Cladistic analysis of 157 characters of definitive plumages and soft parts, natal plumages, tracheae, and nontracheal skeletons of 59 Anatini (sensu Livezey 1986) provided a phylogenetic hypothesis of high consistency (CI = 0.71, excluding unique autapomorphies) and resolution (tree completely resolved except for two nested trichotomies, a trichotomy within the northern-hemisphere mallards, and the tentative placements of two poorly known species of Anas). Major phylogenetic inferences (lists of three or more taxa are in order of increasing relatedness) include the following: (1) monophyly of the tribe is weakly demonstrated; (2) the tribe comprises three subtribes--Cairineae (Cairina, Pteronetta, Aix), Nettapodeae (Chenonetta, Nettapus), and Anateae (all other genera); (3) subtribe Anateae comprises three "supergenera" (each comprising two genera)--Amazonetta (A. brasiliensis and Callonetta leucophrys), Lophonetta (L. specularioides and Speculanas specularis), and Anas (genera Mareca and Anas); (4) the genus Mareca or wigeons includes six species--capensis, strepera, falcata, sibilatrix, penelope, and americana; and (5) the large genus Anas comprises two weakly supported subgroups or cohorts, the first of which includes two subgenera (mallards [Anas] and blue-winged ducks [Spatula]) and the second includes four subgenera (Australasian teal [Nesonetta], pintails [Dafila], Holarctic teal [Querquedula], and spotted teal [Punanetta]). Other findings include that a sister-relationship exists between Anas sparsa and other mallards, that subgroups of the "true" mallards are largely congruent with biogeographic subdivisions (northern-hemispheric, African, and South Pacific), that the four species of shoveler are monophyletic, that a sister-relationship between the speckled teals (flavirostris and andium) and brown pintails (georgica, acuta, and eatoni) exists, and that A. querquedula is the sister-group to the green-winged teals (formosa, crecca, and carolinensis) and not closely related to the blue-winged ducks. Supplementary data and related theory indicated that (1) interspecific interfertility is a poor indicator of relationship, (2) the phylogenetic species concept provided the most practical definition of terminal taxa, (3) a majority of groups within the Anatini originated in the southern hemisphere, (4) body size, sexual size dimorphism, and egg size are strongly constrained phylogenetically, whereas sexual dichromatism and clutch size are less predictable, (5) biparental attendance of broods is primitive within Anatini, and (6) characters of definitive plumages, natal plumages, tracheae, and skeletons had similar consistencies but attained maximal utility at different levels within the phylogeny, which indicates different rates of character evolution within the tribe. Received 19 July 1990, accepted 4 December 1990.
Museum of Natural History, Dyche Hall, University of Kansas,
Lawrence, Kansas, 66045-2454 USA
TRIBE Anatini (dabbling ducks; sensu Livezey
! 986) comprises all typical surface-feeding ducks
and the smaller "perching ducks," which were
formerly grouped under the tribal name "Cairi-
nini" (Delacour and Mayr 1945) or included in
the subfamily Plectropterinae (Phillips 1922).
These are perhaps the most familiar waterfowl
and together include roughly one third of the
extant species of Anseriformes. Bock and Far-
rand (1980) listed Anas as one of the largest
avian genera, yet they conservatively recog-
nized only 36 species. Current taxonomic
groupings within the Anatini, like other sub-
groups of waterfowl, derive principally from
the classic work by Delacour and Mayr (1945)
and, to a lesser extent, earlier investigations
(Salvadori 1895; Phillips 1922, 1923, 1925, 1926;
Peters 1931; Kuroda 1939; and Boetticher 1942).
The taxonomy and inferred evolutionary "af-
finities" of dabbling and perching ducks pro-
posed by Delacour and Mayr (1945), based on
comparisons of behavioral and external simi-
larities, were expanded by Delacour (1954, 1956,
! 959, 1964). Subsequent research on the system-
atics of dabbling ducks used comparisons of be-
havior and morphology (e.g. Boetticher 1952;
Lorenz 1941, 1951-1953; Johnsgard 1960a, b,
1961a, b, 1962, 1965; Kaltenhauser 1971; Scherer
and Hilsberg 1982) and largely confirmed the
phenetic groupings defined by Delacour and
Mayr (1945). Important changes proposed at two
major taxonomic levels included the relation-
ships of several problematic species to the tribe,
and relationships among the species within the
Anatini.
Most of the taxonomic revisions recommend-
ed subsequent to Delacour and Mayr's (1945)
proposal pertained to generic or tribal mem-
bership. Johnsgard (1960c) determined that the
Ringed Teal ("Anas" leucophrys) differed suffi-
ciently from typical Anas to be returned to the
monotypic genus Callonetta. In a comprehen-
sive study of waterfowl osteology, Woolfenden
(1961) recommended that the "perching ducks"
(Tribe Cairinini, sensu Delacour and Mayr 1945,
but exclusive of Plectropterus) be merged into
the "dabbling ducks" (Tribe Anatini). Johns-
gard proposed to re-assign the Pink-headed
Duck (Rhodonessa caryophyllacea; 1961a) and
Marbled Teal (Marmaronetta [Anas] angustiros-
tris; 1961c) to the pochards (Tribe Aythyini).
Johnsgard (1961a) also advocated the inclusion
of the Crested Duck (Lophonetta specularioides)
within the Anatini rather than among the shel-
ducks (Tribe Tadornini) as proposed by Dela-
cour and Mayr (1945). Salvadori's Duck (Sal-
vadorina [Anas] waigiuensis) was included in Anas
by Delacour and Mayr (1945), but earlier au-
thors placed it in a separate subfamily Merga-
nettinae with Merganetta (Salvadori 1895, Phil-
lips 1926), and others retained it as a monotypic
genus of problematic relationships (Mayr 1931,
Peters 1931, Kear 1975). Several other species
included as aberrant members of the Anatini
by Delacour and Mayr (1945) subsequently have
had varied taxonomic treatments. These include
the Blue Duck (Hymenolaimus malacorhynchos),
Pink-eared Duck (Malacorhynchus membrana-
ceus), and Freckled Duck (Stictonetta naevosa).
Hymenolaimus was studied in detail (Kear 1972),
and Stictonetta was later removed from the Anat-
inae on the basis of morphological and behav-
ioral comparisons (see Johnsgard 1960a, 1961a,
1962). The unique Torrent Duck (Merganetta ar-
mata) was placed in the monospecific tribe Mer-
ganettini (Delacour and Mayr 1945) but consid-
ered to be closely related to Anas (Niethammer
1952). Merganetta was included by Delacour
(1956) and Johnsgard (1961a, 1965) within the
Anatini, although Johnsgard (1978) later re-
turned it to its own tribe. Eldridge (1979) con-
cluded that Merganetta is most similar ethol-
ogically to Tadorninae.
These taxonomic revisions were adopted in
large part by Johnsgard (1979) in the latest edi-
tion of the "Checklist of Birds of the World,"
although tribes within the Anatinae were omit-
ted. In a recent phylogenetic analysis of Recent
genera of Anseriformes, Livezey (1986) con-
cluded that (1) Stictonetta and Plectropterus are
representatives of monotypic, pre-anatine
branches of subfamilial rank, (2) Sarkidiornis,
Malacorhynchus, Hymenolaimus, and Merganetta
are unusual members of the Tadorninae, (3)
Marmaronetta and Rhodonessa are members of
the Aythyini, and (4) the relationships among
the remaining members of Cairinini and Ana-
tini could not be determined from osteology
and therefore were merged into the single, pos-
sibly paraphyletic tribe Anatini. Livezey (1986)
omitted Salvadorina from this analysis, but MI-
kovsk (1989) reexamined the partial skeletons
of S. waigiuensis described by Mayr (1931) and
concluded that the species may be more closely
related to Hymenolaimus and Malacorhynchus than
to Anas.
Relationships among dabbling ducks, partic-
ularly within the genus Anas, have received
comparatively little study. Special attention was
given relationships within Anas (Delacour and
Mayr 1945; Lorenz 1951-1953; Johnsgard 1961a,
1965). These studies were based largely on com-
parisons of behavior (and to a lesser extent,
plumage) and none attempted to compile com-
parative data for even a majority of species. All
(except perhaps Lorenz 1951-1953) were phe-
netic in nature (i.e. groupings of species were
based on assessments of overall similarity ir-
respective of possible polarities of characters).
A pronounced "tradition" of taxonomic se-
quences of dabbling ducks developed (bench-
mark works include Salvadori 1895; Phillips
1922-1926; Peters 1931; Delacour and Mayr 1945;
Johnsgard 1961a, 1979), which reflected a con-
sensus of roughly "primitive-to-advanced" in-
tratribal relationships. These classifications pri-
marily reflect changing taxonomic conventions
and secondarily indicate differences in percep-
tions of relationships among Anatini. Varia-
tions in species names aside, important trends
include a reduction in numbers of species of
Anatini (sensu Livezey 1986, excluding Salva-
dorina) recognized (65 by Salvadori 1895, 64 by
Phillips 1922-1926, 60 by Peters 1931, 46 by
Delacour and Mayr 1945 and by Johnsgard
1961a); a reduction in number of genera rec-
ognized (17 by Salvadori 1895, 10 by Phillips
1922-1926, 13 by Peters 1931, 7 by Delacour and
Mayr 1945, and 8 by Johnsgard 1961a); and an
increase in the numbers of presumed "natural"
groups within Anas, a change that largely re-
flected the "Groups 1-14" of Delacour and Mayr
(1945) and the clusters depicted by Johnsgard
(1961a) or considered "superspecies" by Johns-
gard (1979).
Molecular studies of Anseriformes have con-
tributed significant, largely confirmational in-
formation on probable relationships (Scherer
and Sontag 1986). A number of biochemical
studies have included more than one species of
Anatini. Among these are compositional com-
parisons of uropygial secretions (Jacob and Gla-
set 1975, Jacob 1982); electrophoretic studies of
proteins from a diversity of tissues (Sibley and
Ahlquist 1972, Brush 1976, Numachi et al. 1983,
Oates et al. 1983, Patton and Avise 1985); im-
munological comparisons of blood plasma
(Bottjer 1983); restriction endonuclease analysis
of mitochondrial DNA (Kessler and Avise 1984,
Avise et al. 1990); and DNA hybridization
(Madsen et al. 1988). None of these studies,
however, included samples from >14 species
of Anas or > 19 species of Anatini (sensu Livezey
1986), few considered problematic species, and
none employed cladistic methodologies.
Branching diagrams in these studies usually
were based on simple UPGMA clustering of
taxa based on pairwise distances. For the resul-
tant branching diagrams to represent phylo-
genetic relationships, such clustering algo-
rithms require the additional assumption of
equal rates of molecular evolution in all lin-
eages (Wiley 1981, Hillis 1987). Moreover, some
of the, studies were hampered by (I) small num-
bers of loci compared (e.g. I0 loci in Numachi
et al. [1983] and 26 in Patton and Avise [1985]),
(2) data matrices that lack substantial propor-
tions of pairwise distances and have undesira-
ble metric properties (Madsen et al. 1988), (3) a
substantial dependence on traditional classifi-
cations in investigational design and inferences
(Bottjer 1983, Patton and Avise 1985), or (4) a
reliance on traditional, phenetic classifications
of fossil species for estimates of divergence times
and evolutionary rates (Patton and Avise 1985,
Madsen et al. 1988).
I present a phylogenetic (cladistic) analysis
of the Anatini from 157 polarized characters of
the skulls, syringeal bullae, natal plumages, de-
finitive plumages, and soft parts of 59 taxa. I
discuss relative consistencies and evolutionary
rates of character groups, ecological and bio-
geographical correlates, and relationships of
traditionally problematic taxa and closely re-
lated tribes, and I propose an annotated Lin-
nean classification of the Anatini.
MATERIALS AND METHODS
Taxa included.--All 88 specific and subspecific taxa
of Recent Anatini were included for analysis as mem-
bers of the ingroup, although skin specimens of downy
young, tracheae, and (especially) skeletons were not
available for all taxa. For the derivation of trees, I
combined taxa with identical character-states, which
reduced the number of analytical units to 59. These
analytical combinations merged taxa typically con-
sidered to be subspecies. I defined subspecies for prac-
tical purposes as lineages that differed only quanti-
tatively (often in intensity of plumage colors or size)
from conspecific taxa. These differences probably re-
flect spatially separated samples of clinal variation.
This practice produced the nontraditional combina-
tion of Anas fulvigula and A. diazi (while maintaining
the qualitatively distinguishable A. platyrhynchos and
A. rubripes), and the elevation to species rank of a
number of taxa commonly treated as subspecies (A.
wyvilliana, A. laysanensis, A. oustaleti, A. zonorhyncha,
A. albogularis, A. chlorotis, A. eatoni, A. andium, A. car-
olinensis, and A. puna). Several other taxa are either of
problematic tribal assignment (e.g. Salvadorina, Mer-
ganetta) or are "basal," Anatini-like members of other
tribes of Anatinae (e.g. Polysticta, Marmaronetta, Het-
eronetta) and were included for ancillary comparisons.
These latter genera and several others (Sarkidiornis,
Tadorna, Somateria) were included as members of the
outgroup for determination of polarities.
Specimens examined.--I examined study skins of
downy young (mostly age-class Ia, brightly patterned
with no plumaceous feathers) and adults, skeletal ma-
terial (particularly skulls), and syringeal bullae (most
mounted with tracheae) of all species of Anatini ex-
cept for the following: Anas oustaleti (downy young
not examined, but described by Phillips [1923]), A. chlo-
rotis and A. aucklandica (downy young not examined,
but described and illustrated in Delacour [1956, 1964]);
A. melleri (skeleton and syrinx not available), A. al-
bogularis (skeleton and syrinx not available), and A.
bernieri (skeleton, syrinx, and downy young not
known). I included a series of study skins of adults
of all species, and for a majority of species, samples
of three or more were studied for characters of the
skull, trachea, and natal plumage. The collections of
study skins of adults and downy young at the Na-
tional Museum of Natural History (NMNH) and
American Museum of Natural History (AMNH), and
the skeletal collections at the NMNH and the Uni-
versity of Kansas Museum of Natural History
(KUMNH), were especially important. I received a
generous loan of skins of downy young and mounted
tracheae from the Wildfowl Trust (WT), Slimbridge,
England.
