The distribution of Aphanius dispar dispar (Rüppell, 1829) populations in Iran which is mostly known from eastern and southern part of the country, and occurrence of a new population in western Iran, about 50 km northwest of Ilam City and 20 km east of Iran-Iraq border, is recorded. The habitat is an odd environment with sulfide water in a remote area. This is the first report of collection of this species in western Iran and at such a high latitude in its distribution range
