Melanotaenia urisa (∧ male ∨ female) © B. Dwisusilo

Melanotaenia urisa

Species Summary
Mature males of Melanotaenia urisa have a basic body that is brown dorsally; body scales with narrow dark outline dorsally and below pectoral region; lower half of side of body and belly whitish; eight brown stripes, corresponding with horizontal scale rows on side of body, alternating with narrower orange to yellowish stripes; a diffuse dark blotch immediately behind eye on uppermost part of operculum; a darkest midlateral stripe of one scale wide with blue hues extending from upper edge of preopercle to caudal-fin base; pectoral fin translucent with rays marked with several melanophores; remaining fins uniformly orange to reddish. The overall colour of the females is similar but paler than males. The body stripes are less vivid and median fins slightly yellow. Except for the colouration, which is less intense for the female, there appears to be little differences between male and female. The species was named urisa, with reference to the village name near the type locality.

Melanotaenia urisa is related to the species occurring on the Bomberai Peninsula and on the Bird's Head Peninsula (Vogelkop or Doberai Peninsula) of far western New Guinea. The Bird's Head Peninsula forms the north-western end of the island of New Guinea. To the east is Cenderawasih Bay and to the south Bintuni Bay. To the west, across the Dampier Strait is Waigeo Island, and Batanta Island lies just off the northwest tip. The peninsula south is Bomberai Peninsula.

Distribution & Habitat
Melanotaenia urisa is currently known only from the type locality, a karst spring emerging from Berari Anticline on the north side of the Sewiki Lake outlet. The spring consists of an artesian resurgence of blue freshwater in a brackish swampy environment with a size and volume varying with the season and with the tidal fluctuation. The bottom of the spring consists of white sand and limestone boulder with substantial dead tree branches.

Remarks
Specimens of Melanotaenia urisa were collected in November 2010 during the Lengguru-Kaimana Expedition led by Balai Riset Budidaya Ikan Hias in Depok, Indonesia (BRBIH-KKP), the Akademi Perikanan Sorong, Indonesia (APSOR-KKP), the Lembaga Ilmu Pengetahuan Indonesia (LIPI) and by the Institut de Recherche pour le Développement Montpellier, France (IRD).

Literature
Kadarusman, R.K. Hadiaty, G. Segura, G. Setiawibawa, D. Caruso & J. Pouyaud (2012) Four new species of Rainbowfishes (Melanotaeniidae) from Arguni Bay, West Papua, Indonesia / Quatre nouvelles espèces de poissons arc-en-ciel (Melanotaeniidae) de la baie d'Arguni en Papouasie occidentale, Indonésie. Cybium, 36(2): 369-382.

Adrian R. Tappin
July, 2012