Anatidae Totally Explained

Everything about Anatidae totally explained

ť Waterbird redirects here. See also shorebirds and seabirds.
Anatidae is the biological family that includes the ducks and most duck-like waterfowl, such as geese and swans. These are birds that are evolutionarily adapted for swimming, floating on the water surface, and in some cases diving in at least shallow water. (The Magpie-goose is no longer considered to be part of the Anatidae, but is placed in its own family Anseranatidae.)
   Extant species range in size from the Cotton Pygmy Goose, at as little as 26.5 cm (10.5 inches) and 164 grams (5.8 oz), to the Trumpeter Swan, at as much as 183 cm (6 ft) and 17.2 kg (38 lb). They have webbed feet and bills which are flattened to a greater or lesser extent. Their feathers are excellent at shedding water due to special oils. Anatidae are remarkable for being one of the few families of birds that possess a penis; they're adapted for copulation on the water only. Duck, eider, and goose feathers and down have long been popular for bedspreads, pillows, sleeping bags and coats. The members of this family also have long been used for food.
   Humans have had a long relationship with ducks, geese and swans; they're important economically and culturally to humans, and several duck species have benefited from an association with people. On the flip side some anatids are damaging agricultural pests, and have acted as vectors for zoonosis such as avian influenza. Numerous ducks and geese have become extinct due to the activities of humans, and many more are currently considered threatened species.
   While the status of the Anatidae as a family is straightforward, and there's little debate about which species properly belong to it, the relationships of the different tribes and subfamilies within it are poorly understood. The listing in the box at right should be regarded as simply one of several possible ways of organising the many species within the Anatidae; see discussion in the next section.

Systematics

Currently, the systematics of the Anatinae is in a state of flux. Previously divided into six subfamilies, a study of anatomical characters by Livezey suggest that the Anatidae are better treated in nine subfamilies. This classification was popular in the late 1980s to 1990s. But mtDNA sequence analyses indicate that for example the dabbling and diving ducks don't belong in the same subfamily. While there are certainly shortcomings in Livezey's analysis, mtDNA is an unreliable source for phylogenetic information in many waterfowl (especially dabbling ducks) due to their ability to produce fertile hybrids, in rare cases possibly even beyond the level of genus (see for example the "Barbary Duck"). Due to the small sample size of many molecular studies available to date, mtDNA results must be considered with caution.
But while a comprehensive review of the Anatidae which unites all evidence into a robust phylogeny is still lacking, the reasons for the confusing data are at least clear: As demonstrated by the Late Cretaceous fossil Vegavis iaai — an early modern waterbird which belonged to an extinct lineage — the Anatidae are an ancient group among the modern birds. Their earliest direct ancestors, though not documented by fossils yet, likewise can be assumed to have been contemporaries with the dinosaurs. The long period of evolution and shifts from one kind of waterbird lifestyle to another have obscured many plesiomorphies, while apomorphies apparently are quite often the result of parallel evolution, for example the "non-diving duck" type displayed by such unrelated genera as Dendrocygna, Amazonetta, and Cairina. For the fossil record, see below.
Alternatively, the Anatidae may be considered to consist of 3 subfamilies (ducks, geese, and swans, essentially) which contain the groups as presented here as tribes, with the swans separated as subfamily Cygninae, the goose subfamily Anserinae also containing the whistling ducks, and the Anatinae containing all other clades.

Dendrocygninae: whistling ducks

One pantropical genus, of distinctive long-legged goose-like birds:

Dendrocygna: whistling ducks (9 living species)

Thalassorninae: White-backed Duck

One genus in Africa, most closely related to the subfamily Dendrocygninae, though also showing convergent similarities to the subfamily Oxyurinae:

Thalassornis: White-backed Duck

Anserinae: swans and geese

Three to seven extant genera with 25-30 living species, mainly cool temperate Northern Hemisphere but also some Southern Hemisphere species, with the swans in one genus (two genera in some treatments), and the geese in three genera (two genera in some treatments). Some other species are sometimes placed herein, but seem somewhat more distinct (see below):

Cygnus: true swans (7 species, 4 sometimes separated in Olor)

Anser: grey geese (7 species)

Chen: white geese (3 species, sometimes included in Anser)

Branta: black geese (8 living species)

Stictonettinae: Freckled Duck

One genus in Australia, formerly included in the Oxyurinae, but with anatomy suggesting a distinct ancient lineage perhaps closest to the Anserinae, especially the Cape Barren Goose:

Stictonetta: Freckled Duck

Plectropterinae: Spur-winged Goose

One genus in Africa, formerly included in the "perching ducks", but closer to the Tadorninae:

Plectropterus: Spur-winged Goose

Tadorninae: shelducks and sheldgeese

This group of larger, often semi-terrestrial waterfowl can be seen as intermediate between Anserinae and Anatinae. The 1986 revision and the group in the traditional lineup is likely to be paraphyletic:

