Anseriformes is an order of

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s also known as waterfowl that comprises about 180 living

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and

Anatidae The Anatidae are the biological family (biology), family of water birds that includes ducks, goose, geese, and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica. These birds are adapted f ...

, the largest family, which includes over 170 species of waterfowl, among them the

duck Duck is the common name for numerous species of waterfowl in the family (biology), family Anatidae. Ducks are generally smaller and shorter-necked than swans and goose, geese, which are members of the same family. Divided among several subfam ...

s, geese, and

swan Swans are birds of the genus ''Cygnus'' within the family Anatidae. The swans' closest relatives include the goose, geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe (biology) ...

s. 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 Neoaves is a clade that consists of all modern bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard ...

, the clade consisting of all other modern birds except the

galliformes Galliformes is an order (biology), order of heavy-bodied ground-feeding birds that includes turkey (bird), turkeys, chickens, Old World quail, quail, and other landfowl. Gallinaceous birds, as they are called, are important in their ecosystems ...

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 The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

alongside the other dinosaurs, and in fact were among the very few birds to survive their extinction, along with their cousins, the

Galliformes Galliformes is an order (biology), order of heavy-bodied ground-feeding birds that includes turkey (bird), turkeys, chickens, Old World quail, quail, and other landfowl. Gallinaceous birds, as they are called, are important in their ecosystems ...

. These two groups only occupied two ecological niches during the Mesozoic, living in water and on the ground, while the toothed

Enantiornithes The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct Avialae, avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teet ...

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. 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 Mongolia is a landlocked country in East Asia, bordered by Russia to the north and China to the south and southeast. It covers an area of , with a population of 3.5 million, making it the world's List of countries and dependencies by po ...

. 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

( pheasants, etc.) belong to a common group, the Galloanserae. They are the most primitive neognathous birds, and as such they should follow the

Palaeognathae Palaeognathae (; ) is an infraclass of birds, called paleognaths or palaeognaths, within the class Aves of the clade Archosauria. It is one of the two extant taxon, extant infraclasses of birds, the other being Neognathae, both of which form Neo ...

( 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 other researchers who described a nearly complete skull of ''Vegavis'' in 2025, supporting its placement within crown group Anseriformes. Below is the general consensus (prior to Torres et al. (2025)) of the phylogeny of anseriforms and their stem relatives.

Systematics

systematics, especially regarding placement of some "odd" genera in the dabbling ducks or shelducks, is not fully resolved. See the Anatidae article for more information, and for alternate taxonomic approaches. Anatidae is traditionally divided into subfamilies Anatinae and Anserinae. The Anatinae consists of tribes Anatini, Aythyini, Mergini and Tadornini. The higher-order classification below follows a

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

analysis performed by Mikko's Phylogeny ArchiveMikko's Phylogeny Archiv

and John Boyd's website.John Boyd's websit

* Order Anseriformes ** ?†'' Conflicto antarcticus, Conflicto'' Claudia P. Tambussi et al. 2019 – tentatively placed here; possibly family Conflictonidae ** †'' Anatalavis'' Olson & Parris 1987 (Late Cretaceous/Early Paleocene – Early Eocene) – including ''Nettapterornis''; may belong in Anseranatidae or Conflictonidae ** †'' Naranbulagornis'' Zelenkov 2019 ** †'' Anachronornis'' ** †'' Paakniwatavis'' Musser & Clarke 2024 ** Suborder Anhimae Wetmore & Miller 1926 *** Genus †'' Chaunoides'' de Alvarenga 1999 *** Family Anhimidae Stejneger 1885 (screamers) **** Genus '' Anhima'' (Linnaeus 1766) Brisson 1760 (horned screamer) **** Genus '' Chauna'' Illiger 1811 ** Suborder Anseres (true Anseriformes) *** Superfamily Anseranatoidea **** Family Anseranatidae Sclater 1880 ***** Genus †'' Anserpica'' Mourer-Chauviré, Berthet & Hugueney 2004 ***** Genus †'' Eoanseranas'' Worthy & Scanlon 2009 (hand's dawn magpie goose) ***** Genus '' Anseranas'' (Latham 1798) Lesson 1828 (magpie goose) *** Superfamily Anatoidea **** Family † Presbyornithidae? Wetmore 1926 (wading-"geese") ***** Genus †'' Teviornis'' Kuročkin, Dyke & Karhu 2002 ***** Genus †'' Telmabates'' Howard 1955 ***** Genus †'' Presbyornis'' Wetmore 1926 ***** Genus †'' Wilaru'' Boles et al. 2013 ***** Genus †'' Bumbalavis'' Zelenkov 2021 ***** Genus †'' Murgonornis'' Worthy et al. 2023 **** Family † Paranyrocidae Miller & Compton 1939 ***** Genus †'' Paranyroca'' Miller & Compton 1939 (Rosebud Early Miocene of Bennett County, USA) **** Family