Analysis of some characters was facilitated by study
of several published references: Phillips (1922-1926),
Delacour and Mayr (1945), Delacour (1956, 1964), Rip-
ley (1957a, b), Huey (1961), Woolfenden (1961),
Johnsgard (1965, 1978), Oring (1968), Palmer (1976),
Soothill and Whitehead (1978), Todd (1979), Weller
(1980), Hosking and Kear (1985), Madge and Burn
(1988). Data on body mass, sexual dimorphism, dis-
tributions, and reproductive parameters were com-
piled from these references and others listed by Live-
zey (1990).
Definition and analysis of characters.--A total of 157
characters that had two or more discrete states were
included in the analysis (Appendix 1). Based on out-
group comparisons, I divided characters into a single
primitive state (for the Anatini) and one or more de-
rived states. To confirm the monophyly of terminal
taxa, representative autapomorphies were compiled
(but not included in the analysis; a list is available
from the author on request). Key references for char-
acter descriptions were as follows: Humphrey and
Parkes (1959) for definitive plumages, Humphrey and
Clark (1964) and Warner (1971) for the syrinx, and
Butendieck and Wissdoff (1982) for the skull. Several
skeletal characters given by Woolfenden (1961) for
subgroups of the Anatini (especially Amazonetta and
Callonetta) were excluded because of intraspecific
variation and problematic definition of states. Behav-
ioral characters of Anatini have been studied intense-
ly (Delacour and Mayr 1945; Lorenz 1951-1953; Mc-
Kinney 1953, 1965; Delacour 1956; Johnsgard 1961a,
1962, 1965), but they were excluded because of dif-
ficulties in definition of character states and numer-
ous missing data.
Derivation of phylogenetic trees.--Searches for most-
parsimonious topologies (trees requiring the fewest
character changes) were made with "global" branch-
swapping algorithms with "MULPAR$" (MAXTREE
= 250) in the PAUP program (Swofford 1985). Both
procedures search for the "shortest" tree(s) possible
and permit the storage of a number of equally par-
simonious topologies, but neither guarantees the de-
termination of the shortest possible tree(s). Exhaus-
tive search algorithms (e.g. branch-and-bound) were
not employed because of the prohibitively great com-
putational expenditure necessitated by data sets of
this size. The 16 multistate characters (those with two
or more derived states) were analyzed as unordered,
with the exception of the meristic, ordinal counts of
rectrices (character 27). To find preliminary topolo-
gies within reasonably short computing times, I re-
placed several unknown syringeal character states in
A. bernieri with those shared by other Australian teal
(A. gibberifrons, A. castanea, A. chlorotis, and A. aucklan-
dica); similarly, several natal character states of A.
bernieri were hypothesized to be those shared by A.
gibberifrons and A. albogularis. I also described the to-
pological differences of subsequent analysis with
missing-data codes replaced. All characters were as-
signed unit weight. Trees were rooted using an "hy-
pothetical ancestor" (vector of plesiomorphous char-
acter states), which was prepared from polarities
inferred from outgroup comparisons. (See Appendix
3 for an annotated data matrix.) Theory and meth-
odological rationales for phylogenetic analysis are
given by Wiley (1981) and Swofford (1985). All com-
putations were made on the IBM mainframe com-
puter at the University of Kansas.
Phylogenetic classification.--The hierarchical group-
ings within phylogenetic trees can be summarized in
Linnean classifications (Wiley 1981). Parageneric
taxa--supergenera, subgenera, and infragenera--were
erected as needed to conserve phylogenetic infor-
mation and based on synonomies presented by Phil-
lips (1923), Brodkorb (1964), and Wolters (1976).
RESULTS
Trees found.--Under the constraint of char-
acter states hypothesized (as detailed above) in
the Madagascan Teal (A. bernieri), inferred trees
had consistency indices of 0.71 and lengths of
250 (inclusion of representative autapomor-
phies inflated the consistency index by 0.05).
Only three unresolved sections of the phylog-
eny were indicated (Fig. 1). The first poorly
resolved segment involved the relationships
among three subgenus-groups in the genus Anas
(sensu stricto). Three topological variants were
found: (1) the groups (Nesonetta, Dafila, and Pun-
anetta-Querquedula) as a trichotomy; (2) Dafila as
the sister-group to a clade that comprises Dafila
and Punanetta-Querquedula; and (3) Punanetta-
Querquedula as the sister-group to a clade com-
posed of Dafila and Nesonetta. The second poorly
resolved section involved the relationships
among four entities: the poorly known A. ber-
nieri; the relatively similar A. gibberifrons and A.
albogularis; and a resolved clade that includes A.
castanea, A. chlorotis, and A. aucklandica (Fig. 1).
Four equally parsimonious topological variants
were found for these four groups: (1) A. bernieri,
A. albogularis, and A. gibberifrons composing a
grade paraphyletic to the "reddish teal" (A. cas-
tanea, A. chlorotis, and A. auklandica); (2) A. ber-
nieri as the sister-group to a trichotomy involv-
ing A. albogularis, A. gibberifrons, and the clade
of "reddish teal"; (3) a trichotomy involving A.
bernieri, a clade of A. albogularis and A. gibberi-
frons, and the clade of "reddish teal"; and (4) A.
bernieri as the sister-group to A. gibberifrons + A.
albogularis, and together these three as the sister-
group to the "reddish teal." Given the poor res-
olution of these two segments of the tree, the
included relationships are considered indeter-
minate and depicted as trichotomies (Fig. I).
The third poorly resolved segment involved two
nested trichotomies including A. diazi, A. ful-
vigula, and the clade composed of A. platyrhyn-
chos and its Pacific relatives (Fig. I). All other
parts of the phylogeny in the constrained anal-
ysis were invariant.
Replacement of the hypothesized character
states in A. bernieri with missing-data codes re-
suited in 81 trees (CI = 0.715), in which A. ber-
nieri is associated with the "first cohort," either
as a monotypic branch of a trichotomy with or
as the sister-group to the other two member
clades. This placement was based entirely on
the questionably homologous reddish foot-col-
or of A. bernieri. If this character is coded as not
homologous to the orange feet of mallards and
shovelers, then A. bernieri was placed with equal
parsimony in a diversity of "basal" positions
among the subgenera throughout the genus
Anas. Exclusive of A. bernieri and the two tri-
chotomies described above, the tree based on
the unconstrained analysis (Fig. 1) was invari-
ant.
Tribal monophyly and "perching ducks."--
Monophyly of the Anatini is only weakly sup-
ported by three character changes of which two
were lost by reversal in subsequent groups. The
"perching ducks" comprises two clades para-
phyletic to the remainder of the Anatini, hence-
forth referred to as Anateae (Fig. 2). The first
and more primitive of these was the clade com-
posed of two species of Cairina and its mono-
typic sister-genus Pteronetta, and two species of
Aix. The two species of Aix have been consid-
ered sister-species by most authorities in recent
decades (e.g. Delacour and Mayr 1945, Delacour
1959, Johnsgard 1965, Numachi et al. 1983).
The second clade of "perching ducks," a group
more closely related to the true dabbling ducks
(Fig. 2), comprises two genera--Chenonetta (one
species) and Nettapus (three species). The close
relationship of these two genera, and the para-
phyly of the smaller "perching ducks" differs
from earlier reviews (e.g. Delacour and Mayr
1945; Delacour 1959; Johnsgard 1961a, 1965,
1978). Particularly divergent previous treat-
ments include the placement of Chenonetta in
the monotypic subfamily Chenonettinae (Sal-
vadori 1895, Phillips 1922) or inclusion of Che-
nonetta within the true geese, subfamily Anser-
inae (Peters 1931). In contrast, Chenonetta and
Aix were depicted as sister-genera by Johnsgard
(1961a, 1978).
Basal Anateae.--Two monotypic genera of
small, uniquely patterned waterfowl of South
America--Amazonetta and Callonetta--were
found to be sister-genera and together formed
the sister-group to the rest of the subtribe An-
ateae (Fig. 2). Boetticher (1952) and Johnsgard
(1960c, 1961a, 1965, 1978) included both genera
among the "Cairinini," but Delacour (1964) re-
tained them within the Anatini as formerly as-
signed (Delacour and Mayr 1945, Delacour 1959).
Delacour (1964) also resisted the hypothesis of
close relationship between Amazonetta and Cal-
lonetta supported by Derscheid (1938), Verhey-
en (1955), Johnsgard (1960b), and Woolfenden
(1961).
I found another couplet of taxonomically con-
troversial, relatively primitive, Neotropical
dabbling ducks--Lophonetta specularioides and
"Anas" specularis--to be sister-species, and these
composed the sister-group to the true dabbling
ducks (Fig. 2). With the exceptions of Delacour
and Mayr (1945), Delacour (1954, 1964), Boet-
ticher (1958), and Woolfenden (1961), who
placed Lophonetta within the shelducks (Tador-
ninae), systematists have considered both forms
to be somewhat aberrant members of the An-
atini (e.g. Johnsgard 1961a, 1965; Brush 1976;
Livezey 1986). The proposal of close relation-
ship between specularioides and specularis has re-
ceived less support by previous studies (e.g. De-
lacour and Mayr 1945). Although the two species
were listed next to one another by Salvadori
(1895), Phillips (1923), and Peters (1931), a sis-
ter-relationship was depicted by Johnsgard
(1961a). Morphological evidence that indicates
a close relationship was cited by Johnsgard
(1965).
Wigeons and allies.--The remaining members
of the tribe make up two major clades. Ranked
as genera, they are the wigeons and close rel-
atives (Mareca, 6 species) and the typical dab-
bling ducks (Anas, 40 species). The wigeons are
typified by a combination of primitive syringeal
bullae and uniquely derived natal and defini-
tive plumages. In addition to the typical wi-
geons (M. sibilatrix and the sister-species M.
americana and M. penelope), the unique Cape Teal
(M. capensis) and two transitional forms (M.
strepera and M. falcata) were included within
this clade (Fig. 2). The Cape Teal (or Cape Wi-
geon, locally; Delacour 1956) formerly was in-
HYPOTHETICAL
Chononotta j'ubata
ANCESTOR ____ r- Nottapus auritus
[ At coromandel/anus
' N. pulchellu$
Callonotta /oucophrys
Lophonotta spoculorJoidos
peculanas specularis
MoroCa caponsis
ANAS
t A. galer/culata
Cairina mo$chata
C, scutulata
' Ptoronotta hartlaub/
Ancestor ? ? ? ? ? m o (c) N, coromande/ianu$
ig. 2. Detailed topology of ph3/41ogen3/4 of Anatini exclusive of genus Ana$; taxonomy follows Appendix
2. Characters are explained in Appendix 1; autapomorphies are given in parentheses following corresponding
taxa.
cluded with either the "spotted teal" (e.g.A.
versicolor; Delacour 1956) or the "green-winged
teal" (e.g.A. crecca; Johnsgard 1961a, 1965, 1979).
Mareca capensis combines a natal plumage and
several features of definitive plumages shared
uniquely with typical wigeons with a moder-
ately derived syringeal bulla and a diversity of
autapomorphies of definitive plumage and soft
parts.
The Gadwall (M. strepera), long known for a
number of wigeon-like characters of behavior,
plumage, and biochemistry (Delacour and Mayr
1945; Boetticher 1952; Delacour 1956; Johnsgard
1961a, 1965, 1978; Kessler and Avise 1984),
proved to be a mosaic of a mallard-like natal
plumage, several wigeon-like characters of de-
finitive plumages, and a syrinx and soft parts
that combine features of both groups with an
assortment of unique autapomorphies. The close
relationship of the Falcated Duck (M. falcata) to
the typical wigeons was corroborated (four
characters of adult plumage, two natal charac-
ters). Delacour and Mayr (1945) allied falcata
most closely with the Baikal Teal (A. formosa),
but most previous workers noted some "affin-
ity" between falcata and the wigeons or strepera
(e.g. Delacour and Mayr 1945, Delacour 1956,
Boetticher 1958, Johnsgard 1978). Johnsgard
(1961a) depicted a sister-relationship between
falcata and the typical wigeons, a topology at
variance with subsequent commentary (Johns-
gard 1965). The terminal clade of typical wi-
geons--wherein the Chilo Wigeon (M. sibila-
trix) is the sister-species to the northern-
hemisphere "superspecies" that comprises M.
penelope and M. americana (Johnsgard 1979)--is
especially well supported here (Fig. 2). A sister-
relationship between these two species was in-
tuited earlier by Johnsgard (1961a).
Typical dabbling ducks (Ana$).--Approximate-
ly two thirds of the tribe Anatini are members
of the large, comparatively derived clade of
Fig. 1. Phylogeny of dabbling ducks (Anatini). Poorly resolved relationships within the lower clade of
Anas and among austral teal shown as trichotomies; position of A. bernieri is tentative. Taxonomy follows
Appendix 2.
"typical" dabbling ducks. The group includes
several of the most widespread, numerous, and
familiar species of waterfowl in the world. My
analysis defines two weakly supported sub-
clades within the group, which I informally
refer to as "cohorts" (Fig. 3). The first cohort
comprises two major subgroups, the mallards
(subgenus Anas; 14 species) and the blue-winged
ducks (subgenus Spatula; 6 species). The sec-
ond cohort comprises three primary clades,
which are shown as a trichotomy because of the
poor resolution of this segment of the tree. It
includes the Australasian Teal (subgenus Neso-
netta; 6 species), the pintails (subgenus Dafila;
7 species), and a two-parted clade that com-
prises the Holarctic teal (subgenus Querquedula;
4 species) and the spotted teal (subgenus Puna-
netta; 3 species).
Mallards.--Monophyly of the mallard com-
plex is supported by six characters of definitive
and natal plumages, colors of soft parts, and
syrinx (Fig. 3). The first dichotomy within the
complex separated the African Black Duck (Anas
sparsa), a species that combines primitive ana-
tomical characters with atypical (evidently aut-
apomorphic) behavioral attributes, from a spe-
close clade of more-typical mallards. Other
investigators recognized the "distinctness" of
A. sparsa (e.g. Delacour and Mayr 1945, Boet-
ticher 1952, McKinney et al. 1978), and several
even considered the species to be among the
most primitive members of the Anatini (Dela-
cour 1956; Johnsgard 1961a, 1965, 1978), al-
though Johnsgard (1979) listed A. sparsa with
the more typical mallards.
