A neotype designation for the Ascension Frigatebird Fregata aquila ( Aves : Fregatidae )

A neotype is designated for Pelecanus aquilus Linnaeus, 1758 (currently Fregata aquila ; Aves, Fregatidae) to fix the identity of this nominal species.

Perhaps the most important element in the process of naming a taxon is the clear, unequivocal designation of a name-bearing type.However, this was not always so.In the years around the publication of the 'Systema Naturae', by Linnaeus in 1758, names were mainly based on texts and illustrations produced by naturalists and/or artists of the 17 th and 18 th centuries.In the absence of designated type specimens, those often impressive illustrations and/or meagre descriptions of that time have posed, and continue to pose, problems to taxonomists (Dubois & Nemésio 2007).
An example of such problems is the formal description, by Johann Friedrich Gmelin, of the Southern Giant Petrel Macronectes giganteus (J.F.Gmelin, 1788).According to VoisiN (1981), a painting and drawing by Sydney Parkinson, the artist on Captain James Cook's first voyage around the world (1768-1771), that were interpreted to represent 'types' of the Southern Giant Petrel actually depict specimens that cannot be identified to species.Its brief descriptive text, however, corresponds with the other species in the genus, the Northern Giant Petrel M. halli Mathews, 1912(VoisiN 1981).In order to avoid disrupting the taxonomic stability, VoisiN et al. (1992) asked the International Commission on Zoological Nomenclature to use its plenary powers to validate a neotype of the Southern Giant Petrel for M. giganteus, and this was accepted in Opinion 1751 (ICZN 1993).
In this contribution, we address a similar case involving another seabird species -the Ascension Frigatebird Fregata aquila (Linnaeus, 1758).The Ascension Frigatebird is a large seabird that currently breeds only on Boatswain Bird Islet near Ascension Island in tropical South Atlantic Ocean, and ranges at sea off West Africa from the Gulf of Guinea to the mouth of the Congo River (orta 1992, ashmole et al. 1994, ratcliffe et al. 2008).It is a member of the family Fregatidae Degland & Gerbe, 1867, which contains five living species and 13 subspecies, all in Fregata Lacépède, 1799, distributed throughout tropical and subtropical oceans.Frigatebirds have a mostly black plumage (particularly males), long pointed wings, deeply forked tails, and long hooked bills.Adult females have a varying amount of white mostly on breast and belly.Juveniles are white or rufous-headed and have extensive white on underparts (harrisoN 1991(harrisoN , orta 1992(harrisoN , WalbriDge et al. 2003)).
liNNaeus (1758: 133) described the Ascension Frigatebird under the name Pelecanus aquilus as follows: 'P[elecanus] cauda forficata, corpore nigro, capite abdomineque albis' (tail forked, body black, white on head and belly).By the end of the 19 th century, only two valid species of frigatebirds were generally recognized, the larger Ascension Island frigatebird occurring in all tropical oceans, and a smaller frigatebird, Fregata ariel (G.R. Gray, 1845) restricted to Indian and Pacific Oceans (ogilVie-graNt 1898).matheWs (1914) revised frigatebird taxonomy, naming new taxa and determining the status of names already published.There (p.117-118) he argued that the name F. aquila was applicable exclusively to birds from Ascension Island, since it was based on a specimen collected there by Osbeck.Furthermore, in his 'Birds of Australia', he (matheWs 1915: 243) opined that the five 'pre-Linnaean' names quoted in the preceding paragraph were 'purely of historical interest'.
As to the first point, we agree with matheWs (1914) that Linnaeus's description, ultimately taken from Odhelius's dissertation, is essentially a summary in Latin of a longer text from osbeck (1757 [1771]), who (p. 88) described a frigatebird from Ascension Island, recording its plumage as: 'the colour of the whole body... is black: but the head, breast, belly, and fore part of the neck are of a fine white'.This pattern recalls that of a juvenile Ascension Frigatebirds, wherein, however, a complete or broken black band runs across the upper-chest (harrisoN 1991(harrisoN , WalbriDge et al. 2003)).
Osbeck was a student of Linnaeus who travelled to Asia in 1750-1752 and brought home a collection of natural items, chiefly from China (merril 1916).En route he collected a specimen of the Ascension Frigatebird, as inferred from Odhelius (in liNNaeus 1759: 239): 'Avis in insula Ascensionis a P. Osbeck capta' (a bird captured by P. Osbeck on Ascension Island).Nevertheless, there is nothing to clearly suggest that Odhelius, or even Linnaeus, ever saw this specimen themselves, or that it is still extant (cf., e.g., WalliNg 1992, Zoology sectioN 1996, 2001).As to the other point, that pre-Linnaean names are of historical interest only, it is necessary to note that, according to the Article 72.4.1 of the Code (ICZN 1999), 'the type series of a nominal species-group taxon consists of all the specimens included by the author in the new nominal taxon (whether directly or by bibliographic reference), except any that the author expressly excludes'.Therefore, all the specimens described and/or illustrated by authors quoted by liNNaeus (1758) in his description of Pelecanus aquilus are, in principle, syntypes.