Leach 1820 (almost 150 species) ***** Genus †'' Garganornis ballmanni'' Meijer 2014 ***** Subfamily † Romainvilliinae Lambrecht 1933 ****** Genus †'' Romainvillia'' Lebedinský 1927 (Late Eocene/Early Oligocene) ****** Genus †'' Saintandrea'' Mayr & De Pietri 2013 ***** Subfamily Dendrocygninae Reichenbach 1849–50 ****** Genus ''

Dendrocygna The whistling ducks or tree ducks are a subfamily, Dendrocygninae, of the duck, goose and swan family of birds, Anatidae. In other Taxonomy (biology), taxonomic schemes, they are considered a separate family (biology), family, Dendrocygnidae. S ...

'' Swainson 1837 (whistling ducks) ****** Genus '' Thalassornis'' Eyton 1838 (white-backed duck) ***** Subfamily † Dendrocheninae Livezey & Martin 1988 ****** Genus †'' Dendrochen'' Miller 1944 ****** Genus †'' Manuherikia'' Worthy et al. 2007 ****** Genus †'' Mionetta'' Livezey & Martin 1988 ***** Subfamily Stictonettinae ****** Genus '' Stictonetta'' (Gould 1841) Reichenbach 1853 (freckled duck) ***** Subfamily

Anserinae The Anserinae are a subfamily in the waterfowl family Anatidae. It includes the swans and the true Goose, geese. Under alternative systematics, systematical concepts (see e.g., Terres & NAS, 1991), it is split into two subfamilies, the Anserina ...

Vigors 1825 sensu Livezey 1996 (swans and geese) ****** Genus †'' Anserobranta'' Kuročkin & Ganya 1972 ****** Genus †'' Asiavis'' Nesov 1986 ****** Genus †'' “Chenopis”'' De Vis 1905 ****** Genus †'' Cygnavus'' Lambrecht 1931 ****** Genus †'' Cygnopterus'' Lambrecht 1931 ****** Genus †'' Eremochen'' Brodkorb 1961 ****** Genus †'' Megalodytes'' Howard 1992 ****** Genus †'' Annakacygna'' Matsuoka & Hasegawa 2022 ****** Genus †'' Paracygnus'' Short 1969 ****** Genus †'' Presbychen'' Wetmore 1930 ****** Genus †'' Cnemiornis'' Owen 1866 (New Zealand geese) ****** Genus †'' Afrocygnus'' Louchart et al. 2005 ****** Genus '' Coscoroba'' (Molina 1782) Reichenbach 1853 (Coscoroba swan) ****** Genus '' Cereopsis'' Latham 1801 (Cape Barren goose) ****** Genus '' Cygnus'' Garsault 1764 ****** Genus '' Branta'' Scopoli 1769 ****** Tribe Anserini Vigors 1825 ******* Genus '' Anser'' Brisson 1760 ***** Subfamily

Tadorninae The Tadornini is a biological tribe that includes the shelducks and sheldgeese, which is placed in subfamily Anatinae of family Anatinae, which includes the ducks and most duck-like waterfowl such as the geese and swans. It has been treated a ...

Reichenbach 1849–50 (shelducks and sheldgeese) ****** Genus †'' Australotadorna'' Worthy 2009 ****** Genus †'' Brantadorna'' Howard 1964 ****** Genus †'' Centrornis'' Andrews 1897 (Malagasy sheldgoose) ****** Genus †'' Miotadorna'' Worthy et al. 2007 (St. Bathans shelduck) ****** Genus †'' Nannonetta'' Campbell 1979 ****** Genus †'' Pleistoanser'' Agnolín 2006 ****** Genus '' Plectropterus'' (Linnaeus 1766) (spur-winged goose) ****** Genus '' Merganetta'' Gould 1842 (Torrent duck) ****** Genus '' Chloephaga'' Eyton 1838 ****** Genus '' Neochen'' Oberholser 1918 ****** Genus '' Cyanochen'' (Rüppell 1845) Bonaparte 1856 (blue-winged goose) ****** Genus '' Tadorna'' Boie 1822 ****** Genus †'' Balcanas'' Boev 1998 ****** Genus '' Radjah'' Reichenbach, 1853 ****** Genus '' Alopochen'' Stejneger 1885 ****** Genus '' Cairina'' (Linnaeus 1758) Fleming 1822 (Muscovy duck) ****** Genus '' Hymenolaimus'' (Gmelin 1789) Gray 1843 (blue duck) ****** Genus '' Sarkidiornis'' Eyton 1838 ****** Genus '' Tachyeres'' Owen 1875 (steamer ducks) ****** Genus †'' Zqueheanas'' Agnolin et al 2025 ***** Subfamily

