Apatemon gracilis (Rudolphi, 1819) is a species of trematode belonging to the family Strigeidae. As a member of the subclass Digenea, it follows a complex life cycle involving multiple hosts. The adult flukes typically inhabit the upper small intestine of avian hosts. In Australia, the species has been documented in the Pacific black duck (Anas superciliosa), and domestic ducks (Anas platyrhynchos) have demonstrated susceptibility to experimental infection.[1][2][3]
The life cycle of A. gracilis includes an intermediate stage where metacercariae encyst in freshwater fish. Specifically, the species has been recorded utilizing Galaxias auratus as an intermediate host in Lake Crescent, Tasmania.[2]