Pachyanas: Chatham Island Duck (prehistoric)

Tadorna: shelducks (7 species, one probably extinct) - possibly paraphletic

Salvadorina: Salvadori's Teal

Centrornis: Madagascar Sheldgoose (prehistoric, tentatively placed here)

Alopochen: Egyptian Goose and Mascarene Shelducks (1 living species, 2 extinct)

Neochen: Orinoco Goose

Chloephaga: sheldgeese (5 species)

Hymenolaimus: Blue Duck

Merganetta: Torrent Duck

Anatinae: dabbling ducks and moa-nalos

The dabbling duck group, of worldwide distribution, were previously restricted to just one or two genera, but had been extended. Furthermore, while morphologically close to dabbling ducks, the mtDNA data indicates that a treatment as distinct subfamily is indeed correct, with the Tadorninae being actually closer to dabbling ducks than the diving ducks are:

Netta: Red-crested Pochard and allies (4 species, one probably extinct)

Aythya: pochards, scaups, etc (12 species)

Merginae: eiders, scoters, sawbills and other sea-ducks

There are 9 extant genera and some 20 living species; most of this group occur in the Northern Hemisphere, but a few (mostly extinct) mergansers in the Southern Hemisphere:

Chendytes: Diving-geese (prehistoric)

Polysticta: Steller's Eider

Somateria: eiders (3 species)

Histrionicus: Harlequin Duck (includes Ocyplonessa)

Camptorhynchus: Labrador Duck (extinct)

Melanitta: scoters (3 species)

Clangula: Long-tailed Duck (1 species)

Bucephala: goldeneyes (3 species)

Mergellus: Smew

Lophodytes: Hooded Merganser

Mergus: mergansers (5 living species, one extinct).

Oxyurinae: stiff-tail ducks

A small group of 3-4 genera, 2-3 of them monotypic, with 7-8 living species:

Oxyura: stiff-tailed ducks (5 living species)

Nomonyx: Masked Duck

Biziura: Musk Ducks (1 living species, provisionally placed here)

Heteronetta: Black-headed Duck

Unresolved

The largest degree of uncertainty concerns whether a number of genera are closer to the shelducks or to the dabbling ducks. See also the monotypic subfamilies above, and the "perching ducks"

Coscoroba: Coscoroba Swan - Anserinae or same subfamily as Cereopsis?

Cereopsis: Cape Barren Goose - Anserinae, Tadorninae, or own subfamily?

Cnemiornis: New Zealand geese (prehistoric) - as Cereopsis

Malacorhynchus: Pink-eared ducks (1 living species) - Tadorninae, Oxyurinae or Dendrocheninae?

Sarkidiornis: Comb Duck - Tadorninae or closer to dabbling ducks?

Tachyeres: steamer ducks (4 species) - Tadorninae or closer to dabbling ducks?

Cyanochen: Blue-winged Goose - Tadorninae or more distant clade?

Nettapus: pygmy geese (3 species) - Anatinae or part of Southern Hemisphere radiation?

Pteronetta: Hartlaub's Duck - traditionally dabbling ducks, but may be closer to Cyanochen

Cairina: Muscovy Duck and White-winged Wood Duck (2 species) - traditionally dabbling ducks, but may be paraphyletic, with one species in Tadorninae and the other closer to diving ducks

Aix: Mandarin Duck and Wood Duck (2 species) - dabbling ducks or Tadorninae?

Callonetta: Ringed Teal - dabbling ducks or Tadorninae?

Chenonetta: Maned Duck (1 living species) - dabbling ducks or Tadorninae? Includes Euryanas.

Marmaronetta: Marbled Duck - Formerly dabbling ducks; actually a diving duck or a distinct subfamily From subfossil bones found on Kauaʻi (Hawaiian Islands), two enigmatic waterfowl are known. The living and assignable prehistoric avifauna of the archipelago contains as Anseriformes Branta geese and their descendants, and the moa-nalos as mentioned above. The following taxa, although certainly new species, can't be assigned even to subfamily; that Kauaʻi is the oldest of the large Hawaiian Islands, meaning the species may have been evolving in isolation for nearly up to 10 mya (since the Late Miocene), doesn't help in determining their affinities:

Long-legged "Shelduck", Anatidae sp. et gen. indet.

Small-eyed Duck, Anatidae sp. et gen. indet. Similarly, Wetmore's Goose (Geochen rhuax) from the Big Island of Hawaiʻi, and a gigantic goose-like anatid from Oʻahu are known only from very incomplete and in the former case much damaged bone fragments. The former has been alleged to be a shelduck, but this was generally dismissed because of the damage to the material and biogeographic considerations. The long-legged Kauaʻi bird, however, hints at the possibility of a former tadornine presence on the archipelago.