The Irish physician and botanist Patrick Browne briefly diagnosed his Alcyon major pulla as: 'cauda longiore bifurca' (long forked tail) and added: 'The Man-of-war bird; or the dark-coloured Alcyon with slender forked tail' (broWNe 1756: 483).The word 'Alcyon' comes from the Ancient Greek word ἀλκυών (alkuōn), which means 'Kingfisher' (JobliNg 2010).Thus, the species name translates as 'The Greater dark Kingfisher', no doubt a reference to the species feeding on fish (orta 1992).In the Caribbean, where Browne lived for many years, frigatebirds were called by English sailors as 'Man-of-War bird', the term itself derived from a British Royal Navy expression for a class of warship.broWNe (1756) neither designated nor illustrated a specimen, but his allusion to a 'wholly dark bird with forked tail' suggests a male Magnificent Frigatebird F. magnificens Mathews, 1914, since it is the only member of the family that breeds in the Caribbean (orta 1992).
In the Latin edition of his 'History of the New World' (De laet 1663), the Dutch geographer Johannes de Laet mentioned a seabird from Brazil called 'Caripira', of which he said 'caudam habet bifurcatam, unde & nomen invenit apud Hispanos Raboforcado' (has a forked tail, hence its name Raboforcado among the Spanish).The word 'Caripira' is a corruption of the word 'Grapirá', which is a Brazilian indigenous (Tupi-Guarani) name for the Magnificent Frigatebird (iheriNg 1940).'Rabiforcado' is an old Spanish spelling of 'Rabihorcado' (forked tail; hartog 1993).Laet neither mentioned nor illustrated specimens.
During his voyage to Jamaica, the Irish naturalist Hans Sloane reported he saw several 'Men of War Birds [sic]' while passing near Barbados (sloaNe 1707: 30).He quoted other authors who had also described frigatebirds in their works, De laet (1663) among them.Again no specimen was illustrated or otherwise reported.
In 1702-1706, James Petiver, an English apothecary known for his contributions to natural history, published 'Gazophylaceum naturae et artis', a descriptive catalogue of animals and plants from different parts of the World.This work was collected with others posthumously republished in 1764 under the title 'Jacob Petiver Opera, historiam naturalem spectantia' (Weiss 1927).There, PetiVer (1764) gave an illustration (plate LIV, fig.2) and brief text of 'The Indian Forked Tail'.Its text reads: 'This bird's tail open and shuts like a Taylor's sheers, and for that reason the Portuguese call it Rabo Forcado'.As noted by eDWarDs (1760: 211), Petiver copied both the figure and text from Willughby's 'Ornithology' (1678: 395; plate LXXVII).This figure, reproduced here as Fig. 1, is very imprecise, and were it not for the fact that the name 'Rabo forcado' has been mentioned, we would hardly associated the bird represented with a frigatebird.
Eleazar Albin, a German-born, English wildlife illustrator, published 'A natural history of birds' in 1731-1738.Its paintings were based on actual birds, either living individuals or prepared specimens.Plate LXXX (albiN 1738: 75) illustrated an oddly-perched individual titled 'The Frigate Bird' (Fig. 2), with the attached description: 'The Males are as black as Ravens...He has great red Gills under his throat... which do not appear but in the old ones, the Females had none; they are whiter than Males, especially under the Belly'.According to albiN (1738), the specimen depicted came from an island in the Caribbean called 'Isle of Frigats'.It is clearly a male (the all-black plumage and red gular pouch are unmistakable;  name aquilus (-a) is to be tied unchallengeably to the Ascension Island frigatebird, the species for which it has been used for over a century.Accordingly, we choose as neotype of Pelecanus aquilus Linnaeus, 1758: BMNH 1899.1.4.13, adult breeding male, collected on Ascension Island by Dr. Frank Penrose in December 1877, and now in the Natural History Museum at Tring, UK (Fig. 3).Its measurements (in mm) are: bill (culmen from forehead), 88.
Fig. 2), and probably a Magnificent Frigatebird F. magnificens.ZOOLOGIA 33(6): e20160111 | DOI: 10.1590/S1984-4689zool-20160111 | December 15, 2016 3 / 6 In summary, none of the accounts of syntypic material by liNNaeus (1758) in his original description of Pelecanus aquilus applies unambiguously to the Ascension Island Frigatebird; at least one, however, could involve the Magnificent Frigatebird (broWNe 1756).Lectotypifying the lost specimen collected by Osbeck on Ascension Island cannot fix the identity of Pelecanus aquilus either because, in the central Atlantic, it can be argued that the specimen could have been a stray of any of three other species of frigatebirds: F. ariel, F. minor (J.F.Gmelin, 1789) and F. magnificens.Thus neotypification provides the only solution if the