Anatinae
| Dabbling ducks Temporal range:
| |
|---|---|
| |
| Pacific black duck(Anas superciliosa) | |
Scientific classification
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Anseriformes |
| Family: | Anatidae |
| Subfamily: | Anatinae Leach,1820 |
| Type species | |
| Anas platyrhynchos | |
| Genera | |
|
Seetext | |
TheAnatinaeare asubfamilyof thefamilyAnatidae(swans,geeseandducks). Its surviving members are thedabbling ducks,which feed mainly at the surface rather than bydiving.The other members of the Anatinae are the extinctmoa-nalo,a young but highlyapomorphiclineage derived from the dabbling ducks.
There has been much debate about thesystematicalstatus and which ducks belong to the Anatinae. Some taxonomic authorities only include the dabbling ducks and their close relatives, the extinct moa-nalos. Alternatively,[1]the Anatinae are considered to include most "ducks",and the dabbling ducks form atribeAnatiniwithin these. The classification as presented here more appropriately reflects the remaining uncertainty about the interrelationships of the major lineages ofAnatidae(waterfowl).[2]
Systematics
[edit] | This sectionneeds additional citations forverification.(September 2011) |
The dabbling duck group, of worldwide distribution, was delimited in a 1986 study[3]to include eight genera and some 50–60 living species. However,Salvadori's tealis almost certainly closely related to thepink-eared duck,and other genera are likewise of unresolved affiliation.[2][4]The peculiarmarbled duck,formerly tentatively assigned to the dabbling ducks, is thought to be a diving duck or even a distinct subfamily.[2]
This group of ducks has been so named because its members feed mainly on vegetable matter by upending on the water surface, or grazing, and only rarely diving. These are mostly gregarious ducks of freshwater or estuaries. Thesebirdsare strong fliers and northern species are highlymigratory.Compared to other types of duck, their legs are located more towards the centre of their bodies. They walk well on land, and some species feed terrestrially.
"Puddle ducks" generally feed on the surface of the water or feed on very shallow bottoms. They are not equipped to dive down several feet like their diving counterparts. The most prominent difference between puddle ducks and divers is the size of the feet. A puddle duck's feet are generally smaller because they do not need the extra propulsion to dive for their forage.
Another distinguishing characteristic of puddle ducks when compared with diving ducks is the way in which they take flight when spooked or are on the move. Puddle ducks spring straight up from the water, but diving ducks need to gain momentum to take off, so they must run across the water a short distance to gain flight.
Traditionally, most ducks were assigned to either theshelducks,theperching ducks,and the dabbling anddiving ducks;the latter two were presumed to make up the Anatinae. However, the perching ducks turned out to be aparaphyleticassemblage of varioustropicalwaterfowl that happened toevolvethe ability to perch well in their forestedhabitat.Several of these, such as theBrazilian teal,were subsequently assigned to the Anatinae.
As for thediving ducks,mtDNAcytochromebandNADH dehydrogenasesubunit2sequencedata[2]indicates that they are fairly distant from the dabbling ducks. Themorphologicalsimilarities[3]are due toconvergent evolution.
In addition, the genusAnas,as traditionally defined, is notmonophyletic;severalSouth Americanspecies belong to a distinct clade which would include theTachyeressteamer-ducks.[2]Other species, such as theBaikal teal,should also be considered distinct.
Genera
[edit]
The following genera are (with one exception) unequivocaldabbling ducks:
- Amazonetta– status not fully resolved, most likely a dabbling duck
- Sibirionetta–Baikal teal
- Spatula
- Mareca
- Lophonetta–crested duck
- Speculanas–bronze-winged duck
- Anas
The three known genera and four known species ofmoa-nalosall became extinct around AD 1000. They formerly occurred on theHawaiian Islandsand were derived from dabbling ducks, possibly even from a close ancestor of themallard:
Subfossilremains of a small, flightless dabbling duck have been recovered onRotain theMariana Islands.[5]These cannot be assigned to a known genus, but probably are closest toAnas.A most bizarre duck-like bird,Talpanas lippahas been found on theHawaiianisland ofKauai.[6]Because of its uniqueapomorphies(it seems to have had small eyes high and far back on its head), the placement of thisanatidis likewise unresolved; only dabbling ducks and truegeeseare with certainty known to have colonized theHawaiian archipelago.
Another bizarre insular anatine wasBambolinettafrom the LateMioceneofTuscana,then part of the Tuscano-Sardinian insular landmass. Flightless or at least a poor flyer, it instead shows adaptations for wing-propelled diving, occupying a similar ecological niche to that ofpenguinsandplotopterids.
Frequently placed into the Anatinae are these genera, whose relationships must be considered uncertain at present:
- †Chenoanas?
- †Dunstanetta(Johnstone's duck)
- †Lavadytis
- †Pinpanetta
- †Tirarinetta
- Oxyurini(stiff-tailed ducks)
- Heteronetta(black-headed duck)
- Nomonyx(masked duck)
- Oxyura
- Biziura– Oxyurini?
- Aix– Tadorninae?
- Cairina– may beparaphyletic,with one species in Tadorninae and the other closer to diving ducks
- Callonetta– Tadorninae?
- Chenonetta– Tadorninae?
- Pteronetta– may belong into a distinctcladewithCyanochen
- Nettapus– part of ancientGondwananlineage?
- Mergini- (seaducks)
On the other hand, the following genera, usually considered to belong into the Tadorninae, may actually be dabbling ducks:
References
[edit]- ^Terres, John K. &National Audubon Society(1991):The Audubon Society Encyclopedia of North American Birds.Wings Books, New York. Reprint of 1980 edition.ISBN0-517-03288-0
- ^abcdeJohnson, Kevin P.; Sorenson, Michael D. (1999)."Phylogeny and biogeography of dabbling ducks (genus Anas): a comparison of molecular and morphological evidence"(PDF).Auk.116(3): 792–805.doi:10.2307/4089339.JSTOR4089339.
- ^abLivezey, Bradley C. (1986)."A phylogenetic analysis of recent anseriform genera using morphological characters"(PDF).Auk.103(4): 737–754.doi:10.1093/auk/103.4.737.
- ^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.doi:10.1071/ZO9960047.
- ^Steadman, David William (1999)."The Prehistory of Vertebrates, Especially Birds, on Tinian, Aguiguan, and Rota, Northern Mariana Islands"(PDF).Micronesica.31(2): 319–345. Archived fromthe original(PDF)on 2004-07-05.
- ^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.doi:10.2307/3100038.hdl:10088/109.JSTOR3100038.
