Shared response to changes in drainage basin: Phylogeography of the Yunnan Small Narrow-mouthed Frog, Glyphoglossus yunnanensis (Anura: Microhylidae)

Aim: With the late Cenozoic uplift of the Qinghai-Tibetan Plateau (QTP),
drainage of the southeastern edge of the QTP changed significantly.
However, the impact of this dramatic change on the geographical
distribution and genetic diversity of endemic organisms is still poorly
understood. Here, we examined the geographical patterns of genetic
variation in the Yunnan small narrow-mouthed frog, Glyphoglossus
yunnanensis (Microhylidae), and two alternative hypotheses were tested:
that is, the geographical distribution of genetic variation was determined
by either the contemporary drainage basin or by historical drainage
basins. Location: the Mountains of Southwest China. Materials and methods:
Analyses were based on 417 specimens collected from across the
distribution of the species. We reconstructed the genealogy (Bayesian and
maximum parsimony methods) and assessed demographic history based on DNA
sequencing data from mitochondrial and nuclear markers. We also mapped the
genetic diversity and estimated the divergence times by a relaxed clock
model. Results: The species has maintained a relatively stable population
size without recent population expansion. Four major maternal lineages
were identified with good support, one representing a possible cryptic
species and the other three showing further subdivision. The distribution
of these deeply differentiated lineages/sublineages corresponded well to
geographical regions. The secondary contact zones and phylogeographic
breaks in distinct lineages of G. yunnanensis were almost concordant with
those of Nanorana yunnanensis. Main conclusions: Lineage division
conformed to the hypothesis of drainage system evolution, that is, the
phylogeographic pattern of G. yunnanensis was shaped by historical
drainage patterns. Concordance in phylogeographic patterns may suggest a
shared response to common hydrogeological history, and also might indicate
that there was more contribution of the drainage history than ecological
or life history traits in structuring genetic variation between these two
disparate codistributed taxa G. yunnanensis and N. yunnanensis.