An enigmatic new genus and species of rove beetle (Coleoptera: Staphylinidae) is described as Dolichoxenus newtoni, new genus and species, in early Miocene (Burdigalian) amber from the Dominican Republic. The species is the first fossil oxyteline discovered as an amber inclusion. The genus is apparently a member of the tribe Oxytelini (Staphylinidae: Oxytelinae) and may be allied to the African genus Jerozenia Herman, 2003. The genus exhibits several remarkable apomorphies for the subfamily, and in general possesses features otherwise known in the subfamily for inquilines of ants, suggesting a possible paleobiological association for the genus.