Melanotaenia longispina — holotype, female, 78.7 mm SL, near Saluk, Sorong Regency, West Papua — photo © Bambang Dwisusilo

Melanotaenia longispina

Kadarusman, Avarre & Pouyaud, 2015

Species Summary

Melanotaenia longispina is one of eight closely related rainbowfishes from the Birds Head region of West Papua, Indonesia, described together in 2015 on the basis of combined evidence: a cytochrome oxidase I (COI) gene phylogeny, genotyping at 12 microsatellite loci, and diagnostic morphological characters. The approach revealed a level of cryptic diversity in the region well beyond what traditional morphological survey alone had detected. It belongs to the same ‘Central Ayamaru Plateau’ cluster as M. klasioensis and M. susii.

Etymology

The species name longispina combines the Latin longus, long, and spina, spine, referring to the long spines on the dorsal and anal fins.

Etymology compiled from C. Scharpf (2023), “Fishes of Sahul: An Etymological Survey (Part 6), the rainbowfishes (continued)”, Fishes of Sahul 37(1): 2006–2022, and etyfish.org.

Distribution & Habitat

Melanotaenia longispina is known only from the Klahfot River near Saluk village, on the road between Sorong and Teminabuan, in the Ayamaru Plateau karst region of the Birds Head Peninsula.

Melanotaenia longispina — type locality, Klahfot River, near Saluk, Sorong Regency — photo © L. Pouyaud

Description & Comparison with Similar Species

The species is set apart from every one of its Birds Head relatives, including its two closest companions described alongside it, by a single striking feature: the complete absence of any dark stripe or margin on the dorsal fins, a mark otherwise found throughout the group. The body is pale with pinkish-to-greenish reflections, crossed by seven or eight narrow yellowish stripes between the scale rows, and the mid-lateral stripe itself is faint or absent. Beyond the bare dorsal fins, Melanotaenia longispina is further distinguished from M. klasioensis and M. susii by markedly longer spines on the first dorsal, second dorsal and anal fins.

Melanotaenia longispina — paratype, male, 73.3 mm SL, same data as the holotype — photo © Bambang Dwisusilo

Account compiled for Home of the Rainbowfish from M. F. I. Nugraha, Kadarusman, N. Hubert, J.-C. Avarre, R. K. Hadiaty, J. Slembrouck, O. Carman, Sudarto, R. Ogistira & L. Pouyaud (2015), “Eight new species of Rainbowfishes (Melanotaeniidae) from the Birds Head Region, West Papua, Indonesia”, Cybium 39(2): 99–130.

References

• Nugraha M.F.I., Kadarusman, N. Hubert, J.C. Avarre, R.K. Hadiaty, J. Slembrouck, O. Carman, Sudarto, R. Ogistira and L. Pouyaud (2015) Eight new species of Rainbowfishes (Melanotaeniidae) from the Birds Head Region, West Papua, Indonesia. Cybium 39(2): 99-130.