The Tadornini is a biological

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 ...

that includes the shelducks and sheldgeese, which is placed in subfamily Anatinae of family Anatinae, which includes the ducks and most duck-like waterfowl such as the geese and

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. It has been treated as subfamily in the past. 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 Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Systematics

Following the review of Livezey (1986), several species formerly classified as aberrant dabbling ducks or as "

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" were placed in the Tadornini. mtDNA

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 ...

analyses 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 Tadornini 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 ducks and seaducks being more distant. ;Tribe Tadornini *Unequivocally placed in this group: **'' Tadorna'': shelducks (Europe, Africa, Australasia; 6 species) – possibly

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 ...

**'' Radjah'': Radjah shelduck (Australia, New Guinea) **'' Centrornis'': Madagascar sheldgoose (Madagascar,

prehistoric Prehistory, also called pre-literary history, is the period of human history between the first known use of stone tools by hominins million years ago and the beginning of recorded history with the invention of writing systems. The use o ...

) **'' Alopochen'': Egyptian goose, and extinct African and Mascarene shelducks (Africa and Madagascar region; 1 living species, 2–3

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

) **'' Neochen'': Orinoco goose (South America) **'' Chloephaga'': 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" *Provisionally placed in this group: **'' Malacorhynchus'': pink-eared ducks (Australia; 1 living species, 1

) – may be closer to Oxyurinae **'' Cyanochen'': blue-winged goose (Ethiopia) – may belong to a distinct subfamily **'' Tachyeres'': steamer ducks (South America; 4 species) – may belong to Anatinae **'' Plectropterus'': spur-winged goose (sub-Saharan Africa) – may be in monotypic subfamily *May belong to Tadorninae, currently placed elsewhere: **'' Aix'': Mandarin duck and wood duck (East Asia and North America, respectively) **'' Cairina moschata'': Muscovy duck (tropical America; genus '' Cairina'' 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

) **'' Salvadorina'': Salvadori's teal (New Guinea)—formerly in Anatidae and "perching ducks"

References

{{Taxonbar, from1=Q32858230, from2=Q21153 Bird subfamilies Ducks Taxa named by Ludwig Reichenbach