Anas is a genus of dabbling ducks. It includes the pintails, most teals, and the mallard and its close relatives. It formerly included additional species but following the publication of a molecular phylogenetic study in 2009 the genus was split into four separate genera.[2] The genus now contains 31 living species. The name Anas is the Latin for "duck".
Systematics
The genusAnas was introduced by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae.[3][4]Anas is the Latin word for a duck.[5] 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.[2] 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.[6]
Species
There are 31 extant species recognised in the genus:[6]
eastern and southern sub-Saharan Africa from South Africa n north to South Sudan and Ethiopia with outlying populations in western equatorial Africa, in south east Nigeria, Cameroon and Gabon.
Indonesia, New Guinea, Australia, New Zealand, and many islands in the southwestern Pacific, reaching to the Caroline Islands in the north and French Polynesia in the east
Alaska to Mexico, the Hawaiian Islands, across Eurasia, from Iceland and southern Greenland and parts of Morocco (North Africa) in the west, Scandinavia and Britain to the north, and to Siberia, Japan, and South Korea, in the east, south-eastern and south-western Australia and New Zealand
†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.[11]
†"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.[11][12]
†"Anas" albae (Late Miocene of Polgárdi, Hungary), "A." eppelsheimensis (Early Pliocene of Eppelsheim, Germany),[8]"A." isarensis (Late Miocene of Aumeister, Germany) and "A." luederitzensis (Kalahari Early Miocene of Lüderitzbucht, Namibia) are apparently Anatidae of unclear affiliations; the first might be a seaduck.[11]
†"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.[11]
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.[13] 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.[citation needed]
^"Anatidae". aviansystematics.org. The Trust for Avian Systematics. Retrieved 2023-08-05.
^ abcGonzalez, J.; Düttmann, H.; Wink, M. (2009). "Phylogenetic relationships based on two mitochondrial genes and hybridization patterns in Anatidae". Journal of Zoology. 279 (3): 310–318. doi:10.1111/j.1469-7998.2009.00622.x.
^Wilson, R. L. (1968). "Systematics and faunal analysis of a Lower Pliocene vertebrate assemblage from Trego County, Kansas". Contrib. Mus. Paleontol. Univ. Mich. 22 (7): 75–126.