Intraspecific Variation in Morphology and Sexual Dimorphism in Puntius singhala (Teleostei: Cyprinidae)

KB Suneetha Gunawickrama
2009 Ceylon Journal of Science (Biological Sciences)  
Intraspecific morphological variation and differentiation among six populations of the endemic freshwater fish Puntius singhala (Cyprinidae) were investigated. There is significant sexual dimorphism in three morphometric characters (pectoral-fin length, caudal-peduncle length, and length of dorsal-fin base), where males have slightly longer measures than females, indicating adaptive significance related to dispersal. Significant heterogeneity and differentiation was found only among some of the
more » ... populations studied (Wilk's λ for males = 0.079 and for females = 0.129) indicating limited geographic variation, as suggested by relatively large overlap in canonical scores among most of the samples. No significant correlation between the pair-wise differences and inter-locality geographic distances was found, thus isolation-bydistance was not a plausible explanation for the observed variation. The present results show that P. singhala is not phenotypically homogenous. The absence of differences between population samples that experience highly limited present-day interchange may be partly explained by colonization history.
doi:10.4038/cjsbs.v37i2.504 fatcat:t5cpp6oyqjh7vmte2oqoihf2da