Description of two new species of the genus Thaparocleidus Jain, 1952 (Monogenea, Dactylogyridae) from freshwater fish in India: morphological and molecular phylogenetic evidence.

Abstract

The present paper describes the taxonomy of two new monogeneans, namely, Thaparocleidus longiphallus sp. n. and T. siloniansis sp. n., based on morphological, morphometric and molecular biological analysis, collected from the fish Wallago attu (Bloch & Schn.) and Silonia silondia (Ham.), respectively, at Meerut, UP, India. Genetic characterization of the two new species is based on sequence analyses of the rDNA 28S gene using neighbour-joining and maximum-parsimony techniques. These methods are congruent in depicting T. longiphallus sp. n. and T. siloniansis sp. n. as closely related species, but distinct from each other and forming a subclade with other species of the genus Thaparocleidus Jain, 1952. Secondary-structure models of the large subunit rDNA of the two species were also predicted using a combined comparative and thermodynamic approach. Molecular morphometric and phylogenetic relationships of the isolates of the Thaparocleidus species are discussed in detail.