Melanotaenia albimarginata
Whitetip Rainbowfish
Species Summary
The Aru Archipelago, a cluster of islands on the shallow continental shelf between New Guinea and northern Australia, was largely overlooked by ichthyologists for a century after Dutch collectors first sampled its rivers in 1907–09. Aquarium enthusiast Heiko Bleher brought Aru rainbowfishes to hobbyist attention after visits in 2004 and 2007, and two expeditions in 2013 (organised by Gerald Allen, Mark Erdmann and colleagues, with genetic work by Peter Unmack) revealed the islands to be an unexpected hotspot of rainbowfish speciation: seven species in all, most found nowhere else. Melanotaenia albimarginata belongs to the ‘Australis’ group of rainbowfishes and is most closely related to M. patoti of neighbouring Trangan Island, though the two islands are separated by saltwater channels that completely isolate their rivers.
Etymology
The species name albimarginata combines the Latin albus, white, and marginata, margined, referring to the prominent white markings on the caudal-fin lobes — a feature unique among Aru rainbowfishes.
Etymology compiled from C. Scharpf (2022), “Fishes of Sahul: An Etymological Survey (Part 5), the rainbowfishes (continued)”, Fishes of Sahul 36(4): 1968–1992, and etyfish.org.
Distribution & Habitat
Melanotaenia albimarginata is known only from Alur Warnafa, a tributary of Sungai Unmar near Algadang village on Kobroor Island. The site is a clear, slow-flowing stream over a smooth limestone pavement littered with leaf and log debris, reached only via a long tidal-river transit; water levels there are influenced by the tide even though the habitat itself is fresh. Melanotaenia senckenbergianus also occurs at the same site, generally in smaller numbers.
Description & Comparison with Similar Species
Live males show a dappled grey upper body with a dark grey mid-lateral stripe and an equally broad yellow stripe just below it, greyish dorsal and anal fins, and a semi-translucent grey caudal fin marked with bold white patches at the tip of each lobe. It differs from M. patoti mainly in this colour pattern (compare the plain brownish tones and orange-red stripes of that species) and in a slightly more slender caudal peduncle and more cheek scales on average.
Account compiled for Home of the Rainbowfish from G. R. Allen, R. K. Hadiaty, P. J. Unmack & M. V. Erdmann (2015), “Rainbowfishes of the Aru Islands, Indonesia with descriptions of five new species and redescription of M. patoti Weber and M. senckenbergianus Weber”, aqua, International Journal of Ichthyology, 21(2): 71–106.
References
- Allen G.R., R.K. Hadiaty, P.J. Unmack and M.V. Erdmann (2015) Rainbowfishes (Melanotaenia: Melanotaeniidae) of the Aru Islands, Indonesia with descriptions of five new species and redescription of M. patoti Weber and M. senckenbergianus Weber. aqua, International Journal of Ichthyology 21(2): 66-108.