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. These are birds that are adapted through evolution for swimming, floating on the water surface, and in some cases diving in at least shallow water. (The Magpie Goose is no longer considered to be part of the Anatidae, but is placed in its own family Anseranatidae.) The family contains around 146 species in 40 genera. They are generally herbivorous, and are monogamous breeders. A number of species undertake annual migrations. A few species have been domesticated for agriculture, and many others are hunted for food and recreation. Five species have become extinct since 1600, and many more are threatened with extinction.

Description and ecology

The ducks, geese and swans are small to large sized birds that have a general body plan that is broad and elongated.

Anatids are generally herbivorous as adults, feeding on various water-plants, although some species also eat fish, molluscs, or aquatic arthropods. One group, the mergansers, are primarily piscivorous, and have a serrated bill to help them catch fish. In a number of species, the young include a high proportion of invertebrates in their diet, but become purely herbivorous as adults. most species are adapted for copulation on the water only. They construct simple nests from whatever material is close to hand, often lining them with a layer of down plucked from the mother's breast. In most species, only the female incubates the eggs. The young are precocial, and are able to feed themselves from birth. suggest that the Anatidae are better treated in nine subfamilies. This classification was popular in the late 1980s to 1990s. But mtDNA sequence analyses indicate that for example the dabbling and diving ducks do not belong in the same subfamily. While there are certainly shortcomings in Livezey's analysis, mtDNA is an unreliable source for phylogenetic information in many waterfowl (especially dabbling ducks) due to their ability to produce fertile hybrids, in rare cases possibly even beyond the level of genus (see for example the "Barbary Duck"). Because the sample size of many molecular studies available to date is small, mtDNA results must be considered with caution.

But while a comprehensive review of the Anatidae which unites all evidence into a robust phylogeny is still lacking, the reasons for the confusing data are at least clear: As demonstrated by the Late Cretaceous fossil Vegavis iaai — an early modern waterbird which belonged to an extinct lineage—the Anatidae are an ancient group among the modern birds. Their earliest direct ancestors, though not documented by fossils yet, likewise can be assumed to have been contemporaries with the dinosaurs. The long period of evolution and shifts from one kind of waterbird lifestyle to another have obscured many plesiomorphies, while apomorphies apparently are quite often the result of parallel evolution, for example the "non-diving duck" type displayed by such unrelated genera as Dendrocygna, Amazonetta, and Cairina. For the fossil record, see below.

Alternatively, the Anatidae may be considered to consist of 3 subfamilies (ducks, geese, and swans, essentially) which contain the groups as presented here as tribes, with the swans separated as subfamily Cygninae, the goose subfamily Anserinae also containing the whistling ducks, and the Anatinae containing all other clades.

Genera

Subfamily: Dendrocygninae (One pantropical genus, of distinctive long-legged goose-like birds)

* Dendrocygna, whistling ducks (9 living species)

Subfamily: Thalassorninae (One genus in Africa, most closely related to the subfamily Dendrocygninae, though also showing convergent similarities to the subfamily Oxyurinae)

Thalassornis, White-backed Duck

Subfamily: Anserinae, swans and geese (Three to seven extant genera with 25–30 living species, mainly cool temperate Northern Hemisphere but also some Southern Hemisphere species, with the swans in one genus [two genera in some treatments], and the geese in three genera [two genera in some treatments]. Some other species are sometimes placed herein, but seem somewhat more distinct [see below])

* Cygnus, true swans (7 species, 4 sometimes separated in Olor)

* Anser, grey geese (7 species)

* Chen, white geese (3 species, sometimes included in Anser)

* Branta, black geese (8 living species)

Subfamily: Stictonettinae (One genus in Australia, formerly included in the Oxyurinae, but with anatomy suggesting a distinct ancient lineage perhaps closest to the Anserinae, especially the Cape Barren Goose)

* Stictonetta, Freckled Duck

Subfamily: Plectropterinae (One genus in Africa, formerly included in the "perching ducks", but closer to the Tadorninae)

* Plectropterus, Spur-winged Goose

Subfamily: Tadorninae – shelducks and sheldgeese(This group of larger, often semi-terrestrial waterfowl can be seen as intermediate between Anserinae and Anatinae. The 1986 revision Furthermore, while morphologically close to dabbling ducks, the mtDNA data indicates that a treatment as distinct subfamily is indeed correct, with the Tadorninae being actually closer to dabbling ducks than the diving ducks are The living and assignable prehistoric avifauna of the archipelago contains as Anseriformes Branta geese and their descendants, and the moa-nalos as mentioned above. The following taxa, although certainly new species, cannot be assigned even to subfamily; that Kauai is the oldest of the large Hawaiian Islands, meaning the species may have been evolving in isolation for nearly up to 10 mya (since the Late Miocene), does not help in determining their affinities:

Long-legged "Shelduck", Anatidae sp. et gen. indet.

