my-server
← Wiki

Anseriformes

Anseriformes is an order of birds also known as waterfowl that comprises 178 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which includes the other 174 species of waterfowl, among them the ducks, geese, and swans. Most modern species in the order are highly adapted for an aquatic existence at the water surface. With the exception of screamers, males have penises, a trait that has been lost in the Neoaves, the clade consisting of all other modern birds except the galliformes and paleognaths. Due to their aquatic nature, most species are web-footed.

Evolution

Anseriformes are one of only two types of modern bird to be confirmed present during the Mesozoic alongside the other dinosaurs, and in fact were among the very few birds to survive their extinction, along with their cousins, the Galliformes. These two groups only occupied two ecological niches during the Mesozoic, living in water and on the ground, while the toothed Enantiornithes were the dominant birds that ruled the trees and air. The asteroid that ended the Mesozoic destroyed all trees as well as animals in the open, a condition that took centuries to recover from, with some models estimating that greenhouse effects lasted for thousands of years. The Anseriformes and Galliformes are thought to have survived in the cover of burrows and water, and not to have needed trees for food and reproduction.

The earliest known stem anseriform is the presbyornithid Teviornis from the Nemegt Formation of Mongolia. Some members apparently surviving the KT extinction event, including presbyornithids, thought to be the common ancestors of ducks, geese, swans, and screamers, the last group once thought to be Galliformes, but now genetically confirmed to be closely related to geese. The first known duck fossils start to appear about 34 million years ago.

Waterfowl are the best-known examples of sexually antagonistic genital coevolution in vertebrates, causing genital adaptations to coevolve in each sex to advance control over mating and fertilization. Sexually antagonistic coevolution (or SAC) occurs as a consequence of sexual conflict between males and females, resulting in coevolutionary process that reduce fit, or that functions to decrease ease of having sex.

Taxonomy

The Anseriformes and the Galliformes (pheasants, etc.) belong to a common group, the Galloanserae. They are the most primitive neognathous birds, and as such they should follow the Palaeognathae (ratites and tinamous) in bird classification systems. Several unusual extinct families of birds like the albatross-like pseudotooth birds and the giant flightless gastornithids and mihirungs have been found to be stem-anseriforms based on common features found in the skull region, beak physiology and pelvic region. The genus Vegavis for a while was found to be the earliest member of the anseriform crown group but a recent 2017 paper has found it to be just outside the crown group in the family Vegaviidae. However, the monophyly of Vegaviidae was questioned by Torres et al. (2025) who described a nearly complete skull of Vegavis in 2025, supporting its placement within crown group Anseriformes. However, Irazoqui et al. (2026) who redescribed this skull suggested that Vegavis can only be confidently placed as a neognath of uncertain affinities.

Below is the general consensus (prior to Torres et al. (2025)) of the phylogeny of anseriforms and their stem relatives.

Systematics

Anatidae is traditionally divided into subfamilies Anatinae and Anserinae. The systematics, especially regarding placement of some "odd" genera in the dabbling ducks or shelducks, is better resolved following the genetic analysis by Buckner et al. (2018); this has led to the reassignment of many genera to different tribes to which they were traditionally assigned. The list below follows the AviList, which has accepted these revisions: Note that AviList only includes extant and recently extinct genera:

  • Order Anseriformes
  • Suborder Anhimae <small>Wetmore & Miller 1926</small>
  • Family Anhimidae <small>Stejneger 1885</small> (screamers)
  • Genus Anhima <small>(Linnaeus 1766) Brisson 1760</small> (horned screamer)
  • Genus Chauna <small>Illiger 1811</small>
  • Suborder Anseres (true Anseriformes)
  • Family Anseranatidae <small>Sclater 1880</small>
  • Genus Anseranas <small>(Latham 1798) Lesson 1828</small> (magpie goose)
  • Family Anatidae <small>Leach 1820</small> (almost 150 species)
  • Subfamily Dendrocygninae <small>Reichenbach 1849–50</small>
  • Genus Thalassornis <small>Eyton 1838</small> (white-backed duck)
  • Genus Dendrocygna <small>Swainson 1837</small> (whistling ducks)
  • Subfamily Stictonettinae
  • Genus Biziura <small>Stephens 1824</small> (musk ducks)
  • Genus Nettapus <small>von Brandt 1836</small> (pygmy geese)
  • Genus Stictonetta <small>(Gould 1841) Reichenbach 1853</small> (freckled duck)
  • Subfamily Oxyurinae <small>Swainson 1831</small> (stiff-tailed ducks and allies)
  • Genus Heteronetta <small>(Merrem 1841) Salvadori 1865</small> (black-headed duck)
  • Genus Nomonyx <small>(Linnaeus 1766) Ridgway 1880</small> (masked duck)
  • Genus Oxyura <small>Bonaparte 1828</small>
  • Subfamily Anserinae <small>Vigors 1825 sensu Livezey 1996</small> (swans and geese)
  • Genus Plectropterus <small>(Linnaeus 1766) </small> (spur-winged goose)
  • Genus Malacorhynchus <small>Swainson 1831</small> (pink-eared duck)
  • Genus Coscoroba <small>(Molina 1782) Reichenbach 1853</small> (Coscoroba swan)
  • Genus Cereopsis <small>Latham 1801</small> (Cape Barren goose)
  • Genus Cygnus <small>Garsault 1764</small>
  • Genus Branta <small>Scopoli 1769</small>
  • Genus Anser <small>Brisson 1760</small>
  • Subfamily Anatinae <small>Vigors 1825 sensu Livezey 1996</small>
  • Tribe Tadornini <small>Reichenbach 1849–50</small> (shelducks and sheldgeese)
  • Genus Merganetta <small>Gould 1842</small> (Torrent duck)
  • Genus Callonetta <small>Delacour 1936</small> (ringed teal)
  • Genus Cairina <small>(Linnaeus 1758) Fleming 1822</small> (Muscovy duck)
  • Genus Aix <small>Boie 1828</small>
  • Genus Neochen <small>Oberholser 1918</small>
  • Genus Chloephaga <small>Eyton 1838</small>
  • Genus Radjah <small>Reichenbach, 1853</small>
  • Genus Alopochen <small>Stejneger 1885</small>
  • Genus Tadorna <small>Boie 1822</small>
  • Tribe Mergini <small>Rafinesque 1815</small> (eiders, scoters, mergansers and other sea-ducks)
  • Genus Clangula <small>Leach 1819</small> (long-tailed duck)
  • Genus Polysticta stelleri <small>(Pallas 1769) Eyton 1836</small> (Steller's eider)
  • Genus †Camptorhynchus <small>(Gmelin 1789) Bonaparte 1838</small> (Labrador duck)
  • Genus Somateria <small>Leach 1819</small> (eiders)
  • Genus Histrionicus <small>Lesson 1828</small> (harlequin duck)
  • Genus Melanitta <small>Boie 1822</small> (scoters)
  • Genus Bucephala <small>Baird 1858</small>
  • Genus Mergellus <small>Selby 1840</small> (Smew)
  • Genus Lophodytes <small>(Linnaeus 1758) Reichenbach 1853</small> (hooded merganser)
  • Genus Mergus <small>Linnaeus 1758 non Brisson 1760</small>
  • Tribe Aythyini <small>Delacour and Mayr, 1945</small> (diving ducks)
  • Genus Sarkidiornis <small>Eyton 1838</small>
  • Genus Hymenolaimus <small>(Gmelin 1789) Gray 1843</small> (blue duck)
  • Genus Chenonetta <small>von Brandt 1836</small> (Australian wood duck)
  • Genus Cyanochen <small>(Rüppell 1845) Bonaparte 1856</small> (blue-winged goose)
  • Genus Pteronetta <small>(Cassin 1860) Salvadori 1895</small> (Hartlaub's duck)
  • Genus Marmaronetta <small>(Ménétries 1832) Reichenbach 1853</small> (marbled duck)
  • Genus Asarcornis <small>(Müller 1842) Salvadori 1895</small> (white-winged duck)
  • Genus ?†Rhodonessa <small>Reichenbach 1853</small> (pink-headed duck)
  • Genus Netta <small>Kaup 1829</small>
  • Genus Aythya <small>Boie 1822</small>
  • Tribe Anatini <small>Vigors 1825 sensu Livezey 1996</small> (dabbling ducks and moa-nalos)
  • Genus Salvadorina <small>Rothschild & Hartert 1894</small> (Salvadori's teal)
  • Genus Lophonetta <small>(King 1828) Riley 1914</small> (crested duck)
  • Genus Speculanas <small>(King 1828) von Boetticher 1929</small> (bronze-winged duck)
  • Genus Amazonetta <small>(Gmelin 1789) von Boetticher 1929</small> (Brazilian teal)
  • Genus Tachyeres <small>Owen 1875</small> (steamer ducks)
  • Genus Sibirionetta <small>(Georgi 1775)</small> (Baikal teal)
  • Genus Spatula <small>Boie 1822</small>
  • Genus Mareca <small>(Stephens 1824)</small>
  • Genus Anas <small>Linnaeus 1758</small>