The sister-group of A. sparsa includes a sub-
clade of the (largely) northern-hemisphere mal-
lards and another, southern-hemisphere group
that includes South Pacific mallards and two
remaining African members (Fig. 3). Relation-
ships among the northern mallards are incom-
pletely resolved. The American Black Duck (A.
rubripes) is the sister-group to a trichotomy that
includes the Mottled Duck (A. fulvigula), Mex-
ican Duck (A. diazi), and a reasonably well sup-
ported clade that includes the Mallard (A. platy-
rhynchos) and three closely related insular
forms--the Marianas Duck (A. oustaleti) and the
Hawaiian sister-species A. wyvilliana and A. lay-
sanensis. The northern mallards have been con-
sidered closely related for decades, an hypoth-
esis supported by biochemical comparisons
(Kessler and Avise 1984, Patton and Avise 1985).
Several authorities believe that most or all of
the continental forms are conspecific and most
also include the Pacific forms within an en-
larged, polytypic A. platyrhynchos (e.g. Delacour
and Mayr 1945; Boetticher 1952; Delacour 1956;
Johnsgard 1960e, 1961a, 1961d, 1965, 1967, 1978,
1979). Others retained species rank for some
members (e.g. Phillips 1923, Moulton and Wel-
let 1984, Hepp et al. 1988).
The African mallards, Yellow-billed Duck (A.
undulata) and Meller's Duck (A. melleri), consi-
tute one of two clades included in the sister-
group of the northern-hemisphere mallards (Fig.
3). Delacour and Mayr (1945: 21) stated that each
A. undulata and A. melleri "stands alone" within
the mallard complex but listed them next to one
another within their "Group 9." There is a rel-
atively long tradition of listing A. undulata next
to A. sparsa (Salvadori 1895, Phillips 1923, Peters
1931, Johnsgard 1979). Johnsgard (1961a, 1965)
concluded that A. melleri was very closely re-
lated to A. platyrhynchos, but later he (1978) con-
cluded that available information did not per-
mit a precise assessment of the relationships of
A. melleri. Johnsgard (1978, 1979) listed A. un-
dulata and A. melleri consecutively.
The sister-group of the two African forms
comprises the four species of South Pacific mal-
lards (Fig. 3). Within the Pacific complex, the
Philippine Duck (A. luzonica) is the sister-group
to a terminal clade in which the Pacific Gray
Duck (A. superciliosa) is the sister-group to the
spot-billed ducks, here considered to comprise
two species (A. poecilorhyncha and A. zonorhyn-
cha). With few exceptions (Boetticher 1952,
Johnsgard 1961a), recent investigators inferred
the close relationship among the South Pacific
mallards. This led most taxonomists to merge
zonorhyncha with poecilorhyncha (e.g. Johnsgard
1979), to combine both zonorhyncha and super-
ciliosa within poecilorhyncha (Delacour 1956;
Johnsgard 1961a, 1965, 1978), or (less frequent-
ly) to consider all four South Pacific forms (in-
cluding the distinctive luzonica) as subspecies
of a single species (Delacour and Mayr 1945;
opposed by Ripley 1951).
Blue-winged ducks.--The first cohort also in-
cludes the clade that comprises the blue-winged
teal and shovelers (Fig. 3). The two teal are sis-
ter-species, with A. discors significantly more aut-
apomorphic (uniquely derived) than A. cyanop-
tera. The four species of shoveler constitute the
sister group to the blue-winged teal. Within the
A. sparsa (126a-b)
- A. platyrhynohos
J g. A. wyv/ll/ana
A. Iysnenss (28b-o,29b-o)
I - A. rubr/pes
J A. poeilorhynh
A. onorhynh
' ' ' ' A ynopter
-- A. sm/thU
, , , , A. pltle (0b-a)
, , , , , I. A.
ANAS ..... "
A. rhynhot/s
A. bern/ei (96-b *)
A. gibber/frons (Ho- )
? ? ? ? A. hlorot/s
? A. ulnd/ (5o-)
A. lbogulr/s
A. erythrorhynh
A. flWrostr/s (88o-b, 93o-b)
, ?
% % A. andium
..... eatoni
__ . arolnen
. formosa
A. querquedula -
A. versiolor -
? . puna
A. hottentot -,-,-
Fig. 3. Detailed topology of phylogeny of the genus Anas; position of A. bernieri tentative (see text).
Characters are explained in Appendix 1; autapomorphies are given in parentheses following corresponding
ta. Character changes marked by asterisks are mutually contradictor, and alternative arrangements can
support several distinct, equally parsimonious topologies within the trichotomy.
shovelers, A. smithii is the sister-group to a clade
that comprises A. platalea, A. rhynchotis, and A.
clypeata, within which the Australasian (A.
rhynchotis) and Northern (A. clypeata) shovelers
are sister-species (Fig. 3).
The blue-winged teal and shovelers have been
considered to be closely related by most 20th-
century taxonomists, an idea supported by re-
cent biochemical comparisons (Kessler and
Avise 1984, Patton and Avise 1985). However,
the relationships inferred here differ in several
ways. First, the Garganey (A. querquedula), tra-
ditionally grouped with the blue-winged teal,
is shown (Fig. 3) to be more closely related to
the green-winged teal (e.g.A. formosa, A. crecca)
and (to a lesser degree) to the spotted teal (e.g.
A. versicolor). Second, monophyly of the shov-
elers was confirmed, contrary to the suggestions
of polyphyly by Delacour and Mayr (1945) and
Delacour (1956). Specifically, the Red Shoveler
(A. platalea) and Australasian Shoveler (A. rhyn-
chotis) are less closely related to the superficially
similar Cinnamon Teal (A. cyanoptera) and Blue-
winged Teal (A. discors), respectively, than they
are to each other and to the remaining shovelers
(Fig. 3). The relationships proposed here also
imply that the Cape Shoveler (A. smithii) is the
"most primitive" member of the shovelers. Most
extant taxonomic sequences (Delacour and Mayr
1945; Delacour 1956; Johnsgard 1965, 1978, 1979)
and the tree depicted by Johnsgard (196 l a) sug-
gest instead that A. platalea "links" the shov-
elers with the blue-winged teal.
Australasian teal.--Five or six species of small,
grayish or reddish-brown teal (if the poorly
known A. bernieri is included) compose one of
the three clades in the second "cohort" of Anas
(Fig. 3). Three species--A. bernieri, A. albogularis,
and A. gibberifrons--probably form a poorly re-
solved, basal grade paraphyletic to a well-sup-
ported clade of three, variably reddish-brown
teal. The latter species--Chestnut Teal (A. cas-
tanea), Brown Teal (A. chlorotis), and Flightless
Teal (A. aucklandica)--are limited in distribu-
tion to Australia, New Zealand, and the Auck-
land and Campbell islands, and show a pro-
nounced trend toward smaller size, reduced
sexual dichromatism, and flightlessness (Live-
zey 1990).
Members of this clade have been considered
closely related by most taxonomists since De-
lacour and Mayr (1945). This concensus includ-
ed a close relationship between the poorly
known A. bernieri and other austral teal, es-
pecially A. gttberifrons and A. albogularis (e.g. Sal-
vadori 1895; Phillips 1923; Peters 1931; Dela-
cour and Mayr 1945; Verheyen 1955; Johnsgard
1961a, 1965, 1978, 1979), although most taxon-
omists also listed "Anas" capensis with or near
this group. Several authorities discussed or rec-
ommended the conspecific or superspecies sta-
tus of A. bernieri and A. gibberifrons (Boetticher
1952; Delacour 1956; Johnsgard 1965, 1979), and
most authorities considered some or all of the
Australasian "reddish" teal to be conspecific (e.g.
Ripley 1942; Delacour and Mayr 1945; Boetti-
cher 1952; Johnsgard 1978, 1979; Dumbell 1986).
Pintails.--The second major clade within the
second "cohort" of Anas includes the pintails
(Fig. 3). Anas bahamensis and A. erythrorhyncha
form the first of three subgroups, species con-
sidered closely related by virtually all 20th-cen-
tury taxonomists (e.g. Salvadori 1895; Phillips
1923; Peters 1931; Delacour and Mayr 1945;
Johnsgard 1965, 1978, 1979). The second sub-
clade of pintails includes two monophyletic
groups (Fig. 3): two teal-sized species (A. fiavi-
rostris and A. andium), and three species of brown
pintails (A. georgica, A. acuta, and A. eatoni). The
inference of close relationship between the
"pale-cheeked" and brown pintails has re-
ceived widespread support, except for Delacour
and Mayr (1945), who suggested that the "pale-
cheeked" species are more closely related to the
"spotted teal" (e.g.A. versicolor), Cape Teal ("A."
capensis, herein moved to Mareca), and Marbled
Teal (Marmaronetta angustirostris, now placed in
Aythyini; Livezey 1986). Anas fiavirostris (in-
cluding A. andium) was allied with A. crecca by
Delacour and Mayr (1945), Lorenz (1951-1953),
Boetticher (1952), Delacour (1956), and Johns-
gard (1961, 1965, 1978, 1979). The Brown Pintail
(A. georgica), here found to be the sister-group
to A. acuta and A. eatoni, was placed "nearer to"
the superficially similar A. fiavirostris by several
taxonomists (e.g. Salvadori 1895, Delacour and
Mayr 1945), but Johnsgard (1965, 1978, 1979)
indicated a close relationship between A. acuta
(including A. eatoni) and A. georgica. Anas fia-
virostris and A. andium have been considered
closely related for decades and, since Delacour
and Mayr (1945), most authorities have treated
them as a single species. The sister-species A.
acuta and A. eatoni have been considered con-
specific in recent decades (Delacour and Mayr
1945; Johnsgard 1965, 1978, 1979), but Stahl et
al. (1984) supported species-status for both.
Holarctic and spotted teal.--Two well-support-
ed clades of teal compose the third clade in-
cluded within the second "cohort" of Anas (Fig.
3). The larger of these includes the Holarctic
teal, a northern-hemispheric group composed
of the Garganey (A. querquedula) and its sister-
group the green-winged teal (A. formosa and the
"superspecies" including A. crecca and A. car-
olinensis). The finding that A. querquedula is the
sister-group to the green-winged teal, support-
ed by three characters of definitive and natal
plumages, opposes the traditional A. querquedula
association with the blue-winged ducks (Sal-
vadori 1895; Phillips 1923; Peters 1931; Dela-
cour and Mayr 1945; Boetticher 1952; Verheyen
1955; Delacour 1956; Johnsgard 1961a, 1965,
1978, 1979). The classification of A. querquedula
with the blue-winged ducks rested largely on
the gray forewing of the species, a character
that differs from the less extensive, powder-blue
forewing of Spatula and that evidently was de-
rived from the light gray wing-coverts of the
green-winged and spotted teals. A close rela-
tionship between the Baikal Teal (A. formosa)
and the green-winged teal "superspecies" has
been hypothesized by all 20th-century taxon-
omists except Delacour and Mayr (1945), Boet-
ticher (1952), and Delacour (1956), who consid-
ered formosa to be an "isolated" form of uncertain
taxonomic position.
Spotted teal, the distinctive southern-hemi-
sphere sister-group of the Holarctic teal, in-
clude the Hottentot Teal (A. hottentota), and the
superspecies that comprises the Silver Teal (A.
versicolor) and Puna Teal (A. puna) (Fig. 3). Al-
though some writers failed to recognize that A.
hottentota was a member of this well-defined
group (Salvadori 1895, Phillips 1923, Peters
1931), this relationship was supported by De-
lacour and Mayr (1945) and subsequent taxon-
omists. The practice of listing A. querquedula be-
tween A. versicolor and the blue-winged ducks
(Salvadori 1895; Heinroth 1911; Lorenz 1951-
1953; Delacour 1956; Johnsgard 1961a, 1965,
1978, 1979) is not in accord with my results.
This tradition apparently reflects the phenetic
assessment of synapomorphies and symple-
siomorphies between A. querquedula and the
"spotted teal," and superficial (convergent)
similarities between A. querquedula and the blue-
winged ducks.
DISCUSSION
Poorly resolved relationships.--My results con-
stitute a significant clarification of the generic
relationships of Anatini presented earlier (Live-
zey 1986), but monophyly of the tribe remains
only weakly demonstrated. Two of the three
supportive characters had consistency indices
of 0.50, one (character 1) characterized the basal
grade Cairineae + Nettapodeae and the other
(character 101) also supported (by reversal) the
clade Cairina + Pteronetta. The single character
supportive of the tribe (character 128, postor-
bital stripe in natal plumage) is not completely
unambiguous. Although it is absent in most
"allies" placed in other tribes (Sarkidiornis, Mer-
ganetta, Malacorhynchus, Hymenolaimus, and
Marmaronetta), it is suggested in several others
(Plectropterus, Salvadorina, and Heteronetta). In
addition, a few other character states of these
genera resembled those found within Anatini
(particularly Anateae). These include variably
metallic and bordered wing specula (Merganet-
ta, Salvadorina, Polysticta, and Heteronetta) and a
moderately derived condition of cranial fora-
mina (Heteronetta). In all of these "allied" gen-
era (except perhaps Salvadorina), there are other
characters that indicate alliance with other tribes
(Livezey 1986). Presumably the few characters
shared with the Anatini are convergent. Sal-
vadorina appears, on the basis of its (tadornine)
carpal wing-spurs and peculiar, evidently de-
rived wing specula, to be most closely related
to Merganetta, which in turn is related to Hy-
menolaimus by osteological synapomorphies
(Livezey 1986) and a dark, vertical supraorbital
stripe in natal plumage (shared also with Het-
eronetta; pers. obs., Kear 1972). A close relation-
ship among Salvadorina, Merganetta, and Hy-
menolaimus was inferred earlier by Kear (1975),
but this hypothesis must remain tentative until
skeletal comparisons are possible.
The two basal members of the genus Mare-
ca--M. capensis and M. strepera--presented
"conflicts" between definitive, natal, and syrin-
geal characters, and require further investiga-
tion (Fig. 2). Also, the two "cohorts" of Anas are
too poorly documented for formal recognition,
but the determination of relationships among
the included (and well supported) subgenera is
important for biogeographic and ancillary evo-
lutionary inferences (see below).
Relationships among the basal austral teal (A.
bernieri, A. albogularis, and A. gibberifrons) are in-
adequately understood because of incomplete
data for A. bernieri and apparent character con-
flicts between A. albogularis and A. gibberifrons.
The most urgent anatomical needs for further
study of Anatini concern three species endemic
to the Indian Ocean: downy young and tracheae
for A. bernieri, tracheae for A. albogularis, and
tracheal specimens for A. melleri. Relationships
among North American mallards have been
studied intensively (Phillips 1912; Delacour
1956; Johnsgard 1960d, 1961d) but remain in-
adequately resolved. Of particular concern are
the delimitation of species within the complex
(Morgan et al. 1976, Ankney et al. 1986, Hepp
et al. 1988, Avise et al. 1990) and the conser-
vation of genetically "pure" populations of A.
rubripes in the face of increased hybridization
with A. platyrhynchos (Johnsgard 1967, Heus-
mann 1974, Johnsgard and Di Silvestro 1976,
Brodsky and Weatherhead 1984, Ankney et al.
1987). Anas oustaleti, probably extinct, shows ex-
traordinary plumage variability, wherein some
specimens resemble the South Pacific A. super-
ciliosa and others show characteristics of the
Holarctic A. platyrhynchos. Most ornithologists
consider A. oustaleti to be a subspecies of A.
platyrhynchos or a hybrid swarm (Delacour and
Mayr 1945, Yamashina 1948, Delacour 1956,
Amadon 1966, Johnsgard 1978). The hybrid-
swarm hypothesis is validated by the observa-
tion that characteristics of hybrid waterfowl
frequently are not simple "intermediates" or
mosaics of those of parental species (Scherer
and Hilsberg 1982, Gillespie 1985). Detailed cla-
distic analysis of A. oustaleti should permit a test
of its possibly hybrid origin and reticulate phy-
logeny (Humphries 1983, Wagner 1983).
Monophyly of terminal taxa was demonstrat-
ed unambiguously for all except A. diazi, A. ful-
vigula, A. oustaletL A. gibberifrons, and A. eatoni
(list available on request). Although the nom-
inate subspecies of A. gibberifrons is character-
ized by a unique dorsal inflation of the frontal
bones (Ripley 1942), the character evidently does
not unite the entire species. Reduction of sexual
dichromatism distinguishes A. eatoni from its
continental sister-species A. acuta. Reduced di-
chromatism is evident in insular populations of
many anatids (Weller 1980), including several
Anatini (A. wyvilliana, A. laysanensis, A. aucklan-
dica,) and the extinct, possibly specifically dis-
tinct M. (strepera) couesi (Ripley 1957a, b).
Hybridization, species concepts, and phylogenetic
inference.--Frequency of interspecific hybrid-
ization (in the wild or in captivity) and the
fertility of hybrid offspring have been weighed
heavily by traditional systematists as criteria for
the delimitation of species and for the assess-
ment of relationships among species and higher
taxa of waterfowl (e.g. Delacour and Mayr 1945;
Lorenz 1951-1953; Delacour 1956, 1959; Sibley
1957; Johnsgard 1960b, 1961a, 1961d, 1965,
1968a, 1968b, 1978). In spite of an almost uni-
versal capacity for hybridization among Anser-
iformes (Scherer and Hilsberg 1982), such in-
formation has led to a diversity of inferences.
Hybridization between captive A. fiavirostris and
wild A. crecca has "proved" a close interspecific
relationship (Delacour 1964: 341). Infertility of
hybrids between "Anas" leucophrys and Ama-
zonetta brasiliensis was used in "excluding" a close
relationship between the two (Delacour 1964:
343). The unique chromosomal number of Aix
galericulata (Yamashina 1952) was interpreted
by Delacour (1959: 99) as the explanation for
the "strange" absence of interspecific hybrids
in Aix, and a demonstration that karyotypic
characters are not reliable taxonomic criteria.
Phylogenetic inferences based on hybridiza-
tion and sterility are (at least implicitly) based
on the concept of "isolating mechanisms," an
idea central to the widely accepted "biological
species" concept (sensu Mayr 1969), in which
species are conceived of as groups of inter-
breeding, natural, reproductively isolated pop-
ulations. The importance of "isolating mecha-
nisms" in the formation and maintenance of
species of waterfowl has been widely accepted
(e.g. Sibley 1957; Johnsgard 1960d, 1963; but see
McKinney 1970, 1975; McKinney et al. 1990),
but it is supported only by circumstantial evi-
dence and often contradictory reasoning. For
example, Johnsgard (1963: 531) concluded that
"This remarkable capacity for hybridization
[among anatids] indicates that isolating mech-
anisms must be operating effectively if species
are to retain their integrity under natural con-
ditions. Since genetic isolation is practically ab-
sent in the Anatidae, other isolating mecha-
nisms must, of course, have evolved to take their
place. Of these, the most significant appear to
be behavioral differences and various morpho-
logical (plumage and soft part) specializa-
tions .... "With respect to Anatini, however,
Johnsgard (1963: 537) stated, "Thus, isolating
mechanisms are least well developed in the
group, in spite of the fact that courtship displays
and male plumages tend to be elaborate and
diversified." Johnsgard (1963: 539) reasoned that
the frequency of hybrids among species of Anas
"... appears to be the combined result of the
great amount of natural sympatry [cited earlier
(p. 538) as a distributional circumstance con-
ducive to the evolution of isolating mecha-
nisms], the relatively close relationships of all
the species of Anas, and the very uniform pre-
copulatory behavior of all the species in this
genus [i.e., the failure of precopulatory isolat-
ing mechanisms to evolve]." Clearly, if isolating
mechanisms have been selected in waterfowl,
then this selection must have been of low in-
tensity, or the genetic-behavioral capacity of
anatids to evolve and respond to these mech-
anisms is singularly limited. The latter seems
particularly improbable in light of the diversity
of breeding plumages and capacity for recog-
nition of mates characteristic of anatids (Butch-
er and Rohwer 1989).
An alternative model is to consider "isolating
mechanisms" to be incidental effects, not the
causes, of interspecific phenotypic divergence
(West-Eberhard 1983, Paterson 1985) that re-
suits from sexual selection or divergent natural
selection (McKinney 1970, Selander 1972). As
such, it predictably would fail to preclude in-
terspecific mating under a variety of circum-
stances. "Intraspecifically selected" (instead of
isolation-oriented) phenotypic characters func-
tion in selection of mates and facilitate initia-
tion of breeding (Selander 1972, West-Eberhard
1983, Andersson 1986). These characters would
be subject to intense selection in anatids in which
tertiary sex-ratios typically favor males (Bell-
rose et al. 1961, Breitwisch 1989), and they would
be influenced by other life-history factors such
as relative parental investment by males, ter-
ritoriality, and predation (Trivers 1972, Endler
1978, Baker and Parker 1979, Butcher and Roh-
wer 1989).
A recently proposed alternative to the "bio-
logical species" concept is the "recognition con-
cept" of species, in which species are defined
(intrinsically) as populations of organisms that
share a common, functionally adaptive system
of fertilization (Paterson 1985, 1988; see also
West-Eberhard 1983). The "recognition con-
cept" was anticipated by students of waterfowl,
at least with respect to proximate mechanisms,
by an investigational emphasis placed on mech-
anisms of "species recognition" (Sibley 1957;
Dilger and Johnsgard 1959; Hailman 1959;
Klopfer 1959; Johnsgard 1960d, 1961d, 1963,
1968b; Schutz 1965; Williams 1983). Both con-
cepts of species hinge--in fundamentally dif-
ferent ways--on the interfertility of popula-
tions. The first concept focuses on "isolation"
or historico-adaptive partitioning of a common
system of fertilization. The second emphasizes
the internal mechanisms interpreted as adap-
tations for its maintenance through refinement
of fertilization systems. Species concepts based
on inferred or presumed patterns of gene flow
and models of speciation are important for the
development of evolutionary theory, but often
they offer no practical (specimen-based) means
for species delimitation.
For purposes of phylogenetic inference, in-
terfertility is uninformative because it repre-
sents the retention of primitive "recognition
systems" and capacity for interbreeding (i.e. it
is a symplesiomorphous condition). A third al-
ternative, the phylogenetic species concept, de-
fines species as the smallest diagnosable (i.e.
definable by qualitative, apomorphic characters)
monophyletic group of organisms (reviewed by
Cracraft 1983, 1988; McKitrick and Zink 1988)
and permits the comparatively simple defini-
tion of terminal lineages in analyses (regardless
of consideration of allopatry or fertilization sys-
tems) based on the observable effects of evolu-
tionary divergence. Recognition of phyloge-
netic species permits the investigation of
evolutionary problems that tend to be superfi-
cially considered with the merging of evolu-
tionary entities into (phenetically defined) "bi-
ological" species (e.g. relationships within North
American and Hawaiian mallards or among bas-
al Australasian teal). Consequently, I adopted
the phylogenetic species concept for data cod-
ing and the cladistic analyses, and for the clas-
sification proposed below.
A phylogenetic classification of Anatini.--Based
on the phylogenetic relationships inferred
herein (Fig. 1), I propose a Linnean classifica-
tion of Recent dabbling ducks (Appendix 2).
Recognition of subtribal and subgeneric taxa
permitted the incorporation of additional phy-
logenetic information in the classification not
possible within the traditional tribe-genus sys-
tem. The limitations of simple binomial classi-
fication for Anas led Delacour (1956: 19) to con-
clude that "... Either 14 genera, or only one,
must be recognized."
Although subspecies are not considered use-
ful in the phylogenetic species concept (Mc-
Kitrick and Zink 1988), recognized taxa are list-
ed parenthetically (Appendix 2) following those
species considered "polytypic" to clarify the
content of species (e.g. populations included
within A. versicolor and A. puna) and to indicate
traditionally distinguished populations which
may, with further study, be usefully elevated
to species status. The second point is particu-
larly important for widespread species charac-
terized by comparatively great variation (e.g.A.
cyanoptera), for poorly known, possibly diag-
nosable insular isolates (M. [strepera] couesi, A.
[aucklandica] nesiotis), and for terminal taxa not
shown to be monophyletic (e.g.A. gibberifrons).
Biogeographical patterns.--The distributional
ranges of Anseriformes have been well-known
for decades. Conversely, biogeographic infer-
ences have been mostly scattered anecdotal
speculations concerning "centers of origin,"
"relictual" distributions, and possible radia-
tions of groups or "ancestral stock," and have
been made in the absence of an explicit hy-
pothesis of phylogeny (e.g. Ripley 1957b; Wel-
ler 1964; Johnsgard 1978; Murton and Kear 1975,
1978; Kear and Murton 1976). A tabular overlay
of distributional information for my proposed
classification permitted more explicit infer-
ences concerning the historical biogeography
of Anatini (Table 1). Four of six supergenera
and eight of eleven genera are limited to the
southern hemisphere. Within the genus Anas,
only two subgenera (Nesonetta and Punanetta)
are strictly limited to the southern hemisphere,
although infragenera within two other subgen-
era are so distributed (Table 1). Like the genus
Mareca, several subgroups of Anas include
members from both hemispheres (subgenus
Anas, infragenera Pterocyanea, Spatula, Paecilo-
nitta, and Dafila). Only four groups of subge-
neric or higher rank are limited to the northern
hemisphere. These are the genus Aix of Cairi-
neae, the grade that comprises the subgenera
Chaulelasmus and Eunetta of Mareca, and the sub-
genus Querquedula of Anas (Table 1). The pre-
ponderance of southern-hemispheric clades,
particularly among the early branches (Netta-
podeae, and supergenera Cairina, Amazonetta,
and Lophonetta), strongly suggest that the An-
atini originated in the southern hemisphere, as
inferred for the order Anseriformes (Livezey
1986).
Southern origins are indicated throughout the
tribe (Fig. 1, Table 1). The tree originates with
the Asian-African Cairineae (except for the more
northern Aix), followed by the Australasian and
African Nettapodeae and the strictly South
American grade that comprises the supergenera
Amazonetta and Lophonetta. Within the super-
genus Anas, the genus Mareca forms an African
branch (M. capensis) and a largely Holarctic sis-
ter-clade of wigeons and allies. The genus Anas
has five major branches, of which one is Aus-
tralasian (subgenus Nesonetta), three are char-
acterized by African or South American, or both,
basal members (subgenera Anas, Spatula, and
Dafila), and one comprises groups of Afro-Neo-
tropical (subgenus Punanetta) and Holarctic dis-
tributions (subgenus Querquedula). The typical
mallards (subgenus Anas exclusive of A. sparsa)
show pronounced geographical partitioning,
with northern-hemisphere, African, and South
Pacific clades (Fig. 3, Table 1). Departures from
this general pattern are the Neotropical distri-
bution of M. sztilatrix within the otherwise Hol-
arctic clade Chaulelasmus + Eunetta + Mareca;
the Australasian distribution of A. rhynchotis,
the sister-species to the North American 4. cly-
peata; and the insular isolation of A. laysanensis
and A. wyvilliana (infragenus Anas) in the equa-
torial Pacific Ocean, and A. eatoni (infragenus
Dafila) in the Indian Ocean. At least the last
three were probably founded by wayward mi-
grant flocks (Delacour 1956, Weller 1980).
Morphological correlates.--Several physical
characteristics not used in inferring relation-
ships within the Anatini showed strong phy-
logenetic patterns (Table 1). Body size, defined
by three discrete intervals of mean body masses,
varied little within genera of Cairineae and
Nettapodeae, and (to a lesser degree) within
Mareca. In the genus Anas, body-size diversity
occurs within most subgenera. A majority of the
size variation in the subgenus Anas is due to
the dwarfism of the Pacific isolates (A. wyvil-
liana, A. laysanensis). In several other subgenera,
the ranges in body mass reflect phylogeneti-
cally constrained variation among constituent
clades (e.g. between Pterocyanea and Spatula, and
between Dafilonettion and Dafila). Sexual size di-
morphism, as measured by three intervals for
ratios of mean body masses of males and fe-
males, was associated positively with mean body
masses of species (r = 0.54, n = 52). That is, size
dimorphism tended to be greater in large spe-
cies than in small species (Table 1). Exceptions
include the disproportionately small dimor-
phism of Chenonetta and some members of the
infragenera Polionettea and Paecilonitta, and the
disproportionately great dimorphism of A.
aucklandica (subgenus Nesonetta).
Sexual dichromatism, either sexual differ-
ences in color or pattern, or both, in adults in
definitive alternate (breeding) plumage, is less
easily quantified. To permit broad comparisons
with the tribe, I established three categories of
sexual dichromatism: class I, qualitative (i.e. sex-
T^ILE 1. Biogeographical, morphological, and reproductive correlates of phylogeny of Anatini. Classification
follows that proposed in Appendix 2. Codings are explained in footnotes.
Sexual Sexual
Biogeographic Body size di- dichro- Egg Clutch
Taxonomic group area a mass morphism c matism a mass e size f
Subtribe Cairineae AS, AF, NA L-M L-M II M-L M-L
Supergenus Cairina AF, AS L-M L-M I-If M-L M-L
Genus Cairina AF, AS L L II L L
Genus Pteronetta AF M M II M M
Supergenus Aix AS, NA M L I M L
Genus Aix AS, NA M L I M L
Subtribe Nettapodeae AU, AF S-M S I-If S-M M-L
Supergenus Chenonetta AU S-M S I-If S-M M-L
Genus Chenonetta AU M S I M L
Genus Nettapus AU, AF S S II S M-L
Subgenus Nettapus AF S S II S M
Subgenus Cheniscus AU S S II S L
Subtribe Anateae global S-L S-L I-Ill S-L S-L
Supergenus Amazonetta NE S S I-If S M
Genus Amazonetta NE S S II S M
Genus Callonetta NE S S I S M
Supergenus Lophonetta NE M M II M-L S
Genus Lophonetta NE M M II M S
Genus Speculanas NE M M II L S
Supergenus Anas global S-L S-L I-Ill S-L S-L
Genus Mareca HA, NE, AF S-M S-L I-Ill S-M M
Subgenus Notonetta AF S S Ill S M
Subgenus Chaulelasmus HA M M I M M
Subgenus Eunetta PA M L I M M
Subgenus Mareca HA, NE M M I-If M M
Genus Anas global S-L S-L I-Ill S-L S-L
Subgenus Anas HA, AF, SP, S-L S-L I-Ill S-L S-M
HI
Infragenus Melananas AF L L Ill L S
Infragenus Anasg HA (HI) M-L M-L I-Ill M-L S-M
(S-M) (S-M) (11) (S-M) (S-M)
Infragenus Polionetta SP M-L S-M III M M
Infragenus Afranas h AF M M III M M
Subgenus Spatula global S-M S-M 1-11 S-M M-L
Infragenus Pterocyanea NA, NE S S I S L
Infragenus Spatula global M S-M 1-11 M M-L
Subgenus Nesonetta i AU, AS S-M S-L I-II S-L S-L
"Infragenus Virago" AU, AS S S II S M
Infragenus Nesonettai AU M (S) M (L) I (11) M-L (S) S-L (S)
Subgenus Dafila NE, HA, AF S-M S-M 1-111 S-M S-M
Infragenus Paecilonitta AF, NE M S II M M
Infragenus Dafilonettion NE S S II S S
Infragenus Dafila HA, NE M S-M I, Ill M M
Subgenus Querquedula HA S S I S M
Infragenus Querquedula PA S S I S M
Infragenus Nettion HA S S I S M
Subgenus Punanetta NE, AF S-M M II S M
Infragenus Punanetta NE S-M M II S M
Infragenus Micronetta AF S -- II S M
Region: AF = Africa, AS = Asia, AU = Australia, HA = Holarctic, HI = Hawaiian, NA = Nearctic, NE = Neotropic, PA = Palearctic, SP South
Pacific.
b Mean body mass: S = small (< 500 g), M = medium (500-1,000 g), L = large (> 1,000 g); data taken primarily from Madge and Burn (1988).
c Mass dimorphism ratio, (males)/(females): S = small (1.00-1.10), M = medium (1.11-1.20), L = large (> 1.21).
a Chromatic differences: I = qualitative, II = quantitative, III= absent.
Mean egg mass (Rohwer 1988): S = small (25-40 g), M = medium (41-60 g), L = large (>61 g).
Mean clutch size (Rohwer 1988): S smalI (3-6), M = medium (7-9), L large (> 10).
Parenthetical codes refer to "Horizonefta" (Anas wyvilliana and A. laysanensis).
h Reproductive data for A. melleri not available.
Poorly known A. bernieri not included.
Parenthetical codes refer to A. aucklandica.
es differ significantly in pattern as well as de-
gree); class II, quantitative (i.e. sexes differ pri-
marily in intensity or conspicuousness, but un-
derlying pattern is essentially the same); and
class III, obsolete or entirely absent. Despite
problematic assignments of several species with
"intermediate" levels (e.g. Nettapus, Lophonetta,
M. strepera, A. wyvilliana, A. fiavirostris), several
patterns emerged (Table 1). First, 22 of 38 spe-
cies (excluding A. oustaleti) are characterized by
class-I dichromatism and 27 show class-II di-
chromatism. Together, 49 (84%) species of An-
atini are sexual dichromatic. Second, sexually
monochromatic species (class III) are limited to
the supergenus Anas and include members of
Mareca and the subgenus Anas. Third, class-I
dichromatism characterizes all member species
in only three named groups: the genus Aix, sub-
genus Querquedula, and infragenus Pterocyanea.
Sexual dichromatism within the subgenus
Anas is exceptionally variable and ranges from
the monochromatic condition of southern-
hemisphere species and an insular isolate (A.
laysanensis) to the conspicuous dichromatism of
A. platyrhynchos. "Reduced" sexual dichroma-
tism characterizes insular Anatini (especially
Anas) and species of the southern hemisphere
(Table 1). This pattern has been interpreted tra-
ditionally as the adaptive loss of "isolating
mechanisms" in insular communities that lack
phenotypically "confusable" congeners (Ripley
1957b, Sibley 1957, Johnsgard 1963, Lack 1970,
Weller 1980). Alternatively, West-Eberhard
(1983) suggested that the comparatively dull
plumages of insular waterfowl reflect a reduced
intensity of sexual selection related to the pro-
tracted pair-bonds and greater parental invest-
ment by males (Weller 1980). This hypothesis
is supported by the strong association between
biparental care of young and sexual monochro-
matism in Anatidae (Kear 1970). Another pos-
sibility is that the dull, juvenal-like plumages
of insular anatids are nonadaptive characters
developmentally linked to a selectively fa-
vored, paedomorphic reduction of the pectoral
limb (Livezey 1989a, 1990).
Behavioral patterns.--Although homologies
and polarities of behavioral characters were in-
adequately established for inclusion in the phy-
logenetic analysis, evolutionary trends in re-
productive behavior of Anatini can be
documented. Age of sexual maturity ranges from
2 yr in Cairina (characteristic of Tadorninae,
Plectropterus, Sarkidiornis and evidently primi-
tive) to ! yr in all other Anatini (Johnsgard
1961a, 1965; Kear 1970). Cairina is also unique
among Anatini in its promiscuous (polybrach-
ygynous) mating system (Johnsgard 1961a)
while monogamy is typical of dabbling ducks
(McKinney 1985). Biparental attendance of
broods characterizes most members of the out-
group (Kear 1970), Pteronetta (Kear 1970), Net-
tapodeae (Frith 1967), Amazonetta (Phillips 1923),
Callonetta (Brewer !989), Lophonetta (Buitron and
Nuechterlein !989), Speculanas (Kear !970), some
Mareca (Weller 1968, Siegfried 1974), and to
varying degrees the members of most subgen-
era of Anas (Weller 1968, Siegfried 1974, Mc-
Kinney !985, Norman and McKinney 1987, Mc-
Kinney and Brewer 1989). Cairina and (to a lesser
extent) Aix are exceptional among basal Anatini
in the virtual lack of brood attendance by males
(Kear 1970). This pattern strongly suggests that
biparental brood-rearing is a primitive charac-
ter among Anatini (contra Kear 1970), and this
polarity explains, at least in part, the prepon-
derance of southern-hemispheric dabbling
ducks having protracted pair-bonds (Weller
1968, Kear 1970, McKinney 1985). This trait pre-
sumably coevolved with a number of characters
including migratory habit, seasonal plumage
dichromatism, predictability of food resources,
and tertiary sex-ratios (Weller 1968, McKinney
1985).
Most Anatini (especially Anateae) are char-
acterized by monosyllabic distress calls of downy
young (Lorenz 1951-1953) and preflight "in-
tention" movements (McKinney 1965). A num-
ber of presumably derived courtship behaviors
further characterize most or all members of the
supergenera Lophonetta and Anas. These include
marked "inciting displays," variably long "de-
crescendo calls," and postcopulatory bathing by
females; ritualized head-turning and wing-
preening displays by males; and precopulatory
"head-pumping" displays by both sexes (Lo-
renz 1951-1953; Johnsgard 1961a, 1965). Other
behavioral characters, including most "comfort
movements" (McKinney 1965), photoperiodic
rhythms of reproduction (Murton and Kear 1975,
!978; Kear and Murton 1976), and other details
of courtship displays (Johnsgard 1961a, 1962,
1965, 1978), are less readily interpreted phylo-
genetically, primarily because of inadequate in-
formation for a number of species.
Reproductive parameters.--Selected quantita-
tive parameters of reproduction also show mod-
erately pronounced phylogenetic patterns (Ta-
ble 1). Hierarchical relationships preclude
simple statistical comparisons among members
(Felsenstein 1985), but correlations provide use-
ful indices to patterns within the tribe. Rohwer
(1988) found that the mean egg masses of 53
species of Anatini was positively correlated with
mean body masses (r = 0.85). The egg masses
have phylogenetic patterns similar to those de-
scribed for body mass (Table 1). As noted by
Rohwer (1988), insular isolates represent sig-
nificant, statistically influential deviations from
the overall relationship between egg mass and
body mass. Notable examples among Anatini
are A. eatoni, A. chlorotis, and (especially) A. auck-
landica (Table 1). The evolutionary implications
of egg size in A. aucklandica are considered else-
where (Livezey 1990).
Clutch size (data from Rohwer 1988) is not
correlated with body mass among 53 species of
Anatini (r = 0.12, log-transformed data). Ex-
treme examples include the small clutch-sizes
of the comparatively massive S. specularis and
A. sparsa, and the large clutch-sizes of tiny Net-
tapus (Table 1). This finding, and a modest neg-
ative correlation (Rohwer 1988) between clutch
size and egg mass in 53 Anatini (r = -0.62) or
43 noninsular Anatini (r = -0.39), suggests that
clutch mass (product of egg mass and clutch
size) is phylogenetically constrained (see Cody
1966), and that, of the two interrelated param-
eters, egg mass has the greater phylogenetic
component. The primary determinant of clutch
sizes of waterfowl is thought to be energy re-
sources available to the female (Lack 1968,
Klomp 1970), confounded as well by proximate
variations in availability of food (Johnsgard
1973). Other egg characteristics, such as relative
thickness of shells and membranes, and pro-
portions of soluble and insoluble nitrogen in
the shell (Tyler 1964), showed no clear phylo-
genetic patterns among Anatini. These correl-
ative assessments within tribes, like the studies
by Laurila (1988) and Rohwer (1988), are only
partly successful in discriminating between
phylogenetic constraint and adaptive changes
of life-history parameters. Comprehensive as-
sessments of phylogenetic constraint must in-
corporate more completely resolved phyloge-
nies and multivariate techniques that use
hierarchically nested designs (Grafen 1989, Funk
and Brooks 1990).
Evolutionary consistencies and rates of character
evolution.--The consistency index of the pro-
posed phylogenetic hypothesis is moderately
TABLE 2. Summary stafisics for consistency indices
of p characters by anatomical-developmental group.
Character
group p Mean Range
Definifive plumage & soft parts
Analyzed set 107 0.850 0.250-1.000
Additional a 165 0.903 0.250-1.000
Natal plumage 22 0.777 0.250-1.000
Trachea 21 0.865 0.500-1.000
Skeleton
Analyzed set 7 0.809 0.333-1.000
Additional a 10 0.866 0.333-1.000
Includes autapomorphies not in formal analysis; list available.
high, compared with other cladistic analyses of
avian groups, including an earlier, genus-level
analysis of Anseriformes (Livezey 1986). This
consistency was achieved despite the compar-
atively large number of taxa analyzed and the
exclusion of unique autapomorphies. General-
ly, character consistencies tend to decrease as
the number of taxa analyzed increases (Sander-
son and Donoghue 1989). In addition, the four
major groups of characters had comparable con-
sistency indices (Table 2). It is commonly as-
sumed that character suites differ in phyloge-
netic "reliability" or informativeness (e.g.
Delacour and Mayr 1945), and these judgments
may influence the weights characters are given
in phylogenetic inference (Bryant 1989).
A related issue concerns the rates at which
characters evolve, which may in turn determine
the phylogenetic and taxonomic level at which
the characters are informative in a particular
group. Although some inequality of effort ex-
panded on character-groups was unavoidable,
I believe that the distributions of characters an-
alyzed are representative of their relative avail-
abilities. Tallies of character changes, grouped
by both morphological groups and five major
taxonomic levels of the resultant phylogeny
(Figs. 2, 3), indicate that character types were
unevenly distributed among levels within the
tree (Table 3). In particular, characters of defin-
itive plumages and soft parts were useful
throughout the tree but were especially useful
at the lowest levels. Relationships at the level
of subtribes, supergenera, genera, and subgen-
era were supported disproportionately by state
changes in characters of natal plumage and tra-
cheal anatomy. Nontracheal skeletal characters,
of paramount importance for the establishment
TAILE 3. Numbers of character changes, by anatom-
ical-developmental group, that support topological
divergences at five taxonomic levels.
