THE VALIDITY OF SUBSPECIES OF BRACHYMYSTAX LENOK TSINLINGENSIS LI BASED ON MORPHOLOGICAL DIFFERENCE ANALYSIS

The taxonomic status of Brachymystax lenok tsinlingensis Li, distributing in Qinling area of China, is controversial since it was found. In this study, the morphological differences among three Brachymystax groups (B. lenok lenok (Pallas, 1773) and B. tumensis (Mori, 1930) from Amur river basin and B. lenok tsinlingensis (Li, 1966) from the Qinling area) were investigated, including five meristic characters and thirty-four standardized morphometric characters through multivariate morphometrics methods. Results of one-way ANOVA showed that five meristic characters and thirty-two standardized morphometric characters were significantly different (P<0.01) among three groups. Principal component analysis indicated that the cumulative contribution of the top three principal components was 92.779%. Effective linear discriminant formulas were obtained from fourteen standardized morphometric characters, with the discriminating accuracy of 99.4% in the three groups. The tree diagram of these groups based on the squared Euclidean distance showed thatB. lenok tsinlingensis had a close distance with B. lenok lenok, but it is distant from B. tumensis. The coefficient of difference (CD) for the outer gill raker number in the first gill arch between B. lenok tsinlingensis and B. lenok lenok is larger than the threshold value of 1.28, and the CD for the thirty-one standardized morphometric characters and two meristic characters in B. lenok tsinlingensis and B. tumensis was also greater than 1.28. According to the results listing above, and the geographical isolation of B. lenok tsinlingensis together with its morphological differences from B. lenok lenok and B. tumensis, it is deduced that the morphological difference between B. lenok tsinlingensis in Qinling and B. lenok lenok in Amur river basin has at least reached subspecies level.