The status of the Mountain Thornbill Acanthiza katherina

Abstract

The Mountain Thornbill Acanthiza katherina, which occurs in the rainforests of the Atherton Highlands, is intermediate in coloration and morphology between the New Guinean A. murina and the Australian A. pusilla. Various origins are possible: development in isolation from the Acanthiza stock that originally colonized New Guinea, back-invasion from New Guinea or introgression between A. pusilla and A.,murina. Its rather minor level of differentiation poses taxonomic problems, as is the case with many islolated forms, but it would seem best for the present to let it retain the status of a full species.