Fossil Anatidae

The fossil record of anatids is extensive, but many prehistoric genera can't be unequivocally assigned to present-day subfamilies for the reasons given above. Some (such as Eonessa) seem to belong to subfamilies which are completely extinct. For prehistoric species of extant genera, see the respective genus accounts. Eonessinae - extinct ancient anatids

Eonessa (Eocene of Utah, USA) Dendrocheninae - a more advanced relative of the whistling-ducks or a more ancestral relative of stifftail ducks paralleling whistling-ducks; probably extinct but Malacorhynchus might belong here

Mionetta (Late Oligocene - Middle Miocene of C Europe) - includes "Anas" blanchardi, "A." consobrina, "A." natator, "Aythya" arvernensis

Manuherikia (Bathans Early/Middle Miocene of Otago, New Zealand)

Dendrochen (Early - Late? Miocene) - includes "Anas" integra, "A." oligocaena

Dendrocheninae gen. et sp. indet. (Late Miocene of Argentina) - dendrochenine? Anserinae

Cygnavus (Early Oligocene of Kazakhstan - Early Miocene of Germany)

Cygnopterus (Middle Oligocene of Belgium - Early Miocene of France) - sometmes included in Cygnavus

Megalodytes (Middle Miocene of California, USA)

"cf. Megalodytes" (Haraichi Middle Miocene of Annaka, Japan)

Anserobranta (Late Miocene of C Europe) - includes "Anas" robusta, validity doubtful

Presbychen (Temblor Late Miocene of Sharktooth Hill, USA)

Afrocygnus (Late Miocene ?- Early Pliocene of C Sahara, Africa)

Paracygnus (Kimball Late Pliocene of Nebraska, USA)

Eremochen (Pliocene) Tadorninae

Miotadorna (Bathans Early/Middle Miocene of Otago, New Zealand)

Tadorninae gen. et sp. indet. (Calvert Middle Miocene of Maryland, USA)

Balcanas (Early Pliocene of Dorkovo, Bulgaria) - may be synonym of Tadorna or even Common Shelduck

Anabernicula (Late Pliocene ?- Late Pleistocene of SW and W North America)

Brantadorna (Middle Pleistocene of Vallecito Creek, USA)

Nannonetta (Late Pleistocene of Peru) Anatinae

Sinanas (Middle Miocene)

Wasonaka (Middle Pliocene) incertae sedis

Guguschia (Oligocene of Azerbaijan) - Anserinae?

"Anas" luederitzensis (Kalahari Early Miocene of Lüderitzbucht, Namibia) - Anatinae?

Dunstanetta (Bathans Early/Middle Miocene of Otago, New Zealand)

Matanas (Bathans Early/Middle Miocene of Otago, New Zealand)

Anatidae gen. et sp. indet. MNZ S42797 (Bathans Early/Middle Miocene of Otago, New Zealand)

"Oxura" doksana (Early Miocene of Dolnice, Czechia)

"Aythya" chauvirae (Middle Miocene of Sansan, France and Credinţa, Romania) - 2 species

Anatidae gen. et sp. indet. (Middle Miocene of Nördlinger Ries, Germany) - tadornine?

Anatidae gen. et sp. indet. (Sajóvölgyi Middle Miocene of Mátraszõlõs, Hungary

"Anas" meyerii (Middle Miocene of Öhningen, Germany)

"Anas" velox (Middle - Late? Miocene of C Europe) - Anatinae? May include "A." meyerii

"Anas" isarensis (Late Miocene of Aumeister, Germany) - Anatinae?

?Anser scaldii (Late Miocene of Antwerp, Belgium) - anserine or tadornine

"Anas" eppelsheimensis (Early Pliocene of Eppelsheim, Germany) - Anatinae?

Aldabranas (Late Pleistocene of Aldabra, Indian Ocean) - Tadorninae or Anatinae

"Chenopis" nanus - at least 2 taxa, may be living species (Pleistocene of Australia) Putative or disputed prehistoric anatids are:

Romainvillia (Late Eocene/Early Oligocene) - Anseranatidae or Anatidae (own subfamily)

Loxornis (Deseado Early Oligocene of Argentina)

Paracygnopterus (Early Oligocene of Belgium and England)

Limicorallus (Indricotherium Middle Oligocene of Chelkar-Teniz, Kazakhstan)

Teleornis (Deseado Early Oligocene of Argentina)

Chenornis (Early Miocene) - Anserinae or Phalacrocoracidae

Paranyroca (Rosebud Early Miocene of Bennett County, USA) - distinct Anatinae subfamily or own family

Eoneornis (Miocene of Argentina) - Anatinae? A nomen dubium

Eutelornis (Miocene of Argentina) - Anatinae?

Footnotes

Further Information

Get more info on 'Anatidae'.

External Link Exchanges

Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:

<a href="http://anatidae.totallyexplained.com">Anatidae Totally Explained</a>

Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned.