The southern royal albatross or toroa, (Diomedea epomophora) is a large seabird from the albatross family. At an average wingspan of above , it is one of the two largest species of albatross, together with the wandering albatross. Recent studies indicate that the southern royal albatross may, on average, be somewhat larger than the wandering albatross in mass and have a similar wingspan, although other sources indicate roughly similar size for the two species and the wandering species may have a larger average (and maximum) wingspan in some colonies. Taxonomy Albatrosses belong to family Diomedeidae of the order Procellariiformes, along with shearwaters, fulmars, storm petrels, and diving petrels. They share certain identifying features. First, they have nasal passages that attach to the upper bill called naricorns; the nostrils of the albatross are on the sides of the bill. The bills of Procellariiformes are also unique in that they are split into between seven and nine horny plates. Finally, they produce a stomach oil made up of wax esters and triglycerides that is stored in the proventriculus. This is used against predators as well as an energy rich food source for chicks and for the adults during their long flights. This species was once considered conspecific with the northern royal albatross (Diomedea sanfordi) as the royal albatross. The split into two species is widely though not universally accepted: it is recognized by, for example, the IOC World Bird List, BirdLife International, Brooke, and Robertson & Nunn, but not by Clements, while the American Ornithologists' Union has recognized the need for a proposal. Etymology Diomedea refers to Diomedes, a figure from Greek mythology whose companions turned to birds. Description The southern royal albatross has a length of and a mean weight of . At Campbell Island, 11 males were found to have a mean mass of and 7 females were found to have a mean mass of , thus may be heavier on average than most colonies of wandering albatross. Males are about heavier than females. Average wingspan has been reported from , with an upper limit of about . The wandering albatross can exceed this species in maximum size and averages slightly larger in linear dimensions if not bulk, but the two species are close enough in dimensions that size cannot be used to distinguish between them. The juvenile has a white head, neck, upper mantle, rump, and underparts. There are