Character group
Defini-
tive
exter- Tra- Skele-
Taxonomic level nal Natal cheal tal
Tribe and subtribe 7 5 1 5 a
Supergenus and genus 41 5 9 3
Cohort and subgenus 21 8 10 0
Infragenus and
species-group 76 9 6 1
Species 72+ 1 2 4
Analyzed set 14 1 2 1
Additional b 58 + 0 0 3
Includes four skeletal synapomorphies of Anatinae (Livezey 1986).
Characters not included n formal analysis but compiled to confirm
monophyly of species; list available on request.
of genus-level relationships in Anseriformes
(Livezey 1986), were primarily useful in this
analysis for resolutions at the tribal and sub-
tribal levels (Table 3). This heterogeneity of
character change strongly suggests that char-
acters evolve at significantly different rates. They
are of greatest phylogenetic utility for segments
of the tree where rates of evolutionary change
are moderately high. Consequently systematists
should select those character suites that evo-
lutionarily "target" the phylogenetic relation-
ships of concern.
Osteological studies of Anatini indicate a
paucity of phylogenetically informative char-
acters of the skeleton (Woolfenden 1961, Live-
zey 1986, present study), which underscores the
need for extreme caution in the classification of
fossil dabbling ducks. Although avian paleon-
tologists generally are cognizant of the diffi-
culties of classifying fragmentary specimens (e.g.
Howard 1964, Olson 1985), the phenetic as-
signment of fossils and widespread preoccu-
pation with discovery of possibly ancestral lin-
eages have seriously compromised the
contributions of traditional paleontology to an
understanding of avian phylogeny (Cracraft
1980). Based on an osteologically based analysis
of Recent genera of Anseriformes (Livezey 1986),
many fossil anseriforms, including a number of
purported anatines and most pre-Pliocene forms
assigned to "Anas," were incorrectly classified
(Livezey and Martin 1988, Livezey 1989b). Ten
post-Miocene fossils assigned to Anas (or ge-
neric synonyms) appear, on the basis of the
compendia of Brodkorb (1964) and Howard
(1964), to have been classified based on assess-
ments of size and phenetic comparisons of un-
reliable skeletal features. Size is not phyloge-
netically deterministic within the Anatini, and
most skeletal variation has not proved reliable
for classification. Although analysis of fossils
can contribute much to phylogenetic system-
atics (Schoch 1986), I agree with Howard (1964:
237) that evolutionary insights to be gained from
fossil waterfowl must await an improved
knowledge of phylogenetic relationships among
Recent representatives of the Anseriformes.
ACKNOWLEDGMENTS
This research was funded by National Science
Foundation grant BSR-8516623. I am indebted to G.
Mack, H. Levenson, and R. L. Zusi for their hospi-
tality, and to P.S. Humphrey for discussions and
encouragements concerning the phylogery of water-
fowl. Curatorial staffs of the following institutions
permitted access to or loans of study skins, mounted
tracheae, or skeletal specimens of waterfowl: Division
of Birds, National Museum of Natural History, Wash-
ington, D.C. (USNM); Department of Ornithology,
American Museum of Natural History, New York
(AMNH); Wildfowl Trust, Slimbridge, Gloucester,
United Kingdom (WT); Division of Birds, Museum of
Zoology, University of Michigan, Ann Arbor; Sub-
department of Ornithology, British Museum (Natural
History), Tring, Hertfordshire, United Kingdom; Di-
vision of Birds, Field Museum of Natural History,
Chicago (FMNH); Department of Ornithology, San
Diego Museum of Natural History, San Diego; Mu-
seum of Natural Science, Louisiana State University,
Baton Rouge; Division of Vertebrate Zoology, Bernice
P. Bishop Museum, Honolulu; Department of Orni-
thology, Royal Ontario Museum, Toronto; and De-
partment of Ornithology, Los Angeles County Mu-
seum of Natural History, Los Angeles. I thank P.S.
Humphrey and R. F. Johnston for access to research
facilities at the Museum of Natural History, Univer-
sity of Kansas. I appreciate the helpful comments of
P.S. Humphrey, and D. G. Homberger, and an anon-
ymous referee, and I am grateful for the secretarial
assistance of M. Schmalz.
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APPENDIX I. Characters used in the phylogenetic analysis of Anatini. The sequence corresponds to that used
in the figures and text. Presumed primitive character states are defined as "a"; derived states are designated
alphabetically thereafter (with the exception of character 27). Characters with two or more derived states,
with the exception of rectrix number (character 27), were analyzed as unordered. Characters are grouped
by general anatomical or developmental class, but groupings of some bill characters that involved the
integument and underlying bones were necessarily arbitrary. To avoid biased comparisons of character
groups, two particularly difficult cases involving bill shape (characters 97 and 157) were assigned to "soft-
parts" and "skeleton," respectively. Potentially confusable characters are cross-referenced parenthetically.
Unless indicated otherwise, characters of definitive plumages pertain to both alternate and basic plumages
and to both sexes. Characters of syringeal bulla pertain to males. Consistency indices (CI) for each character
correspond to the topology given in Figures 2 and 3.
ADULT (DFINITIVE) PLUMAGES
1. Tail: (a) moderately short; (b) long, broad, rounded, generally
black (extends well beyond feet in normally prepared skins); CI = 0.50.
2. Rump of definitive males: (a) not as follows; (b) with contrasting
black lateral margins; CI = 0.50.
3. Lateral vanes of outer rectrlces: (a) colored as medial vanes; (b)
whitish, contrasting with medial vanes, producing fine pale borders of
tail; CI = 0.50.
4. Central pair of rectrices: (a) of approximately equal length to
other rectrices; (b) distinctly elongate relative to other rectrices; CI =
1.00.
5. Central pair of rectrices: (a) straight; (b) dorsally curled; CI =
1.00.
6. White vertical shoulder mark: (a) absent; (b) present in males;
CI = 0.50.
7. Narrow white antorbital facial crescent: (a) absent; (b) present
in males (only in basic of A. clypeata; occurs also in hybrids involving
A. clypeata, see Scherer and Hilsberg 1982); CI 1.00.
8. Pale flank patches, formed by laterodorsal extensions of pale
venter to sides of rump: (a) absent; (b) present in males, alternate plum-
age (compare with character 18); CI = 0.33.
9. Secondary coverts pale blue, forming contrasting blue forewing
patch: (a) absent; (b) present (excludes more extensive, gray forewing
of A. querquedula and infregenus Punanetta); CI 1.00.
10. Distinct, whitish "horseshoe"-shaped marks on breast feathers,
all definitive plumages (exclusive of alternate plumage of male A. cly-
peata): (a) absent; (b) present (variable, weak in A. smithii; compare with
character 38); CI = 0.50.
11. Dark, contrasting cap, extending to below orbit and including
nape: (a) absent; (b) present; CI = 0.50.
12. Contrasting, white vertical neck stripe: (a) absent; (b) present
(reduced in A. eatoni; Stahl et al. 1984); CI = 1.00.
13. Secondary coverts white, forming contrastingly pale forewing
patch: (a) absent; (b) present; CI 1.00.
14. Contrasting, pale buff or white forecrown: (a) absent; (b) present;
CI = 1.00.
15. Greenish postorbital patch, washed with purplish-bronze iri-
descence, lacking contrasting border: (a) absent; (b) present (compare
with characters 28, 31); CI 1.00.
16. Smudgy black crown, from bill base to occiput: (a) absent; (b)
present in definitive alternate plumages of males; CI = 1.00.
17. Sharply defined, narrow white eye-ring: (a) absent; (b) present,
both sexes; CI 1.00.
18. Black-bordered buff flank patches: (a) absent; (b) present in males,
alternate plumage; CI = 0.50.
19. Rump: (a) not as follows; (b) dark brown with greenish irides-
cence, in males; CI = 1.00.
20. Broad white stripes on lateral vanes of tertials: (a) absent; (b)
present in both sexes; CI = 1.00.
21. "True" speculum, a contrastingly colored, metallic patch limited
to secondaries: (a) absent (includes the nonmetallic white "speculum"
or generalized alar iridescence of Cairineae and Chenonetteae); (b)
present; CI = 1.00.
22. Color of (true) speculum (where present; not codable for autapo-
morphic M. strepera): (a) metallic purplish-bronze; (b) metallic green
and blue, variably washed with purplish or black (obsolete in A. ber-
nieri); CI 1.00.
23. Rufous or pinkish-red sides: (a) absent; (b) present, both sexes;
CI = 1.00.
24. Pinkish-brown wash on breast: (a) absent; (b) present, both sexes;
CI 1.00.
25. Cinnamon wash on sides and belly: (a) absent; (b) present in
males, alternate plumage; CI = 1.00.
26. Chestnut wash on sides, belly and breast: (a) absent; (b) present;
CI = 1.00.
27. Number of pairs of rectrices (state "b" considered primitive;
modal condition in nonmolting adults): (a) 6; (b) 7; (c) 8; (d) 9; CI =
0.33.
28. Entire head and neck (including chin and throat) of male in
alternate plumage a bright, metallic green: (a) not so (includes green
iridescence on sides of head in male A. clypeata); (b) as described (ves-
tigial in A. oustaleti and A. wybilliana); CI = 0.50.
29. Brick-red coloring of breast, as distinct from sides, belly: (a)
absent; (b) present in males, especially in alternate plumage (vestigial
in A. fulvigula, A. oustaleti, and A. wyvilliana); CI = 0.50.
30. Generalized, poorly differentiated greenish postorbital irides-
cence: (a) absent; (b) present; CI = 1.00.
31. Intense, metallic-green postorbital patch with black and/or buff
border: (a) absent; (b) present; CI = 1.00.
32. Entire rump contrastingly black with green iridescence: (a) not
so (includes the purplish-brown rump of A. poecilorhyncha and greenish-
brown rump of male A. clypeata); (b) as described (vestigial in A. oustaleti,
A. wyvilliana, A. laysanensis); CI = 1.00.
33. Sharp, black-and-white vermiculations on undertail coverts: (a)
absent; (b) present; CI = 1.00.
34. Sharp, black-and-white barring on flanks: (a) absent; (b) present;
CI = 0.50.
35. Fine blackish vermiculations on flanks: (a) absent; (b) present;
CI = 1.00.
36. Fine blackish vermiculations on whitish or pale buff belly feath-
ers of males: (a) absent; (b) present; CI = 0.50.
37. Constrasting black wing linings: (a) absent; (b) present; CI =
0.50.
38. Alternating brown and white, U-shaped marks on breast feath-
ers: (a) absent; (b) present, males in alternate plumage (Fig. 4a; compare
with character 10); CI = 0.67.
39. Contrastingly pale caudal border on speculum (where present):
(a) present, white or buffy; (b) obsolete; CI = 0.50.
40. Pale caudal border of speculum (where present): (a) narrow,
(cranio-caudal) width significantly less than that of metallic speculum;
(b) broad, width approximating or exceeding that of speculum; CI =
1.00.
41. Breast feathers of males in alternate plumage: (a) not as follows;
(b) with dark central subterminal spot subtended proximally by trans-
verse row of four lighter spots (Fig. 4b); CI = 1.00.
42. Cranial border of speculum, formed by tips of caudal-most row
of greater secondary coverts: (a) not contrastingly colored; (b) black;
(c) white; (d) buff or rufous; CI = 0.38.
43. Tips of greater secondary coverts (character 42) subtended with
contrasting white or light brown subterminal band: (a) not so; (b) as
described; CI = 1.00.
44. Basal half of greater secondary coverts: (a) brown; (b) white; (c)
black; CI = 0.67.
45. Lateral vane of tertials of males in alternate plumage: (a) not as
follows; (b) with sharply defined, narrow white edge, bordered me-
dially by black (excludes white edge subtended by brown in M. capensis,
A. querquedula); CI = 1.00.
46. Scapulars of males in alternate plumage: (a) not as follows; (b)
with distally widened, sharply defined, typically asymmetrical, white
central stripe (Fig. 5d); CI = 0.50.
47. Scapulars of males in alternate plumage: (a) not as follows; (b)
A
C
t I
Fig. 4. Breast feathers of four species of Anateae (definitive alternate plumages of males, ventral views):
(A) Mareca falcata (AMNH 732,314), (B) Anas crecca (AMNH 424,195), (C) A. discors (AMNH 749,780), and (D)
A. erythrorhyncha (AMNH 262,156).
with distal portion of lateral vane blue, and medial vane blackish with
distally widening buff stripe along rachis (Fig. 5c); CI = 1.00.
48. Back feathers of both sexes in alternate plumage: (a) brownish
with margins variously lighter; (b) finely vermiculated with buff; CI =
1.00.
49. Back feathers of males in alternate plumage: (a) not as follows;
(b) crossed by 3-4 straight bars of white; CI = 0.50.
50. Back feathers of females: (a) not as follows; (b) marked in mid-
vane by wide, whitish, U-shaped bar; CI = 1.00.
51. Back feathers: (a) not as follows: (b) dichromatic--with buffy-
cinnamon crescent distally and similarly colored, irregular line prox-
imally in males, and a single central buffy crescent in females; CI =
1.00.
52. Shape of scapulars of males in alternate plumage: (a) typically
pinnate; (b) tapering abruptly to long narrow point (Fig. 5c, d); CI =
1.00.
53. Buff mottling on basal half of lateral vanes of scapulars of males
in alternate plumage: (a) absent; (b) present; CI = 1.00.
54. Uppertail coverts of both sexes: (a) not as follows; (b) largely
black with distal edges of medial vanes buff; CI = 1.00.
55. Scapulars of males in alternate plumage: (a) not as follows; (b)
finely vermiculated with gray and white, especially medial vane; CI =
1.00.
56. Sharply defined black chin patch: (a) absent; (b) present in males
in alternate plumage; CI = 1.00.
57. Fine, black, circular speckling of head: (a) absent; (b) present on
whitish background in basic plumage of males and all definitive plum-
ages of females; (c) present on brownish background (all definitive
plumages except alternate of male A. acuta); CI = 1.00.
58. Short mane of feathers on nape, relatively well developed in
lower (nuchal) portion: (a) absent; (b) present (compare with characters
87, 88); CI = 1.00.
59. Dorsal contour feathers characterized by an irregular buff mar-
ginal and one irregular central buff mark: (a) not so; (b) as described;
CI = 1.00.
