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Home , Aix (bird), Alopochen, American wigeon, Anabernicula, Anas, Anatidae

A PHYLOGENETIC ANALYSIS OF RECENT ANSERIFORM GENERA USING MORPHOLOGICAL CHARACTERS

BRADLEY C. LIVEZEY Museumof NaturalHistory and Department of Systematicsand Ecology, University of Kansas, Lawrence, Kansas 66045 USA

ABSTRACT.--Aphylogenetic analysis of all Recentgenera of the Anseriformesusing 120 morphologicalcharacters supports much of the current consensusregarding intraordinal relationships.I found that (1) Anseranasshould be placedin a monotypicfamily; (2) Dendro- cygna,Thalassornis, geese and ,and Stictonettaare paraphyleticto the rest of the Anati- dae; (3) Cereopsisis the sistergroup to Anserand ,and Coscorobais the sistergroup to Cygnusand Olor; (4) Plectropterusis the sistergroup to the () and the (typical );(5) the shelducksare monophyleticand include (pro- visionally), ,Hymenolaimus, Merganetta, and Tachyeres;(6) the tribe "Cairinini" ("perchingducks") is an unnatural,polyphyletic assemblage and is rejected;(7) the dabbling ducks(including the smaller"perching ducks") comprise an unresolved,probably paraphy- letic group;(8) tribal of the pochards(including Marmaronettaand Rhodonessa), seaducks (including the ),and stiff-tailedducks (including Heteronetta)is confirmed; and (9) the retention of Mergellusand resurrectionof Noraonyxare recommendedbased on clarificationsof intratribal relationships.Problematic groups, effects of homoplasy,phenetic comparisons,life-history correlates,biogeographic patterns, and fossilspecies are discussed, and a phylogeneticclassification of Recentgenera is proposed.Received 18 November1985, accepted2 April 1986. THE is considered to 1962; Davies and Frith 1964; Raikow 1971; Kear comprisethe families Anhimidae (2 genera, 3 and Murton 1973). Most authors assumed the )and (approximately43 gen- validity of the tribesand usedthem asworking era and 150 species).The Anatidae is units in phylogenetic analysesof the family undoubtedlyone of the best-studiedgroups of (e.g. Johnsgard 1961a, Bottjer 1983). A few , owing largely to the historical impor- workers named additional tribes (Moynihan tance of waterfowl for (Weller 1964a), 1958, Delacour 1959, Woolfenden 1961, Weller domestication (Delacour 1964a), and 1968b) or attempted to test the naturalnessof (Delacour 1964b). those originally proposed(Cotter 1957, Wool- The classificationof the Anatidae proposed fenden 1961, Brush 1976). by Delacour and Mayr (1945) has been fol- Behavioral characters have been accorded lowed, with only minor revisions,in recent de- considerableweight in classificationsof water- cades (e.g. Delacour 1954, 1956, 1959, 1964c; . Delacour and Mayr (1945) based their Johnsgard 1961a, 1962, 1965a, 1978, 1979; revision on charactersthey consideredto be Woolfenden 1961; Frith 1967; Bellrose 1976; "non-adaptive,"including behavioraldisplays, Palmer 1976; A.O.U. 1983; Bottjer 1983; Scott nesting and feeding habits, and selected mor- 1985). Perhaps the most innovative aspect of phological characters(e.g. posture, body pro- this system(inspired by the works of Salvadori portions,head shape,syringeal bulla). Reliance 1895;Phillips 1922, 1923, 1925;and Peters 1931) on comparativeethology in anatid was the erection of "tribes," groups of genera was furthered by the studiesof Lorenz (1951- that were consideredto be closelyrelated with- 1953), McKinney (1953), and Myres (1959) and in the subfamilies of the Anatidae. These tribes was increased significantly by Johnsgard becamethe primary focusof subsequentworks (1960a-c, 1961a-d, 1962, 1964, 1965a, b, 1966a, on anatid classification,many of which ad- b, 1967, 1978), whose work was largely etho- dressedthe tribal assignmentsof problematic logical and influenced profoundly by that of genera (e.g. Humphrey and Butsch 1958; Delacour (1954, 1956, 1959, 1964c). This em- Johnsgard1960a, 1961b; Humphrey and Ripley phasis, work on interspecific hybridization

737 The 103: 737-754. October 1986 738 BRADLEYC. LIVEZEY [Auk, Vol. 103

(Sibley 1957;Gray 1958;Johnsgard 1960d, 1963), Casarca(= Tadorna),Metopiana (= ), Oidemia(= and studyof plumagepatterns of downy young Melanitta), and Charitonetta(= Bucephala).For , (Delacour 1954, 1956, 1959; Frith 1955, 1964b; speciesfrom several subgenerawere examined: Mal- Kear 1967) were prompted in part by the op- lard (Anasplatyrhynchos), (A. acuta), portunity to observe waterfowl in avicultural American (A. americana),Green-winged Teal collections. (A. crecca),and Northern (A. clypeata).Oth- er speciesof Anaswere studied for certain characters. Other data used in the classification of wa- Salvadori'sDuck [Anas(Salvadorina) waigiuensis], pro- terfowl include syringealanatomy (Humphrey visionally assignedto Anas but considered problem- 1955,1958; Johnsgard 1961e), cytogenetics (Ya- atic by some(Mayr 1931, Kear 1975), was not includ- mashina 1952), serology (Cotter 1957, Bottjer ed because no skeletal specimens were available 1983), osteology(DeMay 1940, Verheyen 1955, (Wood et al. 1982).Except for Rhodonessa(monotypic, Humphrey and Butsch1958, Woolfenden 1961, probably extinct; one complete skeleton) and Camp- Humphrey and Ripley 1962, Raikow 1971), torhynchus(monotypic, extinct; castsof two partial lice (Timmermann 1963), eggshell skeletons),all genera analyzed were representedby structure (Tyler 1964), -white proteins (Sib- at least two complete skeletons. For all polytypic genera at least two specieswere studied, and a num- ley 1960, Sibley and Ahlquist 1972), feather ber of the common, diverse, or problematic genera proteins(Brush 1976), royology (Zusi and Bentz were represented by large series. 1978), lipids from the (Jacob For Camptorhynchus,character states for unavail- and Glaser 1975, Jacob 1982), and mitochon- able elementseither were assumedprovisionally (for drial DNA (Kessler and Avise 1984). characters invariant within the anatines) or coded as These studies, with the possible exceptions "missing." Assumption of anatine characters for of those by Lorenz (1953) and Kesslerand Av- Camptorhynchusis conservative (cf. Humphrey and ise (1984), estimatedthe evolutionaryrelation- Butsch 1958, Zusi and Bentz 1978) and did not alter ships of groups by assessmentsof overall sim- its positionin the resultanttree (comparedwith anal- ilarities; no attempts were made to determine yses without this assumption),but permitted more efficient computation of trees and a shorter final so- primitive conditions or to distinguish shared lution. primitive charactersfrom shared derived char- Analysisof characters.--Forthe phylogenetic anal- acters ("special" similarity). Moreover, the ysis presented, 120 characterswere used (Appendix "evolutionary trees" presentedin mostof these 1); a majority of the osteologicalcharacters were de- works lack referencesto the specificcharacters scribed in Woolfenden (1961) and illustrated in used to support the branching patterns (e.g. Howard (1929). Some characterswere rejected be- Delacourand Mayr 1945;Johnsgard 1961a, 1978; causevariation prevented even modal state assign- Woolfenden 1961). ments for somegenera or becausediscrete states could I performed a phylogenetic (cladistic) anal- not be distinguished. ysis of Recent genera of Anseriformes using Sourcesfor data on the postcranialskeleton were Wetmore (1951), Rand (1954), Verheyen (1955), 120 morphologicalcharacters. I present a hy- Woolfenden(1961), Humphrey and Clark (1964), and pothetical evolutionary tree for the order, con- Raikow (1971). Additional sourceswere (by anatom- sider the taxonomic implications, and discuss ical region): integument and molt (DeMay 1940, selectedlife-history and biogeographiccorre- Siegfried 1970, Palmer 1976), trachea and syrinx lates and the classification of selected (Wetmore 1926; Niethammer 1952; Wolff and Wolff species.Many of the characterswere described 1952; Humphrey 1955, 1958, unpubl. data; Hum- first in the pioneering work of Woolfenden phrey and Butsch 1958; Johnsgard1961b, e; Hum- (1961), to whom I dedicatethis paper. phrey and Ripley 1962; Humphrey and Clark 1964; Weller 1968b), and skull (Abbott 1938, Harrison 1958, Raikow 1970a, Olson and Feduccia 1980a). I included METHODS only qualitative charactersbecause the polarities and Taxaand specimens.--Both genera of Anhimidae and statesof mensural charactersare especially difficult all Recent genera of Anatidae were studied. I ana- to determine. Each character is an anatomical trait for lyzed separatelyseveral subgenera (sometimes con- which two or more discrete character states were de- sidered genera), including Olor, Lophonetta,Pteronet- fined. ta, Amazonetta,Callonetta, Mergellus, Lophodytes, and Derivationof trees.--Polarities of each character Nomonyx.Several other "subgenera"were found to (primitive states) were determined by comparison be identical to the taxa with which they generally with outgroups--Burhinus and Larus (Charadri- are merged and are not labeled separatelyin the trees: iformes), Ortalis and Meleagris(), Ciconia October1986] Phylogenyofthe Anseriformes 739

