Phylogeny, biogeography, and taxonomy of Australasian teals

The taxonomy of the Australasian teals has been particularly unstable. Aust ralasian Grey Teal (Anas gracilis) and Chestnut Teal (A. castanea) are wide ly viewed as specifically distinct, but the taxonomy of the New Zealand tea ls remains unsettled. Because conservation status is affected by taxonomic rank, it is important to resolve the status of the rare subantarctic teals. To estimate phylogenetic relationships of teals, we sequenced three mitoch ondrial DNA genes (12S, and ATPase 6 and 8). The resultant phylogeny unequi vocally groups the Chestnut Teal with the Grey Teal, rather than with the N ew Zealand teals as has traditionally been held (Fleming 1953). A greater l evel of sequence divergence occurred within the New Zealand teals than betw een the Grey and Chestnut teals. This diversity together with morphological and behavioral differences, implies that the New Zealand teals should be a ccorded specific status as A. aucklandica, A. nesiotis, and A. chlorotis. A lthough it is most likely that the teal that colonized the Auckland Islands and Campbell Islands originated in New Zealand, our data do not allow us t o determine whether the ancestors of the Campbell Island Teal came from mai nland New Zealand or the Auckland Islands. This uncertainty arises because, as our data show, the colonization events were separated by a short period of time.