60. One or two V-shaped white marks on dorsal contour feathers:
(a) absent; (b) present; CI = 1.00.
61. Entire back and crown iridescent green: (a) not so; (b) as de-
scribed; CI = 1.00.
62. Faces of females with three adjacent cheek stripes, alternating
white, black, and white: (a) not so; (b) as described; CI = 1.00.
63. Entire underwing, excluding remiges; (a) variably mottled or
black; (b) immaculate white; (c) dark chestnut; CI = 1.00.
64. Coloration of body, including dorsum, tail, sides, venter, head,
and neck: (a) various, but not as follows; (b) black; (c) dark brown; CI
= 1.00.
65. Primary remiges: (a) uniformly dark; (b) dark with fine, whitish
lateral margins; CI = 1.00.
66. Alternating black and white crescents on sides of breast: (a)
absent; (b) present in males in alternate plumage; C1 = 1.00.
67. Black-and-white scalloping on sides: (a) absent; (b) present in
males in alternate plumage; CI = f.00.
68. White, drop-shaped postocular streaks: (a) absent; (b) present in
females; CI = 1.00.
69. Crown and nape darkened by a contrastingly dark, dull-brown
"hood": (a) not so; (b) present in males in alternate plumage; CI 1.00.
70. Speculum (where present and "true"): (a) not as follows; (b)
strongiy washed with iridescent bronze and distinctly dichromatic,
those of females having little or obsolete iridescence; CI 1.00.
71. Wings rounded, primary remex I0 distinctly shorter than pri-
mary remiges 8 and 9: (a) not so (includes uniquely rounded condition
in A. aucklandica, in which both remex 9 and I0 are shorter than remex
8); (b) characteristic of both sexes; CI = 1.00.
72. Rectrices progressively shortened laterally, producing wedge-
shaped tail: (a) not so; (b) as described; CI = 1.00.
73. Scapulars of males in alternate plumage: (a) not as follows; (b)
patterned with fine, white, obliquely oriented vermiculations (Figs. 5a
vs. 5b); CI = 1.00.
74. Entire upper forewing, including all secondary coverts and less-
er primary coverts (alular region): (a) not contrastingiy patterned; (b)
immaculate white; (c) pale blue; CI = 1.00.
75. Color of lower breast and belly: (a) variously colored, often
mottled, but if pale not distinctly demarcated from color of sides, flanks,
and breast; (b) white, sharply contrasting with darker sides, fianks, and
breast; CI = 1.00.
76. Scapulars of adults, especially males: (a) not as follows; (b) with
contrasting black stripe along rachis; CI = 1.00.
77. Uppertail coverts distinctly pointed with pale lateral edges: (a)
not so; (b) as described; CI = 1.00.
78. Axillars of adults (both sexes): (a) not as follows; (b) white with
minute grayish spotting distally; (c) with minute brown spotting dis-
tally; CI = 0.67.
79. Diffuse greenish iridescence of dorsum of wing, if present: (a)
variable in intensity, typically including secondary converts, secondary
remiges, tertials, and (in some) primary remiges; (b) limited to specular
region of secondary remiges; CI = 1.00.
80. Upperwing: (a) not as follows; (b) generally iridescent green
(particularly intense on secondary remiges) with laterally widening,
white band formed by tips of greater secondary coverts (reduced prox-
imafly in N. auritus); (c) generally iridescent green with white band on
secondary coverts obsolete; CI = 1.00.
81. Rump paler than rectrices, finely scalloped with dark gray: (a)
not so; (b) as described; CI = 1.00.
82. Flanks of males in alternate plumage: (a) not as follows; (b)
marked by subrectangular whitish patch surrounded by dark areas; CI
83. Flanks of males in alternate plumage: (a) not as follows; (b)
marked by subcircular whitish patch surrounded by dark areas; CI =
1.00.
84. Breast feathers of males in alternate plumage: (a) not as follows;
rust,
white
A
brownish
B C D
I I
)lue
Fig. 5. Scapulars of four species of Anateae (definitive alternate plumages of males, dorsal views, right
pterylae): (A) Mareca americana (AMNH 350,657), (B) M. sibilatrix (AMNH 443, 631), (C) Anas cyanoptera (AMNH
731,952), and (D) A. rhynchotis (AMNH 732,785).
(b) with one dark, central terminal spot, subtended by a staggered row
of three dark spots, followed by a more-proximal row of four paler
spots (Fig. 4c); CI = 1.00.
85. Breast feathers of males in alternate plumage: (a) not as follows;
(b) with one dark, central terminal spot, subtended by two variably
distinct dark spots, followed by a blurred basal line (Fig. 4d); CI = 0.50.
86. Edge of lateral vane of tertials of males in alternate plumage:
(a) not as follows; (b) with sharp defined, narrow black border, sub-
tended medially by buffy brown (interrupted proximally by white in
A. crecca); CI = 1.00.
87. Long crest, emerging from crown to nape, the longest plumes
originating anteriorly: (a) absent; (b) present in both sexes; CI = 1.00.
88. Nuchal crest of moderate, relatively uniform length: (a) absent;
(b) present, longer in males (comparatively long in M. falcata; cf. char-
acters 58, 87); CI = 0.33.
89. Heads of adults of both sexes: (a) poorly demarcated from breast,
or differs qualitatively from breast in color; (b) sharply demarcated quan-
titatively from breast in the darkness of brownish-gray color; CI = 1.00.
90. Ground color of axillars (both sexes): (a) white; (b) dark brown
to black; CI = 0.25.
91. Axillars: (a) without conspicuous dark transverse barring or
spotting; (b) so marked, especially pronounced in females (excludes
dull brownish mottling of A. laysanensis and A. aucklandica; includes
reduced, subspecifically variable markings of A. bahamensis and almost
completely darkened A. georgica; CI = 0.33.
So Ps
92- Background color of bill: (a) dark gray; (b) greenish yellow to
orange (less bright in A, wyvilliana, A. laysanensis; excludes lemon-yellow
of N. auritus); (c) bright bluish gray; (d) scarlet, in males (excludes unique
red-colored bills of M. capensis, Amazonetta); CI = 1.00.
93. Lateronasal regions of bill: (a) of same color as rest of bill; (b)
marked by contrasting yellow patches; (c) marked by contrasting red
patches; CI = 0.50.
94. Sharply defined, dark stripes along culmen, especially conspic-
uous in males: (a) absent; (b) present (Fig. 6c; brownish in A. erythrorhyn-
cha, obscured by background color in A. bahamensis); CI = 0.50.
95. Dark stripe along tomium and forming variably broad, dark line
of base of bill: (a) absent; (b) present; CI = 0.50.
96. Color of feet: (a) dark gray; (b) yellow to reddish orange; (c)
bright pink or coral red; CI = 0.29.
97. Bill (lateral view): (a) with concave dorsal ridge, nostrils basal
to midpoint of culmen; (b) short, stout, with convex dorsal ridge, nos-
trils located approximately at midpoint of culmen (Fig. 6b); CI = 1.00.
98. Base of bill swelling in breeding males: (a) not so; (b) as described
(Fig. 6a); CI - 1.00.
99. Variable, flesh-colored subterminal patch on dorsum of bill: (a)
absent; (b) present (Fig. 6a); CI = 0.50.
100. Contrasting, dark nasal patches on dorsum of bill (obscured in
most older skin specimens): (a) absent; (b) present in both sexes (see
photograph in Hosking and Kear [1985: 98]; excludes the perinasal
patches of S. specularis and the sexually dichromatic, irregularly shaped,
comparatively blurred markings in some members of subgenus Arias);
CI = 1.00.
101. Base of bill: (a) with marked angular dorsal prominences (Fig.
6a); (b) sloping, without angular prominence (Fig. 6: b-c); CI - 0.50.
102. Claws of pedal phalanges: (a) straight or moderately curved; (b)
strongly curved, very robust; CI = 1.00.
103. Contrastingly dark tomial stripe (without basal extension): (a)
absent; (b) present (Fig. 6c); CI = 1.00.
104. Iris color: (a) brown, both sexes; (b) yellow in males, brown in
females; (c) reddish-yellow, both sexes; (d) red, both sexes, males bright-
er (excludes sexually dichromatic, scarlet irides of Aix sponsa, and vari-
able iris color of M. capensis, L. specularioides); CI = 0.75.
105. Cartilaginous carpal knobs (without elongation of underlying
process of metacarpal I as in Tadominae): (a) absent; (b) present, often
naked of feathers in adult males (excludes suggestions of knobs present
in males of some Anateae, e.g.L. specularioides, S. specularis, and A. sparsa);
CI = 1.00.
106. Bright yellow patch on upper bill tip, immediately caudad to
nail: (a) absent; (b) present (both sexes); CI = 1.00.
NATAL PLUMAGES
(The most variable and problematical characters used in this analysis
are natal characters. Evaluations of states requires reference to series
of specimens of very young ducklings. Caution is required to avoid badly
"foxed" or faded skins or specimens of uncertain species identification,
including hybrid birds from avicultural holdings; detection of facial
and dorsal markings can be difficult in the convergently darkened,
variable natal plumages of some insular forms, e.g.A. albogularis and
A. laysanensis.)
107. Sharp, dark postorbital stripe without any trace of preorbital
stripe: (a) absent; (b) present; CI = 0.50.
108. Diffuse, darkish, suborbital cheek patch extending from base of
bill: (a) absent; (b) present (Fig. 7b); CI = 0.50.
109. Buffy supraorbital spot: (a) absent; (b) present; CI = 1.00.
110. Background color of face: (a) white or yellowish; (b) washed
with tannish-rust; CI = 1.00.
D
Fig. 6. Bills of four species of Anatini (adult males in breeding season, lateral views): (A) Cairina rnoschata
(KUMNH 28,524), (B) Nettapus auritus (KUMNH 36,230), (C) Anas acura (KUMNH 9,593), and (D) A. clypeata
(KUMNH 64,924).
D
Fig. 7. Heads of downy young of six species of Anatini (age class I, lateral views): (A) Nettapus coroman-
delianus, female (FMNH 4,323); (B) Mareca capensis, unsexed (AMNH 348,435); (C) Anas fulvigula, male (AMNH
816,980); (D) A. castanea, unsexed (WT 680); (E) A. acura, female (NMNH 299,286); and (F) A. querquedula, male
(WT 622).
D
Fig. 8. Syringeal bullae of eight species of Anatini (adult males, ventral views): (A) Cairina moschata (WT
1,252), (B) Callonetta leucophrys (WT 1,652), (C) Mareca penelope (WT 1,043), (D) Arias rubripes (WT 2,164), (E) A.
platalea (WT 922), (F) A. erythrorhyncha (WT 938), (G) A. formosa (WT 130), and (H) A. puna (WT 1,442).
111. Pale scapular and rump spots: (a) rounded, well separated; (b)
elongated, the lateral pairs sometimes joining to form pale dorsal stripes;
CI = 0.50.
112. Sides, flanks, and belly: (a) colored like breast and throat; (b)
distinctly mottled with irregular blotches of dark gray; CI = 1.00.
113. Fine, dark, sharply contrasting breast band: (a) absent; (b) pres-
ent (Fig. 7d); CI 0.50.
114. Dark malar spot: (a) absent; (b) present; CI = 1.00.
115. Black-bordered, contrasting orange-buff gape spot: (a) absent;
(b) present; CI = 1.00.
116. Darkish orbital stripe passing from bill to nape, sharply defined
along dorsal edge but blending with color of cheeks ventrally: (a)
absent; (b) present; CI 1.00.
117. Dark auricular spot: (a) absent (Fig. 7a); (b) present (Fig. 7: b-f);
CI = 0.50.
1 IS. Cheek stripe (if present) wide, incorporating dark auricular patch,
forming the ventral border to a very narrow, pale suborbital stripe, and
typically converging broadly with dark orbital stripe anterior to orbit:
(a) not so (includes unique two-toned, "false" cheek stripe of Cheno-
netta); (b) as described (Fig. 7d); CI = 1.00.
119. Cheek stripe (if present) narrow, well separated from orbital
stripe by wide white band (rarely occluded anteriorly): (a) not so (in-
cludes unique two-toned cheek stripe of Chenonetta); (b) as described
(Fig. 7f); CI = 1.00.
120. Cheek stripe (if present) broad, bordered dorsally by relatively
wide white suborbital band, variably convergent with orbital stripe
anteriorly, and widening posteriorly: (a) not so (includes unique two-
toned, "false" cheek stripe of Chenonetta); (b) as described (Fig. 7c); CI
= 1.00.
121. Bright yellow wash on throat and upper breast: (a) absent; (b)
present (especially variable in some species); CI = 0.50.
122. Pale stripe between dark orbital and cheek stripes buffy, con-
trasting with whitish of throat: (a) absent; (b) present (Fig. 7d); CI =
1.00.
123. Pale supraorbital stripes: (a) terminate at nape (Fig. 7: b-f); (b)
continue caudally to meet across nape (Fig. 7a); CI = 1.00.
124. Rectrices: (a) short, not stiflened; (b) disproportionately long,
stiff; CI = 1.00.
125. Wing linings: (a) variably mottled with dark; (b) immaculate
white or yellow; CI = 0.25.
126. Dark cheek stripe: (a) absent (Fig. 7: a-c); (b) present (Fig. 7: d-
f); CI = 0.33.
127. Uneven, variable dark streak passing obliquely from orbit through
auricular region to nape: (a) absent; (b) present; CI = 0.50.
128. Dark, variably extensive postorbital stripe (often retained in
juvenal and definitive basic plumages of both sexes, as well as definitive
basic of males): (a) absent; (b) present (Fig. 7); CI = 1.00.
TRACHEA AND SYPaUx (ADULT M^LrS)
129. Medial margin of syringeal bulla: (a) subcircular in outline (Fig.
8: b-c; includes intermediate conditions of M. strepera and M. americana);
(b) flattened or concave, bulla often tending toward subtriangular shape
(Fig. 8: d-h); C1 = 0.50.
130. Medial extremity of syringeal bulla: (a) variably rounded; (b)
distinctly pointed (Fig. 8f; not codable for uniquely conformed bullae
of the subgenera Spatula and Punanetta, or for A. querquedula and A.
formosa); CI = 0.50.
