Morphological and molecular description of Pallisentis roparensis n. sp. (Acanthocephala: Quadrigyridae) infecting the freshwater cat fish Wallago attu from Ropar Wetland, Punjab, India

The study describes a new species of Pallisentis Van Cleave, 1928 infecting the freshwater cat fish Wallago attu Bloch and Schneider, 1801 from Ropar wetland, Punjab, India. The morphological characters of Pallisentis roparensis include proboscis with 4 circles of 10 hooks each gradually declining in size, first circle of hooks <100 μm in length, 15–16 circles of Y-shaped collar spines and conical trunk spines present up to the posterior end in the females and the anterior region of cement gland in males. Saefftigen's pouch is present and cement gland nuclei are 22–25 in males. The sequences generated for 18S, 28S and ITS1-5.8S-ITS2 molecular markers of the newly described species are nested well among the other comparable sequences from the GenBank. The phylogenetic analyses show the monophyly of the genus Pallisentis but point towards the paraphyletic relationship among the three subgenera. The histopathology of fish intestine indicates that the parasite stimulates the inflammatory immune response causing serious injury to the mucosa and dilation of the lymphatic vessels of small intestine.