The Anatinae are a

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

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 ...

(

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, geese and

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). Its surviving members are the dabbling ducks, which feed mainly at the surface rather than by

diving Diving most often refers to: * Diving (sport), the sport of jumping into deep water * Underwater diving, human activity underwater for recreational or occupational purposes Diving or Dive may also refer to: Sports * Dive (American football), ...

. The other members of the Anatinae are the extinct moa-nalo, a young but highly apomorphic lineage derived from the dabbling ducks. There has been much debate about the systematical status and which ducks belong to the Anatinae. Some taxonomic authorities only include the dabbling ducks and their close relatives, the extinct moa-nalos. Alternatively, the Anatinae are considered to include most "

s", and the dabbling ducks form a

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide use of the term in English is in the discipline of anthropology. The definition is contested, in part due to conflict ...

Anatini within these. The classification as presented here more appropriately reflects the remaining uncertainty about the interrelationships of the major lineages of

(waterfowl).

Systematics

The dabbling duck group, of worldwide distribution, was delimited in a 1986 study to include eight genera and some 50–60 living species. However, Salvadori's teal is almost certainly closely related to the

pink-eared duck The pink-eared duck (''Malacorhynchus membranaceus'') is a species of duck found in Australia. Description The pink-eared duck has a large spatulate bill like the Australasian shoveler, but is smaller at 38–40 cm length. Its brown back ...

, and other genera are likewise of unresolved affiliation. The peculiar marbled duck, formerly tentatively assigned to the dabbling ducks, is thought to be a diving duck or even a distinct subfamily. This group of ducks has been so named because its members feed mainly on vegetable matter by upending on the water surface, or grazing, and only rarely diving. These are mostly gregarious ducks of freshwater or estuaries. These

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 are strong fliers and northern species are highly migratory. Compared to other types of duck, their legs are located more towards the centre of their bodies. They walk well on land, and some species feed terrestrially. "Puddle ducks" generally feed on the surface of the water or feed on very shallow bottoms. They are not equipped to dive down several feet like their diving counterparts. The most prominent difference between puddle ducks and divers is the size of the feet. A puddle duck's feet are generally smaller because they do not need the extra propulsion to dive for their forage. Another distinguishing characteristic of puddle ducks when compared with diving ducks is the way in which they take flight when spooked or are on the move. Puddle ducks spring straight up from the water, but diving ducks need to gain momentum to take off, so they must run across the water a short distance to gain flight. Traditionally, most ducks were assigned to either the shelducks, the

perching duck The term perching ducks is used colloquially to mean any species of ducks distinguished by their readiness to perch high in trees. Until the late 20th century, perching ducks meant ''Cairinini'', a tribe of ducks in the duck, goose and swan fam ...

s, and the dabbling and

diving duck The diving ducks, commonly called pochards or scaups, are a category of duck which feed by diving beneath the surface of the water. They are part of Anatidae, the diverse and very large family that includes ducks, geese, and swans. The diving ...

s; the latter two were presumed to make up the Anatinae. However, the perching ducks turned out to be a

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

assemblage of various

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

waterfowl that happened to evolve the ability to perch well in their forested

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

. Several of these, such as the

Brazilian teal The Brazilian teal or Brazilian duck (''Amazonetta brasiliensis'') is the only extant species of duck in the genus ''Amazonetta''. It is widely distributed in eastern South America. Taxonomy The Brazilian teal was Species description, formally ...

, were subsequently assigned to the Anatinae. As for the

mtDNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the DNA contained in ...

cytochrome ''b'' and

NADH dehydrogenase NADH dehydrogenase is an enzyme that converts nicotinamide adenine dinucleotide (NAD) from its reduced form (NADH) to its oxidized form (NAD+). Members of the NADH dehydrogenase family and analogues are commonly systematically named using the f ...

subunit 2

sequence In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is cal ...

data indicates that they are fairly distant from the dabbling ducks. The morphological similarities are due to

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...

. In addition, the genus ''

Anas ''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 s ...

'', as traditionally defined, is not

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

; several

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

n species belong to a distinct clade which would include the ''Tachyeres'' steamer-ducks. Other species, such as the Baikal teal, should also be considered distinct. Dabbling Spot billed Ducks 01

Genera

The following genera are (with one exception) unequivocal dabbling ducks: * '' Amazonetta'' – status not fully resolved, most likely a dabbling duck * ''Sibirionetta'' – Baikal teal * ''

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 ...

'' * ''

Mareca ''Mareca'' is a genus or subgenus of ducks in the family Anatidae that includes the wigeons. The species now placed in this genus were formerly placed in the genus ''Anas''. A molecular phylogentic study comparing mitochondrial DNA sequences pub ...

'' * ''Lophonetta'' – crested duck * ''Speculanas'' – bronze-winged duck * ''

'' The three known genera and four known species of moa-nalos all became extinct around AD 1000. They formerly occurred on the

Hawaiian Islands The Hawaiian Islands () are an archipelago of eight major volcanic islands, several atolls, and numerous smaller islets in the Pacific Ocean, North Pacific Ocean, extending some from the Hawaii (island), island of Hawaii in the south to nort ...

and were derived from dabbling ducks, possibly even from a close ancestor of 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. It has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Arge ...

