First molecular identification and phylogenetic tree of Petasiger exaeretus Dietz, 1909 (Digenea: Echinostomatidae) from an intermediate host Radix auricularia (L., 1758) in Greater Zab river, Iraq.

Introduction: (Linnaeus, 1758) is a freshwater gastropod belongs to the Lymnaeidae (pond snails) family which act as intermediate hosts or vectors of various parasitic flukes. No study has yet been undertaken on the prevalence of spp. infection in . Species of (Dietz, 1909) are a cosmopolitan parasite that utilize snails as the first intermediate host, with vertebrates like amphibians larvae and fish as the second intermediate host, followed by fish-eating birds. The current paper is considered to be the first report of parasitized in Iraq, which is supported with molecular and phylogenetic analysis.

Material And Methods: Freshwater snails were collected during October 2016 - September 2017 from different locations of Sufaia village on the Greater Zab river, Erbil province, Iraq.

Results: A total of 307 freshwater snails were collected, only five of them were infected with a prevalence of (1.62%).

Conclusions: The current study agrees with the opinion of Selbach, Soldánová (26), which suggested the possibility of a much higher morphological diversity within species, based on the number of described cercariae, compared with adult forms.It is clear that specimens have often been erroneously designated as by many authors (Našincová et al., 1994). Certain morphological similarities and dissimilarities between and can be detected: the pear-shaped body resembles , whereas, have an elongated body.