Anseriformes — Waterfowl

Galliformes — Landfowl

The 46 Orders














NEOGNATHAE Pycraft, 1900

The Neognathae divide into two parts: Galloanserae and Neoaves.

GALLOANSERAE Sclater, 1880


The Anseriformes are one branch of the Galloanserae, comprised of 3 families divided into 58 genera and 171 species. Linnaeus himself already recognized an order Anseres, but does not get priority because he did not base it on the genus Anser.

Anhimidae: Screamers Stejneger, 1885 (1831)

2 genera, 3 species HBW-1

Anseranatidae: Magpie-Goose P.L. Sclater, 1880

1 genus, 1 species Not HBW Family

Anatidae: Ducks, Geese, Swans Leach, 1820

56 genera, 173 species HBW-1

The large-scale organization of the ducks is based on Gonzalez et al. (2009b), with support from Bulgarella et al. (2010), Donne-Goussé et al. (2002), and Sorenson et al. (1999). The whistling-ducks are the basal group. There is uncertainty about whether Thalassornis belongs here or is basal to the rest of the ducks. The remaining ducks generally follow a cascade which is hard to break into convenient pieces. Not all of these pieces are included in these analyses, so information from other sources has to be added. These include Bulgarella et al. (2014), Fulton et al. (2012), Johnson and Sorenson (1999), McCracken et al. (1999, 2010), Worthy and Olson (2002), St. John et al. (2005), Pointer and Mundy (2008), and the discussion of Sraml et al. (1996) in Christidis and Boles (2008).

Anatidae tree
Click for genus-level tree
for Anseriformes

The resulting paste-up yields the tree above. There are some issues with this tree, but it was what I could do with the information I have.

It's generally thought that Stictonetta is the basal genus of the remaining ducks, but Sraml et al. (1996) found it in a clade with Cereopsis, which Donne-Goussé et al. (2002), St. John et al. (2005), Pointer and Mundy (2008), and Gonzalez et al. (2009b) group with Coscoroba. Here I separate them, putting Stictonetta in its own subfamily and grouping Cereopsis with Coscoroba in Anserinae.

Plectropterus is another duck of uncertain affinities. It may be quite basal, near Stictonetta, but there is less certainty about this, hence the blue color.

Gonzalez et al. (2009b) found that the remaining ducks fall into two clades: here designated Anserinae and Anatidae (they use a narrower Anserinae).

Anserinae contains four pieces. One is Oxyrunini. McCracken et al. (1999) made clear that the Musk Duck Biziura lobata is not one of the stiff-tailed ducks (Oxyrunini). In fact, it seems to be sister to Anserini + Oxyrunini (Gonzalez et al., 2009b). There's some evidence that the Nettapus Pygmy-Geese also belong in this subfamily (Sraml et al., 1996). Exactly where the pygmy-geese go is not clear, so I have put them in a relatively basal position pending information on their true relatives.

I have also made some adjustment to Anserini. Gonzalez et al. (2009b) placed Malacorhynchus basally in Anserini (which here includes the swans). Although Gonzalez et al. (2009b) found that the Black-necked Swan groups with the Cygnus swans, Pointer and Mundy (2008) found it sister to the geese. I've compromised here by putting it between the two. The genus name Sthenelides (Stejneger 1884) is revived for this.

The genus Chen has been merged into Anser. Donne-Goussé et al. (2002) and Gonzalez et al. (2009b) found that Chen is not monophyletic. However, they found different topologies for Anser + Chen. The arrangement here is based on Ottenburghs et al. (2016). Their calibrated phylogeny suggests that the two genus treatment of the geese (Anser and Branta) is best.

The AOU allocated subspecies between Canada Goose and Cackling Goose with asiatica, leucopareia, minima, taverneri, and hutchinsii as Cackling Geese and occidentalis, fulva, maxima, parvipes, moffitti, interior, canadensis as Canada Geese. Those curious about why the split works this way should consult Paxinos et al. (2002) and Scribner et al. (2003). Some questions have been raised about whether all of parvipes Canada Geese are really parvipes. Most of the range has been little-sampled.

I am now treating the Bean Goose as three species instead of two. Sangster and Oreel (1996) presented evidence that the Taiga Bean-Goose and Tundra Bean-Goose interbred rarely or not at all, that they are separate biological species. Although Ruokonen et al. (2008) presented evidence that they are reciprocally monophyletic, increased sampling in Ruokonen and Aarvak (2011) contradicted this. I am presuming this represents incomplete lineage sorting.

