Description of a new species pegosomum aftabi n.sp (trematoda: echinostomatidae) in little egret egretta garzetta (ciconiiformes: ardeidae) of larkano, Sindh, Pakistan

During present study on the helminth parasites of birds, a total of five Little Egret Egretta garzetta (Ciconiiformes: Ardeidea) were collected from different locations of river Indus at Jamshoro, Sindh, Pakistan. During examination of gut contents and visceral organs, seven trematodes belonging to genus Pegosomum Ratz, 1903 were collected from liver of two host birds. Present species differs from its congeners by having 26 number of collar spines, sub-terminal oral sucker, pre-pharynx absent, longer, tubular esophagus, ventral sucker rounded located at mid- level of body, cirrus sac elongated and wider at its base overlapping acetabulum, ovary spherical, slightly sub-median, both testes have smooth margin, anterior testis overlaps ceca from right side, posterior testis overlaps ceca from both sides, vitellarria commencing from lower level of pharynx, overlapping ceca reaching upto anterior testis, ceca with regular smooth outline and other varying characters.