Talpanas

Similarly, Geochen rhuax from the Big Island of Hawaii, and a gigantic goose-like anatid from Oahu are known only from very incomplete and in the former case much damaged bone fragments. The former has been alleged to be a shelduck, but this was generally dismissed because of the damage to the material and biogeographic considerations. The long-legged Kauai bird, however, hints at the possibility of a former tadornine presence on the archipelago.

Fossil Anatidae

The fossil record of anatids is extensive, but many prehistoric genera cannot be unequivocally assigned to present-day subfamilies for the reasons given above. For prehistoric species of extant genera, see the respective genus accounts.

Dendrocheninae – a more advanced relative of the whistling-ducks or an ancestral relative of stifftail ducks paralleling whistling-ducks; if not extinct possibly belong in Oxyurinae (including Malacorhynchus) Mionetta (Late Oligocene – Middle Miocene of C Europe) – includes "Anas" blanchardi, "A." consobrina, "A." natator, "Aythya" arvernensis Manuherikia (Bathans Early/Middle Miocene of Otago, New Zealand) Dendrochen (Early – Late? Miocene) – includes "Anas" integra, "A." oligocaena Dendrocheninae gen. et sp. indet. (Late Miocene of Argentina)

Anserinae Cygnavus (Early Oligocene of Kazakhstan – Early Miocene of Germany) Cygnopterus (Middle Oligocene of Belgium – Early Miocene of France) – sometimes included in Cygnavus

Megalodytes (Middle Miocene of California, USA)

"cf. Megalodytes" (Haraichi Middle Miocene of Annaka, Japan)

Anserobranta (Late Miocene of C Europe) – includes "Anas" robusta, validity doubtful Presbychen (Temblor Late Miocene of Sharktooth Hill, USA)

Afrocygnus (Late Miocene – Early Pliocene of EC Africa)

Paracygnus (Kimball Late Pliocene of Nebraska, USA) Eremochen (Pliocene)

Tadorninae

Australotadorna (Late Oligocene – Early Miocene of Australia)

Miotadorna (Bathans Early/Middle Miocene of Otago, New Zealand) Tadorninae gen. et sp. indet. (Calvert Middle Miocene of Maryland, USA)

Balcanas (Early Pliocene of Dorkovo, Bulgaria) – may be synonym of Tadorna or even Common Shelduck

Anabernicula (Late Pliocene ?– Late Pleistocene of SW and W North America) Brantadorna (Middle Pleistocene of Vallecito Creek, USA) Nannonetta (Late Pleistocene of Peru)

Anatinae

Sinanas (Middle Miocene)

Wasonaka (Middle Pliocene)

Oxyurinae

Pinpanetta (Late Oligocene – Early Miocene of Australia)

Dunstanetta (Bathans Early/Middle Miocene of Otago, New Zealand) – tentatively placed here

Tirarinetta (Pliocene of Australia)

Incertae sedis "Anas" luederitzensis (Kalahari Early Miocene of Lüderitzbucht, Namibia) – anatine? Matanas (Bathans Early/Middle Miocene of Otago, New Zealand) Anatidae gen. et sp. indet. MNZ S42797 (Bathans Early/Middle Miocene of Otago, New Zealand)

"Oxura" doksana (Early Miocene of Dolnice, Czechia)

"Aythya" chauvirae (Middle Miocene of Sansan, France and Credinţa, Romania) – 2 species Anatidae gen. et sp. indet. (Middle Miocene of Nördlinger Ries, Germany) – tadornine? Anatidae gen. et sp. indet. (Sajóvölgyi Middle Miocene of Mátraszõlõs, Hungary) "Anas" meyerii (Middle Miocene of Öhningen, Germany) Described from a single badly crushed tarsometatarsus and phalanges. This species was named in 1867 by Milne-Edwards and then recombined in 1964 by Brodkorb to the genus Aythya. This species is currently regarded as Aves incertae sedis. "Anas" velox (Middle - Late? Miocene of C Europe) – anatine? May include "A." meyerii

"Anas" albae (Late Miocene of Polgárdi, Hungary) – mergine? Formerly in Mergus

"Anas" isarensis (Late Miocene of Aumeister, Germany) – anatine? "Anser" scaldii (Late Miocene of Antwerp, Belgium) – anserine or tadornine

Anatidae gen. et sp. indet. (Waite Late Miocene of Alcoota, Australia) – anatine, oxyurine?