According to Ruokonen and Aarvak (2011), the sister taxa johanseni and middendorffii were basal to both, and I have split them as Middendorf's Bean-Goose, Anser middendorffii. There is a complication in that birds identified as neglectus in all three groups. Apparently the neglectus specimens were quite diverse in appearance too, and this subspecies seems better left unrecognized. The evidence here is not conclusive, but my best guess as to how to divide the Bean-Geese is this:

The actual sequence of the Pink-footed/Bean Goose group is not completely resolved. Ottenburghs et al. (2016) does not include Middendorf's Bean-Goose and does not match up well with Ruokonen and Aarvak (2011). Comparison with Ottenburghs et al. (2016) suggests Ruokonen and Aarvak's (2011) tree of these geese may be improperly rooted in addition to the possible incomplete lineage sorting. This renders the position of Middendorf's Bean-Goose somewhat uncertain.

The other ducks belong to Anatinae, which contains almost three-fourths of the Anatidae. I split it into six tribes. How to order them is an issue. Donne-Goussé et al. (2002) present a couple of alternatives. A third in found in Sorenson et al. (1999), while Gonzalez et al. (2009b) have another and Bulgarella et al. (2010) yet another. Most pair Anatini and Aythyini. I've followed that, but left the relative position of Tadornini, Mergini, Cairinini, and Callonettini unresolved. The different analyses handle this differently, and I don't have sufficient reason to choose one over the other.

Within Tadornini, Gonzalez et al. (2009b) found that the Radjah Shelduck does not group together with the other Tadorna shelducks. This is handled by returning it to the monotypic genus Radjah (Reichenbach, 1852). The extinct Mascarene Sheldgoose, Alopochen mauritiana, has been split into Reunion Sheldgoose, Alopochen kervazoi, and Mauritius Sheldgoose, Alopochen mauritiana. The Andean Goose has moved to Oressochen from Chloephaga and the remaining Chloephaga have been rearranged. See McCracken et al. (2010) and Bulgarella et al. (2014).

Gonzalez et al. (2009b) have Cairinini sister to Tadornini. However, other studies have a different arrangement (e.g., Bulgarella et al. (2010) place Cairinini sister to Anatini + Aythyini).

One of the nice features of Gonzalez et al. (2009b) is that they have sufficient taxon sampling to reasonably resolve Aythyini. The arrangement of Aythya itself is loosely based on Gonzalez et al. Note that Cairina and Asarcornis, formerly considered congeneric, end up in different tribes, Cairinini and Aythyini.

About one-third of all the ducks and geese are in the tribe Anatini, and many are conventionally placed in the genus Anas. The data presented by Johnson and Sorenson (1998, 1999), and Gonzalez et al. (2009) suggest that Anas should be split as some species of Anas end up closer to the Lophonetta-Tachyeres clade. Bulgarella et al. (2010) have a different arrangement with a monophyletic Anas, but only sample one of the relevant Anas species. The Lophonetta-Tachyeres clade is treated as in Fulton et al. (2012), but alternative topologies cannot be ruled out. Salvadori's Teal has been moved to an indeterminate position at the end. Kear (1975) made the case it is not in Anas, but could not pin down its true affinities.

Appropriate genus names exist for the Anas split, and I've used them for the ducks from Baikal Teal (now Sibirionetta formosa) to Northern Shoveler (Spatula clypeata). The point here is that the smallest monophyletic group that includes these species and the Mallard may be all of Anatini. Thus we either change the genus names or call all of them Anas. I prefer the former option.

Had they survived, the flightless Moa-nalos of Hawaii would be the basal group in the Anatini (Sorenson et al., 1999). Of the exant Anatini, the basal clade includes several South American ducks. The other clade includes Baikal Teal (Sibirionetta), Garganey, the silver teals, and the shovelers and blue-winged teals, all placed in Spatula, as in Dickinson and Remsen (2013, aka H&M-4).

The remaining ducks are left in Anas. This natural division results in a narrower Anas, but one that still has substantial structure within it. The arrangement within Anas, is based on Johnson and Sorenson (1999), Gonzalez et al. (2009b), and Mitchell et al. (2014a), with a tilt toward the last. All use much of the same data, and all agree agree that the wigeons are the basal group within Anas, strepera through sibilatrix. Some have argued these should also be placed outside Anas (Dickinson and Remsen (2013) place them in Mareca). I'm happy to think of them as a subgenus of Anas.