131. Trachea: (a) without distinct swellings craniad to syrinx; (b) with
one (versicolor and puna) or two (hottentota) swellings; CI = 1.00.
132. Syrigneal bulla (uniquely derived bulla of A. formosa not com-
parable): (a) large, lateromedial width more than twice that of trachea;
(b) small, lateromedial width less than twice that of trachea (Fig. Be,
see also Fig. 8g); CI = 0.50.
133. Syringeal bulla: (a) distinctly asymmetrical, medial extremity
uninflated (Fig. 8: a-d, f-h); (b) almost symmetrical, medial extremity
inflated, producing a distinct medial lobe aligned with trachea (Fig.
Be); CI = 0.50.
134. Laterocaudal margin of syringeal bulla: (a) smoothly inflated or
slightly depressed (Fig. 8: b-d); (b) with distinct depression in ventral
surface (Fig. 8f; not codable for the uniquely conformed bullae of A.
querquedula, A. formosa, and the subgenus Punanetta); CI = 1.00.
135. Syringeal bulla uniformly inflated so as to obscure 1obing and
produce a subcubic ventral appearance: (a) not so (Fig. 8: a-g); (b) as
described (Fig. 8h); CI = 1.00.
136. Medial lobe of syringeal bulla enlarged (at least one-half as large
as lateral lobe); ventrally knobbed, and demarcated from lateral lobe
by distinct constriction: (a) not so; (b) as described (Fig. 8d); CI = 1.00.
137. Syringeal bulla: (a) absent, conspicuous; (b) obsolete; CI = 1.00.
138. Syringeal bulla: (a) comparatively densely walled, opaque; (b)
thinly walled, uniformly translucent; CI = 1.00.
139. Syringeal bulla: (a) rounded ventrally; (b) distinctly dorsoven-
trally compressed (Fig. 8a); CI = 1.00.
140. Syringeal bulla: (a) tracheal involvement in syrinx compara-
tively small, typically four rings fused into syrinx, and pessulus thin,
weakly supported dorsally (Fig. 8: a-b); (b) tracheal chamber large,
typically incorporating at least six rings, and pessulus dense, folded,
and stoutly supported dorsally (Fig. 8: c-h); CI = 1.00.
141. Distinct ventro-caudal bulge in bulla in vicinity of divergence
of bronchii: (a) absent (Fig. 8: a-f); (b) present (Fig. 8: g-h); CI = 0.50.
142. Paired, laterally and medially directed flanges on caudal margin
of pessulus (visible within syringeal bulla in caudal view): (a) absent;
(b) present; CI = 1.00.
143. Laterocranial elongation of lateral lobe of syringeal bulla: (a)
absent; (b) apparent; CI = 1.00.
144. A distinct cranial displacement of lateral lobe of syringeal bulla,
producing an indentation lateral to caudal tracheal aperture: (a) absent;
(b) present (Fig. 8d); CI = 1.00.
145. Craniocaudal compression of lateral lobe of syringeal bulla, pro-
ducing lateral lobe of approximately uniform width: (a) absent; (b)
present; CI = 1.00.
146. Medial rim of trachea, within syringeal bulla: (a) remains dis-
tinct ventrally; (b) reduced, merging with wall of bulla ventrally; CI
= 0.67.
147. Prominent, square, lateral flange of passullus: (a) absent; (b)
present; CI = 1.00.
148. Caudodorsal extremity of caudal tracheal aperture of syringeal
bulla: (a) rounded; (b) pointed, angular; CI 1.00.
149. Lateral lobe of syringeal bulla: (a) uniformly walled; (b) typically
with unossified gap caudally (Fig. 8b); CI = 1.00.
SKELETON (EXCLUSIVE OF TRACHEA)
150. Ventral manubrium of sternum: (a) without conspicuous prom-
inence; (b) with prominent, peg-like, medial spine (includes L. specu-
larioides, state incorrectly given in Livezey 1986: fig. 4); CI = 0.33.
151. Dorsal manubrium of sternum: (a) marked medially by rounded
notch; (b) marked medially by a rounded notch enclosing a small,
central prominence (variable); CI = 1.00.
152. Distal elongation of entepicondylar process, relative to ectepi-
condylar process of humerus: (a) lacking; (b) evident; CI = 1.00.
153. Supraorbital processes of skull: (a) lacking or elongate, essen-
tially coplanar with dorsal surface of interorbital surface; (b) substantial,
flat, medially appressed to dorsal margin of orbit; (c) moderately elon-
gated, with comparatively great dorsolateral prominence; CI = 1.00.
154. Brachial tuberosity of coracold: (a) nonpneumatic; (b) with pneu-
matic depression under caudal edge (variable, especially in A. galericu-
lata); CI = 0.33.
155. Ventral surface of basioccipital shield of skull: (a) rounded; (b)
with medial ridge; CI = 1.00.
156. Posterior surface of orbit, anterolateral view of skull: (a) foramen
nervus maxillomandibularis distinctly smaller than foramen opticum;
(b) foramen nervus maxillomandibularis approaching size of foramen
opticurn; CI = 1.00.
157. Bill shape: (a) typically anatine; (b) spatulate, with anterior third
laterally expanded and (externally) lamellae lengthened so as to pro-
trude ventrally from tomium (Fig. 6d); CI = 1.00.
APPENDIX 2. A Linnean classification of modern dabbling ducks, Tribe Anatini; subtribal names were formed
in the manner of the sections given by Boetticher (1942) based on the included genus first elevated to
suprageneric rank. Sedis mutabilis indicates that included taxa of next-lower rank are of undetermined
sequence. Asterisks mark extinct forms. Currently recognized subspecific taxa included within "polytypic"
species are listed parenthetically (nominate subspecific taxa abbreviated as "nom.").
Order Anseriformes (Waglet, 1831)
Suborder Anseres Waglet, 1831
Family Anatidae Vigors, 1825
Subfamily Anatinae Swainson, 1837
Tribe Anatini Delacour and Mayr, 1945; Surface-feeding Ducks ß
Subtribe Cairineae Boetticher, 1942; Long-billed Wood Ducks
Supergenus Cairina Fleming, 1822; Greater Wood Ducks
Genus Cairina Fleming, 1822; Muscovy Ducks
C. moschata (Linnaeus, 1758); Muscovy Duck
C. scutulata (Milller, 1842); White-winged Duck
Genus Pteronetta Salvadori, 1895
P. hartlaubi (Cassin, 1859); Hartlaub's Duck
Supergenus Aix Bole, 1828
Genus A/x Bole, 1828; Northern Wood Ducks
A. sponsa (Linnaeus, 1758); American Wood Duck
A. galericulata (Linnaeus, 1758); Mandarin Duck
Subtribe Nettapodeae, new taxon; Stout-billed Wood Ducks
Supergenus Chenonetta Brandt, 1836
Genus Chenonetta Brandt, 1836
C. jubata (Latham, 1801); Maned Duck
Genus Nettapus Brandt, 1836; Pygmy-geese
Subgenus Nettapus Brandt, 1836
N. auritus (Boddaert, 1783); African Pygmy-goose
Subgenus Cheniscus Eyton, 1838; Pale-rumped Pygmy-geese
N. coromandelianus (Gmelin, 1789); Cotton Pygmy-goose
(nom., albipennis)
N. pulchellus (Gould, 1842); Green Pygmy-goose
Subtribe Anateae Boetticher, 1942; Dabbling Ducks
Supergenus Amazonefta Boetticher, 1929; Micro-teal
Genus Amazonefta Boetticher, 1929
A. brasiliensis (Gmelin, 1789); Brazilian Teal (nom., ipecutiri)
Genus Callonetta Delacour, 1936
C. leucophrys (Vieillot, 1816); Ringed Teal
Supergenus Lophonetta Riley, 1914; Proto-dabbling Ducks
Genus Lophonetta Riley, 1914
L. specularioides (King, 1828); Crested Duck (nom., alticola)
Genus Speculanas Boetticher, 1929
S. specularis (King, 1828); Bronze-winged Duck
Supergenus Anas Linnaeus, 1758; True Dabbling Ducks
Genus Mareca Stephens, 1824; Wigeons
Subgenus Notonetta Roberts, 1922
M. capensis (Gmelin, 1789); Cape Teal
Subgenus Chaulelasmus Bonaparte, 1838
M. strepera (Linnaeus, 1758); Gadwall (nom., couesi*)
APPENDIX 2. Continued.
Phylogeny of Dabbling Ducks
499
Subgenus Eunetta Bonaparte, 1856
M. falcata (Georgi, 1775); Falcated Duck
Subgenus Mareca Stephens, 1824; True Wigeons
M. sbilatrix (Poeppig, 1829); Chilo Wigeon
M. penelope (Linnaeus, 1758); Eurasian Wigeon
M. ameriana (Gmelin, 1789); American Wigeon
Genus Anas Linnaeus, 1758; Typical Dabbling Ducks, sedis mutablis
Subgenus Anas Linnaeus, 1758; Mallards
Infragenus Melananas Roberts, 1922
A. sparsa Eyton, 1838; African Black Duck (nom., leu-
costigma)
Infragenus Anas Linnaeus, 1758; Northern Mallards, sedis
mutabilis
A. rubripes Brewster, 1902; American Black Duck
A. fulvigula Ridgway, 1874; Mottled Duck (nom., macu
1osa)
A. diazi Ridgeway, 1886; Mexican Duck
A. platyrhynchos Linnaeus, 1758; Mallard (nom., conbos-
chas)
A. wyvilliana b Sclater, 1878; Hawaiian Duck
A. laysanensis Rothschild, 1892; Laysan Duck
[A. oustaleti Salvadori, 1894; Marianas Duck]
infragenus Polionetta Oates, 1899; South Pacific Mallards
A. luzonica Fraser, 1839; Philippine Duck
A. superciliosa Gmelin, 1789; Pacific Gray Duck (nom.,
pelewensis, rogersi)
A. poecilorhyncha Forster, 1781; Indonesian Spot-billed
Duck (nom., baringtoni)
A. zonorhyncha Swinhoe, 1845; Chinese Spot-billed Duck
Infragenus Afranas Roberts, 1922; African Mallards
A. undulata Dubois, 1839; Yellow-billed Duck (nom.,
ruppellO
A. melleri Sclater, 1865; Meller's Duck
Subgenus Spatula Boie, 1822; Blue-winged Ducks
Infragenus Pterocyanea Bonaparte, 1841; Blue-winged Teal
A. discors Linnaeus, 1766; Blue-winged Teal
A. cyanoptera Vieillot, 1816; Cinnamon Teal (nom., or-
inomus, borreroi, tropica, septentrionalium)
Infragenus Spatula Boie, 1822; Shovelers
A. smithii Hartert, 1891; Cape Shoveler
A. platalea Vieillot, 1816; Red Shoveler
A. rhynchotis Latham, 1801; Australasian Shoveler (nom.,
variegata)
A. clypeata Linnaeus, 1758; Northern Shoveler
Subgenus Nesonetta Gray, 1844; Australasian Teal
Infragenus incertae sedis
A. bernieri a Hartlaub, 1860; Madagascan Teal
[infragenus Virago Newton, 1871; Gray Teal]
A. albogularis Hume, 1873; Andaman Teal
A. gbberifrons Muller, 1842; Gray Teal (nom., gracilis,
remissa )
Infragenus Nesonetta Gray, 1844; Reddish Teal
A. castanea Eyton, 1838; Chestnut Teal
A. chlorotis (Gray, 1845); Brown Teal
A. aucklandica (Gray, 1844); Flightless Teal (nom., nesi-
otis)
Subgenus Dafila Stephens, 1824; Pintails
Infragenus Paecilonitta Eyton, 1838; Pale-cheeked Pintails
A. bahamensis Linnaeus, 1758; White-cheeked Pintail
(nom., rubrirostris, galapagensis)
A. erythrorhyncha Gemlin, 1789; Red-billed Pintail
infragenus Dafilonettion Boetticher, 1937; Speckled Teal
A. fiavirostris Vieillot, 1816; Yellow-billed Teal (nom.,
oxyptera)
A. andlure (Sclater and Salvin, 1873);Andean Teal (nom.,
altipetans)
Infragenus Dafila Stephens, 1824; Brown Pintails
A. georgica Gmelin, 1789; Brown Pintail (nom., spinicau-
da, niceforoi* )
A. acuta Linnaeus, 1758; Northern Pintail
A. eatoni Sharpe, 1875; Eaton's Pintail (nom., drygalskii)
Subgenus Querquedula Stephens, 1824; Holarctic Teal
Infragenus Querquedula Stephens, 1824
A. querquedula Linnaeus, 1758; Garganey Teal
Infragenus Nettion Kaup, 1829; Green-winged Teal
A. formosa Georgi, 1775; Baikal Teal
A. crecca Linnaeus, 1758; Common Green-winged Teal
(nom., nimia)
A. carolinensis Gmelin, 1789; American Green-winged
Teal
Subgenus Punanetta Bonaparte, 1856; Spotted Teal
infragenus Punanetta Bonaparte, 1856; Pale-cheeked Teal
A. versicolor (Vieillot, 1816); Silver Teal (nom., fretensis)
A. puna (Tschudi, 1844); Puna Teal
Infragenus Micronetta Roberts, 1922
A. hottentota (Eyton, 1838); Hottentot Teal
Nine monotypic genera of waterfowl, included by some authors in the Anatini (or Cairinini), are here included in other tribes or subfamilies
(Livezey 1986): Stictonetta naevosa to Stictonettinae; Plectropterus gambensis to Plectropterinae; Sarkidiornis melanotos, Malacorhynchus membranaceus,
Hymenolaimus malacorhynchos, Merganetta armata, and Salvadorina waigiuensis to Tadorninae; and Marmaronetta angustirostris and Rhodonessa cary-
ophyllacea to Aythyini.
Assignable to lesser subgeneric taxon Horizonetta Oberholser, 1917, the North Pacific Mallards.
Status tentative, possibly of hybrid origin (A. platyrhynchos x A. superciliosa; cf. Yamashina 1948); probably extinct.
Position tentative.
Possibly paraphyletic.
Frequently used variants--Poecilonitta Gray 1840, Poecilonetta Reichenbach 1845, and Paecilonetta Bonaparte 1856--are junior synonyms.
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