''Anas'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

dabbling duck 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 yo ...

s. It includes the pintails, most teals, and the

mallard The mallard () or wild duck (''Anas platyrhynchos'') is a dabbling duck that breeds throughout the temperate and subtropical Americas, Eurasia, and North Africa, and has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Arge ...

and its close relatives. It formerly included additional species but following the publication of a

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

study in 2009 the genus was split into four separate genera. The genus now contains 31 living species. The name ''Anas'' is the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...

for "duck".

Systematics

The

''Anas'' was introduced by the Swedish naturalist

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, ...

in 1758 in the tenth edition of his ''

Systema Naturae ' (originally in Latin written ' with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial nom ...

''. ''Anas'' is the Latin word for a duck. The genus formerly included additional species. In 2009 a large molecular phylogentic study was published that compared mitochondrial DNA sequences from ducks, geese and swans in the family

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

. The results confirmed some of the conclusions of earlier smaller studies and indicated that the genus as then defined was non-monophyletic. Based on the results of this study, ''Anas'' was split into four proposed monophyletic genera with five species including the wigeons transferred to the resurrected genus '' Mareca'', ten species including the shovelers and some teals transferred to the resurrected genus '' Spatula'' and the Baikal teal placed in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

genus '' Sibirionetta''.

Species

There are 31 extant species recognised in the genus: Extinct Species * Mariana mallard, ''Anas oustaleti'' * Mascarene teal, ''Anas theodori'' * Chatham Island Duck, ''Anas chathamica'' Formerly placed in ''Anas'': * Bronze-winged duck, ''Speculanas specularis'' * Crested duck, ''Lophonetta specularioides'' * Baikal teal ''Sibirionetta formosa'' * Salvadori's teal, ''Salvadorina waigiuensis'' *species in the genus '' Mareca'', the wigeons (including the

gadwall The gadwall (''Mareca strepera'') is a common and widespread dabbling duck in the family Anatidae. Taxonomy The gadwall was first described by Carl Linnaeus in his landmark 1758 10th edition of ''Systema Naturae''. DNA studies have shown th ...

and the falcated duck) *species in the genus '' Spatula'', the shovelers and related teals

Phylogeny

Cladogram based on the analysis of Gonzalez and colleagues published in 2009.

Fossil record

Anas blanchardi aquitaniano st gerard les puys

A number of

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

species of ''Anas'' have been described. Their relationships are often undetermined: * †''Anas'' sp. (Late Miocene of China) * †''Anas'' sp. (mid-sized species from the Late Miocene of Rudabánya, Hungary) * †''Anas amotape'' (Campbell 1979) (Talara Tar Seeps Late Pleistocene of Peru) * †''Anas bunkeri'' (Wetmore 1944) (Early -? Middle Pliocene – Early Pleistocene of WC USA) – ''Nettion'' red-and-green head clade? * †''Anas cheuen'' Agnolín 2006 (Early-Middle Pleistocene of Argentina) – ''Dafila''? * †''Anas elapsum'' (Chinchilla Late Pleistocene of Condamine River, Australia) ("Nettion") * †''Anas ganii'' (Late Pliocene/Early Pleistocene of Tchichmiknaia, Moldavia) * †''Anas gracilipes'' (Late Pleistocene of Australia) (likely junior synonym of '' Anas castanea'') * †''Anas greeni'' (Brodkorb 1964) (Ash Hollow Late Miocene?/Early Pliocene of South Dakota, USA) – ''Nettion'' red-and-green head clade (doubtful)? * †''Anas itchtucknee'' McCoy 1963 * †''Anas kisatibiensis'' 'Anser kisatibiensis''(Early Pliocene of Kisatibi, Georgia) * †''Anas kurochkini'' Zelenkov & Panteleyev 2015 * †''Anas lambrechti'' 'Archaeoquerquedula lambrechti'' Stephens; ''Querquedula lambrechti''; ''Archeoquerquedula'' Spillman 1942* †''Anas ogallalae'' (Brodkorb 1962) (Ogallala Late Miocene?/Early Pliocene of Kansas, USA) – ''Nettion'' red-and-green head clade (doubtful)? *

Bermuda Islands flightless duck The Bermuda flightless duck (''Anas pachyscelus'') is an extinct species of flightless duck which was endemic to the island of Bermuda in the North Atlantic Ocean. It was described in 1960 by Alexander Wetmore, from Late Pleistocene subfoss ...

†''Anas pachyscelus'' Wetmore 1960 (Shore Hills Late Pleistocene of Bermuda, W Atlantic) * †''Anas pullulans'' (Juntura Late Miocene?/Early Pliocene of Juntura, Malheur County,

Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idah ...

, USA) – ''Punanetta''? * †''Anas schneideri'' Emslie 1985 (Late Pleistocene of Little Box Elder Cave, USA) * †''Anas sansaniensis'' Milne-Edwards 1868 'Dendrocygna sansaniensis'' (Milne-Edwards 1868) Mlíkovský 1988* †''Anas strenuum'' (Late Pleistocene of Patteramordu, Australia) ("Nettion") Several prehistoric waterfowl supposedly part of the ''Anas'' assemblage are nowadays not placed in this genus anymore, at least not with certainty: * †''"Anas" basaltica'' (Late Oligocene of "Warnsdorf", Czech Republic) is apparently an indeterminate

heron The herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera ''Botaurus'' and ''Ixobrychu ...

. * †''"Anas" blanchardi'', ''"A." consobrina'', ''"A." natator'' are now in '' Mionetta'' * †''"Anas" creccoides'' (Early-mid Oligocene of Belgium), ''"A." risgoviensis'' (Late Miocene of Bavaria, Germany) and ''"A." skalicensis'' (Early Miocene of "Skalitz", Czech Republic), though possibly anseriform, cannot be placed with any certainty among modern birds at all. * †''"Anas" albae'' (Late Miocene of Polgárdi, Hungary), ''"A." eppelsheimensis'' (Early Pliocene of Eppelsheim, Germany), ''"A." isarensis'' (Late Miocene of Aumeister, Germany) and ''"A." luederitzensis'' (Kalahari Early Miocene of Lüderitzbucht, Namibia) are apparently

of unclear affiliations; the first might be a seaduck. * †''"Anas" integra'' and ''"A." oligocaena'' are now in '' Dendrochen''. * †''"Anas" lignitifila'' from the Late Miocene of Tuscana has been moved to its own genus, '' Bambolinetta'', being a highly unusual marine waterfowl. * †''"Anas" robusta'' is now tentatively placed in '' Anserobranta''. * †''"Anas" velox'' (Middle – Late? Miocene of C Europe) and ''"A." meyerii'' (Middle Miocene of Öhningen, Germany; possibly the same species) do not seem to belong ''Anas'', and they may be ancestral dabbling ducks. Highly problematic, albeit in a theoretical sense, is the placement of the

moa-nalo The moa-nalo are a group of extinct aberrant, goose-like ducks that lived on the larger Hawaiian Islands, except Hawaii itself, in the Pacific. They were the major herbivores on most of these islands until they became extinct after human settl ...

s. These are in may be derived from a common ancestor of the Pacific black duck, the Laysan duck, and the

, and an unknown amount of other lineages. Phylogenetically, they may even form a clade within the traditional genus ''Anas''. However, as opposed to these species – which are well representative of dabbling ducks in general – the moa-nalos are the most radical departure from the anseriform bauplan known to science. This illustrates that in a truly evolutionary sense, a strictly phylogenetic taxonomy may be difficult to apply.

References

External links