One hundred and fifty specimens of
Pelteobagrus intermedius
from 12 drainage systems were collected to measure 21 morphometric characters using traditional taxonomic methods. Data on the morphometric characters were analyzed using principal component analysis in order to discuss the morphological variation and geographical differentiation of the characters. The populations of the 12 drainage systems are divided into three clusters by the first three principal components, which express 58.918% of the cumulative variance. The populations of
P.intermedius from the coastal area of western South China were more closelyrelated to the populations of Hainan Island than to the populations of the Xijiang River. In addition, distinct differences were shown in the populations from the three small drainage systems of Fangchenggang. The main morphological differences between populations were related to the snout, eyes and tail.
