Belongs within: Anatinae.
The Mergini are a group of ducks primarily found in marine habitats. They are mostly found in temperate and boreal regions of the Northern Hemisphere with the exception of the Brazilian merganser Mergus octosetaceus and the recently extinct New Zealand merganser M. australis. The mergansers of the genus Mergus have long, slender bills with a hooked tip and serrated edges, adapted for catching fish. The hooded merganser Lophodytes cucullatus and smew Mergellus albellus are smaller birds with similar but shorter bills.
The eiders of the genera Polysticta and Somateria, sometimes treated as a distinct tribe Somateriini, are found around the Arctic Ocean and are known for the dense down (eiderdown) they use for lining their nests. The goldeneyes and bufflehead of the genus Bucephala are characterised by large-appearing heads; males are boldly patterned in white and black or dark metallic colours.
The Hawaiian superducks
Published 12 June 2008
Moa-nalo were large (up to 7.6 kg—Ziegler 2002), flightless goose-like birds that were once found in the Hawaiian Islands, but seem to have not long survived the arrival of hungry humans. To date, four species have been described from various islands (Olson & James 1991)—Chelychelynechen quassus from Kauai*, Thambetochen xanion from Oahu, T. chauliodous from lowland Maui and Molokai, and Ptaiochen pau from highland Maui. Moa-nalo are not yet known from the main island of Hawaii, which was home to two species of Branta goose (Paxinos et al. 2002), including the (just) surviving nene (B. sandvicensis). Branta geese were also found on the other Hawaiian islands. Wetmore (1943) described a fossil anserid species from Hawaii, Geochen rhuax, that he regarded as distinct from Branta (and very like the Australian Cereopsis), but the fragmentary remains this species was described from are not really sufficient to tell whether it is a goose or moa-nalo (or something else again)**. The unnamed ‘giant Hawaiian goose’ of Olson & James (1991) is quite definitely a Branta (Paxinos et al. 2002).
*Wryly amusing quote of the day comes from the etymology of the species name for this taxon (Olson & James 1991): “Latin, quassus , broken, shattered, in reference to the regrettably fragmented condition of the type material, which was probably deposited as a complete skeleton but was unfortunately exposed in a jeep trail.”
**Olson & James (1991) again, referring to the discovery of the Geochen material underneath an old lava flow: “From their very friable and warped appearance, the bones were almost certainly heated until glowing, with all organic material in the bone having been combusted.”
Perhaps most interesting about the moa-nalo is their phylogenetic relationships (isn’t it always?). Despite their goose-like appearance, Olson & James (1991) suggested on the basis of their ossified syringeal bullae that moa-nalo were actually more closely related to the dabbling ducks of the genus Anas (two species of which are also found on Hawaii), and possibly even derived from the common mallard (A. platyrhynchos). This view was corroborated to some extent by ancient DNA analysis (Sorenson et al. 1999) which, while it found the moa-nalo as the sister group to Anas rather than within it, definitely indicated a duck rather than goose ancestry for them. The moa-nalo therefore seem to have undergone a rapid and significant change in morphology as they adapted to flightless herbivory. The Molokai population of Thambetochen chauliodous seems to have actually gone so far as to lose the furcula!