The remaining Anas species fall into 5 groups: mallards, green-winged teals, pintails, gray teals, and brown teals. The exact branching order is somewhat uncertain. It seems most likely that the mallard group is sister to the rest, and the brown and gray teals are sisters.

The Mallard complex continues to be a particular problem, with potential hybridization issues equalling those of the large gulls (see McCracken et al., 2001; Kulikova et al., 2004, 2005; Lavretsky et al., 2014). Based on McCracken et al. (2001), I've decided to include the Mexican Duck as a separate species. Unless one takes an expansive view of the Mallards that includes Mottled and Black Ducks as subspecies, it's not a Mallard. It's closer to the Mottled Ducks and Black Ducks than to Mallards, so it doesn't make sense to list them separately and treat the Mexican Duck as a Mallard subspecies. In fact, there's a question about whether the Florida Mottled Ducks should be split from the other Mottled Ducks.

McCracken et al. (2001) also propose a solution to the problem that the Mallard appears to be in two separate group of mallard-type ducks. They argue that an mallard-type ducks have twice colonized North America. In that view colonization by a monochromatic ancestral mallards resulted in three monochromatic species (Black Duck, Mexican Duck, and Mottled Duck). The dichromatic Mallard we all known developed in the other clade, and subsequently colonized North America. It was able to hybridize with the existing mallard-type ducks and its North American descendents still carry the DNA of both ancestors. This makes the Mallard appear in two places on the tree. It also serves as a reminder that the phylogenetic network need not always form a tree, but may sometimes be more complex.

This of course creates problems handling the mallard complex. Avise et al. (1990) discovered two haplotypes in North American Mallards. It appears that the type B haplotype arises from hybridization with black ducks (including Mottled, Mexican, and Hawaiian), while pure Mallards are type A. Kulikova et al. (2004) note that the Eastern Spot-billed Duck has a variant of the type B haplotype, while the Indian Spot-billed and Philippine Ducks are type A. This suggests that the Eastern Spot-billed Duck should be grouped with the black ducks and that the Indian Spot-billed and Philippine Ducks go next to the Mallard. Lavretsky et al. (2014) try to see through the effects of rampant mallard hybridization. The arrangement here is inspired by their efforts. See Rhymer (2001) and Kulikova et al. (2004, 2005) for more details on the mallard complex.

Note that the Green-winged Teal, Anas carolinensis, and Eurasian Teal, Anas crecca, do not appear to be sister species. Rather, Johnson and Sorenson (1999), Gonzalez et al. (2009b), and Mitchell et al. (2014a) found that the Green-winged Teal is sister to two South American teals: Andean Teal, Anas andium and Yellow-billed Teal, Anas flavirostris. The green-winged teal complex could go by the name Nettion, which is used as subgenus name on the tree.

We put the pintails next, Cape Teal, Anas capensis, through Kerguelen (Eaton's) Pintail, Anas eatoni. They are in subgenus Dafila.

The last two groups are the gray and brown teals. The gray teals are Chestnut Teal, Anas castanea through Gray Teal, Anas gracilis, and the brown teals are the rest. The subgenus name Virago applies to the gray teals, and Nesonetta to the brown teals. The extinct Chatham Duck, usually placed in its own genus Pachyanas, actually belongs with the brown teals (Mitchell et al., 2014a). It is believed to have become extinct in the 16th century.

Dendrocygninae: Whistling-Ducks Reichenbach, 1849-50

Stictonettinae: Freckled Duck von Boetticher, 1950

Plectropterinae: Spur-winged Goose Eyton, 1838

Anserinae: Geese, Swans Vigors, 1825 (1815)

Biziurini: Musk Duck Mathews, 1946

Nettapodini: Pygmy-Geese Bonaparte, 1856

Oxyurini: Stiff-tailed Ducks Swainson, 1831

Anserini: Geese, Swans Vigors, 1825 (1815)

Anatinae: Ducks Leach, 1820

Tadornini: Shelducks and Sheldgeese Reichenbach, 1849-50

Mergini: Sea Ducks Rafinesque, 1815

Cairinini: Perching Ducks von Boetticher, 1936-38

Callonettini: Ringed Teal Verheyen, 1953

Aythyini: Diving Ducks Delacour and Mayr, 1945 (1831)

Anatini: Dabbling Ducks Leach, 1820

Incertae Sedis: Anatinae

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