Oxyurini

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Oxyurini
Temporal range: Late Oligocene to present
Blue-billed-duck.jpg
Blue-billed duck (Oxyura australis)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae
Subfamily: Anatinae
Tribe: Oxyurini
Swainson, 1831
Genera

Oxyura
Nomonyx
Heteronetta

The Oxyurini are a tribe of the duck subfamily of birds, the Anatinae. It has been subject of considerable debate about its validity and circumscription. Some taxonomic authorities place the group in its own subfamily, the Oxyurinae. Most of its members have long, stiff tail feathers which are erected when the bird is at rest, and relatively large, swollen bills. Though their relationships are still enigmatic, they appear to be closer to swans and true geese than to the typical ducks. The highest diversity is found in the warmer parts of the Americas, but at least one species occurs in a major part of the world[ clarification needed ].

Contents

Their habitus resembles a freshwater diving duck, particularly when moving on dry land. Their legs are set far back, making them awkward walkers, so they rarely leave the water. When at rest, their tails are a notable difference, and in the water they often swim very deep-set. Their unusual courtship displays involve drumming noises from inflatable throat sacs, head throwing, and erecting short crests. Most display singly with a very elaborate and peculiar display, but musk ducks congregate at leks and have a more limited display.

Systematics

One mid-sized genus and two or three which are monotypic are described today:

ImageGenusLiving Species
Heteronetta atricapilla blackheadedduck (cropped).jpg Heteronetta Salvadori, 1866
  • black-headed duck (Heteronetta atricapilla)
Nomonyx dominicus Pato enmascarado Masked Duck (10724525153).jpg Nomonyx Ridgway, 1880
  • masked duck, Nomonyx dominicus
White-headed duck - witkopeend - Oxyura leucocephala.jpg Oxyura Bonaparte, 1828 – stiff-tailed ducks

The black-headed duck of Heteronetta is indisputably quite basal, looking more like a typical duck-like Anatidae with a short tail and normal bill. The masked duck of Nomonyx has a more intermediate position; it probably diverged from the lineage leading to the main radiation some time after Heteronetta.

The musk ducks ( Biziura ), sometimes included in this group, are noted for their bizarre habitus and pronounced sexual dimorphism; they are of uncertain position and decidedly aberrant. Their anatomy is more similar to Oxyura than to the two less derived genera, but still unique in many respects. mtDNA cytochrome b sequence data suggest a closer relationship with the pink-eared ducks ( Malacorhynchus ) which if correct would represent one of the most drastic cases of divergent adaptation in the whole Anseriformes. [1] [2]

Altogether, however, the only thing that seems clear is that the musk ducks probably are not part of the stiff-tailed ducks in the strict sense, but rather represent a not-too-distantly related lineage that is highly convergent as regards their hind limb anatomy. These two are probably part of a very ancient radiation of Gondwanan (often Australian) waterfowl, including such forms as the Cape Barren goose (Cereopsis), the coscoroba swan (Coscoroba), the freckled duck (Stictonetta) which once was placed in the Oxyurinae, or the pygmy geese (Nettapus), but the exact relationships between these lineages remains unresolved. For example, the African white-backed duck (Thalassornis) also shows some similarities to Oxyura, but again, this may be yet another case of convergent evolution. [1] [2] [3]

One fossil genus of Oxyurini, Tirarinetta from the Pliocene of Australia, and some prehistoric members of genera are still extant. Three enigmatic genera of waterfowl, Mionetta from the Late Oligocene to Middle Miocene of central Europe and Dunstanetta and Manuherikia from the Bathans Early/Middle Miocene of Otago, New Zealand, show some similarities to oxyurine ducks and judging from biogeography, the latter two may plausibly be related. However, Manuherikia and Mionetta are sometimes held to be Dendrocheninae adapted to diving, so closer to whistling ducks, a very ancient lineage of the Anatidae.

Related Research Articles

<span class="mw-page-title-main">Goose</span> Common name for a group of waterfowl

A goose is a bird of any of several waterfowl species in the family Anatidae. This group comprises the genera Anser and Branta. Some members of the Tadorninae subfamily are commonly called geese, but are not considered "true geese" taxonomically. More distantly related members of the family Anatidae are swans, most of which are larger than true geese, and ducks, which are smaller.

<span class="mw-page-title-main">Anatidae</span> Biological family of water birds

The Anatidae are the biological family of water birds that includes ducks, geese, and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica. These birds are adapted for swimming, floating on the water surface, and, in some cases, diving in at least shallow water. The family contains around 174 species in 43 genera.

<span class="mw-page-title-main">Anseriformes</span> Order of water birds

Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae, Anseranatidae, and Anatidae, the largest family, which includes over 170 species of waterfowl, among them the ducks, geese, and swans. Most modern species in the order are highly adapted for an aquatic existence at the water surface. With the exception of screamers, males have penises, a trait that has been lost in the Neoaves. Due to their aquatic nature, most species are web-footed.

