Abstract:Morphometric differences of neonates and adults of clone HE1 and HE5, clone HE3 and SE1, and clone LE9 which respectively represented three sibling species in Brachionus calyciflorus species complex collected from three water bodies in Wuhu City were compared by means of one-way ANOVA and discriminant analysis. The results showed that all morphometric parameters of clone HE3 adult were the smallest, but those of the other two clones were similar. The distance between the two anterior medial spines and the posterior lateral spine length of clone HE1 and HE3 neonates as well as the distances between the two anterior lateral spines and between anterior lateral and medial spines of clone LE9 and HE1 neonates were similar, but all the other morphometric parameters were the longest for clone LE9 neonates but the shortest for clone HE3 neonates. The distribution regions of morphometric parameters with statistical differences were extensive overlap. Discriminant analysis showed that the total discriminant accuracies of the discriminant functions for the adults of the three clones in morphometric analysisⅠand Ⅱ was 47.8% and 55.6%, respectively, while those of neonates were both 71.1%. The identification accuracies based on morphometric analysis Ⅰ and Ⅱ for clone HE1 were low and 0-76.7% and 0-742%, respectively. The morphometric characteristics used in this study is unsuitable to accurately identify sibling species in Brachionus calyciflorus species complex.