Two new species of rainbowfishes (Melanotaenia: Melanotaeniidae), from, western New Guinea (Papua Barat Province, Indonesia)

Two new species of rainbowfishes are described from the southwestern Birds Head region of western New Guinea (Papua Barat Province, Indonesia). Melanotaenia ammeri n. sp. is described on the basis of 19 specimens, 46.5-82.2 mm SL, collected near Gusimawa Village, Arguni Bay. It is most closely related to M. kokasensis n. sp., also described as new from 25 specimens, 27.2-68.5 mm SL, collected near Kokas Village on the northern Fakfak Peninsula. The two species are easily distinguished on the basis of colour pattern: M. ammeri has a distinctive pattern of alternating mauve to greyish blue and yellow stripes and the colour pattern of M. kokasensis is dominated by a broad, black midlateral stripe. In addition, males of M. ammeri are significantly deeper bodied (maximum body depth as % of standard length 39.3 versus 34.5) than those of M. kokasensis. Analysis of genetic relationships based on cytochrome b sequences indicates a close relationship between the two species and demonstrates that they are part of the unique rainbowfish clade found mainly on the Vogelkop Peninsula and some offshore islands. The new species differed in their mean Kimura 2-parameter genetic divergences by 2.4% from each other. Both were between 5.4 and 5.6% divergent from M. parva, the next most closely related species that we obtained genetic data for.