Anatinae
Encyclopedia
The Anatinae is a subfamily of the family
Anatidae
(swan
s, geese
and duck
s). 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 young but highly apomorphic lineage derived from the dabbling ducks.
There has been much debate about the dabbling ducks' systematical
status and what ducks belong to the Anatinae. As understood here, the subfamily contains only the dabbling ducks and their close relatives, the extinct moa-nalos. Alternatively, the Anatinae are considered to include most "duck
s" and the dabbling ducks form a tribe
Anatini within these. The classification as presented here more appropriately reflects the remaining uncertainty about the interrelationships of the major lineages of Anatidae
(waterfowl).
is almost certainly closely related to the Pink-eared Duck
, and other genera are likewise of unresolved affiliation. The peculiar Marbled Duck
, formerly tentatively assigned to the dabbling ducks, is actually a diving duck or even a distinct subfamily.
This group of ducks is so named because its members feed mainly on vegetable matter by upending on the water surface, or grazing, and only rarely dive. These are mostly gregarious ducks of freshwater or estuaries. These bird
s are strong fliers and northern species are highly migratory
. Compared to other types of duck, their legs are placed 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 predominant difference between puddle ducks and divers are the size of the feet. Puddle ducks 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 to 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 and diving ducks need to gain momentum to take off, so they must run across the water a short distance to gain flight.
s, the perching duck
s, and the dabbling and diving duck
s; the latter two were presumed to make up the Anatinae. However, the perching ducks turned out to be a paraphyletic assemblage of various tropical waterfowl that simply had happened to evolve
the ability to perch well in their forested habitat
. Several of these, such as the Brazilian Teal, were subsequently assigned to the Anatinae.
As for the diving duck
s, mtDNA cytochrome b
and NADH dehydrogenase
subunit
2 sequence
data indicates that they are fairly distant from the dabbling ducks, the morphological
similarities being due to convergent evolution
.
In addition, the genus Anas
as traditionally defined is not monophyletic; several South America
n species belong to a distinct clade which would include the Tachyeres steamer-ducks, and other species such as the Baikal Teal
should also be considered distinct.
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The following genera are (with one exception) unequivocal dabbling ducks:
The 3 known genera and 4 known species of moa-nalo
s are went extinct around 1000 AD. They formerly occurred on the Hawaiian Islands
and were derived from dabbling ducks, possibly even a close ancestor of the mallard
:
Subfossil
remains of a small, flightless dabbling duck have been recovered on Rota
in the Mariana Islands
. These cannot be assigned to a known genus, but probably are closest to Anas. A most bizarre ducklike bird, Talpanas
has been found on the Hawaii
an island of Kauaʻi. Due to its unique apomorphies (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 chain.
Frequently placed into the Anatinae are these genera, whose relationships must be considered uncertain at present:
On the other hand, the following genera, usually considered to belong into the Tadorninae, may actually be dabbling ducks:
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Anatidae
Anatidae
Anatidae is the biological family of birds that includes ducks, geese and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica and on most of the world's islands and island groups...
(swan
Swan
Swans, genus Cygnus, are birds of the family Anatidae, which also includes geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe Cygnini. Sometimes, they are considered a distinct subfamily, Cygninae...
s, geese
Goose
The word goose is the English name for a group of waterfowl, belonging to the family Anatidae. This family also includes swans, most of which are larger than true geese, and ducks, which are smaller....
and duck
Duck
Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...
s). 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
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...
, a young but highly apomorphic lineage derived from the dabbling ducks.
There has been much debate about the dabbling ducks' systematical
Systematics
Biological systematics is the study of the diversification of terrestrial life, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees...
status and what ducks belong to the Anatinae. As understood here, the subfamily contains only the dabbling ducks and their close relatives, the extinct moa-nalos. Alternatively, the Anatinae are considered to include most "duck
Duck
Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...
s" and the dabbling ducks form a tribe
Tribe (biology)
In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
Anatini within these. The classification as presented here more appropriately reflects the remaining uncertainty about the interrelationships of the major lineages of Anatidae
Anatidae
Anatidae is the biological family of birds that includes ducks, geese and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica and on most of the world's islands and island groups...
(waterfowl).
Systematics
The dabbling duck group, of worldwide distribution, was delimited in a 1986 study to include 8 genera and some 50–60 living species. However, Salvadori's TealSalvadori's Teal
The Salvadori's Teal or Salvadori's Duck is a species of bird native to New Guinea. It is placed in the monotypic genus Salvadorina....
is almost certainly closely related to the Pink-eared Duck
Pink-eared Duck
The Pink-eared Duck is a species of duck found in Australia.It has a large spatulate bill like the Australasian Shoveler, but is smaller at 38–40 cm length. Its brown back and crown, black and white barred sides and black eye patches on its otherwise white face make this bird unmistakable...