<span class="mw-page-title-main">Anserinae</span> Subfamily of birds

The Anserinae are a subfamily in the waterfowl family Anatidae. It includes the swans and the true geese. Under alternative systematical concepts, it is split into two subfamilies, the Anserinae contain the geese and the ducks, while the Cygninae contain the swans.

<span class="mw-page-title-main">Stiff-tailed duck</span> Genus of birds

The stiff-tailed ducks, the genus Oxyura, are part of the Oxyurini tribe of ducks.

<span class="mw-page-title-main">Diving duck</span> Tribe of birds

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 Anatidae, the diverse and very large family that includes ducks, geese, and swans.

<span class="mw-page-title-main">Anatinae</span> Subfamily of birds

The Anatinae are a subfamily of the family Anatidae. 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.

<span class="mw-page-title-main">Tadorninae</span> Subfamily of birds

The Tadorninae is the shelduck-sheldgoose subfamily of the Anatidae, the biological family that includes the ducks and most duck-like waterfowl such as the geese and swans.

<span class="mw-page-title-main">Musk duck</span> Species of bird

The musk duck is a highly aquatic, stiff-tailed duck native to southern Australia. It is the only living member of the genus Biziura. An extinct relative, the New Zealand musk duck or de Lautour's duck, once occurred on New Zealand, but is only known from prehistoric subfossil bones. It was about 8% longer than the living species, with a particularly large head.

<span class="mw-page-title-main">White-backed duck</span> Species of bird

The white-backed duck is a waterbird of the family Anatidae. It is distinct from all other ducks, but most closely related to the whistling ducks in the subfamily Dendrocygninae, though also showing some similarities to the stiff-tailed ducks in the subfamily Oxyurinae. It is the only member of the genus Thalassornis.

<span class="mw-page-title-main">Anseranatidae</span> Family of birds

Anseranatidae, the magpie-geese, is a biological family of waterbirds. The only living species, the magpie goose, is a resident breeder in northern Australia and in southern New Guinea.

<i>Anas</i> Genus of birds

Anas is a genus of dabbling ducks. It includes the pintails, most teals, and the mallard and its close relatives. It formerly included additional species but following the publication of a molecular phylogenetic study in 2009 the genus was split into four separate genera. The genus now contains 31 living species. The name Anas is the Latin for "duck".

<span class="mw-page-title-main">Black-headed duck</span> Species of bird

The black-headed duck is a South American duck in subfamily Oxyurinae of family Anatidae. It is found in Argentina, Bolivia, Brazil, Chile, Paraguay, and Uruguay.

<span class="mw-page-title-main">Pygmy goose</span> Genus of birds

Pygmy geese are a group of very small "perching ducks" in the genus Nettapus which breed in the Old World tropics. They are the smallest of all wildfowl. As the "perching ducks" are a paraphyletic group, they need to be placed elsewhere. The initially assumed relationship with the dabbling duck subfamily Anatinae has been questioned, and it appears they form a lineage in an ancient Gondwanan radiation of waterfowl, within which they are of unclear affinities. An undescribed fossil species from the late Hemphillian of Jalisco, central Mexico, has also been identified from the distal end of a tarsometatarsus. It is only record of the genus in the New World.

<span class="mw-page-title-main">Spotted whistling duck</span> Species of bird

The spotted whistling duck is a member of the duck family Anatidae. It is also referred to as the "spotted tree duck". This duck can be found in Indonesia, New Guinea, Australia and the Philippines. Spotted ducks are also held in captive populations.

<span class="mw-page-title-main">Pink-eared duck</span> Species of bird

The pink-eared duck is a species of duck found in Australia.

<span class="mw-page-title-main">Masked duck</span> Species of bird

The masked duck is a tiny stiff-tailed duck ranging through the tropical Americas.

<span class="mw-page-title-main">Maccoa duck</span> Species of bird

The Maccoa duck is a stiff-tailed diving duck found across Eastern and Southern Africa.

Manuherikia is a genus of extinct species of ducks from the Miocene of New Zealand. It was described from fossil material of the Saint Bathans Fauna, in the lower Bannockburn Formation of the Manuherikia Group, found by the Manuherikia River in the Central Otago region of the South Island. The genus name comes from the name of the geological formation in which the fossils were found and, ultimately, from the Manuherikia River and its valley.

References

  1. 1 2 Livezey, Bradley C. (1986). "A phylogenetic analysis of recent anseriform genera using morphological characters" (PDF). Auk . 103 (4): 737–754. JSTOR   4087184.
  2. 1 2 Sraml, M.; Christidis, L.; Easteal, S.; Horn, P. & Collet, C. (1996). "Molecular Relationships Within Australasian Waterfowl (Anseriformes)". Australian Journal of Zoology. 44: 47. doi:10.1071/ZO9960047.
  3. McCracken, Kevin G.; Harshman, John; McClellan, David A. & Afton, Alan D. (1999). "Data set incongruence and correlated character evolution: An example of functional convergence in the hind-limbs of stifftail diving ducks" (PDF). Systematic Biology. 48 (4): 683–714. doi: 10.1080/106351599259979 . PMID   12066296. Archived from the original (PDF) on 2011-06-14.

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