Systematics of Mergini
<==Mergini [Merganserinae, Mergidia, Merginae]
| i. s.: Camptorhynchus labradoriusCS77
|--+--Clangula Leach 1819BKB15, M02 [incl. Harelda Stephens 1824B94; Clangulinae, Hareldinae]
| | |--‘Pagonetta’ glacialis Winge 1898S05 [=Fuligula glacialisS05, Harelda glacialisD56]
| | `--C. hyemalis (Linnaeus 1758)CS77 [=Anas hyemalisCS77, Harelda hyemalisS05, A. hiemalis Fabricius 1780S05]
| `--+--+--Histrionicus Lesson 1828BKB15, S05
| | | `--H. histrionicus (Linnaeus 1758)CS77 (see below for synonymy)
| | `--ThambetocheniniPJ02
| | |--Chelychelynechen quassusPJ02
| | |--Ptaiochen pauSC99
| | `--ThambetochenBKB15
| | |--T. chauliodousBKB15
| | `--T. xanionSC99
| `--Somateriini [Somateriinae]CS77
| |--Polysticta Eyton 1836BKB15, B94 [incl. Macropodus Nuttall 1834B94]
| | `--P. stelleri (Pallas 1769)CS77 (see below for synonymy)
| `--Somateria Leach 1819BKB15, M02
| |--S. fischeri (Brandt 1847)BKB15, CS77 (see below for synonymy)
| `--+--S. mollissima (Linnaeus 1758)BKB15, M02 [=Anas mollissimaM02; incl. S. gravipes Harrison 1979M02]
| | |--S. m. mollissima [incl. S. thulensis Malmgren 1864, S. mollissima thulensis]S05
| | |--S. m. borealis (Brehm 1824) [=Platypus borealis]S05
| | |--S. m. dresseri Sharpe 1871CS77
| | |--S. m. faeroeensis Brehm 1831CS77
| | |--S. m. sedentaria Snyder 1941CS77
| | `--S. m. v-nigrum Bonaparte 1855CS77 [=S. v-nigraS05]
| `--S. spectabilis (Linnaeus 1758)BKB15, CS77 [=Anas spectabilisCS77, Erionetta spectabilisS05]
`--+--Melanitta Boie 1822BKB15, M02 [incl. Oidemia Flemming 1822B94; Melanittinae, Oidemiinae]
| |--M. nigra (Linnaeus 1758)BKB15, M02 [=Anas nigraM02, Oedemia nigraS05, Oidemia nigraS05]
| | |--M. n. nigraCS77
| | `--M. n. americana (Swainson 1832)CS77 [=Oidemia americanaS05, Oedemia americanaS05]
| `--+--M. fusca (Linnaeus 1758)BKB15, CS77 [=Anas fuscaCS77, Oedemia fuscaJ63, Oidemia fuscaS05]
| | |--M. f. fuscaCS77
| | |--M. f. deglandi (Bonaparte 1850)CS77 (see below for synonymy)
| | |--M. f. dixoniRN72
| | `--M. f. stejnegeri (Ridgway 1887)CS77
| `--M. perspicillata (Linnaeus 1758)BKB15, CS77 (see below for synonymy)
`--+--Bucephala Baird 1858BKB15, M02 [incl. Glaucionetta Stejneger 1885B94; Glaucionettinae]
| | i. s.: B. cereti Boeuf & Mourer-Chauviré 1992M02
| | B. ossivallisFP64
| |--B. albeola (Linnaeus 1758)BKB15, CS77 [=Anas albeolaCS77, Charitonetta albeolaS05, Clangula albeolaS05]
| `--+--B. clangula (Linnaeus 1758)BKB15, M02 (see below for synonymy)
| | |--B. c. clangulaCS77
| | `--B. c. americana (Bonaparte 1838)CS77
| `--B. islandica (Gmelin 1789)BKB15, CS77 (see below for synonymy)
`--+--Mergellus Selby 1840BKB15, M02
| `--M. albellus (Linnaeus 1758) [=Mergus albellus]M02
`--+--Lophodytes cucullatusBKB15
`--Mergus Linnaeus 1758BKB15, CC10 [=Merganser Brisson 1760CC10; incl. Promergus Mathews & Iredale 1913CC10]
| i. s.: M. australis Hombron & Jacquinot 1841 [=Merganser australis, *Promergus australis]CC10
| M. connectens Jánossy 1972M02
| M. cucullatus Linnaeus 1758CS77
| M. minutus Linnaeus 1758L58
| M. octosetaceusJT12
|--M. serrator Linnaeus 1758BKB15, M02 (see below for synonymy)
`--+--M. merganser Linnaeus 1758BKB15, M02 [=Merganser merganserS05]
| |--M. m. merganserCS77
| |--M. m. americanus Cassin 1852CS77 [=Merganser americanusS05]
| `--M. m. comatus (Salvadori 1895)CS77
`--M. squamatus Gould 1864BKB15, I92
Bucephala clangula (Linnaeus 1758)BKB15, M02 [=Anas clangulaM02, Glaucionetta clangulaD56; incl. B. angustipes Jánossy 1965M02]
Bucephala islandica (Gmelin 1789)BKB15, CS77 [=Anas islandicaCS77, Clangula islandicaS05, Glaucionetta islandicaS05; incl. C. barrowii Holböll 1843S05]
Histrionicus histrionicus (Linnaeus 1758)CS77 [=Anas histrionicaCS77, Clangula histrionicaS05, Cosmonetta histrionicaS05, Harelda histrionicusS05; incl. Histrionicus minutus Nelson 1883S05, Hi. histrionicus pacificus Brooks 1915CS77, Hi. torquatus Kumlien 1879S05]
Melanitta fusca deglandi (Bonaparte 1850)CS77 [=Oidemia deglandiS05, Oedemia deglandiS05; incl. Oi. velvetina Cass. 1850S05]
Melanitta perspicillata (Linnaeus 1758)BKB15, CS77 [=Anas perspicillataCS77, Oidemia perspicillataS05, Pelionetta perspicillataS05]
Mergus serrator Linnaeus 1758BKB15, M02 [=Merganser serratorS05; incl. *Mergus castorCC10, *Merganser castorCC10, Mergus serrator schioleriCS77]
Polysticta stelleri (Pallas 1769)CS77 [=Anas stelleriCS77, Eniconetta stelleriS05, Heniconetta stelleriS05, Somateria stelleriS05; incl. So. dispar Winge 1898S05, Stelleria disparS05]
Somateria fischeri (Brandt 1847)BKB15, CS77 [=Fuligula fischeriCS77, Arctonetta fischeriS05, Lampronetta fischeriS05]
*Type species of generic name indicated
References
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[BKB15] Burleigh, J. G., R. T. Kimball & E. L. Braun. 2015. Building the avian tree of life using a large-scale, sparse supermatrix. Molecular Phylogenetics and Evolution 84: 53–63.
