Scanning Electron Microscopic Observations on Scale Surface Structures of Cyprinus in Qilu Lake,Yunnan

The present paper mainly deals with the scales surface structures of 5 species of Cyprinus in Qilu Lake by means of scanning clectron microscopy.The scales of other genera of subfamily Cyprininae are observed in the same time.It is described in detail that morphological characters of the scales including circuli,focus and radii.Denticular knobbles on the circuli are only found in chilia among 5 species of Cyprinus.They are aleo found in carassioides cantonensis and Carassius auratus.The former studies were showed that Carassioides and Carassius were the advanced group in Cyprininae.Based on above facts,it is inferred that denticular knobbles,are derived from normal circuli.Scales with denticular knobbles,or without them are a good diagnostic character for taxonomic identification.Cyprinus carpio chilia and Cyprinus carpio rubrofuscus were seen as different subspecies.Now authors are inclined that Cyprinus carpio chilia is deserved the statu of species instead of subspecies according the evidences that scale of chilia is with denticular knobbles and rubrofuscus without them,that skull of rubrofuscus is with fontanelle and chilias without it.Depending on ultrastructure of radii,it is deduced that radii may act on two aspects.One is that it may regulate expansion or contraction of scales because of fluctuation of surrounding water temperature.The other is that it may strengthen flexibility of scales.