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The 'Anatinae' is a subfamily of the family Anatidae (swans, geese and ducks).
It is made up of the ' dabbling ducks' and the moa-nalos, a young and very distinct evolutionary lineage derived from them.
The dabbling duck group, of worldwide distribution, includes 8 genera and some 50-60 living species according to Livezey (1986). However, Salvadori's Teal is almost certainly closely related to the Pink-eared Duck, and other genera are likewise of unresolved affiliation (Sraml ''et al.'' 1996, Johnson & Sorenson 1999). The peculiar Marbled Duck, formerly tentatively assigned to the dabbling ducks, is actually a diving duck or even a distinct subfamily (Johnson & Sorenson 1999).
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 birds 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.
The dabbling ducks' systematical status and what ducks belong to the Anatinae has been much disputed. As understood here, the subfamily contains only the dabbling ducks and their close relatives, the extinct moa-nalos. In other treatments (e.g. Terres & NAS 1991), all Anatidae except geese, swans, and whistling-ducks are included in it as tribes.
Traditionally, most ducks were assigned to either the shelducks, the perching ducks, and the dabbling and diving ducks; 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 Duck, were subsequently assigned to the Anatinae.
As for the diving ducks, mtDNA cytochrome ''b'' and NADH dehydrogenase subunit 2 sequence data (Johnson & Sorenson 1999) indicates that they are fairly distant from the dabbling ducks, the morphological similarities (Livezey 1986) being due to convergent evolution.
In addition, the genus ''Anas'' as traditionally defined is not monophyletic; several South American species belong to a distinct clade which would include the ''Tachyeres'' steamer-ducks (Johnson & Sorenson 1999), and other species such as the Baikal Teal should also be considered distinct. See the genus article for more on this subject.

The following genera are (with one exception) unequivocal 'dabbling ducks':

★ ''Amazonetta'' - status not fully resolved, most likely a dabbling duck

★ ''Anas'' - probably paraphyletic:

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★ Baikal Teal

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★ Garganey

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★ Silver Teal group

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★ Blue-winged teals

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★ Shovelers

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★ Wigeons

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★ Gadwall

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★ Falcated Duck

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★ Pintails

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★ True teals

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★ African Black Duck

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★ Mallard group

★ ''Lophonetta'' - formerly ''Anas''

★ ''Speculanas'' - formerly ''Anas''
The 3 known genera and 4 known species of 'moa-nalos' 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:

★ ''Chelychelynechen''

★ ''Thambetochen''

★ ''Ptaiochen''

Subfossil remains of a small, flightless dabbling duck have been recovered on Rota in the Mariana Islands (Steadman 1999). These cannot be assigned to a known genus, but probably are closest to ''Anas''. A most bizarre ducklike fowl has been found on the Hawaiian island of Kaua‘i. 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:

★ ''Aix'' - Tadorninae?

★ ''Cairina'' - 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 clade with ''Cyanochen''

★ ''Nettapus'' - part of ancient Gondwanan lineage?
On the other hand, the following genera, usually considered to belong into the Tadorninae, may actually be dabbling ducks:

★ ''Sarkidiornis''

★ ''Tachyeres''

Contents

References

References

★ 'Johnson', Kevin P. & 'Sorenson', Michael D. (1999): Phylogeny and biogeography of dabbling ducks (genus Anas): a comparison of molecular and morphological evidence. ''Auk'' '116'(3): 792–805. PDF fulltext

★ 'Livezey', Bradley C. (1986): A phylogenetic analysis of recent anseriform genera using morphological characters. ''Auk'' '103'(4): 737-754. PDF fulltext

★ 'Sraml', M.; Christidis, L.; Easteal, S.; Horn, P. & Collet, C. (1996): Molecular Relationships Within Australasian Waterfowl (Anseriformes). ''Australian Journal of Zoology'' '44'(1): 47-58. (HTML abstract)

★ 'Steadman', David William (1999): The Prehistory of Vertebrates, Especially Birds, on Tinian, Aguiguan, and Rota, Northern Mariana Islands. ''Micronesica'' '31'(2): 319-345. PDF fulltext

★ 'Terres', John K. & 'National Audubon Society' (1991): ''The Audubon Society Encyclopedia of North American Birds''. Wings Books, New York. ISBN 0-517-03288-0