A minute, elongated beetle species belonging to a new taxon of the Platypodidae-Scolytidae clade in Curculionoidea was found mining leaves of Pandanus boninensis (Pandanaceae, Monocotyledonopsida) in the Bonin (Ogasawara) Islands in the western Pacific. This beetle species is described as a new genus and species, Phylloplatypus pandani. Presence of pregular sutures, absence of a rostrum, and several other characters suggest its close relationship to Platypodidae and Scolytidae, although the hypostomal spines indicate its relationship with Rhyncolini (Cossoninae, Curculionidae). Cladistic analysis suggests that this species constitutes a separate phyletic line isolated from these families, and this species is tentatively placed in a neu tribe, Phylloplatypodini, of the Platypodidae (Coptonotinae). The beetles constructed 2 types of leafmines (i.e., a simple longitudinal straight mine and a radiate mine composed of long longitudinal mines and transverse burrows across leaf veins). The former was regarded as a temporary feeding site, the latter as a mating and brooding site. This species was monogynous and occasionally polygynous. Relatively large eggs were laid by the female from the mine in the neighboring parenchyma through the vein. Hatched larvae fed on the parenchyma and pupated there. The leafmining habit is unique in the bark beetle clade.
