Multivariate morphometric differentiation of Macrobrachium species (Crustacea: Palaemonidae) along the northern rivers of Bangladesh

Abstract

Understanding interspecific morphometric variation is a prerequisite of species identification, evolutionary and taxonomic studies. The external features (i.e. morphometric and ratios) of five Macrobrachium species viz., Macrobrachium rosenbergii, M. lanchesteri, M. dolichodactylus, M. idella and M. lamarrei from three rivers in northern Bangladesh, were used to analyze interspecific morphometric variation. Macrobrachium samples were collected from Jamuneshwari river, Tangon river and Atrai river. Morphometric and ratios data were subjected to univariate ANOVA test. To assess variations among the species, a principal component analysis (PCA) and canonical variate analysis (CVA) were performed. Four PCA explained 95.31% of the variation in morphometric and ratios data. Four CVA were correctly classified as 46.53%, 30.02%, 18.10% and 5.35% respectively using morphometric and ratios data. Morphometric and ratio results from PCA formed a compact cluster among species while in CVA showed that species were completely formed a separate cluster. A dendrogram independently developed based on phenotypic traits among the individuals of the five Macrobrachium species confirmed the presence of phenotypic differentiation. The baseline evidence ensuing from the current study would be advantageous for geometric morphometric, genetic investigations and further in situ conservation of Macrobrachium species in Bangladesh.