Taxonomy

The internal taxonomy of the albatross family was long regarded as stable, with 13 species recognized, but it has been revised significantly in recent decades, with as many as 24 species total, and most post-2000 references recognizing at least 21 species.  All of the uncertainty resides in two groups that breed on islands of the Southern Ocean: the great albatrosses (Diomedea) and the mollymawks (Thalassarche).

The great albatrosses were formerly classified as two widespread species—Royal (Diomedea epomophora) and Wandering (D. exulans)—which are now generally regarded as six or seven based on plumage differences and supported by genetic evidence.  The distinction that remains unsettled is between the two forms that breed exclusively on New Zealand’s outlying southern territories, which are either separated as Gibson’s (D. gibsoni) and Antipodes (D. antipodensis) or combined as the New Zealand Albatross (D. antipodensis)

The mollymawks were traditionally regarded as five species, and their diversity has increased to nine based on discernibly different appearances supported by genetic analyses.  The widely accepted subdivisions are of the former Yellow-nosed into Atlantic Yellow-nosed (Thalassarche chlororhynchos) and Indian Yellow-nosed (T. bassi), the former Black-browed into Black-browed (T. melanophris) and Campbell (T. impavida), and the former Shy into White-capped (T. cauta), Chatham (T. eremita), and Salvin’s (T. salvini).

Additional subdivisions of White-capped and Buller’s (T. bulleri) populations have been proposed on the basis of genetic analyses.  However, the populations are not readily identifiable, so these proposals will likely require further research and analysis to decide.

The total number of albatross species therefore falls somewhere between 21 and 24 species.