Anatidae gen. et sp. indet. (Waite Late Miocene of Alcoota, Australia) – tadornine?

"Anas" eppelsheimensis (Early Pliocene of Eppelsheim, Germany) – anatine?

Aldabranas (Late Pleistocene of Aldabra, Indian Ocean) – anatine or tadornine

"Chenopis" nanus (Pleistocene of Australia) – at least 2 taxa, may be living species

Putative or disputed prehistoric anatids are:

Romainvillia (Late Eocene/Early Oligocene) – anseranatid or anatid (own subfamily)

Loxornis (Deseado Early Oligocene of Argentina) Paracygnopterus (Early Oligocene of Belgium and England) Teleornis (Deseado Early Oligocene of Argentina)

Guguschia (Late Oligocene of Pirəkəşkül, Azerbaijan) – anserine or Pelagornithidae (same as Caspiodontornis?)

Chenornis (Early Miocene) – anserine or Phalacrocoracidae

Paranyroca (Rosebud Early Miocene of Bennett County, USA) – anatid (own subfamily) or distinct family? Eoneornis (Miocene of Argentina) – anatine? A nomen dubium Eutelornis (Miocene of Argentina) – anatine?

The Middle Oligocene Limicorallus (from Chelkar-Teniz (Kazakhstan) was sometimes considered an anserine. It is, however, a primitive cormorant. The middle Eocene Eonessa wa formerly thought to belong to Anatidae, however reexamination of the holotype in 1978 resulted in the genus being placed as Aves incertae sedis.

Footnotes

References

Burney, David A.; James, Helen F.; Burney, Lida Pigott; Olson, Storrs L.; Kikuchi, William; Wagner, Warren L.; Burney, Mara; McCloskey, Deirdre; Kikuchi, Delores; Grady, Frederick V.; Gage, Reginald II & Nishek, Robert (2001): Fossil Evidence for a Diverse Biota from Kauaʻi and Its Transformation since Human Arrival. Ecological Monographs 71(4): 615–641.

Carboneras, Carles (1992): Family Anatidae (Ducks, Geese and Swans). In: del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (eds.): Handbook of Birds of the World (Volume 1: Ostrich to Ducks): 536–629. Lynx Edicions, Barcelona. ISBN 84-87334-10-5

Collar, N. J.; Andreev, A. V.; Chan, S.; Crosby, M. J.; Subramanya, S. & Tobias, J. A. (eds.) (2001): Pink-headed Duck. In:Threatened Birds of Asia: The BirdLife International Red Data Book: 489–501. BirdLife International. ISBN 0-946888-44-2 HTML fulltext

Gál, Erika; Hír, János; Kessler, Eugén & Kókay, József (1998–99): Középsõ-miocén õsmaradványok, a Mátraszõlõs, Rákóczi-kápolna alatti útbevágásból. I. A Mátraszõlõs 1. lelõhely [Middle Miocene fossils from the sections at the Rákóczi chapel at Mátraszőlős. Locality Mátraszõlõs I.]. Folia Historico Naturalia Musei Matraensis 23: 33–78. [Hungarian with English abstract] PDF fulltext

Johnsgard, Paul A. (2010): Ducks, Geese, and Swans of the World, Revised edition PDF fulltext

Johnsgard, Paul A. (2010): Waterfowl of North America, Revised edition PDF fulltext

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 DjVu fulltext

Madge, Steve & Burn, Hilary (1987): Wildfowl : an identification guide to the ducks, geese and swans of the world. Christopher Helm, London. ISBN 0-7470-2201-1

McCracken, Kevin G. (2000): "The 20-cm Spiny Penis of the Argentine Lake Duck (Oxyura vittata)". The Auk 117(3) p. 820–825.

Short, Lester L. (1970): A new anseriform genus and species from the Nebraska Pliocene. Auk 87(3): 537–543. 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 (NAS) (1991): The Audubon Society Encyclopedia of North American Birds. Wings Books, New York. Reprint of 1980 edition. ISBN 0517032880

External links

Anatidae videos on the Internet Bird Collection

Anatidae sounds on the xeno-canto collection

Anatidae stamps – Stamps on ducks, swans and geese

* Category:Bird families Category:Waterfowl