Studies on species classification for genus Cranoglanis Peters with the method of morphometrics

Abstract

The genus Cranoglanis Peters is a group of fishes only distributed in East Asia. They live in the drainages of Guangdong, Guangxi, Yunnan, Hainan and the Red River drainage in northern Vietnam. At present, there are only three species in this genus, named Cranoglanis bouderius, C. multiradiatus and C. henrici. However, the described species, Cranoglanis bouderius, only based on one picture then and the name of C. multiradiatus was also depended on only three specimens. So there are still some arguments on the validity of these species. Now there is still no study related to their morphometries within these species living in different environment. This article is about the research on the species classification of Cranoglanis Peters to clarify the confusion and form a better classification. The method of morphometrics was used on 43 measurements in 66 individuals collected from Zhujiang drainage, Yuanjiang drainage and Hainan Island. Then, the principle component analysis was conducted on these variables. The preliminary analysis result indicates that there are no prominent differences among the three species, so they could not be divided into three species. They should be considered as one species: Cranoglanis bouderius