(Ciconiiformes), and Phoenicopterus(Ciconiiformes or tropterus(Peters 1931, Delacour and Mayr 1945) )--each of which has been proposed and the proposition that Anseranasis an aber- as closelyrelated to the Anseriformes(Delacour and rant "true "(Davies and Frith 1964,Frith Mayr 1945;Delacour 1954;Mainardi 1962;Simonetta 1967). Both the anhimids and Anseranashave 1963; Sibley et al. 1969; Sibley and Ahlquist 1972; undergone substantialautapomorphic change Brush 1976; Feduccia 1977, 1978; Olson and Feduccia 1980a,b; Olson 1985).Generally, the galliforms were since divergence,much of which is unique in the order. most useful for establishing polarities. Outgroups were used to constructa hypothetical ancestor(a vec- Geese,swans, and proto-ducks.--!found that tor of primitive character states) for the Anseri- the "," as currently defined (e.g. formes,which was usedto root the evolutionarytree; Johnsgard1978), is paraphyleticto the rest of the primitive condition of nine characterscould not the family (Fig. 2), in contrastto the monophy- be determined and were codedas missing(Appendix ly depictedby Delacourand Mayr (1945),Boet- 1). Transformation series were treated as linear un- ticher (1952), and Woolfenden (1961). Johns- less they appeared to be nonlinear or problematic; gard (1961a, e) depicted the group as the latter were treated as unordered (Appendix 1). paraphyleticto the "Anatinae,"but later (1978) The syringealbulla was given a weight of 2 because it is a locomotion-independent charactercomplex in- diagrammedit asmonophyletic, as did Bellrose volving enlargement,symmetry, and fenestration;all (1976). These variations, however, may reflect other characterswere assignedunit weight. different approaches to tree construction as The logic and terminology of phylogenetic analy- muchas changing perceptions of relationships. sis are discussedin Wiley (1981). The tree was de- The branchingsequence (Fig. 2) differs from rived using the PAUP program (Swofford 1984), a conventional schemes(Johnsgard 1967, 1978; program that seekstrees of maximum parsimony(i.e. Kear 1967; Raikow 1971; Brush 1976) in that requires the least number of character-statechanges; Dendrocygnaand Thalassornisare not sistergen- see Kluge 1984) and that permits the examinationof era but instead comprisea grade. !n an equally seriesof "equally short" trees.The large size of the parsimonioustopology, Thalassornisdiverged data set prohibited an exhaustive searchguaranteed to find the shortest tree(s), but two thorough meth- immediatelyafter the goose-swanbranch. Most ods-alternate and global branch swapping--were of the 13 autapomorphiesin Thalassornisrep- employed and produced identical topologies. resent adaptationsfor diving and include sev- A data matrix for all outgroups and the Anseri- eral convergenceswith diving ducks in other formes and a list of specimensexamined are available .Until the works of Johnsgard(1967) and from the author on request. Raikow (1971), Thalassorniswas considered to be an aberrant stiff-tailed and allied with

RESULTS Oxyura (e.g. Peters 1931; Delacour and Mayr 1945; Delacour 1959, 1964c), a treatment re- Generalfindings.--Of 50 equally short trees peatedrecently (Howard and Moore 1984,Scott examined that resulted from minor changesin 1985). characterdistributions, only three distinct to- Ten characterchanges confirmed the mono- pologieswere found. The tree illustrated (Fig. phyly of the geeseand swans(Fig. 2), as hy- 1) has the topology of 46 of these trees (consis- pothesizedby most authorities in recent de- tency index = 0.59). Two treesreversed the or- cades(Delacour and Mayr 1945;Delacour 1954; der of branchingof Thalassorniswith the geese Johnsgard1961a, e, 1965a, 1978; Woolfenden and swans, and two others altered relation- 1961;Bottjer 1983).Also, there is a sister-group ships in the -merganserclade (Bu- relationship between Coscorobaand the "typi- cephala,Mergellus, Lophodytes, ). cal" swans(Cygnus, Olor; 6 characters)and be- Anhimidsand Anseranas.--Monophyly of the tween Cereopsisand the "typical" geese(, Anhimidae and the waterfowl and the early Branta;2 characters).My analysisdemonstrated branchingof Anseranaswere confirmed(Fig. 2). monophylyof Olor,but no apomorphiesdistin- The "primitive" status of Anseranashas been guishedCygnus from the commonancestor of recognizedwidely (Miller 1919;Boetticher 1943; Cygnusand Olor (Fig. 2); hence, the topology Delacour 1954;Johnsgard 1961c, e, 1962, 1978, of Cygnusremains unresolved. The generic 1979; Woolfenden 1961; Olson and Feduccia monophyly of Anserand Brantaalso was not 1980a).Notable exceptionswere the placement established. Traditionally, Coscorobaand Cer- of Anseranaswith the superficiallysimilar Plec- eopsishave been consideredto be either "links" 740 BRADLEYC.LIVEZE¾ [Auk,Vol. 103

