Rainbowfishes (Melanotaenia: Melanotaeniidae) of the Aru Islands, Indonesia with descriptions of five new species and redescription of M. patoti Weber and M. senckenbergianus Weber

The Aru Archipelago is a relict of the former land bridge connecting Australia and New Guinea and its freshwaterMelanotaenia strongly reflect this past connection. Sea level changes over the past 2-3 million years have apparently provided sufficient isolation for the radiation of a minispecies flock consisting of at least seven species.Melanotaenia patoti and M. senckenbergianus were described from the islands by Weber in the early 1900s, but subsequently considered as junior synonyms of the New Guinea mainland species M. rubrostriata and M. goldieirespectively. Recent collections by the authors facilitated a reassessment of their status based on morphological and genetic investigations, consequently both are here recognised as valid and redescriptions are provided. In addition, the current study reveals the existence of five new taxa described herein. M. albimarginata n. sp. is described from 36 specimens, 35.3-90.9 mm SL, collected at Kobroor Island. It is allied to the “Australis” group of species of Australia and southern New Guinea. It differs from its closest Aru relatives, M. patoti and M. aruensis, on the basis of colour pattern, caudal peduncle depth, lateral scale counts and average number of cheek scales.Melanotaenia aruensis n. sp. is described from 19 specimens, 38.5-76.4 mm SL from Trangan and Kobroor islands. It is superficially similar to M. albimarginata and M. patoti, but exhibits marked genetic separation, unique colour pattern features, and several slight morphological differences. Melanotaenia kolaensis, M. picta, and M. wokamensisn. spp. are described from 95 (17.9-78.8 mm SL), 51 (17.2-93.2 mm SL), and 156 (14.1-75.6 mm SL) specimens respectively, collected at Kola, Kobroor, and Wokam islands. They comprise a close-knit group allied to the “Goldiei” group (along with M. senckenbergianus), but are differentiated on the basis of live colour patterns and various genetic, morphometric, and meristic features.