Anatinae The Anatinae are a subfamily 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-nalo, a ...

Vigors 1825 sensu Livezey 1996 ****** Genus †'' Dunstanetta'' Worthy et al. 2007 (Johnstone's duck) ****** Genus †'' Lavadytis'' Stidham & Hilton 2015 ****** Genus †'' Pinpanetta'' Worthy 2009 ****** Genus †'' Tirarinetta'' Worthy 2008 ****** Genus '' Aix'' Boie 1828 ****** Genus '' Callonetta'' Delacour 1936 (ringed teal) ****** Genus '' Chenonetta'' von Brandt 1836 (Australian wood duck) ****** Genus '' Biziura'' Stephens 1824 (musk ducks) ****** Genus '' Pteronetta'' (Cassin 1860) Salvadori 1895 (Hartlaub's duck) ****** Genus '' Marmaronetta'' (Ménétries 1832) Reichenbach 1853 (marbled duck) ****** Genus '' Asarcornis'' (Müller 1842) Salvadori 1895 (white-winged duck) ****** Genus '' Netta'' Kaup 1829 ****** Genus '' Lophonetta'' (King 1828) Riley 1914 (crested duck) ****** Genus '' Amazonetta'' (Gmelin 1789) von Boetticher 1929 (Brazilian teal) ****** Tribe Oxyurini Swainson 1831 (stiff-tailed ducks and allies) ****** Genus †'' Anabernicula'' Ross 1935 ******* Genus '' Heteronetta'' (Merrem 1841) Salvadori 1865 (black-headed duck) ******* Genus '' Nomonyx'' (Linnaeus 1766) Ridgway 1880 (masked duck) ******* Genus '' Oxyura'' Bonaparte 1828 ****** Genus '' Nettapus'' von Brandt 1836 (pygmy geese) ****** Genus '' Malacorhynchus'' Swainson 1831 (pink-eared duck) ****** Genus '' Salvadorina'' Rothschild & Hartert 1894 (Salvadori's teal) ****** Genus '' Speculanas'' (King 1828) von Boetticher 1929 (bronze-winged duck) ****** Tribe Mergini Rafinesque 1815 (eiders, scoters, mergansers and other sea-ducks) ******* Genus †'' Chendytes'' Miller 1925 ******* Genus †'' Shiriyanetta'' Watanabe & Matsuoka 2015 ******* Genus †'' Camptorhynchus'' (Gmelin 1789) Bonaparte 1838 (Labrador duck) ******* Genus '' Histrionicus'' Lesson 1828 (harlequin duck) ******* Genus '' Clangula'' Leach 1819 (long-tailed duck) ******* Genus '' Polysticta stelleri'' (Pallas 1769) Eyton 1836 (Steller's eider) ******* Genus '' Somateria'' Leach 1819 (eiders) ******* Genus '' Melanitta'' Boie 1822 (scoters) ******* Genus '' Bucephala'' Baird 1858 ******* Genus '' Mergellus'' Selby 1840 (Smew) ******* Genus '' Lophodytes'' (Linnaeus 1758) Reichenbach 1853 (hooded merganser) ******* Genus '' Mergus'' Linnaeus 1758 non Brisson 1760 ****** Tribe Anatini Vigors 1825 sensu Livezey 1996 (dabbling ducks and moa-nalos) ******* Genus †'' Matanas'' Worthy et al. 2007 (Enright's duck) ******* Genus '' Anas'' Linnaeus 1758 ******* Genus '' Sibirionetta'' (Georgi 1775) (Baikal teal) ******* Genus '' Mareca'' (Stephens 1824) ******* Genus ''

Spatula A spatula is a broad, flat, flexible blade used to mix, spread and lift material including foods, drugs, plaster and paints. In medical applications, "spatula" may also be used synonymously with tongue depressor. The word ''spatula'' derives ...

