds to the separation  of  two  geographic  terrains  of  southern China.   Those  ancient  divergence  occurred  during middle  to  late  Miocene  and  likely  correlate  with paleoclimatic fluctuations caused by the uplift of the Qinghai-Xizang  (Tibet)  Plateau  (QTP).   Particularly, the  strengthening  and  weakening  of  Asian  summer monsoons during the Miocene may have profoundly impacted  southern  China  and  led  to  repeatedly vicariance  in  those  newts.   However,  despite differences  in  realized  niches  between  lineages, there  is  no  evidence  for  divergence  of  fundamental niches.  Preservation of old newt matriline lineages in mountains  of  southern  China  suggests  that  the region  acts  as  both  museums  and  cradles  of speciation.   Based  on  those  results,  we  advocate  a multi-pronged  protection  strategy  for  newts  in  the three genera.