Southwest New Guinea - Trans-Fly Lowland




J. Hales


Papua New Guinea

Major Habitat Type

Tropical and subtropical coastal rivers

Drainages flowing into

Gulf of Papua, Arafura Sea, Torres Strait, Coral Sea

Main rivers to other water bodies

The main rivers in this ecoregion include the Digul, Fly, and Purari. There is also the Lorentz, Aramia, Turama, Kikori, and Bensbach. Lakes include Lake Murray and Lake Tebera.



This ecoregion encompasses the southern part of central New Guinea. It includes the Arafura, Trans-Fly, and Papuan Gulf coastal lowlands, with the Central Highlands forming a formidable boundary to the north and the Arafura Sea, Torres Strait, and Papuan Gulf bordering the south. It also includes the Aru Islands.

Terrestrial habitats

The main terrestrial ecoregions include the Southern New Guinea lowland rain forests [AA0122], Southern New Guinea freshwater swamp forests [AA0121], New Guinea Mangroves [AA1401], and Northern Australia and Trans-Fly savannas [AA0708] (WWF 2001).

Description of endemic fishes

Nearly half of this ecoregion’s species are endemic, including several endemic genera: Kiunga, Cochlefelis, and Nedystoma. Their endemic species include Cochlefelis danielsi, C. spatula, Nedystoma dayi, N. novaeguineae, and Kiunga ballochi. The Lake Tebera rainbowfish (Melanotaenia herbertaxelrodi) is endemic to the Lake Tebera basin (Allen 1991).

Other noteworthy fishes

The Saratoga (Scleropages jardinii), a member of the primitive bony tongue family (Osteoglossidae), is the oldest fish represented in New Guinea (Allen 1991).

Justification for delineation

Freshwater biotas in New Guinea center around foci of high endemism clustered around tectonic provinces. This ecoregion comprises the Arafura, Trans-Fly, and Papuan Gulf coastal lowlands areas of endemism recognized by Allen (1991) and Polhemus et al. (2004). Genera that contribute to the distinctiveness of this ecoregion include Scleropages, Cinetodus, Cochlefelis, Nedystoma, Iriatherina and Kiunga.


  • Allen, G. R. (1991). "Field guide to the freshwater fishes of New Guinea, Publ. 9" Madang, Papua New Guinea: Christensen Research Institute.
  • World Wildlife Fund (WWF) (2001) \Terrestrial Ecoregions of the World\ "<"">"
  • Polhemus, D.A.,England, R.A.;Allen, G.R. (2004) \Freshwater biotas of New Guinea and nearby islands: analysis of endemism, richness, and threats. Bishop Museum Technical Report 31\ Honolulu, HI. Bishop Museum.