ANCESTOR PART 1 Anhima Anseranas Dendrocygna Thalassornis

Cygnus Coscoroba Anser Branta Cereopsis

SarkidiOFnis TadoFna Malacorhynchus

Chloephaga CyanochenTachyeres Merganetta aimus

Pteronetta PART

Lophonetta Nettapus Anas

Chenonetta Amazonetta IGallonefta MaFmaronetta Rhodonessa Netta

PART 4 Somateria

Camptorhynchus ßMelanitta . Clangula Mergellus

Lophodytes Mergus

Nomonyx

Biziura

Fig. 1. Phylogenetictree of Recentanseriform genera and selected subgenera based on 120morphological characterslisted in Appendix1. Lengthsof horizontallines correspond to the numberof characterchanges (apomorphies)in the lineages.Sections of the tree are detailedin Figs.2-5. between tribes, early branchesfrom the com- rived from an earlier "anserine" branch of the mon ancestorto the "true" geese and swans, Anatidae (Verheyen 1955; Johnsgard 1960c, or, for Cereopsis,an aberrant or the 1961a, b, 1962, 1965a, b, 1978; Woolfenden 1961; sole member of a separatetribe (Peters 1931; Frith 1964a, b, 1967; Brush 1976; Olson and Delacour and Mayr 1945;Delacour 1954, 1964c; Feduccia 1980a). Johnsgard 1961a, e, 1978; Woolfenden 1961; Plectropterusand the shelducks.--I found that Frith 1967;Kear and Murton 1973;Bottjer 1983). Plectropterusis not related closely to the My analysisshowed Stictonettato be the last "perching ducks"(e.g. Sarkidiornis,Cairina, and branch in the grade of waterfowl with reticu- Nettapus)as generally recognizedsince Dela- late tarsi (Figs. I and 2). Stictonettalong was cour and Mayr (1945). Instead, Plectropterusis believed to be an aberrant member of the the earliest branch of the waterfowl with scu- shelducks (near Tadorna; Peters 1931, Boettich- tellate tarsi, and lacks five synapomorphies er 1952) or the dabbling ducks (e.g. Anas;De- uniting more-derivedmembers of the family lacour and Mayr 1945; Delacour 1956, 1964c). (Fig. 3). Woolfenden (1961) concluded that Basedon anatomicalcomparisons, however, Plectropteruswas mostsimilar osteologicallyto otherworkers suggested that the genuswas de- the shelducks,and Tyler (I 964)found that egg- October1986] Phylogenyofthe Anseriformes 741

106a-b

I05 b-c

o 85 a-b

33 a-b 79 c -d

52- 55- 23 a-b 64- 65 43 a-b

78- 38+ a-b

74 a-b

4 b-c

45 - a-b

63 - a-b 68 - a-b

72 - a-b 77 - a-b 78 b-a 79 89 53 a-b 92 58 a -b 93 96 m J= 70 a -b 99

I09 105 a-c 17 a-b 94 a-b

120 5 a-b 86I a-b I 0 a -b 4 o -b 31 a -b 9 a -b 40 a-b 12 a-b 42 a-b 18 a-b 50 a -b 88 a-b 91 a -b ] O0 a -b ]16 a-b

Fig. 2. Detailed diagram of Part 1 of the phylogenetictree of the Anseriformesshown in Fig. 1. Characters are listed in Appendix I.

shells of Plectropteruswere intermediate be- volving Tadorna,Malacorhynchus, and two clades tween those of anserines and shelducks in containing three genera each (Fig. 3). I found structure.Bottjer (1983) found that Plectropterus Malacorhynchusto be a highly derived shel- differed greatly from other "perching ducks" duck; this has been assignedmost fre- serologicallybut attributed the result to exper- quently to the dabbling ducks (e.g. Delacour imental error. 1956, Woolfenden 1961, Frith 1967, Johnsgard My analysissupports the monophyly of the 1978),although Frith (1955) noted that the pat- shelducks,although only by a single, possibly of its downy young differed greatly from convergentcharacter; further study may show those of Anas and Brush (1976) found that Ma- the shelducksto be a grade of relatively prim- lacorhynchuswas distinctly different from Anas itive ducks.The includesa polytomy in- in its feather proteins.A single synapomorphy 742 BR•DI,œYC. LZVEZEY [Auk, Vol. 103

.... Plectropterus

I Sarkidiornis

v Tadorna

: I ', ', : ; Malacorhynchus • F•o•.• •o• Chloephaõa - L© • Alopochen

•'• •[llllllllll Tachyeres

• I.....I Cyanochen Merganetta

Hymenolafmus

• TOFIGURE4

Fig.3. Detaileddiagram of Part2 of the phylogenetictree of the Anseriformesshown in Fig. 1. Characters are listedin Appendix1. Graphicalproximity of brancheswithin the polytomyin the shelducksdoes not reflect relatedness.

of the skull supportsthe monophyly of the diving ducks in other clades(see Discussion). three genera of "sheldgeese"--Alopochen, Hymenolaimusand Merganettahave been treat- Chloephaga,and Neochen(Fig. 3). ed as allied either with the shelducks,"perch- The (Sarkidiornismelanotos), tra- ing ducks,"or as exceptional,possibly primi- ditionally placed in the "Cairinini" (Delacour tive dabbling ducks (Delacour and Mayr 1945, and Mayr 1945,Johnsgard 1978), appears to be 1946; Delacour 1956; Ripley 1957; Johnsgard an early branch of the shelducks. However, 1965a,1966a). Some workers placed Merganetta three humeral charactersthat were important in its own tribe, Merganettini (Woolfenden in distinguishing the "anserines" and shel- 1961; Kear and Steel 1971; Kear 1972, 1975; ducks from the "anatines"[capital shaft ridge Brush1976; Johnsgard 1978). My analysisdoes (character 22), deltoid crest (25), and external not supportthe suggestion(Olson and Feduc- tuberosity (32)] were of equivocal or "inter- cia 1980a:22) that "... the typical membersof mediate"condition in this species.In addition, the 'subfamily' Anserinaeand the typical mem- the enlarged, uniquely distally directed meta- bers of the 'subfamily' Anatinae are more carpal I of Sarkidiornis,a character complex closelyrelated to one another than to Stictonet- herein consideredto incorporatetwo aspects ta, Malacorhynchus,or Merganetta." [orientation(41) and length (42)], proved dif- The third and most derived member of this ficult to characterize. Perhaps Sarkidiornis clade is Tachyeres(Fig. 3), a neotropical genus branchedimmediately before Cairinaor, alter- generallyplaced in the shelducksor in a sep- natively, after Plectropterusbut before the di- arate tribe allied with the shelducks (Delacour vergence of the shelducks from other "ana- 1954; Moynihan 1958; Johnsgard1965a, 1978; tines." Weller 1976;but see Ripley 1957, Woolfenden Three problematic genera--Hymenolaimus, 1961).Like all shelducks,Merganetta and Tachy- Merganetta,and Tachyeres--comprisea highly eres show an enlargement of metacarpal I derived cladeof shelducks(Figs. 1 and 3). Sev- (adornedwith keratinspurs in Merganetta)that eral of the charactersuniting thesegenera are is sexuallydimorphic and age related (Weller evidently related to diving and are sharedby 1968a,Livezey unpubl. data). Cyanochenis hy- October1986] Phylogenyofthe Anseriformes 743 pothesizedto be the sistergenus to the Hymen- olaimus-Merganetta-Tachyeresclade, although 28 a -b 55 this relationship is supportedby only two syn- 56 apomorphies. Bottjer (1983) suggested that Cyanochenmay have branchedbefore the other shelducks.

