Trends in morphological relationships among Gangetic Cyprinids

Cyprinidae is the predominant and most diverse taxonomic group of
freshwater fishes, exhibiting enormous diversity in shape, size
and biology. The morphological diversity of Indian Cyprinids especially
the Gangetic Cyprinids is largely unquantified. Geometric morphometrics
(GM) approach is an efficient tool to quantify overall body shape
variations and has wide application in taxonomic, evolutionary and
ecological studies. In this study, digital photographs of 47 Cyprinid fish
species from Ganga River were used to measure geometric body
shape so as to evaluate interspecific morphometric
relationships. Combined results of principal component analysis
(PCA), canonical variate analysis (CVA) and Cluster analysis (CA) revealed
interspecific differences in Cyprinid fishes. Phenogram showed that all
the species of different genus like Barilius, Garra, Labeo,
Pethia, Schizothorax and Tor are clustered together in
their respective group. This indicates that species of respective
genus share common phenotypic traits and there is evolutionary
relatedness among them. The present study showcases the efficient use of
digital images and strongly supports the application of
costeeffective GM method in discriminating distinct groups and
representing the morphological relationships between species of Cyprinid
fishes. Overall, we suggest that the body shape disparity and
proximity among groups can therefore be used as an
effective approach in rapid diagnosis of a species and
understanding evolutionary relationships between species.