[CC10] Checklist Committee (OSNZ). 2010. Checklist of the Birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica 4th ed. Ornithological Society of New Zealand and Te Papa Press: Wellington.
[CS77] Cramp, S., & K. E. L. Simmons (eds) 1977. Handbook of the Birds of Europe, the Middle East and North Africa: The Birds of the Western Palaearctic vol. 1. Ostrich to Ducks. Oxford University Press: Oxford.
[D56] Dawes, B. 1956. The Trematoda with special reference to British and other European forms. University Press: Cambridge.
[FP64] Fisher, J., & R. T. Peterson. 1964. The World of Birds: A comprehensive guide to general ornithology. Macdonald: London.
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[J63] Jánossy, D. 1963. Letztinterglaziale Vertebraten-Fauna aus der Kálmán Lambrecht-Höhle (Bükk-Gebirge, nordost-Ungarn) I. Acta Zoologica Academiae Scientiarum Hungaricae 9 (3–4): 293–331.
[JT12] Jetz, W., G. H. Thomas, J. B. Joy, K. Hartmann & A. Ø. Mooers. 2012. The global diversity of birds in space and time. Nature 491: 444–448.
[L58] Linnaeus, C. 1758. Systema Naturae per Regna Tria Naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Laurentii Salvii: Holmiae.
[M02] Mlíkovský, J. 2002. Cenozoic Birds of the World. Part 1: Europe. Ninox Press: Praha.
Olson, S. L., & H. F. James. 1991. Descriptions of thirty-two new species of birds from the Hawaiian Islands: part I. Non-Passeriformes. Ornithological Monographs 45: 1–88.
[PJ02] Paxinos, E. E., H. F. James, S. L. Olson, M. D. Sorenson, J. Jackson & R. C. Fleischer. 2002. mtDNA from fossils reveals a radiation of Hawaiian geese recently derived from the Canada goose (Branta canadensis). Proceedings of the National Academy of Sciences of the USA 99: 1399–1404.
[RN72] Rutgers, A., & K. A. Norris (eds.) 1972. Encyclopaedia of Aviculture vol. 1. Blandford Press: London.
[S05] Schalow, H. 1905. Die Vögel der Arktis. In: Römer, F., & F. Schaudinn (eds) Fauna Arctica. Eine Zusammenstellun der arktischen Tierformen, mit besonder Berücksichtigung des Spitzbergen-Gebietes auf Grund der Ergebnisse der Deutschen Expedition in das Nördliche Eismeer im Jahre 1898 vol. 4 pp. 79–288. Gustav Fischer: Jena.
[SC99] Sorenson, M. D., A. Cooper, E. E. Paxinos, T. W. Quinn, H. F. James, S. L. Olson & R. C. Fleischer. 1999. Relationships of the extinct moa-nalos, flightless Hawaiian waterfowl, based on ancient DNA. Proceedings of the Royal Society of London Series B—Biological Sciences 266: 2187–2193.
Wetmore, A. 1943. An extinct goose from the island of Hawaii. Condor 45 (4): 146–148.
Ziegler, A. C. 2002. Hawaiian Natural History, Ecology, and Evolution. University of Hawaii Press.