Tadorninae
Encyclopedia
The Tadorninae is the shelduck-sheldgoose subfamily of the Anatidae
, the biological family
that includes the duck
s and most duck-like waterfowl such as the geese
and swan
s.
This group is largely tropical or Southern Hemisphere in distribution, with only two species, the Common Shelduck
and the Ruddy Shelduck
breeding in northern temperate regions, though the Crested Shelduck
(presumed extinct) was also a northern species.
Most of these species have a distinctive plumage, but there is no pattern as to whether the sexes are alike, even within a single genus
.
s" were placed in the Tadorninae. mtDNA sequence
analyses (Sraml et al. 1996, Johnson & Sorenson 1999) cast doubt on the allocation of several genera; many supposed dabbling ducks and one peculiar goose may more correctly belong here, while some genera believed to be close to shelducks appear to have different relationships altogether.
The available data indicates that the Tadorninae are indeed, as their appearance suggests, somewhat intermediate between geese and dabbling ducks, but the molecular data suggests they are not the only lineage to evolve towards a more duck-like morphology
, with the diving duck
s and seaducks being more distant.
FAMILY ANATIDAE
Subfamily Tadorninae
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...
, the biological family
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...
that includes the 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 most duck-like waterfowl such as the 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 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.
This group is largely tropical or Southern Hemisphere in distribution, with only two species, the Common Shelduck
Common Shelduck
The Common Shelduck is a waterfowl species shelduck genus Tadorna. It is widespread and common in Eurasia, mainly breeding in temperate and wintering in subtropical regions; in winter, it can also be found in the Maghreb...
and the Ruddy Shelduck
Ruddy Shelduck
The Ruddy Shelduck, Tadorna ferruginea, is a member of the duck, goose and swan family Anatidae. It is in the shelduck subfamily Tadorninae...
breeding in northern temperate regions, though the Crested Shelduck
Crested Shelduck
The Crested Shelduck or Korean Crested Shelduck, Tadorna cristata, is a species of bird in the family Anatidae. It is critically endangered and believed by some to be extinct. The male Crested Shelduck has a greenish-black crown, breast, primaries, and tail, while the rest of its face, chin, and...
(presumed extinct) was also a northern species.
Most of these species have a distinctive plumage, but there is no pattern as to whether the sexes are alike, even within a single genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
.
Systematics
Following the review of Livezey (1986), several species formerly classified as aberrant dabbling ducks or as "perching duckPerching 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" were placed in the Tadorninae. mtDNA 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...
analyses (Sraml et al. 1996, Johnson & Sorenson 1999) cast doubt on the allocation of several genera; many supposed dabbling ducks and one peculiar goose may more correctly belong here, while some genera believed to be close to shelducks appear to have different relationships altogether.
The available data indicates that the Tadorninae are indeed, as their appearance suggests, somewhat intermediate between geese and dabbling ducks, but the molecular data suggests they are not the only lineage to evolve towards a more duck-like morphology
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....
, with 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 and seaducks being more distant.
FAMILY ANATIDAE
Subfamily Tadorninae
- Unequivocally placed in this group:
- Pachyanas: Chatham Island Duck (Chatham Islands, prehistoricLate Quaternary prehistoric birdsPrehistoric birds are various taxa of birds that became extinct before recorded history, or more precisely, before they could be studied alive by bird scientists...
) - TadornaShelduckThe 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....
: shelducks (Europe, Africa, Australasia; 7 species) - possibly paraphyletic - Salvadorina: Salvadori's Teal (New Guinea) - formerly in Anatidae and "perching ducks"
- Centrornis: Madagascar Sheldgoose (Madagascar, prehistoricLate Quaternary prehistoric birdsPrehistoric birds are various taxa of birds that became extinct before recorded history, or more precisely, before they could be studied alive by bird scientists...
) - Alopochen: African and Mascarene shelducks (Africa and Madagascar region; 1 living species, 2-3 extinct)
- Neochen: Orinoco Goose (South America)
- ChloephagaSheldgooseThe sheldgeese are a genus of birds in the family Anatidae.- Species :* Andean Goose, Chloephaga melanoptera* Upland Goose or Magellan Goose, Chloephaga picta* Kelp Goose, Chloephaga hybrida...
: sheldgeese (South America; 5 species) - Hymenolaimus: Blue Duck (New Zealand) - formerly in "perching ducks"
- Merganetta: Torrent Duck (Andes mountains, South America) - formerly in "perching ducks"
- Pachyanas: Chatham Island Duck (Chatham Islands, prehistoric
- Provisionally placed in this group:
- Malacorhynchus: pink-eared ducks (Australia; 1 living species, 1 prehistoricLate Quaternary prehistoric birdsPrehistoric birds are various taxa of birds that became extinct before recorded history, or more precisely, before they could be studied alive by bird scientists...
) - may be closer to OxyurinaeOxyurinaeOxyurinae is a subfamily of the duck, goose and swan family of birds, Anatidae. It has been subject of considerable debate about its validity and circumscription. Most of its members have long stiff tail feathers which are erected when the bird is at rest, and relatively large swollen bills... - Sarkidiornis: Comb Duck (South America, Africa, India) - formerly in "perching ducks"; may belong into Anatinae
- Cyanochen: Blue-winged Goose (Ethiopia) - may belong into distinct subfamily
- 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...
: steamer ducks (South America; 4 species) - may belong into Anatinae
- Malacorhynchus: pink-eared ducks (Australia; 1 living species, 1 prehistoric
- May belong into Tadorninae, currently placed elsewhere:
- 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...
: Mandarin Duck and Wood Duck (East Asia and North America, respectively) - Cairina moschata: Muscovy Duck (tropical America; genus 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) - Cereopsis: Cape Barren Goose (Australia)
- Callonetta: Ringed Teal (South America)
- Chenonetta: Maned Duck (Australia and formerly New Zealand; 1 living species, 1 extinct)
- Aix