Diomedea spadicea J.F. Gmelin 1789

Application of Diomedea spadicea J.F. Gmelin, 1789, Diomedea adusta Tschudi, 1856 and Diomedea dabbenena Mathews, 1929

With the application of exulans Linnaeus to the large subantarctic member of the Wandering Albatross complex, the next-senior names spadicea J.F. Gmelin, 1789, adusta Tschudi, 1856 and dabbenena Mathews, 1929 come into potential contention for the smaller temperate zone forms. Of these names, dabbenena, a nomen novum for Diomedea chionoptera alexanderi Dabbene, 1926 (preoccupied), has been the only one taken up, coming into prevailing use over the last 50 years for the small wandering albatrosses breeding on Tristan da Cunha, Gough and Inaccessible Islands in the South Atlantic (Murphy 1936; Clancey 1968; Condon 1975; Blakers et al. 1984; Bourne 1989, 1999; Carboneras 1992; Medway 1993; Prince et al. 1997; Gales 1998; Nunn 1998; Robertson & Gales 1998; Walker & Elliott 1999; BirdLife International 2000; Neves et al. 2000; Ryan 2000; Ryan et al. 2001; Thompson & Hamer 2000; Croxall & Wood 2002; Cuthbert et al. 2003, 2004, 2005; Brooke 2004; Burg & Croxall 2004; Cuthbert & Sommer 2004; Penhallurick & Wink 2004; Alderman et al. 2005; Clements 2007; Dénes & Silveira 2007; Onley & Scofield 2007; Password 2007; Wilcox & Donlan 2007; Chambers et al. 2009; Gill et al. 2010: 65; Dickinson & Remsen 2013; Gill & Donsker 2016). As recorded by Dabbene (1926: 338–339) in his description of alexanderi, its two syntypes from 38° 30´S and 56° W in the South Atlantic are small, with wing 600 mm and culmen 152–160 mm, and match members of the Wandering Albatross complex breeding on those islands. The name dabbenena was originally introduced conditionally (and unavailably) by Mathews (1929), to replace alexanderi Dabbene if the prospective prior homonym Thalassogeron chrysostoma alexanderi Mathews, 1916 was ever included in the genus Diomedea. This step was taken implicitly by Murphy (1936) before 1961 (Article 59.3 of the Code), thereby permitting use of dabbenena under Articles 11.5.1 and 15.1 of the Code

Diomedea spadicea J.F. Gmelin, 1789, senior to dabbenena, does not appear to have been used as the valid name for any albatross after 1895 (Salvin 1896, as spadacea). It is based on material in juvenile-type plumage. Medway (1993) concluded that it probably applied to the small temperate South Atlantic form on the presumption that its holotype, a specimen in stage 1 (–2) plumage (Harrison 1989: 223; Marchant & Higgins 1990: 276–277), had been collected at 37°S in the South Atlantic on 23 December 1768 on Cook’s first voyage. This specimen was drawn by Sydney Parkinson (folio 25 in vol. 1 of Parkinson’s drawings from the voyage — see Lysaght 1959), and has since been reproduced by Medway (l.c.). Its recorded measurements (wing 610 mm, bill 127 mm) agree with the small South Atlantic form (Medway l.c.). Gmelin (1789), however, had explicitly based spadicea on records and material not only from Cook’s first voyage to the south Pacific (Hawkesworth 1773), but also Cook’s second voyage to that ocean (Forster 1777) and on the Chocolate Albatross of Latham (1785); the latter includes reference to general material both from Cook’s first and second voyages (footnote), and in the Leverian Museum at the time. Pace Schifter et al. (2007: 39), syntypes are clearly involved from both south Atlantic and south Pacific Oceans, including all relevant specimens in the Leverian Museum. Understandably, Gill et al. (2010: 65) concluded that Gmelin’s spadicea was of uncertain identity and so a nomen dubium.