"Perching"ducks and "dabbling"ducks.--The • 33 b-c sister group to the shelduckscomprises four groups (Fig. 1): a poorly resolved grade of "perching" and "dabbling" genera (Pteronetta, Cairina,, Lophonetta,Nettapus, Anas, Callonet- ta, ,and Amazonetta), which in turn • 97 o-b • gave rise to the pochardsand independently to the sea ducks and stiff-tailed ducks. The first group (Fig. 4), henceforth termed "dabbling ducks," is a paraphyletic group of genera pre- viously allocatedto either the "Anatini" or the "Cairinini" (Delacour and Mayr 1945; Delacour Fig. 4. Detailed diagram of Part 3 of the phylo- 1956;Johnsgard 1960c, d, 1961a,e, 1962, 1965a, genetic tree of the Anseriformesshown in Fig. 1. 1978). Charactersare listed in Appendix 1. Graphical prox- The polyphyleticcharacter of the "Cairinini" imity of brancheswithin the polytomyin the dab- was inferred by Woolfenden (1961). The tribe bling ducksdoes not reflectrelatedness. has been recognizedby subsequentworkers in spiteof the equivocalallocation of severalgen- era (e.g. Callonettaand Amazonetta;Johnsgard 1960a, 1965a, 1978), the widely recognized het- Anas, Callonetta, Chenonetta,Amazonetta, and the erogeneity of its members in behavior, mor- sea ducks and stiff-tailed ducks (Fig. 4), sug- phology, and biochemistry(Johnsgard 1960c, gestingthat the pochardsarose independently 1961a,1962, 1965a,1978; Woolfenden 1961;Ty- of other diving ducks.I found that Rhodonessa ler 1964; Brush 1976; Bottler 1983), the lower is the sister group to Netta and , which incidence of interspecifichybridization within agrees with most studies (Verheyen 1955; the tribe than between its members and those Johnsgard1961a, e, 1962, 1978, 1979;Woolfen- of other tribes (Johnsgard1960d), and the con- den 1961; Humphrey and Ripley 1962; Brush spicuouslack of a single character(or combi- 1976) sinceDelacour and Mayr (1945, 1946) and nation of characters)that uniquely distinguish- Delacour (1956) provisionally placed Rhodones- es its members from other anatines. Johnsgard sain the dabbling ducks.Marmaronetta, a genus (1965a, 1978) admitted that retention of the tribe believed to "link" the Anatini with the po- was partly a taxonomic convenienceto avoid chards but retained within the Anatini (Johns- creationof "a comparativelylarge tribe" (1978: gard 1961a, b, e, 1978; Delacour 1964c; Brush xxi) and omitted it as a suprageneric in 1976), is supported in my study as the sister his latest list (Johnsgard1979). genusto the pochardsby two osteologicalsyn- The genera of dabbling ducks (on the basis apomorphies (Fig. 4). This relationship is cor- of three variable multistate characters) form a roboratedby the secondaryloss of metallic col- grade from relatively primitive (e.g. Cairina,Lo- oration in the speculum (Delacour and Mayr phonetta)to more-derivedforms (e.g. Anas,Cal- 1946). lonetta). A single osteological synapomorphy Seaducks.--The sea ducks comprise a mono- supports a close relationship between Cairina phyletic group related to the stiff-tailedducks, and Aix (Fig. 4), a relationship suggestedpre- although this relationshipis supportedby only viously by karyotypic and serological compar- a few, possibly convergent charactersrelated isons (Yamashina 1952, Cotter 1957, Bottjer to diving (Fig. 5). My result contradictsthe pre- 1983). viously proposedclose relationship between sea Pochards.--Thepochards are a monophyletic ducks and "perching ducks" (Delacour and groupin an unresolvedpolytomy that involves Mayr 1945, Delacour 1959, Bottler 1983). With 744 BRADLEYC. LIVEZEY [Auk,Vol. 103

main tentative because of the limited material available. Humphrey and Butsch(1958) placed Camptorhynchusafter Melanitta but before Clan- gula, and Zusi and Bentz (1978) allied the genus with eiders, evidently on the basisof shared primitive characters. The very close relation- ship of goldeneyesand mergansershas had unanimous support in recent decades(e.g. De- lacour and Mayr 1945; Boetticher 1952; Hum- phrey 1955; Delacour 1959; Myres 1959; Johns- == • ss o-b,,,.-- gard 1960b, d, 1961a, 1978; Brush 1976). This analysisshows the Sinew (Mergellusal- bellus)to be either the sistergenus to Bucephala (Fig. 5) or the sister group to the Lophodytes- Mergusclade. The former topologyis corrobo- rated by the relatively high frequency of Mer- gellusx Bucephalahybrids in the wild (Phillips 1925,Ball 1934,Gray 1958,Nilsson 1974,Johns- gard 1978). Previous workers either listed the Sinew between the goldeneyes(Bucephala) and the mergansers(Mergus, Lophodytes) as a mono- typic genus (Peters 1931, Woolfenden 1961, Fig. 5. Detailed diagram of Part 4 of the phylo- A.O.U. 1983), or merged it (with Lophodytes) genetictree of the Anseriformesshown in Fig. 1. into Mergus(Delacour and Mayr 1945;Boettich- Charactersare listed in Appendix 1. Placementof er 1952;Humphrey 1955;Delacour 1959, 1964c; Camptorhynchusis tentative. Johnsgard1960c, 1961a, d, 1965a, 1978, 1979). Stiff-tailedducks.--My study supports the monophyly of the stiff-tailed ducks, wherein the possible exception of a few workers who Heteronettais the sister genus to the more typ- advocated(largely on the retention of primi- ical members(Fig. 5). The position of the clade tive Anas-like characters)the tribal separation as closely related to the sea ducks and highly of the eiders (Somateriaand Polysticta)from the derived (especiallyBiziura) agrees with recent other sea ducks (Humphrey 1955, 1958; Dela- orderingsof generaby taxonomists(e.g. Johns- cour 1959; Brush 1976; Todd 1979), the mono- gard 1979) but disagreeswith suggestionsof a phyly of the seaducks has not been questioned pre-dabbling duck (Raikow 1970b, Johnsgard recently (e.g. Johnsgard1960b, 1961a, e, 1964, 1978)or pre-shelduck(Johnsgard 1965b, Bottjer 1978;Woolfenden 1961;Bottjer 1983). 1983) origin for the group. A few workers have The proposedsequences of generawithin the expressed doubts about the relationships of group hasvaried (e.g. Delacourand Mayr 1945; Heteronetta(Johnsgard 1960c, Brush 1976), and Delacour 1959;Johnsgard 1960b, 1961a, 1965a, others accepted the relationship between Het- 1978, 1979). My analysis(Fig. 5) indicatesthat eronettaand other stiff-tailed ducks but sug- Polysticta,Somateria, Histrionicus, and Campto- gested that the genus be accordedtribal rank rhynchuscomprise a lessspecialized, basal grade (Weller 1967, 1968b; Rees and Hillgarth 1984). of genera retaining primitive, unfenestrated My analysis shows that the syringealbullae. This seriesof genera givesrise [Nomonyx(Oxyura) dominica] is the sistergroup to a well-supported clade of, in order of in- to the highly derived Oxyura-Biziuraclade (Fig. creasingrelatedness, Melanitta, Clangula, and the 5), i.e. Oxyurais relatedmore closelyto goldeneye-merganserclade. The eiders (Poly- than to the very similar Nomonyx.This topol- sticta,Somateria) appear to be paraphyleticto ogy is supportedas well by the derived lossof the other seaducks; this is support- a speculum in Oxyura and Biziura,which is re- ed only weakly, and downy patterns suggest tained in Nomonyx(Delacour 1959). This find- that the eidersmay be monophyletic(see Dis- ing supports the resurrection of Nomonyx cussion).Placement of Camptorhynchusmust re- as advocatedby Woolfenden (1961), a recom- October1986] Phylogenyof theAnseriformes 745

