Type locality, Northern Territory, East Alligator River, Cannon Hill Lagoon, NTM S.14083-007 (holotype of Leptachirus polylepis, 5.89 cm SL, male). Specimens were collected from the East Alligator, South Alligator, West Alligator, Mary, and Adelaide Rivers in the Northern Territory, all of which empty into Van Diemen's Gulf to the east of Darwin (Ref. 84817).