, and other genera are likewise of unresolved affiliation. The peculiar Marbled Duck
Marbled Duck
The Marbled Duck, or Marbled Teal , is a medium-sized duck. It used to be included among the dabbling ducks, but is now classed as a diving duck....
, formerly tentatively assigned to the dabbling ducks, is actually a diving duck or even a distinct subfamily.
This group of ducks is so named because its members feed mainly on vegetable matter by upending on the water surface, or grazing, and only rarely dive. These are mostly gregarious ducks of freshwater or estuaries. These bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s are strong fliers and northern species are highly migratory
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
. Compared to other types of duck, their legs are placed 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 predominant difference between puddle ducks and divers are the size of the feet. Puddle ducks 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 to 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 and diving ducks need to gain momentum to take off, so they must run across the water a short distance to gain flight.
History of classification
Traditionally, most ducks were assigned to either the shelduckShelduck
The shelducks, genus Tadorna, are a group of large birds in the Tadorninae subfamily of the Anatidae, the biological family that includes the ducks and most duck-like waterfowl such as the geese and swans....
s, the perching duck
Perching duck
The perching ducks were previously treated as a small group of ducks in the duck, goose and swan family Anatidae, grouped together on the basis of their readiness to perch high in trees...
s, and the dabbling and diving duck
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 the diverse and very large Anatidae family that includes ducks, geese, and swans....
s; the latter two were presumed to make up the Anatinae. However, the perching ducks turned out to be a paraphyletic assemblage of various tropical waterfowl that simply had happened to evolve
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
the ability to perch well in their forested habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
. Several of these, such as the Brazilian Teal, were subsequently assigned to the Anatinae.
As for the diving duck
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 the diverse and very large Anatidae family that includes ducks, geese, and swans....
s, mtDNA cytochrome b
Cytochrome b
Cytochrome b/b6 is the main subunit of transmembrane cytochrome bc1 and b6f complexes. In addition, it commonly refers to a region of mtDNA used for population genetics and phylogenetics.- Function :...
and NADH dehydrogenase
NADH dehydrogenase
NADH dehydrogenase is an enzyme located in the inner mitochondrial membrane that catalyzes the transfer of electrons from NADH to coenzyme Q...
subunit
Protein subunit
In structural biology, a protein subunit or subunit protein is a single protein molecule that assembles with other protein molecules to form a protein complex: a multimeric or oligomeric protein. Many naturally occurring proteins and enzymes are multimeric...
2 sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
data indicates that they are fairly distant from the dabbling ducks, the morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
similarities being due to convergent evolution
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
.
In addition, the genus Anas
Anas
Anas is a genus of dabbling ducks. It includes mallards, wigeons, teals, pintails and shovelers in a number of subgenera. Some authorities prefer to elevate the subgenera to genus rank...
as traditionally defined is not monophyletic; several South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
n species belong to a distinct clade which would include the Tachyeres steamer-ducks, and other species such as the Baikal Teal
Baikal Teal
The Baikal Teal , also called the Bimaculate Duck or Squawk Duck, is a dabbling duck that breeds in eastern Russia and winters in East Asia.- Description :...
should also be considered distinct.
Genera
- Amazonetta – status not fully resolved, most likely a dabbling duck
- AnasAnasAnas is a genus of dabbling ducks. It includes mallards, wigeons, teals, pintails and shovelers in a number of subgenera. Some authorities prefer to elevate the subgenera to genus rank...
– probably paraphyletic:- Baikal TealBaikal TealThe Baikal Teal , also called the Bimaculate Duck or Squawk Duck, is a dabbling duck that breeds in eastern Russia and winters in East Asia.- Description :...
- GarganeyGarganeyThe Garganey is a small dabbling duck. It breeds in much of Europe and western Asia, but is strictly migratory, with the entire population moving to southern Africa, India Santragachi and Australasia in winter, where large flocks can occur. This species was first described by Linnaeus in 1758...