mendationrejected by Delacour(1964c), Johns- osteologicalevidence, appear monophyletic in gard (1967), and most subsequentworkers. I their dusky undersides,obsolete dorsal spots, did not examineskeletons of all speciesof Oxy- and dark cheeks;(2) other lack the su- ura, so monophyly of the genus was not es- praorbitalstripe and dorsalspotting of the dab- tablishedwith certainty. bling ducks (loral spot and vestigial back spots retained in Histrionicus); (3) Melanitta and its DISCUSSION sister genera are synapomorphicin their dark breast bands, a character secondarily lost in Diving habit and homoplasy.--Considerable Mergus;(4) the BlackScoter (Melanitta nigra) and homoplasy(convergence) of charactersis shown Surf (M. perspicillata)are united by the in the tree (Figs. 1-5) and by the consistencies derived darkening of the lower breastand bel- of characters(Appendix 1). The majorityof the ly; (5) Bucephala,Mergeflus, Lophodytes, and Mer- convergencesare associatedwith adaptations gusshare a reversalin (presenceof) dorsalspot- for diving, and most involve the leg elements ting; (6) obscured(Lophodytes) to dark (Mergus) (characters52, 55, 56, 64, 65, 69, 75), pelvis (119), cheeksunite the mergansers;and (7) Mergusis and skeletal pneumaticity (28, 78). These fea- derived further in the anteriorly incomplete tures tend to co-occur,especially within ele- breastband and pale suborbitalstripe. ments. Convergence between Thalassornisand Similarityvs. relatedness.--Recognitionof the the stiff-tailed ducks is particularly pervasive different types of characterchange is important (Figs. 2 and 5). It appears,however, that the in light of the conspicuouslyunequal rates of moderately large number of charactersinclud- morphologicalevolution in different lineages, ed in this analysisreduced the impact of such e.g. autapomorphiesof Brantavs. Cereopsis(Fig. homoplasy on the resultant tree, although 2) and Oxyura vs. Biziura (Fig. 5). The inade- deletionsor heavy weighting of selectedchar- quacy of simple distancetechniques was dem- acterscan produce topological changes. For ex- onstratedusing thesedata through a compari- ample, becauseof a number of diving-related son of phylogenetic relationshipswith "path homoplasies,postulation of the Hymenolaimus- lengths" or patristic distances.Selected results Merganetta-Tachyeresclade as the sister group were: (1) Anseranasis roughly equidistantfrom to the sea ducksand stiff-tailedducks is only the anhimids and other anatids [corroborated slightly less parsimoniousthan the topology immunologicallyby Bottjer(1983)], but is the presented(Fig. 1). Similarly, heavierweighting sistergroup to the latter (Fig. 2); (2) Thalassornis of appendicularcharacters places Heteronetta as is most similar to Dendrocygnabut is more the sistergroup to both the seaducks and other closelyrelated to other anatids,excluding An- stiff-tailed ducks. seranas(Fig. 2); (3) Heteronettaappears "nearer" Patternsof downyyoung.--Although an anal- to Anasthan to Oxyura,a member of the sister ysis of downy patterns for the entire order is group of Heteronetta(Figs. 4 and 5); and (4) be- not possibleat present, a cladisticreevaluation cause of autapomorphiesin Oxyura, Biziurais of the downy young illustrated in Delacour phenetically "closer" to Nomonyxthan it is to (1954, 1956, 1959) permits an independent test its sister genus Oxyura(Fig. 5). of two parts of my phylogenetic hypothesis Life-historycorrelates.--Diving, at least as an (usingAnas as the outgroup).Patterns in downy escapebehavior, occursthroughout the order stiff-tailed ducks agree well, wherein (1) Het- except in the anhimids and possiblyAnseranas eronetta retains virtually all dabbling-duck (Johnsgard1962, Todd 1979). Groups that rou- characters;(2) Nomonyx, Oxyura, and Biziura tinely dive for food are fewer, but occur in six share a synapomorphic,dark cheek stripe; (3) lineagesthroughout the family (Weller 1964b): Oxyura and Biziuraare united by the derived Dendrocygna,Thalassornis, Hymenolaimus-Mer- lossof the pale supraorbitalstripe; and (4) Bi- ganetta-Tachyeres,pochards, sea ducks, and stiff- ziurashares a lossof dorsaland wing spotting tailed ducks. with the Peruvian (O. ferruginea) Perchinghabit, the probablyprimitive char- and dark cheeks with the Australian Blue-billed acterused traditionally to define the polyphy- Duck (O. australis).Patterns of downy Mergini letic "perchingducks," occurs in many genera, also are informative: (1) eiders retain the su- includingAnseranas, Dendrocygna, Plectropterus, praorbital stripe of dabblersbut, in contrastto Sarkidiornis,Tadorna, Malacorhynchus, Cairina, Aix, 746 BRADLEYC. LIVEZEY [Auk, Vol. 103

