TAO, NGUYEN DINH, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, Hubei Province, P.R. China Graduate School of Life Science, Central China Normal University, Wuhan 430079, Hubei Province, P.R. China Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, No. 18 Hoang Quoc Viet, Hanoi City, Vietnam