: * '' Chelychelynechen'' * '' Thambetochen'' * '' Ptaiochen''

Subfossil 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 ...

remains of a small, flightless dabbling duck have been recovered on Rota in the

Mariana Islands The Mariana Islands ( ; ), also simply the Marianas, are a crescent-shaped archipelago comprising the summits of fifteen longitudinally oriented, mostly dormant volcanic mountains in the northwestern Pacific Ocean, between the 12th and 21st pa ...

. These cannot be assigned to a known genus, but probably are closest to ''Anas''. A most bizarre duck-like bird, '' Talpanas lippa'' has been found on the

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

an island of

Kauai Kauai (), anglicized as Kauai ( or ), is one of the main Hawaiian Islands. It has an area of 562.3 square miles (1,456.4 km2), making it the fourth-largest of the islands and the 21st-largest island in the United States. Kauai lies 73 m ...

. Because of its unique

apomorph In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to ha ...

ies (it seems to have had small eyes high and far back on its head), the placement of this anatid is likewise unresolved; only dabbling ducks and true geese are with certainty known to have colonized the Hawaiian archipelago. Another bizarre insular anatine was '' Bambolinetta'' from the Late

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

of Tuscana, then part of the Tuscano-Sardinian insular landmass. Flightless or at least a poor flyer, it instead shows adaptations for wing-propelled diving, occupying a similar ecological niche to that of

penguin Penguins are a group of aquatic flightless birds from the family Spheniscidae () of the order Sphenisciformes (). They live almost exclusively in the Southern Hemisphere. Only one species, the Galápagos penguin, is equatorial, with a sm ...

s and plotopterids. Frequently placed into the Anatinae are these genera, whose relationships must be considered uncertain at present: * †'' Chenoanas''? * †'' Dunstanetta'' (Johnstone's duck) * †'' Lavadytis'' * †'' Pinpanetta'' * †'' Tirarinetta'' * ''

Oxyurini The Oxyurini are a tribe of the duck subfamily of birds, the Anatinae. It has been subject of considerable debate about its validity and circumscription. Some taxonomic authorities place the group in its own subfamily, the ''Oxyurinae''. Most of ...

'' (stiff-tailed ducks) ** '' Heteronetta'' (black-headed duck) ** '' Nomonyx'' (masked duck) ** '' Oxyura'' * '' Biziura'' – Oxyurini? * '' Aix'' – Tadorninae? * '' Cairina'' – may be

, with one species in Tadorninae and the other closer to diving ducks * '' Callonetta'' – Tadorninae? * '' Chenonetta'' – Tadorninae? * '' Pteronetta'' – may belong into a distinct

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

with '' Cyanochen'' * '' Nettapus'' – part of ancient

Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...

n lineage? * '' Mergini'' - (seaducks) ** †'' Chendytes'' ** †'' Shiriyanetta'' ** '' Polysticta'' ** ''

Somateria The eiders () are large seaducks in the genus ''Somateria''. The three extant species all breed in the cooler latitudes of the Northern Hemisphere. The down feathers of eider ducks and some other ducks and geese are used to fill pillows and q ...

'' ** '' Histrionicus'' ** †'' Camptorhynchus'' ** '' Melanitta'' ** ''

Clangula The long-tailed duck (''Clangula hyemalis'') or coween, is a medium-sized sea duck that breeds in the tundra and taiga regions of the arctic and winters along the northern coastlines of the Atlantic and Pacific Oceans. It is the only member of ...

'' ** '' Bucephala'' ** '' Mergellus''? ** '' Lophodytes''? ** '' Mergus''? On the other hand, the following genera, usually considered to belong into the Tadorninae, may actually be dabbling ducks: * '' Sarkidiornis'' * '' Tachyeres'' File:Anas formosa (Aqua zoo).jpg, Baikal teal (''Sibirionetta formosa'') File:Spot-billed Duck (Anas poecilorhyncha) in Hyderabad W2 IMG 8867.jpg,

Indian spot-billed duck The Indian spot-billed duck (''Anas poecilorhyncha'') is a species of large dabbling duck that is a non-migratory breeding duck throughout freshwater wetlands in the Indian subcontinent. The name is derived from the red spot at the base of the bi ...

(''Anas poecilorhyncha'') in

Hyderabad Hyderabad is the capital and largest city of the Indian state of Telangana. It occupies on the Deccan Plateau along the banks of the Musi River (India), Musi River, in the northern part of Southern India. With an average altitude of , much ...

, India File:Philippine duck.jpg, Philippine duck (''Anas luzonica'') File:Mallard (female).jpg,

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

(''Anas platyrhynchos'') (female) File:Female Mallard duck, with ducklings.jpg,

(''Anas platyrhynchos'') with six ducklings File:Comb duck.jpg, Knob-billed duck (''Sarkidiornis melanotos''): a misplaced dabbling duck?

References

{{Authority control Bird subfamilies Ducks