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

Mosaic-tailed rodents of the genus Melomys 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 Melomys burtoni from the island of Halmahera (in the North Moluccas, Indonesia). Our molecular phylogenetic results highlight close relationships and recent evolutionary divergences among M. burtoni from Halmahera and the Australo-Papuan taxa M. burtoni and M. lutillus and other Moluccan taxa, including M. paveli. Multivariate as well as geometric morphometric analyses of cranial, and dental features support the recognition of M. burtoni 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 AustraloPapuan ancestor and subsequent isolation is the probable mode of diversification for M. burtoni in Halmahera. The discovery of Melomys in Halmahera fills a previously puzzling gap in knowledge of the murine fauna of the Moluccas and the biogeography of the Wallacean region.