Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 10 4 2015 12 14 605 616 EN Neelima GUPTA Centre of Excellence Laboratory, Department of Animal Science, M.J.P. Rohilkhand University, Bareilly-243 006,U.P., India Dileep K. GUPTA Fisheries and Aquaculture Laboratory, Department of Zoology, Bareilly College, Bareilly-243 006, U.P., India Priyanka SINGHAL Centre of Excellence Laboratory, Department of Animal Science, M.J.P. Rohilkhand University, Bareilly-243 006,U.P., India 2015 12 14 2015 12 14 Background: The genus Pallisentis is an endoparasitic acanthocephalan inhabit­ing the intestinal walls. Hooks and spines of the worm are significant taxonomical and adaptive tools. Methods: The parasites were fixed, dehydrated and examined under Olym­pus BX 53 Microscope with DIC attachment, digital camera and CELLSENS imag­ing system [Light microscopy (LM)] and fixed in 2% glutaraldehyde in 0.1 M cacodylate buffer, dehydrated, rotary-coated with gold palladium in NeoCoater 100-240V and examined in Neo JCM-6000 [scanning electron microscopy (SEM)]. Results: P. punctati n. sp. (prevalence 65.51%; mean intensity 3-6 par/host) is de­scribed. Females almost twice as large as males; proboscis hooks small; collar spine rows similar [16] and constant in both sexes but number of spines per row greater in females [22] than males [14]; trunk spine rows 28-39 (spines per row 14-18) in females and 20-26 (spines per row 10-12) in males. spine length of females almost twice as long as males, spines extend up to posterior testis in males and ¾ of total body length in females, Saefftigen’s pouch present, nuclei in cement gland 10-11, seminal vesicle, bursa and egg size small. SEM indicated lack of micro sculptures, and spines embedded on pre-trunk and trunk. Sex-based differences apparent (hook sizes, greater number of spines per row and longer spines in pre-trunk and trunk of females). Male trunk spine was narrower and of lateral spine with characteristic hooked appearance. Conclusion: A new species of Pallisentis based on LM and SEM is described, sexual diversity in hook and spine structure is reported. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/662 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/662/543