Description and molecular phylogeny of an exotic Myxozoan, Myxobolus arcticus (Pugachev and Khokhlov, 1979) in kidney of Clarias batrachus from river Gomti, Lucknow, India

The Myxobolus arcticus Pugachev and Khokhlov, 1979 (P.- Myxozoa; C.-Myxosporea; O.-Bivalvulida; F.-Myxobolidae) is a protozoan parasite residing in brain, nerves and spinal cord of the salmons (F.-Salmonidae). Its principal fish hosts are sockeye salmon - Oncorhynchus nerka, masu salmon - O. masou and Arctic char Salvelinus alpinus found in North Pacific coast of Far East Asia and North America. This is the first report revealing two new facts; first that Myxobolus arcticus was in the kidney (a new site of infection) and, second the host is a freshwater native catfish Clarias batrachus (O.- Siluriformes; F.- Clariidae), from river Gomti at Lucknow, Uttar Pradesh, India. The present article deals with morphological, morphometric and molecular description of this parasite Myxobolus arcticus. Further the morphometric parameters and small sub unit ribosomal gene (SSu rDNA) sequences of mature spores (trophozoites) were compared to demonstrate the morphological and genetic similarities between geographically distant isolates of M. arcticus. Sequence analysis of present M. arcticus (accession number KF662475) revealed that it has 98% sequence similarity with M. arcticus from O. nerka of Canada (accession number JN003829) and O. masou of Japan (NCBI accession number JN003830). Based on the maximum parsimony and maximum likelihood inferences, it is confirmed that present M. arcticus is conspecific to M. arcticus from Japan and Canada.