Phenotypic variation using truss network system in the deep-sea shrimp Heterocarpus chani Li, 2006 (Caridea: Pandalidae) off Arabian Sea and Bay of Bengal

This study assesses the morphological differentiation of deepsea caridean shrimp, Heterocarpus chani Li, 2006 using a truss network system, to investigate different phenotypic stocks. Total, 1879 specimens were collected from Kalamuku (KAL), Sakthikulangara (SAK), and Colachel (COL) on the southwest coast of Arabian Sea (AS) and from Nagapattinam (NAG) and Tuticorin (TUT) on the southeast coast (BOB: Bay of Bengal) during 2013-2015. Multivariate analysis, such as Principal Component Analysis (PCA), Discriminant Factor Analysis (DFA), and Hierarchical Cluster Analysis (HCA) were used as statistical tools for differentiating the populations between the locations. Sex ratio was found to be 1:1. The coefficient of variation (CV) analysis was conducted for males and females using 39 morphometric truss variables which observed > 25 % variation. PCA indicates initial three components aggregately explained > 47 % of the total morphometric variation following the size effect correction. DFA demonstrated through the original and cross-validation 76.75 %, 72.26 % and 78.64 %, 74.81 % for male and female respectively, indicating significant variation in the first two canonical variables. DFA confirmed the presence of three distinct populations along the southern coasts of India. HCA also grouped the population into three major clusters specifically based on the 4th abdominal pleuron characters. The group-I included populations from NAG, group-II consisted of the TUT and group-III with SAK, KAL, and COL populations. Morphologically, the initial four abdominal pleuron characters were proved to be differentiating the population. The present study indicates the base study on morphological stock identification of H. chani indicating significant phenotypic heterogeneity between the populations of AS and BOB.