Molecular characterization of and (Crustacea: Argulidae) infecting the cultured carps in West Bengal, India using 18S rRNA gene sequences.

The present study characterized spp. infecting the cultured carps using 18S rRNA gene sequences, estimated the genetic similarity among spp. and established their phylogenetic relationship. Of the 320 fish samples screened, 34 fish (10.6%) had infection. The parasitic frequency index (PFI) was observed to be high (20%) in and . The frequency of infection was high in September (PFI: 17%) and October (PFI: 12.9%). The 18S rRNA sequences of five (KF583878 KF192316, KM016968, KM016969, and KM016970) and one (KF583879) of this study showed genetic heterogeneity and exhibited 77-99% homology among the 18S rRNA gene sequences of spp. of NCBI GenBank database. Among the Indian spp. the sequence homology was 87-100%. Evolutionary pair-wise distances between Indian spp. and other spp. ranged from 0 to 20.20%. In the phylogenetic tree, all the crustaceans were clustered together as a separate clade with two distinct lineages. The lineage-1 comprised exclusive of Branchiura ( spp.). All clustered together and (KF583879) was closely related to sp. JN558648. The results of the present study provided baseline data for future work on population structure analysis of Indian species.