Chenonetta, Rhodonessa,and Amazonetta (All Mayr 1945: 51), most previous biogeographers 1960,Johnsgard 1978, Todd 1979).A relatedtrait contendedthat the Anseriformesoriginated in (alsoused to justify the "Cairinini"), nestingin the Northern Hemisphere,probably the Pale- tree cavities, occurs in Dendrocygna, some arctic (Howard 1950, Weller 1964d). Although shelducks(Sarkidiornis, Neochen, Alopochen, Ta- the fossilrecord of waterfowlis morecomplete dorna,Malacorhynchus), a number of dabbling for the Northern Hemisphere (Howard 1964), ducks(e.g. Aix, someAnas), and somesea ducks early forms are known from both hemispheres, (Histrionicus,Bucephala, Mergellus, Lophodytes, and the apparent disparity in representation Mergus). probably reflects intensity of paleontological Use of terrestrial cavitiesfor nesting also oc- research.The only essentiallynorthern groups cursin someshelducks (Tadorna, Hymenolaimus, are Olor, Anser-Branta,Cyanochen, Rhodonessa, Merganetta,Tachyeres), in someAnas, and in the and the sea ducks;genera that have roughly sea ducks cited above (Hobbs 1957, Warham equal distributions in both hemispheresare 1959, Johnsgard 1962, Johnson 1963, Weller Cygnus,Tadorna, Alopochen, Anas, Netta, Aythya, 1964c,Kear 1970, Moffett 1970, Humphrey and and Oxyura.The remaining 20 genera are lim- Livezey 1985).Other speciesnest on the ground ited to or mostspeciose in the SouthernHemi- or over water (Weller 1964c,Kear 1970). Only sphere,and, with the anhimids, include most the Black-headedDuck (Heteronettaatricapilla) of the early branches in the order. Further- is an obligate nest parasite, although infre- more, the earliestbranches (Fig. 2) in the quent nest parasitismoccurs in a number of and goose clades are genera limited to the other genera including Dendrocygna,Branta, SouthernHemisphere. The numerousholarctic Anas,Aythya, and Mergus(Weller 1959,1968b). speciesof Anas, Aythya, and the sea ducks Although ground nesting appearsto be prim- (Weller 1964d) may represent radiations has- itive for the order (Johnsgard1965a, Kear 1970), tened by widespread glaciations(cf. Ploeger nesting habit is probably unreliable for intraor- 1968). Consequently, I agree with Cracraft dinal phylogenetic inferences. Clutch size, (1980) that the Anseriformes probably origi- proportion of yolk in , incubation period, nated in the Southern Hemisphere. parental carrying of young, and sexual dimor- Taxonomicimplications.--The tribes of Anati- phism also appear to be quite plastic (Johns- dae originally proposedby Delacour and Mayr gard 1961f,1966b; Lack 1967,1968, 1974; Johns- (1945) were defined primarily in terms of gen- gard and Kear 1968; Kear 1970; Livezey and era of the Northern Hemisphere. Although Humphrey 1984). most tribes were assignedmembers from both Selected reproductive characteristics,how- hemispheres,only the monotypic "Merganet- ever, show distinct primitive-to-derived se- tini" was limited to the Southern Hemisphere. quences(Kear 1970). Most change near the di- A number of "aberrant" southern genera were vergence of the goose-swanclade but may be sorted tentatively among these tribes: Anser- confoundedby an evolutionary trend toward anasand Plectropterusto the Cairinini; Cereopsis, reduced body size: (1) nest bowl unlined vs. Tachyeres,and Lophonettato the Tadornini; Stic- lined with down (secondarilylost in stiff-tailed tonetta,Malacorhynchus, and Hymenolaimusto the ducks); (2) biparental nest construction,incu- Anatini; and Thalassornisto the . Since bation, and attendance of young vs. female then four of these genera have been placed in alone responsible;and (3) broodingperiod and their own subfamilies or tribes, one has been pair bond long ("anserines,"roughly 6 months) moved to another subfamily, and the others vs. moderately long (shelducks, roughly 4 have remained problematic(Wolfenden 1961, months)vs. comparativelyshort (dabblersand Johnsgard1978). Severalfindings in my study divers, less than 2 months). Participation of involve these genera,and suggesta revision of malesin brood rearing is variable within Anas, the classificationof waterfowl (Appendix 2). however, wherein several neotropicalspecies The dabbling ducks are paraphyletic and are characterizedby protracted, perhaps per- should be considered a phylogenetically un- manent pair bonds(Johnsgard 1978). resolved group. I therefore place these genera Biogeographicpatterns.--Despite the early ac- in a provisionaltaxon, the "Anatini" (Appen- knowledgmentof the diversityof "aberrantand dix 2). If paraphyly of this group is corrobo- primitive" genera in (Delacour and rated by further work, the erection of addition- October1986] Phylogenyof the Anseriformes 747 al tribes correspondingto the branchesin the ALI, $. 1960. The Pink-headed Duck Rhodonessacar- grade would be warranted. yophylacea(Latham). Wildfowl 11: 55-60. Classificationof fossilgroups.--Several early AMERICAN ORNITHOLOGISTS' UNION. 1983. Check-list fossilscan be classifiedtentatively on the basis of birds, 6th ed. ,D.C., Amer. Ornithol. Union. of published descriptions(Howard 1964). Ro- BALL,$. C. 1934. ducks, including descrip- mainvillia(upper or lower ), tions of two crossesof Bucephalaand Lophodytes. Cygnopterus(upper Oligocene),and Paranyroca PeabodyMus. Nat. Hist. Bull. 3: 1-26. (lower ) possessthe primitive procor- B^UMEI,,J. J. (Ed.). 1979. Nomina anatomicaavium. acoidal foramen (character92) retained among New York, Academic Press. Recentgenera only by anhimids and Anseranas. BELLROSE,F. C. 1976. Ducks, geese and swans of Conformation of the tarsometatarsal trochlea North America. Harrisburg, Pennsylvania, (68) indicates that at least Romainvillia and Par- Stackpole Books. anyrocaare derived with respectto Anseranas, BOETTICHER,H. VON. 1943. Die phylogenetisch-sys- and the hypotarsus(72) of Paranyrocashows it tematischestellung yon Anseranas.Zool. Anz. 142: 55-58. to be more primitive than Dendrocygna.Ac- --. 1952. Ganse-und Entenv6gelaus aller Welt. cordingly, these should be listed after Leipzig, Germany, Geese&Portig K.-G. Anseranas and before Dendrocygna and se- BOTTJER,P.D. 1983. Systematicrelationships among quenced (provisionally by epoch of occur- the Anatidae: an immunological study: with a rence) as Romainvillia,Cygnopterus, and Parany- history of anatid classification,and a systemof roca;the fossilsmay be given familial namesor classification.Unpublished Ph.D. dissertation, be designated"piesions" (Wiley 1981) at fa- New Haven, Connecticut, Yale Univ. milial rank. Phylogeneticreappraisals of sev- BRVSH,A. H. 1976. Waterfowl feather proteins: eral other fossilAnseriformes [e.g. Anas(?) blan- analysis of use in taxonomic studies. J. Zool. chardi, the tadornines and London 179: 467-498. Brantadorna,and ;Howard 1964], and COTTER,W. B., JR. 1957. A serologicalanalysis of some anatid classifications. Wilson Bull. 69: 291- the probableanseriform (Olson and 300. Feduccia1980a), should provide minimum ages CRACRAFT,J. 1980. Avian phylogeny and intercon- of branch points in the phylogeny. tinental biogeographicpatterns. Pp. 1302-1308 in Acta 17th Congr. Intern. Ornithol., vol. II (R. ACKNOWLEDGMENTS Nohring, Ed.). Berlin, DeutschenOrnithologen- Gesellschaft. This work was supported in part by National Sci- ence Foundation grant BSR-83-19900and the Uni- DAVIES,$. J. J. F., & H. J. FRITH. 1964. Some com- versity of KansasMuseum of Natural History. I am ments on the taxonomicposition of the Magpie most grateful for the enthusiasmand insights of P. GooseAnseranas semipalmata (Latham). Emu 63: 265-272. S. Humphrey; his commentson the manuscript,and those of G. E. Woolfenden, D. Siegel-Causey,R. M. DELACOUR,J. 1954. The waterfowl of the world, vol. Chandler, and W. Hoffman are greatly appreciated.I 1. London, Country Life. alsobenefited from discussionswith E. O. Wiley, D. 1956. The waterfowl of the world, vol. 2. L. Swofford,L. M. Witruer, D. Frost,R. L. Mayden, London, Country Life. L. D. Martin, D. E. Seibel,and D. M. Hillis. R. Mengel 1959. The waterfowl of the world, vol. 3. and M. Jenkinsonpermitted accessto specimensand London, Country Life. work space, and loans of specimenswere arranged 1964a. Domestic waterfowl. Pp. 154-166 in by S. L. Olson (National Museum of Natural Histo- The waterfowl of the world, vol. 4 (J. Delacour, ry), R. W. Storer (Museum of Zoology, University of Ed.). London, Country Life. Michigan), G. E. Woolfenden (Department of Biolo- 1964b. Aviculture. Pp. 145-153 in The wa- gy, Universityof SouthFlorida), and P. Devillers (In- terfowl of the world, vol. 4 (J. Delacour, Ed.). stitut Royal des SciencesNaturelies de Belgique). J. London,Country Life. Cracraftand A. H. Bledsoeprovided useful criticisms 1964c. Correctionsand additions. Pp. 327- of the manuscript.I thank M. A. Masten for graphical 354 in The waterfowl of the world, vol. 4 (J. De- help and K. McMannessfor typing the manuscript. lacour, Ed.). London, Country Life. -, & E. MAYR. 1945. The family Anatidae. Wil- son Bull. 57: 3-55. LITERATURE CITED , & . 1946. Supplementarynotes on the A•OTT, C.E. 1938. The skulls of ducks. Wilson Bull. family Anatidae. Wilson Bull. 58: 104-110. 50: 249-253. DEMAY,I. $. 1940. A study of the pterylosisand 740 BI•DLE¾C. LIVEZE¾ [Auk, Vol. 103

