Phylogenetic Studies on Thaparocleidus Jain, 1952, Infecting Wallago attu Bloch and Schneider, 1801 Inferred from 28S rDNA Sequences in India

Five species of the genus Thaparocleidus Jain, 1952 (Ancylodiscoidinae) namely T. wallagonius Jain, 1952, T. yogendraii Agrawal, 1981, T. gomtius Jain, (1952) Lim, 1996, T. indicus (Kulkarni, 1969) Lim, 1996 and T. sudhakari (Gusev, 1976 ) Lim, 1996, gill parasites had been collected and restudied in detail, from siluriform fish host, Wallago attu Bloch and Schneider, 1801. All were oioxenous species. T. yogendraii, T. gomtius, T. indicus and T. sudhakari had been collected for molecular study from freshly killed fish hosts (W. attu). We could not collect T. wallagonius (type species) for DNA isolation (rare species). Obtained sequences of T. yogendraii, T. gomtius, T. indicus, and T. sudhakari had been compared with 18 retrieved sequences of Thaparocleidus sp. (Table 1), using Tetraonchus monenteron (as an out group). The phylogenetic tree of the genus Thaparocleidus sp. had been reconstructed using 28S rDNA region. Phylogenetic trees confirmed monophyly of the genus Thaparocleidus. Secondary structures of obtained sequences had been used to predict the genetical distinction of species, based on highest negative free energy and topology of secondary RNA structure.