Avian specimens from the Cook voyages, a number of which found their way into the Leverian Museum, were dispersed long ago by Joseph Banks and the auction of the Leverian Museum in 1806 (Sharpe 1906; Whitehead 1969; Medway 1976). Most of the specimens have been lost; but among others one bloc of material from the Leverian Museum has survived: the specimens purchased by Baron L. von Fichtel for the Imperial Collection, Vienna, at the sale of the museum (Pelzeln 1873). Two great albatrosses appear to have been sold to von Fichtel there (Pelzeln l.c.: 51, 123, cf. Donovan 1806), one a brown immature, the other a white adult. The former, confirmed by Pelzeln (l.c.: 15) as coming from the Leverian Museum and matching descriptions of Latham’s Chocolate Albatross, is evidently one of the syntypes of spadicea J.F. Gmelin despite Medway’s (1993) reservations. It is listed as no. 37 “ Albatross Diomedea exulans ” in the Sale Catalogue of the third last day of the Leverian Museum auction (Donovan l.c.). Pelzeln (l.c.: 51) cites its Sale Catalogue name as Diomedea exulans grisea, a name we have found published nowhere else than in Pelzeln (l.c.). Although Pelzeln linked that name to referenced descriptions (see Article 12.2.1 of the Code), he quoted it only as a catalogue name without using it as valid. Thus grisea Pelzeln is unavailable under Article 11.5 of the Code. Now in the Naturhistorisches Museum, Wien, as reg. no. 13.648 (Schifter et al. 2007: 39), the specimen itself is a very large bird, in brown, juvenile-type plumage similar to or a little more advanced than the specimen figured by Parkinson (see above), and with wing 700 or 703 mm and culmen 173 or 174 mm (our measurements; A. Gamauf, pers. comm.) (Fig. 2). With a heavy bill and measurements at the high end of the range for the large subantarctic form, it is clearly identifiable with nominotypical exulans. Pelzeln (l.c) and Schifter et al. (l.c.) respectively refer to NHMW 13.648 as “perhaps the type ” and “(?) holotypus ” of spadicea, but, as we have pointed out above, Gmelin explicitly based the name on material from multiple sources. As lectotypifications, these designations lack required precision under Articles 72.4.7 and 74.7 of the Code. Accordingly, we resolve the application of Diomedea spadicea J.F. Gmelin, 1789 objectively by expressly choosing NHMW 13.648 here as its lectotype. By this action, the name becomes a synonym of exulans Linnaeus, leaving dabbenena Mathews unthreatened.

Diomedea adusta Tschudi, 1856, described as the “dunkelbraune Albatross” from three specimens collected in South American waters between 33° and 39°S at c. 89°W in the southeast Pacific, is also senior to dabbenena and was based on presumed adult birds with maximum wing span of 11´9" (Tschudi 1856: 157–158, 161). Along with exulans, it was said to be the largest member in the genus. We have been unsuccessful in tracing type material of adusta. It was collected at sea by the Swiss naturalist J.J. von Tschudi on his first visit to South America in 1838– 1842 (Tschudi l.c.), and can be expected to have been deposited either in NHMW, Vienna, the Muséum d’Histoire Naturelle, Neuchâtel, or the Naturhistorisches Museum, Basel. The type catalogue of birds in NHMW (Schifter et al. 2007) does not list Diomedea adusta Tschudi, and no relevant material has been found in the respective Swiss natural history museums (B. Mulhauser, R. Winkler, pers. comm.). The original description of adusta, which could apply to either large subantarctic or smaller temperate south Atlantic forms, is taxonomically perplexing because it records the head as black, a trait unknown in Diomedea sensu lato. The name has hardly ever been taken up since its publication, but regrettably cannot be rejected as a nomen oblitum under Article 23.9 of the Code because it has been used as valid at least once since 1899, by Paessler (1909). Because of its conflicted description, we treat it as a nomen dubium (see final paragraph below).