pneumaticity of the .Condor 42: 112- -, & A. GLASER.1975. Chemotaxonomyof An- 118ß seriformes. Blochem. Syst. Ecol. 2: 215-220. FEDUCCIA,A. 1977. Hypothetical stagesin the evo- JOHNSGARD,P.A. 1960a. The systematicposition of lution of modern ducksand .J. Theor. the . Bull. Brit. Ornithol. Club 80: Biol. 67: 715-721. 165-167. --. 1978. Presbyornisand the of ducks 1960b. Classification and evolutionary re- and flamingos.Amer. Sci. 66: 298-304. lationshipsof the seaducks. Condor 62: 426-433. FRITH,H.J. 1955. The downy ducklingsof the Pink- ß 1960c. Comparativebehaviour of the Anati- eared and White-eyed ducks. Emu 55: 310-312. dae and its evolutionaryimplications. Wildfowl ß 1964a. Taxonomicrelationship of Stictonetta 11: 31-45. naevosa(Gould). Nature 202: 1352-1353. 1960d. Hybridization in the Anatidae and 1964b. The downy young of the Freckled its taxonomicimplications. Condor 62: 25-33. Duck Stictonetta naevosa. Emu 64: 42-47. 1961a. The of the Anatidae--a 1967. Waterfowl in Australia. Honolulu, behavioural analysis.Ibis 103a:71-85. Hawaiiß East-West Center Press. ß 1961b. The systematicposition of the Mar- GRAY,A.P. 1958. hybrids: a checklistwith bib- bled Teal. Bull. Brit. Ornithol. Club 81: 37-43. liography. Bucks,England, CommonwealthAgr. 1961c. Breeding biology of the Magpie Bur. Goose. Wildfowl 12: 92-103. HARRISONßJ. G. 1958. Skull pneumaticityin wild- 1961d. The behavior and systematicposi- fowl in relation to their mode of life. Wildfowl tion of the .Wilson Bull. 73: 9: 193-196. 227-236. HOBBS,J. N. 1957. Notes on the Pink-eared Duck. 1961e. Tracheal of the Anatidae Emu 57: 263-268. and its taxonomicsignificance. Wildfowl 12:58- HOWARD,H. 1929. The avifauna of Emeryville 69. shellmound. Univ. California Publ. Zool. 32: 301- ß 1961f. Evolutionaryrelationships among the 394. North American . Auk 78: 3-43. 1950. Fossil evidence of avian evolution. Ibis 92: 1-21. 1962. Evolutionary trends in the behaviour and morphologyof the Anatidae.Wildfowl 13: 1964. Fossil Anseriformes. Pp. 233-326 in 130-148. The waterfowl of the world, vol. 4 (J. Delacour, 1963. Behavioralisolating mechanismsin Ed.). London, Country Life. the family Anatidae. Pp. 531-543 in Proc. 13th HOWARDßR., & A. MOOREß1984. A completecheck- list of the birds of the world. Londonß Macmil- Intern. Ornithol. Congr.,vol. I (C. G. Sibley,Ed.). Amer. Ornithol. Union. lan. HUMI•HRE¾,P.S. 1955. The relationships of the 1964. Comparativebehavior and relation- seaducks(Tribe Mergini). Unpublished Ph.D. shipsof the eiders.Condor 66: 113-129. 1965a. Handbook of waterfowl behavior. dissertationßAnn ArborßUniv. Michigan. London, Constable. ß 1958. Classificationand systematicposition of the eiders. Condor 60: 129-135. 1965b. Observations on some aberrant Aus- tralian Anatidae. Wildfowl 16: 73-83. ß & R. S. BUTSCH.1958. The anatomy of the Duckß Camptorhynchuslabradorius 1966a. The biology and relationshipsof the (Gmelin). Smithsonian Misc. Coil. 135: 1-23. . Wildfowl 17: 66-74. , & G. A. CLARK,JR. 1964. The anatomy of 1966b. Behavior of Australian waterfowl. Pp. 167-232 in The waterfowl of the and Blue-billed Duck. Auk 83: 98-110. worldßvol. 4 (J. Delacour, Ed.). LondonßCountry 1967. Observations on the behaviour and Life. relationshipsof the White-backedDuck and the -, & B.C. LIVEZE¾.1985. Nest, eggs,and downy stiff-tailed ducks. Wildfowl 18: 98-107. young of the White-headedFlightless Steamer- 1978. Ducks,geeseß and swansof the world. Duck.Pp. 949-954in Neotropicalornithology (P. Lincoln, Univ. Nebraska Press. A. Buckley, M. S. Foster, E. S. Mortonß R. S. 1979. Order Anseriformes.Pp. 425-506 in Ridgely, and F. G. Buckley, Eds.). Ornithol. Checklist of birds of the world, 2nd ed., vol. 1 Monogr. No. 36. (E. Mayr and C. W. Cottrell, Eds.). Cambridge, ß & S. D. RIPLEY. 1962. The affinities of the MassachusettsßMus. Comp. Zool. Pink-headed Duck (Rhodonessacaryophyllacea). --, & J. KEAR. 1968ß A review of parental car- Postilia 61: 1-21. rying of youngby waterfowl.Living Bird 7: 80- JACOB,J. 1982. Integumentlipide--ihre chemische 102. Struktur und ihre Bedeutungals systematisches JOHNSON,A. W. 1963. Notes on the distribution, Merkmal in der Zoologie. Funkt. Biol. Med. 1: reproductionand displayof the Andean Torrent 83-90. Duck Merganettaarmata. Ibis 105: 114-116. October1986] Phylogenyofthe Anseriformes 749

KEAR,J. 1967. Notes of the eggsand downy young tematischenStellung der Sturzback-Ente.J. Or- of Thalassornis leuconotus. Ostrich 38: 227-229. nithol. 93: 357-360. ß 1970. The adaptiveradiation of parentalcare NILSSON,L. 1974. The behaviourof wintering in waterfowl. Pp. 357-392 in Socialbehaviour in in southern Sweden. Wildfowl 25: 84-88. birds and mammals(J. H. Crook, Ed.). New York, OLSON,S. L. 1985. The fossil record of birds. Pp. Academic Press. 79-238 in Avian biologyßvol. 8 (D. S. Farner, J. 1972. The of . Liv- R. King, and K. C. Parkes,Eds.). New York, Ac- ing Bird I1: 175-192. ademic Press. 1975. Salvadori's Duck of New Guinea. --, & A. FEDUCCIA.1980a. Presbyornisand the Wildfowl 26: 104-111. origin of the Anseriformes(Aves: Charadrio- ß& R. K. MURTON. 1973. The systematicstatus morphae). Smithsonian Contrib. Zool. 323: 1-24. of the CapeBarren Goose as judged by its photo- --, & --. 1980b. Relationships and evolu- responses.Wildfowl 24: 141-143. tion of flamingos (Aves: Phoenicopteridae). ß • T. H. STEEL.1971. Aspectsof social be- Smithsonian Contrib. Zool. 316: 1-73. haviour in the Blue Duck. Notornis 18: 187-198. PALMER,R. S. (Ed.). 1976. Handbook of North KESSLER,L. G., & J. C. AVISE. 1984. Systematicrela- American birdsß vols. 2 and 3. New Haven, Con- tionships among waterfowl (Anatidae) inferred necticut, Yale Univ. Press. from restriction endonucleaseanalysis of mito- PETERS,J. L. 1931. Check- of the world, chondrial DNA. Syst.Zool. 33: 370-380. vol. 1. Cambridge,Massachusetts, Harvard Univ. KLVGE,A. G. 1984. The relevance of parsimony to Press. phylogenetic inference. Pp. 24-38 in : PHILLIPS,J. C. 1922. A natural history of the ducks, perspectiveson the reconstructionof evolution- vol. I. Boston,Houghton Mifflin. ary history (T. Duncan and T. F. Stuessy,Eds.). --. 1923. A natural history of the ducks,vol. 2. New York, Columbia Univ. Press. Boston,Houghton Mifflin. LACK, D. 1967. The significance of clutch-size in 1925. A natural history of the ducks,vol. 3. waterfowl. Wildfowl 18: 125-128. Boston,Houghton Mifflin. 1968. The proportion of yolk in the eggsof PLOEGER,P.L. 1968. Geographicaldifferentiation in waterfowl. Wildfowl 19: 67-69. arctic Anatidae as a result of isolation during the 1974. Evolution illustrated by waterfowl. Last Glacial. Ardea 56: 1-159. Oxford, England,Blackwell Sci. Publ. RAIKOW,R.J. 1970a. The function and evolution of LIVEZEY, B.C., & P.S. HUMPHREYß 1984. Sexual di- the supraorbital processin ducks. Auk 87: 568- 572. morphism in continental steamer-ducks.Condor 86: 368-377. 1970b. Evolution of diving adaptationsin the stifftail ducks. Univ. California Publ. Zool. LORENZ,K. 1951-1953. Comparativestudies on the 94: 1-52. behaviour of Anatinae. Avicult. Mag. 57: 157- 182; 58: 8-17, 61-72, 86-94, 172-184; 59: 24-34, --. 1971. The osteologyand taxonomic position 80-91. of the White-backed Duck, Thalassornis leucono- tus. Wilson Bull. 83: 270-277. MAINARDI,D. 1962. Immunological data on the RAND, A. L. 1954. On the spurs on birds' wings. phylogenetic relationshipsand taxonomicposi- Wilson Bull. 66: 127-134. tion of flamingoes(Phoenicopteridae). Ibis 104: 426-428. REMS,E. C., & Nß HILLGARTH. 1984. The breeding biology of captive Black-headedDucks and the MAYR,E. 1931. Anatomie und systematischenStel- behavior of their young. Condor 86: 242-250. lung der Salvadori-Ente(Salvadorina waigiuensis RIPLEY,S.D. 1957. A paddling of ducks.New York, Rothsch.& Hartert). Ornithol. Monatsberichte 39: Harcourt, Brace, and Co. 69-70. SALVADORI,T. 1895ß Catalogue of the Chenomor- MCKINNEY, F. 1953. Studies on the behaviour of the phae (Palamedeae, Phoenicopteri, Anseres), Anatidae. Unpublished Ph.D. dissertationßBris- Crypturi and Ratitaein the collectionof the Brit- tolßEngland, Univ. Bristol. ish Museum. London, Longmans. MILLER, W. DEW. 1919. Notes on the structure of SCOTT,P. 1985. Duck. Pp. 157-161 in A dictionary Anseranassemipalmata. Auk 36: 562-564. of birds (B. Campbell and E. Lack, Eds.).Vermil- MOFFETTßG. M., JR. 1970. A study of nestingTorrent lion, South Dakota, Buteo Books. Ducks in the Andes. Living Bird 9: 5-28. SIBLEY,C.G. 1957. The evolutionary and taxonomic MOYNIHAN, M. 1958. Notes on the behavior of the significanceof and hybrid- Flying SteamerDuck. Auk 75: 183-202. ization in birds. Condor 59: 166-191. MYRE$,M.T. 1959. Display behavior of Buffiehead, 1960. The electrophoreticpatterns of avian , and goldeneyes at . Wilson egg-white proteins as taxonomiccharacters. Ibis Bull. 71: 159-168. 102: 215-284. NIETHAMMER,G. 1952. Zur Anatomie und sys- --, & J.E. AHLQUIST.1972. A comparativestudy 750 BRADLEYC. LIVEZE¾ [Auk, Vol. 103