'' Boie 1822 ****** Tribe Aythyini Delacour and Mayr, 1945 (diving ducks) ******* Genus '' Aythya'' Boie 1822 Unassigned Anatidae: * †'' "Anas" albae'' Jánossy 1979 ''Mergus''* †'' "Anas" amotape'' Campbell 1979 * †'' "Anas" isarensis'' Lambrecht 1933 * †'' "Anas" luederitzensis'' Lambrecht 1929 * †'' "Anas" sanctaehelenae'' Campbell 1979 * †'' "Anas" eppelsheimensis'' Lambrecht 1933 * †'' Aldabranas cabri'' Harrison & Walker 1978 * †'' Ankonetta larriestrai'' Cenizo & Agnolín 2010 * †'' Bambolinetta'' (Portis 1884) Mayr & Pavia 2014 'Anas lignitifila'' Portis 1884">Anas_lignitifila.html" ;"title="' ' Cayaoa bruneti'' Tonni 1979 * †''Chelychelynechen">Anas lignitifila">'Anas lignitifila'' Portis 1884* †''Cayaoa">Cayaoa bruneti'' Tonni 1979 * †'' Chenoanas deserta'' Zelenkov 2012 * †''Cygnopterus">Cygnopterus alphonsi'' Cheneval 1984 [non ''Cygnavus senckenbergi">Chenoanas">Chenoanas deserta'' Zelenkov 2012 * †''Cygnopterus">Cygnopterus alphonsi'' Cheneval 1984 [non ''Cygnavus senckenbergi'' Mlíkovský 2002] * †''Eoneornis'' Ameghino 1891 (nomen dubium) * †''Eutelornis'' Ameghino 1891 (nomen dubium) * †''Gracanicanetta'' Bochenski et al 2025 * †'' Helonetta brodkorbi'' Emslie 1992 * †'' Heteroanser vicinus'' (Kuročkin 1976) Zelenkov 2012 'Heterochen vicinus'' Kuročkin 1976; ''Anser vicinus">Heterochen_vicinus.html" ;"title="'Heterochen vicinus">'Heterochen vicinus'' Kuročkin 1976; ''Anser vicinus'' (Kuročkin 1976) Mlíkovský & Švec 1986] * †''Kustokazanser'' (Zelenkov 2024) * †''Lavanttalornis'' Bochenski et al. 2023 * †''Loxornis, Loxornis clivus'' Ameghino 1894 * '' Metopiana'' Bonaparte 1856 'Metopias'' Heine & Reichenow 1890; ''Phoeonetta">Metopias.html" ;"title="'Metopias">'Metopias'' Heine & Reichenow 1890; ''Phoeonetta'' Delacour 1937; ''Netta (Phoeoaythia)'' Delacour 1937] * †''Mioquerquedula, Mioquerquedula minutissima'' Zelenkov & Kuročkin 2012 [''Anas velox'' Milne-Edwards 1867] * †''Nogusunna, Nogusunna conflictoides'' Zelenkov 2011 * †'' Oxyura doksana, "Oxyura" doksana'' Mlíkovský 2002 * †'' Paracygnopterus scotti'' Harrison & Walker 1979 * †'' Proanser major'' Umanskaya 1979 * †'' Protomelanitta'' Zelenkov 2011 * †'' Ptaiochen'' Olson & James 1991 (small-billed moa-nalo) * †'' Sharganetta mongolica'' Zelenkov 2011 * †'' Sinanas'' Yeh 1980 * †'' Talpanas'' Olson & James 2009 (Kaua'i mole duck) * †'' Teleornis'' Ameghino 1899 * †'' Thambetochen'' Olson & Wetmore 1976 * †'' Uyrekura'' Zelenkov 2023 * †'' Wasonaka'' Howard 1966 In addition, a considerable number of mainly Late Cretaceous and

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

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 In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. This includes: * ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...

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'' Milne-Edwards 1867 'Aythya meyerii'' (Milne-Edwards 1867) Brodkorb 1964">Aythya_meyerii.html" ;"title="' 'Aythya meyerii'' (Milne-Edwards 1867) Brodkorb 1964* †''Eonessa">Eonessa anaticula'' Wetmore 1938

Phylogeny

Living Anseriformes based on the work by John Boyd. Image:Zoo América-2897-Chauna torquata.jpg"> Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

Evolution

Taxonomy

Systematics

Phylogeny

Molecular studies

See also

References

Cited texts