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Pelangia mbutaensis - photo© Gerald Allen |
Allen, 1998
Lake Mbuta Rainbowfish
Species Summary
The Pelangia genus is the sister group of Glossolepis, which is restricted to northern New Guinea. It differs from Glossolepis with regards to several important features including a lack of teeth on the vomer and palatines, a larger mouth and eye, reduced crenulations on the scale margins, and fewer anal rays. The genus also differs in having the anal fin origin closer to the caudal fin base than to the snout tip, which is the opposite situation compared to Glossolepis. Additionally, the origin of the first dorsal fin is well ahead of the anal fin origin, but in Glossolepis it is either even with the anal fin origin or behind it. Finally, the second dorsal fin origin is approximately level with the third soft anal ray in Pelangia, but in Glossolepis it is usually level with the middle rays.
Pelangia mbutaensis have a yellowish-tan body colour grading to silvery-white on the lower half of sides. Larger males have scattered yellow flecks along the middle of the side. Fins are mainly translucent except for dusky grey pigmentation on the first dorsal fin. They may reach a maximum size of 6 cm, but usually less than 5 cm.
Distribution & Habitat
Lake Mbuta Basin, lying approximately 8 km inland from Etna Bay, West Papua. Lake Mbuta is represented on published maps and charts as a lake, but is actually a swampy basin surrounded by low mountains. The basin, which is roughly circular, is mainly covered by swamp overgrowth with numerous small ponds, creeks, and at least one small river. They were collected from a small clear, but darkly stained freshwater creek, relatively fast flowing through forest that formed a nearly closed canopy. The bottom consisted mainly of mud with occasional rocks and log debris with sparse aquatic vegetation. A water temperature of 25° Celsius and pH of 6.4 were recorded. Co-occurs with Melanotaenia goldiei. Pelangia mbutaensis was relatively common but outnumbered by Melanotaenia goldiei by a 3:1 ratio.
Remarks
The species is named "pelangia" after the Indonesian name for rainbow (pelangi) with reference to the common name for the family Melanotaeniidae. No live specimens have been collected for the aquarium hobby.
Literature
Allen G. R. (1998) A new genus and species of Rainbowfish (Melanotaeniidae) from fresh waters of Irian Jaya, Indonesia. Revue Française d'Aquariologie 25 (1-2): 11-16.
Adrian R. Tappin
Updated December, 2008
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