of the egg white proteins of non-passerinebirds. gentina,, and Chile. U.S. Natl. PeabodyMus. Nat. HistßBullß 39: 1-276. Mus. Bull. 133. ß K. W. CORBIN,& J. H. HAAVIE. 1969. The ß 1951. Observations on the genera of the relationships of the flamingos as indicated by swans.J. WashingtonAcad. Sci. 41: 338-340. the egg-white proteins and hemoglobinsßCon- WILEY,E. O. 1981. Phylogenetics:the theory and dor 71: 155-179. practiceof phylogeneticsystematics. New York, SIEGFRIED,W. R. 1970. Double wing-moult in the J. Wiley and Sons. Maccoa Duckß Wildfowl 21: 122. WOLFF,E., & E. WOLFFß1952. La d•terminisme de la SILEO,L., C. H. TUITE, & J. B. D. HOPCRAFT. 1977ß diff•renciation sexuelle de la syrinx du canard Plumagesand primary moult in LesserFlamin- cultiv•e in vitro. Bull. Biol. 86: 325-349. gosßWildfowl 28: 139-142. WOOD, D. S., R. L. Zusi, & M. A. JENKINSON. 1982. SIMONETTA,A.M. 1963. Cinesi e morfologia del World inventory of avian skeletal specimens, cranio negli uccelli non passeriformi. Studio su 1982. Norman, Oklahoma, Amer. Ornithol. Union varie tenenze evolutive. Parte 1. Archß Zool. Ita- and Oklahoma Biol. Surv. lia (Torino) 48: 53-135. WOOLFENDEN,G. E. 1961. Postcranialosteology of SWOFFORD,D.L. 1984. PAUP: phylogeneticanalysis the waterfowl. Florida State Mus. Bull. 6: 1-129. using parsimony.Illinois Nat. HistßSurv. (Mim- YAMASHINA, Y. 1952. Classification of the Anatidae eo0 based on cytogenetics.Pap. Coord. Comm. Res. TIMMERMANN,G. 1963. Fragen der Anatidensyste- Gen. 3: 1-24. matik in parasitologischerSichr. Pp. 189-197 in ZusI, R. L., & G. D. BENTZ. 1978. The appendicular Proc. 13th Intern. Ornithol. Congr., vol. I (C. G. royologyof the LabradorDuck (Camptorhynchus Sibley, Ed.). Amer. Ornithol. Unionß labradorius).Condor 80: 407-418. TODD,F.S. 1979. Waterfowl:ducks, geese and swans of the worldß New York, Harcourt Brace Jova- novichß TYLER,C. 1964. A study of egg shellsof the Anati- APPENDIX 1 dae. Proc. Zool. Soc. London 142: 547-583ß VERHEYEN,R. 1955. La syst•matiquedes Ans•ri- The 120 charactersused in this analysisare listed formesbas•e sur l'ost•ologiecompar•e. Bullß Instß below and are numbered and grouped anatomically. RoyalSoc. Natur. Belgique31(35): 1-18, (36): 1- Character states are lettered and correspond to the 16, (37): 1-22, (38): 1-16. characterchanges in Figs.2-5. Plesiomorphic(prim- itive) conditions generally are designated "a" and WARHAM,J. 1959. The nesting of the Pink-eared Duckß Wildfowl 9: 118-127. derived character states are ordered alphabetically thereafter (implying a linear transformationseries); WELLER,M. W. 1959. Parasiticegg laying in the charactersfollowed by a "U" were analyzed as unor- (Aythya americana)and other North dered. Characters for which the primitive state was American Anatidae. Ecol. Monogr. 29: 333-365. not determined are marked with "U*." Characters 1964a. Fowling. Pp. 121-127 in The water- judged to be unusually variable, generally necessi- fowl of the world, vol. 4 (J. Delacour, Ed.). Lon- tating determinations of modal conditions, are indi- don, Country Lifeß cated with a "V." Taxa with problematicstate deter- ß 1964b. General habits. Pp. 15-34 in The wa- minations are listed in parentheses after the terfowl of the world, vol. 4 (J. Delacour, Ed.). corresponding character. Consistency indices (CI) London, Country Lifeß follow each character.Anatomical terminology fol- 1964c. The reproductivecycle. Pp. 35-79 in lows Howard (1929) and Woolfenden (1961) unless The waterfowl of the worldß vol. 4 (J. Delacour, annotated otherwise. Ed.). LondonßCountry Life. 1964d. Distribution and species relation- Integument shipsßPp. 108-120in The waterfowlof the world, 1. Molt of remiges:(a) sequential;(b) synchronous,once annually; vol. 4 (J. Delacour,Ed.). London,Country Lifeß (c) synchronous,twice annually. (Variable in Phoenicopteridae; Sileo et al. 1977.) CI = 1.0. 1967. Notes on and weights of 2. Tarsalsheath: (a) scutellateanteriorly and posteriorly;(b) reticu- the Black-headed Duck, Heteronettaatricapilla. late anteriorly and posteriorly;(c) scutellateanteriorly (at least Condor 69: 133-145. distally)and reticulateposteriorly. CI = 1.0. 1968a. Plumagesand wing spurs of Torrent 3. Spongysubcutaneous layer: (a) absent;(b) present.CI = 1.0. 4. Interdigitalwebbing of feet (excludinghallux): (a) lacking(slight DucksMerganetta armata. Wildfowl 19: 33-40ß webbingin anhimids);(b) incomplete(semipalmate); (c) complete --. 1968b. The breedingbiology of the parasitic (incised in Cereopsisand Brantasandwicensis). CI = 1.0. Black-headedDuckß Living Bird 7: 169-207. 5. Apteria: (a) present;(b) obsolete.CI = 1.0. 1976. Ecology and behaviour of steamer Trachea ducksß Wildfowl 27: 45-53ß 6. Bulla osseaof males (U, weight = 2): (a) not enlarged;(b) sym- WETMORE,A. 1926. Observations on the birds of Ar- metrically enlarged;(c) asymmetricallyenlarged, unfenestrated; October1986] