Shared response to changes in drainage basin: Phylogeography of the Yunnan small narrow-mouthed frog, (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, (Microhylidae), and two alternative hypotheses were tested: That is, the geographical distribution of genetic variation was determined by either the contemporary drainage basin or 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 were almost concordant with those of .

MAIN CONCLUSIONS

Lineage division conformed to the hypothesis of drainage system evolution, that is, the phylogeographic pattern of 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 and .