Anas

Systematics

The genus Anas was introduced by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae. Anas is the Latin word for a duck. The genus formerly included additional species. In 2009 a large molecular phylogenetic study was published that compared mitochondrial DNA sequences from ducks, geese and swans in the family Anatidae. 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 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 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

A number of fossil 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 ganii Burchak-Abramovich, Suspanov and David 1996 (Late Pliocene/Early Pleistocene of Moldova)
• †Anas greeni (Brodkorb 1964) (Late Miocene?/Early Pliocene of South Dakota, USA){{cite journal |last1=Brodkorb|first1=Pierce|year=1964|title=A Pliocene Teal from South Dakota
• †Anas itchtucknee McCoy 1963 (Late Pleistocene of Florida, USA) doubtful validity
• †Anas kisatibiensis Burchak-Abramovich and Mczedlidze 1995 (nomen nudum) (Early Pliocene of Kisatibi, Georgia)
• †Anas kurochkini Zelenkov & Panteleyev 2015 (Late Miocene of Sea of Azov, southern Russia)
• †Anas lambrechti Spillman 1942 [Archaeoquerquedula lambrechti] (Pleistocene of Ecuador)
• †Anas ogallalae (Brodkorb 1962) (Late Miocene?/Early Pliocene of Kansas, USA) – Nettion red-and-green head clade (doubtful)?
• Bermuda Islands flightless duck †Anas pachyscelus Wetmore 1960 (Late Pleistocene of Bermuda, W Atlantic)
• †Anas pullulans (Brodkorb 1961) (Late Miocene?/Early Pliocene of Oregon, USA) – Punanetta?
• †Anas schneideri Emslie 1985 (Late Pleistocene of Little Box Elder Cave, USA)

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 Czech Republic) is apparently an indeterminate heron.
• †"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 Czech Republic), though possibly anseriform, cannot be placed with any certainty among modern birds at all.
• †"Anas" albae (Late Miocene of Hungary), "A." eppelsheimensis (Early Pliocene of Germany) and "A." isarensis (Late Miocene of Germany) are apparently Anatidae of unclear affiliations
• †"Anas" integra and "A." oligocaena are now in Dendrochen.
• †"Anas" lignitifila from the Late Miocene of Tuscany has been moved to its own genus, Bambolinetta, being a highly unusual marine waterfowl.
• †"Anas" luederitzensis (Early Miocene of Namibia) may belong within Oxyurini
• †"Anas" robusta is now tentatively placed in Anserobranta.
• †"Anas" sansaniensis is now placed in Chenoanas
• †"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.

Anas elapsum (Late Pleistocene of Australia) is now synonymised with the extant Hardhead. Anas gracilipes and Anas strenuum (Late Pleistocene of Australia) are both junior synonyms of the extant Chestnut teal.

Highly problematic, albeit in a theoretical sense, is the placement of the moa-nalos. These may be descended from a common ancestor of dabbling ducks such as the Pacific black duck, Laysan duck, and mallard. Phylogenetically, they may even form a clade within the traditional genus Anas. However, when compared to these species – which are representative of dabbling ducks in general – the moa-nalos are a radical departure from the Anseriforme bauplan. This illustrates that in a truly evolutionary sense, a strictly phylogenetic taxonomy may be difficult to apply.

References==

References

1. . ["Anatidae"](https://www.aviansystematics.org/4th-edition-checklist?viewfamilies=14). *The Trust for Avian Systematics*.
2. Linnaeus, C.. (1758). "Systema Naturæ per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis, Volume 1". Holmiae:Laurentii Salvii.
3. (1979). "Check-list of Birds of the World". Museum of Comparative Zoology.
4. Jobling, James A.. (2010). "The Helm Dictionary of Scientific Bird Names". Christopher Helm.
5. (2009). "Phylogenetic relationships based on two mitochondrial genes and hybridization patterns in Anatidae". Journal of Zoology.
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7. Stidham, T.A.. (2015). "Re-description and phylogenetic assessment of the Late Miocene ducks ''Aythya shihuibas'' and ''Anas'' sp. (Aves: Anseriformes) from Lufeng, Yunnan, China". Vertebrata PalAsiatica.
8. Campbell, Kenneth E.. (1979). "The non-passerine Pleistocene avifauna of the Talara Tar Seeps, northwestern Peru". Royal Ontario Museum.
9. (2006). "Dos nuevos Anatidae (Aves, Anseriformes) del Pleistoceno Inferior-Medio de Argentina". Studia Geológica Salmanticensia.
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11. Campbell, Kenneth E.. (1980). "A review of the Rancholabrean avifauna of the Itchtucknee River, Florida". Contributions in Science.
12. (1962). "A teal from the Lower Pliocene of Kansas". Quarterly Journal of the Florida Academy of Sciences.
13. (1961). "Birds from the Pliocene of Juntura, Oregon". Quarterly Journal of the Florida Academy of Sciences.
14. Mourer-Chauviré, Cécile. (2008). "Birds (Aves) from the Early Miocene of the Northern Sperrgebiet, Namibia". Memoir of the Geological Survey of Namibia.
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16. Olson, S.L.. (1977). "The identity of the fossil ducks described from Australia by C. W. De Vis". Emu.
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18. Brodkorb, Pierce. (1958). "Birds From the Middle Pliocene of Mckay, Oregon". Condor.
19. Brodkorb, Pierce. (1962). "The Systematic Position of Two Oligocene Birds From Belgium". Auk.
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21. Emslie, Steven D.. (1985). "A New Species of Teal From the Pleistocene (Rancholabrean) of Wyoming". Auk.
22. (2007). "Miocene waterfowl and other birds from central Otago, New Zealand". J. Syst. Palaeontol..
23. (2000). "The evolution of postcopulatory displays in dabbling ducks (Anatini): a phylogenetic perspective". Animal Behaviour.
24. (1999). "Phylogeny and biogeography of dabbling ducks (genus Anas): a comparison of molecular and morphological evidence". [[Auk (journal).
25. (July 2017). "Phylogeography of the Mallard (''Anas platyrhynchos''): Hybridization, dispersal, and lineage sorting contribute to complex geographic structure". [[Auk (journal).
26. Livezey, B. C.. (1991). "A phylogenetic analysis and classification of recent dabbling ducks (Tribe Anatini) based on comparative morphology". [[Auk (journal).
27. (2001). "Molecular population genetics, phylogeography, and conservation biology of the mottled duck (''Anas fulvigula'')". Conservation Genetics.
28. Mlíkovský, Jiří. (2002). "Cenozoic Birds of the World, Part 1: Europe". Ninox Press.
29. (1999). "Relationships of the extinct moa-nalos, flightless Hawaiian waterfowl, based on ancient DNA". Proceedings: Biological Sciences.