Molecular analysis of a novel species, Gangesia punjabensis (Family: Proteocephalidae, Subfamily: Gangesiinae) infecting an Indian freshwater cat fish, Wallago attu evidencing species complex.

In the present study, from August 2015 to July 2016, a total of 159 specimens of Wallago attu Bloch and Scheider, 1801 vern. mully were collected from the Ropar wetland, Punjab, India and were examined for the presence of intestinal tapeworms. The infection rate was 12.5%, out of which, two fishes were heavily infected with a proteocephalidean cestode belonging to the genus Gangesia in the month of February. Gangesia punjabensis sp. nov. was identified and described on the basis of morphology and partial amplification of LSUrDNA (28S rDNA). The histopathogenesis caused by these parasites have also been studied in histological sections. About 9-35 number of worms were collected from a single host. The length of worms ranged from 6.0 to 6.2 cm. The strobila consisted of an armed scolex, neck, immature proglottids (approximately 90 in number) and mature proglottids (approximately 7 in number) and gravid proglottids were not detected. Analysis of 28S large subunit (LSU) rDNA sequence of the isolate of G. punjabensis n. sp. demonstrated maximum similarity of 99% with G. bengalensis, 98% with G. vachai, 97% with G. macrones. The phylogenetic tree based on the final edited alignment (822 bp) with Neighbour-Joining showed the highest bootstrap value of 100 and placed G. punjabensis n. sp. with G. bengalensis and G. macrones in the same clade showing them to be a species complex. The intestinal mucosal lining exhibited blister formation, haemorrhagia and inflammation due to the presence of deeply embedded scolices. Histopathology caused was evident due to disruption of villous surface and cellular infiltration. This is the first report of cestodes belonging to the genus Gangesia from Ropar wetland, Punjab, India.