Extinct Anseriformes (fossil & subfossil)

Early basal Anseriformes:

  • ?†Conflicto <small>Claudia P. Tambussi et al. 2019</small> &ndash; tentatively placed here; possibly family Conflictonidae
  • †Anatalavis <small>Olson & Parris 1987</small> (Late Cretaceous/Early Paleocene – Early Eocene) &ndash; including Nettapterornis; may belong in Anseranatidae or Conflictonidae
  • †Naranbulagornis <small>Zelenkov 2019</small>
  • †Anachronornis
  • †Paakniwatavis <small>Musser & Clarke 2024</small>

Assigned to named families and subfamilies:

  • Family Anhimidae <small>Stejneger 1885</small>
  • Genus †Chaunoides <small>Alvarenga 1999</small>
  • Family Anseranatidae <small>Sclater 1880</small>
  • Genus †Anserpica <small>Mourer-Chauviré, Berthet & Hugueney 2004</small>
  • Genus †Eoanseranas <small>Worthy & Scanlon 2009</small> (hand's dawn magpie goose)
  • Family †Presbyornithidae? <small>Wetmore 1926</small> (wading-"geese")
  • Genus †Teviornis <small>Kuročkin, Dyke & Karhu 2002</small>
  • Genus †Telmabates <small>Howard 1955</small>
  • Genus †Presbyornis <small>Wetmore 1926</small>
  • Genus †Wilaru <small>Boles et al. 2013</small>
  • Genus †Bumbalavis <small>Zelenkov 2021</small>
  • Genus †Murgonornis <small>Worthy et al. 2023</small>
  • Family †Paranyrocidae <small>Miller & Compton 1939</small>
  • Genus †Paranyroca <small>Miller & Compton 1939</small> (Rosebud Early Miocene of Bennett County, USA)
  • Family Anatidae
  • Genus †Garganornis ballmanni <small>Meijer 2014</small>
  • Subfamily †Romainvilliinae <small>Lambrecht 1933</small>
  • Genus †Romainvillia <small>Lebedinský 1927</small> (Late Eocene/Early Oligocene)
  • Genus †Saintandrea <small>Mayr & De Pietri 2013</small>
  • Subfamily †Dendrocheninae <small>Livezey & Martin 1988</small>
  • Genus †Dendrochen <small>Miller 1944</small>
  • Genus †Manuherikia <small>Worthy et al. 2007</small>
  • Genus †Mionetta <small>Livezey & Martin 1988</small>
  • Subfamily Oxyurinae <small>Swainson 1831</small> (stiff-tailed ducks and allies)
  • Genus †Anabernicula <small>Ross 1935</small>
  • Subfamily Anserinae <small>Vigors 1825 sensu Livezey 1996</small> (swans and geese)
  • Genus †Anserobranta <small>Kuročkin & Ganya 1972</small>
  • Genus †Asiavis <small>Nesov 1986</small>
  • Genus †"Chenopis" <small>De Vis 1905</small>
  • Genus †Cygnavus <small>Lambrecht 1931</small>
  • Genus †Cygnopterus <small>Lambrecht 1931</small>
  • Genus †Eremochen <small>Brodkorb 1961</small>
  • Genus †Megalodytes <small>Howard 1992</small>
  • Genus †Annakacygna <small>Matsuoka & Hasegawa 2022</small>
  • Genus †Paracygnus <small>Short 1969</small>
  • Genus †Presbychen <small>Wetmore 1930</small>
  • Genus †Cnemiornis <small>Owen 1866</small> (New Zealand geese)
  • Genus †Afrocygnus <small>Louchart et al. 2005</small>
  • Tribe Tadornini <small>Reichenbach 1849–50</small> (shelducks and sheldgeese)
  • Genus †Australotadorna <small>Worthy 2009</small>
  • Genus †Brantadorna <small>Howard 1964</small>
  • Genus †Centrornis <small>Andrews 1897</small> (Malagasy sheldgoose)
  • Genus †Miotadorna <small>Worthy et al. 2007</small> (St. Bathans shelduck)
  • Genus †Nannonetta <small>Campbell 1979</small>
  • Genus †Pleistoanser <small>Agnolín 2006</small>
  • Genus †Balcanas <small>Boev 1998</small>
  • Tribe Anatini <small>Vigors 1825</small> (dabbling ducks and moa-nalos)
  • Genus †Zqueheanas <small>Agnolin et al 2025</small>
  • Genus †Dunstanetta <small>Worthy et al. 2007</small> (Johnstone's duck)
  • Genus †Lavadytis <small>Stidham & Hilton 2015</small>
  • Genus †Pinpanetta <small>Worthy 2009</small>
  • Genus †Tirarinetta <small>Worthy 2008</small>
  • Genus †Chendytes <small>Miller 1925</small>
  • Genus †Matanas <small>Worthy et al. 2007</small> (Enright's duck)
  • Genus †Shiriyanetta <small>Watanabe & Matsuoka 2015</small>

