Description of Melanotaenia fasinensis, a new species of rainbowfish (Melanotaeniidae) from West Papua, Indonesia with comments on the rediscovery of M. ajamaruensis and the endangered status of M. parva

A new species of rainbowfish (Melanotaeniidae) is described from the Bird's Head Peninsula in West Papua (Indonesia). Melanotaenia fasinensis is described from the Fasin River in the vicinity of Ween village, 25 km W of Lake Ayamaru. It is distinguished from other melanotaeniids occurring on the Peninsula and in the adjacent Raja Ampat Islands by a distinct colour, the number of transverse scales, lateral scales, predorsal scales, cheek scales and gillrakers, a short head with a lone and pointed snout, a narrow interorbital region, relatively small eyes, short and slender caudal, long dorsal and anal fins and a moderately short predorsal length, and moderately short pectoral and pelvic fins. Melanotaenia fasinensis is morphologically similar to M. ajamaruensis, a species that has not been seen since it was first captured in 1955 (Allen, 1990), but rediscovered during our expedition in 2007 near Ajamaru Lakes. It seems likely that the upstream portion of the Kaliwensi River is the last place where M. ajamaruensis still survives. We also highlight the alarming depletion of M. parva, which is endemic to Kurumoi Lake. This lake is now nearly dry and contains large numbers of exotic tilapi