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Anatini

(Tribe)

Overview

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The Anatinae is a of the family Anatidae (swans, geese and ducks). Its surviving members are the dabbling ducks, which feed mainly at the surface rather than by diving. The other members of the Anatinae are the extinct moa-nalos, a young but highly apomorphic lineage derived from the dabbling ducks.

There has been much debate about the dabbling ducks' systematical status and what ducks belong to the Anatinae. As understood here, the subfamily contains only the dabbling ducks and their close relatives, the extinct moa-nalos. Alternatively1], the Anatinae are considered to include most "ducks" and the dabbling ducks form a tribe Anatini within these. The classification as presented here more appropriately reflects the remaining uncertainty about the interrelationships of the major lineages of Anatidae (waterfowl)[2].

Systematics

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The dabbling duck group, of worldwide distribution, was delimited in a 1986 study[3] to include 8 genera and some 50-60 living species. However, Salvadori's Teal is almost certainly closely related to the Pink-eared Duck[citation needed], and other genera are likewise of unresolved affiliation[4][2]. The peculiar Marbled Duck, formerly tentatively assigned to the dabbling ducks, is actually a diving duck or even a distinct subfamily[2].

This group of ducks is so named because its members feed mainly on vegetable matter by upending on the water surface, or grazing, and only rarely dive. These are mostly gregarious ducks of freshwater or estuaries. These birds are strong fliers and northern species are highly migratory. Compared to other types of duck, their legs are placed more towards the centre of their bodies. They walk well on land, and some species feed terrestrially.

Puddle ducks generally feed on the surface of the water or feed on very shallow bottoms. They are not equipped to dive down several feet like their diving counterparts. The most predominant difference between puddle ducks and divers are the size of the feet. Puddle ducks feet are generally smaller because they do not need the extra propulsion to dive for their forage.

Another distinguishing characteristic of puddle ducks when compared to diving ducks is the way in which they take flight when spooked or are on the move. Puddle ducks spring straight up from the water and diving ducks need to gain momentum to take off, so they must run across the water a short distance to gain flight.

History of Classification

Traditionally, most ducks were assigned to either the shelducks, the perching ducks, and the dabbling and diving ducks; the latter two were presumed to make up the Anatinae. However, the perching ducks turned out to be a paraphyletic assemblage of various tropical waterfowl that simply had happened to evolve the ability to perch well in their forested habitat. Several of these, such as the Brazilian Duck, were subsequently assigned to the Anatinae.

As for the diving ducks, mtDNA cytochrome b and NADH dehydrogenase subunit 2 sequence data[2] indicates that they are fairly distant from the dabbling ducks, the morphological similarities[3] being due to convergent evolution.

In addition, the genus Anas as traditionally defined is not monophyletic; several South American species belong to a distinct clade which would include the Tachyeres steamer-ducks[2], and other species such as the Baikal Teal should also be considered distinct. See the genus article for more on this subject.

Genera

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The Baikal Teal
Spotbill, Anas poecilorhyncha in Hyderabad, India.

The following genera are (with one exception) unequivocal dabbling ducks:

The 3 known genera and 4 known species of moa-nalos are went extinct around 1000 AD. They formerly occurred on the Hawaiian Islands and were derived from dabbling ducks, possibly even a close ancestor of the mallard:

The Comb Duck: a misplaced dabbling duck?

Subfossil remains of a small, flightless dabbling duck have been recovered on Rota in the Mariana Islands[5]. These cannot be assigned to a known genus, but probably are closest to Anas. A most bizarre ducklike fowl has been found on the Hawaiian island of Kaua?i[6]. Due to its unique apomorphies (it seems to have had small eyes high and far back on its head) the placement of this anatid is likewise unresolved; only dabbling ducks and true geese are with certainty known to have colonized the Hawaiian chain.

Frequently placed into the Anatinae are these genera, whose relationships must be considered uncertain at present:

On the other hand, the following genera, usually considered to belong into the Tadorninae, may actually be dabbling ducks:

Photos

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Taxonomy

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The Tribe Anatini is a member of the Subfamily Anatinae. Here is the complete "parentage" of Anatini:

The Tribe Anatini is further organized into finer groupings including:

Genera

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Aix

[more]

Amazonetta

The Brazilian Duck or Brazilian Teal (Amazonetta brasiliensis) is the only in the genus Amazonetta. It was formerly considered a "perching duck", but more recent analyses indicate that it belongs to a clade of South American dabbling ducks which also includes the Crested Duck, the Bronze-winged Duck, and possibly the steamer ducks (Johnson & Sorenson, 1999). [more]

Anas

Anas is a of dabbling ducks. It includes mallards, wigeons, teals, pintails and shovelers in a number of subgenera. Some authorities prefer to elevate the subgenera to genus rank. Indeed, as the moa-nalos are very close to this clade and may have evolved later than some of these lineages, it is rather the absence of a thorough review than lack of necessity that this genus is rather over-lumped. [more]

Aythya

Aythya is a of diving ducks. [more]

Bucephala

[more]

Callonetta

The Ringed Teal (Callonetta leucophrys) is a small of South American forests. It is the only species of the genus Callonetta. Usually placed with the dabbling ducks (Anatinae), this species may actually be closer to shelducks and belong in the subfamily Tadorninae; its closest relative is possibly the Maned Duck. [more]

Camptorhynchus

The Labrador Duck, Camptorhynchus labradorius, was a striking black and white -like sea duck that was never known to be common, and is believed to be the first bird to become extinct in North America after 1500. The last Labrador Duck is believed to have been seen at Elmira, New York on ; the last preserved specimen was shot in 1875 on Long Island. It was thought to breed in Labrador, although no nests were ever described, and it wintered from Nova Scotia to as far south as Chesapeake Bay. [more]

