Dimorphic Morphological Features between Sexes of Semiplotus semiplotus McClelland

Understanding of secondary sexual dimorphism in fish is an uphill task and the phenomenon is paradoxical in different species. Considering the importance, a study was carried out to identify the distinguishing morphological characters between the sexes of Semiplotus semiplotus(McClelland). It is a hill-stream fish species endemic to Eastern Himalayas and also important as food. Statistical analysis of various morphological measurements and meristic counts of 30 numbers of freshly collected specimens was the tool of the study. Together, some morphological peculiarities have also been noted for the seasonal sexual dimorphism. The females were found having longer anal fin height than the males by an average of 3.96 mm. Again, the formation of keratinized tubercles on the anal fin of males versus smooth anal fin in females was also observed during breeding season. However, meristic counts were similar in both the sexes. Key words: Sexual dimorphism, anal fin, tuberclesDOI: 10.3126/on.v7i1.2564Our Nature (2009) 7:158-162