Abstract
Rainbowfishes of the family Melanotaeniidae are one of the most speciose group of freshwater fishes from the Aus-tralia-New Guinea region (Eschmeyer, 2014). They typically possess a compressed body covered by relatively large scales, two separate dorsal fins (the first with 3-7 spines and the second with a single spine and 6-22 segmented rays), a long-based anal fin, and no lateral line (Allen et al., 2008). The family is characterized by relatively small (usually less than 10 cm) and often brightly coloured fish. Rainbowfishes are popular ornamental fishes owing to this coloration and their peaceful behaviour and ease of breeding. Sexual dimor-phism is often apparent with males generally deeper-bodied Abstract.-Eight new species of Rainbowfishes are described from the Birds Head region by combining a cyto-chrome oxydase I gene (COI) phylogeny, 12 microsatellite loci and diagnostic morphological characters. The new species Melanotaenia klasioensis, M. longispina and M. susii belong to the "Central Ayamaru Plateau" cluster in the COI phylogeny and are genetically allied to M. ajamaruensis, M. boesemani, M. ericrobertsi and M. fasinensis. A Factorial Component Analysis made on the multilocus microsatellite genotypes reveals that these new species are genetically distinct from each other and from other species known from the area. With the same approach, we also describe M. manibuii, a species belonging to the "Northern Birds Head" mitochondrial clade and M. sembrae, a species genetically close to M. multiradiata. Three additional new species, M. nara-masae, M. rumberponensis and M. sikuensis, belong to the "Birds Neck" cluster and are genetically allied to M. angfa and M. parva. The microsatellite markers were also used to distinguish M. angfa from M. parva, two species sharing the same mitochondrial haplotype. For the sake of comparison, the equivalent morphometric data are provided in appendix for the 20 valid species already described from the Birds Head area.