New record of <italic>Melomys burtoni</italic> (Mammalia, Rodentia, Murinae) from Halmahera (North Moluccas, Indonesia): a review of Moluccan <italic>Melomys</italic>.

Mosaic-tailed rodents of the genus <italic>Melomys</italic> belong to the Australasian old endemic murine radiation and exhibit a rat-like morphology with arboreal or scansorial specializations. Here we report a new population of <italic>Melomys burtoni</italic> from the island of Halmahera (in the North Moluccas, Indonesia). Our molecular phylogenetic results highlight close relationships and recent evolutionary divergences among <italic>M. burtoni</italic> from Halmahera and the Australo-Papuan taxa <italic>M. burtoni</italic> and <italic>M. lutillus</italic> and other Moluccan taxa, including <italic>M. paveli</italic>. Multivariate as well as geometric morphometric analyses of cranial, and dental features support the recognition of <italic>M. burtoni</italic> from Halmahera as a slightly distinctive insular population, preventing us from elevating it as a new taxa. This population is recorded from lowland secondary forest and forest edge habitats in south-central Halmahera. As with other Moluccan endemic murines, colonization by an Australo-Papuan ancestor and subsequent isolation is the probable mode of diversification for <italic>M. burtoni</italic> in Halmahera. The discovery of <italic>Melomys</italic> in Halmahera fills a previously puzzling gap in knowledge of the murine fauna of the Moluccas and the biogeography of the Wallacean region. [ABSTRACT FROM AUTHOR]