Validity ofPseudobagrussinensisand mitochondrial DNA diversity ofPseudobagrusfulvidracopopulations in China

Abstract

Based on the differences in caudal peduncle, snout length, predorsal profile and the lateral color pattern, Ng & Kottelat (2007) supposed that the currently recognized Pseudobagrus fulvidraco represent at least two distinct species, P. sinensis from northern China and P. fulvidraco from southern China. We examined the forenamed morphologic characters and sequenced the cytochrome b gene segments of 70 specimens to test the validity of P. sinensis. We found the differences in predorsal profile and the lateral color pattern do not occur together with the differences in caudal peduncle and snout length. Results of molecular phylogenetic and population genetic analyses were: (1) the most common haplotype detected was shared by P. sinensis and P. fulvidraco; (2) the reciprocal monophyly of both species was not confirmed whereas all samples of the two species were grouped in a monophyletic cluster with 100% bootstrap support; (3) gene flow is ongoing between populations of P. sinensis and P. fulvidraco (Nm = 4.7); and (4) the haplotype network did not detect any disjoint groups corresponding to the two species. We thus speculate that P. sinensis is not valid species but probably a synonym of P. fulvidraco. Low genetic divergence was detected among P. fulvidraco 第 3 期 库喜英等: 中国黄颡鱼的线粒体 DNA 多样性及其分子系统学 263 populations of China’s main river drainages, which was supposed to be resulted from a recent population expansion that occurred about 101,000–141,000 years ago. No significant geological architecture was detected from Chinese populations of P. fulvidraco and the historical river connection might have promoted the gene exchange among different geological populations.