- Silver TealSilver TealThe Silver Teal or Versicolor Teal is a species of dabbling duck in the genus Anas. It breeds in South America....
group - Blue-winged tealBlue-winged TealThe Blue-winged Teal is a small dabbling duck from North America.-Description:The Blue-winged Teal is long, with a wingspan of , and a weight of . The adult male has a greyish blue head with a white facial crescent, a light brown body with a white patch near the rear and a black tail. The adult...
s - ShovelerShovelerThe shovelers, formerly known as shovellers, are four species of dabbling ducks with long, broad spatula-shaped beaks:* Red Shoveler, Anas platalea* Cape Shoveler, Anas smithii* Australasian Shoveler, Anas rhynchotis...
s - WigeonWigeonThe Eurasian Wigeon, also known as Widgeon or Eurasian Widgeon is one of three species of wigeon in the dabbling duck genus Anas. It is common and widespread within its range...
s - GadwallGadwallThe Gadwall is a common and widespread duck of the family Anatidae.- Description :The Gadwall is 46–56 cm long with a 78–90 cm wingspan. The male is slightly larger than the female, weighing on average 990 g against her 850 g...
- Falcated DuckFalcated DuckThe Falcated Duck or Falcated Teal is a Gadwall-sized dabbling duck.-Distribution and habitat:The Falcated duck breeds in eastern Asia...
- Pintails
- True tealsTeal (disambiguation)*Teal is a medium blue-green color.*Teal Wicks is an American singer and stage actress.Teal may also refer to some species of waterfowl in the Anatinae subfamily:...
- African Black DuckAfrican Black DuckThe African Black Duck is a species of duck of the genus Anas. It is genetically closest to the mallard group , but shows some peculiarities in its behavior and plumage; it is accordingly placed in the subgenus Melananas pending further research.The African Black Duck is an...
- MallardMallardThe Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....
group
- Baikal Teal
- Lophonetta – formerly Anas
- Speculanas – formerly Anas
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...
s are went extinct around 1000 AD. They formerly occurred on the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
and were derived from dabbling ducks, possibly even a close ancestor of the mallard
Mallard
The Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....
:
- Chelychelynechen
- Thambetochen
- Ptaiochen
Subfossil
Subfossil refers to remains whose fossilization process is not complete, either for lack of time or because the conditions in which they were buried were not optimal for fossilization....
remains of a small, flightless dabbling duck have been recovered on Rota
Rota (island)
Rota also known as the "peaceful island", is the southernmost island of the United States Commonwealth of the Northern Mariana Islands and the second southernmost of the Marianas Archipelago. It lies approximately 40 miles north-northeast of the United States territory of Guam...
in the Mariana Islands
Mariana Islands
The Mariana Islands are an arc-shaped archipelago made up by the summits of 15 volcanic mountains in the north-western Pacific Ocean between the 12th and 21st parallels north and along the 145th meridian east...
. These cannot be assigned to a known genus, but probably are closest to Anas. A most bizarre ducklike bird, Talpanas
Talpanas
Talpanas is an extinct genus of duck containing only the species Talpanas lippa. It was first described by Andrew L. Iwaniuk, Storrs L. Olson, and Helen F. James in the journal Zootaxa in November 2009. It was endemic to the Hawaiian island of Kauai where the fossil remains were unearthed in the...
has been found on the Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
an island of Kauaʻi. Due to its unique apomorphies (it seems to have had small eyes high and far back on its head) the placement of this anatid
Anatidae
Anatidae is the biological family of birds that includes ducks, geese and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica and on most of the world's islands and island groups...
is likewise unresolved; only dabbling ducks and true geese are with certainty known to have colonized the Hawaiian chain.
Frequently placed into the Anatinae are these genera, whose relationships must be considered uncertain at present:
- AixAix (genus)Aix is a genus that contains two species of ducks: the Wood Duck , and the Mandarin Duck .The genus belongs to the family Anatidae in the waterfowl order Anseriformes...
– Tadorninae? - CairinaCairinaCairina is a genus of ducks in the bird family Anatidae.It has two species, which are similar anatomically but quite distinct in external morphology:* Muscovy Duck, Cairina moschata...
– may be paraphyletic, with one species in Tadorninae and the other closer to diving ducks - Callonetta – Tadorninae?
- Chenonetta – Tadorninae?
- Pteronetta – may belong into a distinct cladeCladeA clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
with Cyanochen - Nettapus – part of ancient GondwanaGondwanaIn paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...
n lineage?
On the other hand, the following genera, usually considered to belong into the Tadorninae, may actually be dabbling ducks:
- Sarkidiornis
- TachyeresTachyeresThe steamer ducks are a genus of ducks in the family Anatidae. All of the four species occur in South America, and all except the Flying Steamer Duck are flightless; even this one species capable of flight rarely takes to the air. The genus name Tachyeres, "having fast oars" or "fast rower", comes...