Morphologic differentiation analysis for rounded caudal fin group of Oreonectes (Balitoridae) from China

Morphological characteristics were compared between three recorded species of rounded caudal fin Oreonectesand specimens collected from Guan’an of Guangxi. The results showed the Oreonectessp. from Guan’an was distinguished from O. anphthalmus. Although some morphologic differentiations existed among Oreonectes sp., O. polystigmus, and O. platycephalus, their differentiations were not enough to distinguish between them. Consequently, we used multivariate morphometrics to determine their morphologic differentiation. Twenty-six frame characteristics and 20 general characteristics of 63 specimens were measured. The resultsof the Principal Component Analysis showed that Oreonectessp. and O. polystigmus,and Oreonectessp. and O. platycephalus occupied obviously different areas in the scatter plot. It is suggested that the specimens collected from Guan’an may be a cryptic new species of Oreonectes. However, its taxonomic status should be decided by evidence from anatomical and molecular biological studies.