Abstract:
Intra specific variation of Puntius chola (Cyprinidae) of six geographically
different populations (Nilwala River, Walawe River, Gin River, Kalu River,
Malwathu Oya, Deduru Oya) of Sri Lanka was studied using landmark based
geometric morphometric technique (GM) (n=20 from all rivers; n=21 from
Gin River). The method is aimed to detect the variation in shape of fishes
unhindered by the size factor. Procrustes ANOVA revealed significant
differences among populations (p<0.05). The first two canonical variates
(CV) explained 66.7% of the total variation in the data and the plot of the CV
revealed significant separation of some of the populations. In this regard,
CV1 indicated clear separation of Deduru Oya population from Malwathu
Oya, Walawe River and Gin River populations while CV2 axis separates
Nilwala River population from Malwathu Oya, Deduru Oya, Kalu River and
Walawe River. Transformation grids indicated that head morphology and
length of dorsal fin has mostly contributed for the shape variations detected.
Mahalonobis distance values revealed that Deduru Oya and Gin River
populations as the most separated populations while Malwathu Oya and
Walawe River population as the most related populations. Some of the
relationships cannot be explained using present day geographic distance, and
therefore, some historical factors may have contributed for the
differentiations observed. In conclusion, the present results reveal significant
morphological heterogeneity among P. chola populations in Sri Lanka, and it
is of scientific interest to investigate if these populations are genetically
divergent as well.