Chenonetta

The Australian Wood Duck or Maned Duck, Chenonetta jubata, is a found throughout much of Australia. It is the only living species in the genus Chenonetta. Traditionally placed in the Anatinae (dabbling duck) subfamily, it might actually belong to the Tadorninae (shelduck) subfamily (Sraml et al. 1996); possibly, the Ringed Teal is its closest living relative (Johnson & Sorenson 1999). [more]

Clangula

The Long-tailed Duck (Clangula hyemalis) is a medium-sized . It is the only living member of its genus, Clangula; this was formerly used for the goldeneyes, with the Long-tailed Duck being placed in Harelda. An undescribed congener is known from the Middle Miocene Sajóvölgyi Formation (Late Badenian, 13-12 mya) of Mátraszőlős, Hungary (Gál et al. 1998-99). [more]

Histrionicus

The Harlequin Duck, Histrionicus histrionicus, is a small . In North America it is also known as Lords and ladies. Other names include painted duck, totem pole duck, rock duck, glacier duck, mountain duck, white-eyed diver, squeaker and blue streak. [more]

Hymenolaimus

The Blue Duck (Hymenolaimus malacorhynchos) is a member of the , goose and swan family Anatidae. It is the only member of the genus Hymenolaimus, placed in the shelduck subfamily Tadorninae[citation needed] after previously being considered part of the paraphyletic "perching duck" assemblage. The Maori name is whio, which is an onomatopoetic rendition of the males' call. the blue duck is born with a green beak for just 8 hours after birth ; where it then develops to its final color. [more]

Lophodytes

The Hooded Merganser (Lophodytes cucullatus) is a small and is the only member of the genus Lophodytes. [more]

Malacorhynchus

The Pink-eared Duck (Malacorhynchus membranaceus) is a species of found in Australia. It has a large spatulate bill like the Australasian Shoveler, but is smaller at 38-40 cm length. Its brown back and crown, black and white barred sides and black eye patches on its otherwise white face make this bird unmistakable. Juveniles are slightly duller, but otherwise all plumages are similar. Its vernacular name refers to a pink spot in the corner formed by the black head pattern; it is only noticeable at close distance however, making the seldom-used Australian name of Zebra Duck more appropriate. [more]

Marmaronetta

The Marbled Duck, or Marbled Teal (Marmaronetta angustirostris), is a medium-sized . It used to be included among the dabbling ducks, but is now classed as a diving duck. [more]

Melanitta

The scoters are stocky in the genus Melanitta. The drakes are mostly black and have swollen bills. Females are brown. [more]

Merganetta

The Torrent Duck (Merganetta armata) is a member of the , goose and swan family Anatidae. It is the only member of the genus Merganetta. Nowadays, it is placed in the shelduck subfamily Tadorninae after the "perching duck" assemblage where it was formerly assigned to was dissolved because it turned out to be paraphyletic[citation needed]. Its closest relative may be the Blue Duck of New Zealand[citation needed]. [more]

Mergellus

The Smew (Mergellus albellus) is a small which is somewhat intermediate between the typical mergansers (Mergus) and the goldeneyes (Bucephala). It is the only member of the genus Mergellus; sometimes included in Mergus, this genus is well distinct (though closely related) and might actually be a bit closer to the goldeneyes. The Smew has interbred with the Common Goldeneye (B. clangula). [more]

Mergus

Mergus is the of the typical mergansers, fish-eating ducks in the seaduck subfamily (Merginae). The Hooded Merganser, often termed Mergus cucullatus, is not of this genus but closely related. The other "aberrant" merganser, the Smew (Mergellus albellus), is phylogenetically closer to goldeneyes (Bucephala). [more]

Netta

Netta is a genus of . Unlike other diving ducks, the Netta species are reluctant to dive, and feed more like dabbling ducks. [more]

Polysticta

The Steller's Eider (Polysticta stelleri) is a medium-large , which breeds along the Arctic coasts of eastern Siberia and Alaska. The lined nest is built on tundra close to the sea, and 6-10 eggs are laid. [more]

Rhodonessa

The Pink-headed Duck (Rhodonessa caryophyllacea) is (or was) a large that was once found in parts of the Gangetic plains of India, Bangladesh and in the riverine swamps of Myanmar but feared extinct since the 1950s. Numerous searches have failed to provide any proof of continued existence. It has been suggested that it may exist in the inaccessible swamp regions of northern Myanmar and some sight reports from that region have led to its status being declared as "critically endangered" rather than extinct. The genus placement has been disputed and while some have suggested that it is closer to the pochards, others have placed it in a separate genus of its own. [more]

Salvadorina

The Salvadori's Teal or Salvadori's Duck (Salvadorina waigiuensis) is a of bird native to New Guinea. It is placed in the monotypic genus Salvadorina. [more]

Somateria

Eiders are large in the genus Somateria. Steller's Eider, despite its name, is in a different genus. [more]

At least 17 species and subspecies belong to the Genus Somateria.

More info about the Genus Somateria may be found here.

References

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Footnotes

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  1. ^ Terres, J. & NAS (1991)
  2. ^ a b c d e Johnson, K. & Sorenson, M. (1999)
  3. ^ a b Livezey, B. (1986)
  4. ^ Sraml, M. et al. (1996)
  5. ^ Steadman, D. (1999)
  6. ^ Burney, D. et al. (2001)

Sources

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Last Revised: September 22, 2009
2009/09/22 15:04:44