Life Cycle: The first intermediate host of parasites in the family heterphyidae are amnicolid and hydrobiid snails (Omrani 2009). The second intermediate hosts of A. felippei are fishes and the definitive host are typically fish eating birds (Santos et al. 2007).
Body tear-shaped, with maximum width at ovarian level. Body entirely spinose. Remnants of eyespot pigment dispersed between pharyngeal and cecal levels. Conical preoral lobe well developed; oral sucker subterminal, invariably with 32 circumoral spines arranged in 2 complete rows of 16 spines each; spines in posterior circlet smaller than those in anterior one. Posterior muscular prolongation of oral sucker very long, reaching almost to pharynx or even ceca. Ventral sucker oval, slightly post-equatorial. Prepharynx long; pharynx strongly muscular, oval; esophagus very short or absent. Intestinal ceca very short, wide, terminating anterior to ventral sucker. Testes symmetrical, oval, close to posterior extremity. Seminal vesicle saccular, submedian (sinistral) or posterolateral to ventral sucker… Uterus forming numerous loops, filling most space between intestinal ceca and posterior extremity. Eggs numerous, operculate. Excretory vesicle Y-shaped, with pretesticular lateral branches. Excretory pore dorsal, slightly subterminal. Metacercaria: Cyst oval to round, with smooth surface, thin-walled. Body of excysted metacercaria tear-shaped; tegument fully spinose. Remnants of eye spot pigments scattered along pharynx and ceca. Oral sucker subterminal, with dorsal conical preoral lobe. Circumoral spines in 2 complete rows of 16 spines (32 in total); spines in posterior circlet smaller than those in anterior one. Posterior prolongation of oral sucker long, dorsal. Ventral sucker round, postequatorial. Prepharynx long; pharynx muscular, oval; esophagus short or absent. Intestinal ceca short, wide, anterior to ventral sucker, filled with discoid corpuscle. Excretory vesicle Y-shaped, with pretesticular lateral branches; excretory pore dorsal, slightly subterminal.
Source: Santos, C.P., Simões, S.B., Barbosa, H.S. and Scholz, T. (2007) Redescription of Ascocotyle (Ascocotyle) felippei Travassos, 1928 (Digenea: Heterophiydae) with new synonyms. Journal of Parasitology: Vol. 93, No. 6, p. 1468-1475.
Shoaibi Omrani B.; Ebrahimzadeh, Mousavi H. A., and Sharifpour, I. 2009. Occurrence and histopathology of Ascocotyle tenuicollis metacercaria in gills of platyfish (Xiphophorus maculatus) imported to Iran. Iranian Journal of Fisheries Sciences, Vol. 9, p.472-477.