Unassigned extinct Anseriformes:

In addition, a considerable number of mainly Late Cretaceous and Paleogene fossils have been described where it is uncertain whether or not they are anseriforms. This is because almost all orders of aquatic birds living today either originated or underwent a major radiation during that time, making it hard to decide whether some waterbird-like bone belongs into this family or is the product of parallel evolution in a different lineage due to adaptive pressures.

  • "Presbyornithidae" gen. et sp. indet. (Barun Goyot Late Cretaceous of Udan Sayr, Mongolia) – Presbyornithidae?
  • UCMP 117599 (Hell Creek Late Cretaceous of Bug Creek West, USA)
  • Petropluvialis (Late Eocene of England) – may be same as Palaeopapia
  • Agnopterus (Late Eocene – Late Oligocene of Europe) – includes Cygnopterus lambrechti
  • "Headonornis hantoniensis" BMNH PAL 4989 (Hampstead Early Oligocene of Isle of Wight, England) – formerly "Ptenornis"
  • Palaeopapia (Hampstead Early Oligocene of Isle of Wight, England)
  • "Anas" creccoides (Early/Middle Oligocene of Belgium)
  • "Anas" skalicensis (Early Miocene of "Skalitz", Czech Republic)
  • "Anas" risgoviensis (Late Miocene of Bavaria, Germany)
  • †"Anas" meyerii <small>Milne-Edwards 1867</small> [Aythya meyerii <small>(Milne-Edwards 1867) Brodkorb 1964</small>]
  • †Eonessa anaticula <small>Wetmore 1938</small> {Eonessinae <small>Wetmore 1938</small>}

Molecular studies

Studies of the mitochondrial DNA suggest the existence of four branches – Anseranatidae, Dendrocygninae, Anserinae and Anatinae – with Dendrocygninae being a subfamily within the family Anatidae and Anseranatidae representing an independent family. The clade Somaterini has a single genus Somateria.

See also

References

Cited texts

  • Murray, P. F. & Vickers-Rich, P. (2004) Magnificent Mihirungs: The Colossal Flightless Birds of the Australian Dreamtime. Indiana University Press.