The Taxonomic Status of Gymnura bimaculata and G. japonica： Evidence from Mitochondrial DNA Sequences

Japanese butterfly ray Gymnura japonica from twinspot butterfly ray G. bimaculata based on a pair of white spots behind eyes or not, which was not reliable. To clarify the taxonomic status of G. japonica and G. bimaculata, the nucleotide variation between the two butterfly rays was examined using mitochondrial DNA sequence comparisons. Approximately 585 bp of 16S ribosomal RNA （rRNA） and 1,128 bp cytochrome b （cyt b） genes were sequenced from representatives of two butterfly rays species in East China Sea. The results showed that there were the same sequences of 16S rRNA gene between two butterfly rays; six sites were variable among two butterfly rays of cyt b genes, the proportion of polymorphie loci was 0.53%, and two haplotypes were defined which genetic distance was 0.5%. Combined with the morphological character and the analysis of mtDNA sequence indicated that twinspot butterfly ray G. bimaculata was a synonym of Japanese butterfly ray G. japonica.

中华绒螯蟹与合浦绒螯蟹两地理亚种的线粒体DNA序列变异

根据线粒体16SrDNA的PCR/RFLP鉴定和对Cytb基因全序列的分析对中国大陆7水系绒螯蟹地理种群的遗传分化进行探讨。结果表明:中华绒螯蟹与合浦绒螯蟹两亚种在17条Cytb全序列上以40个固定的碱基变异位点相区别。前者分布在瓯江及其以北的水系;后者主要分布在瓯江及其以南的水系。发现了4种在鸭绿江以南的北方水系中生活的合浦亚种单元型,对这些单元型的形成提出了3种可能的解释[动物学报51(5):862-866,2005]。