Oxyeleotris kolasi
Blind Cave Gudgeon
Species Summary
The first hypogean (cave-dwelling) fish ever recorded from West Papua, Oxyeleotris kolasi was found in a freshwater pool some 50 metres inside Jabuenggara Cave, part of the Lengguru limestone karst, connected via subterranean drainage to Sewiki Lake and Arguni Bay. Like the unrelated Milyeringa of Western Australia, it has independently evolved the hallmarks of cave life: no eyes, fully depigmented skin and fins, and well-developed sensory papillae standing out as raised fleshy ridges across the head, compensating for the senses lost to a life without light.
Relatives & Origins
Its closest relative is Oxyeleotris caeca, another blind cave fish known from a limestone subterranean drainage connected to the upper Kikori River in Papua New Guinea; both are thought to be derived from the widespread surface-dwelling Oxyeleotris fimbriata of New Guinea and northern Australia. Placed together with the Australian genus Milyeringa in the family Milyeringidae, these New Guinean and Australian blind gudgeons are also linked, more distantly, to the Madagascan cave-fish genus Typhleotris — a trans-oceanic relationship that has been put forward as evidence of a shared Gondwanan ancestry, with each lineage evolving cave-adapted descendants independently after the southern continents went their separate ways.
Compiled for Home of the Rainbowfish from ANGFA sources: Anonymous, “Blind Cave Gudgeons - West Papua”, In-Stream 22, 2013, pp. 12–15 (summarising B. Pouyaud, Sudarto & G. Teugels, “The different colour varieties of the blind cave Barbopsis…” and related descriptions of West Papuan hypogean fishes).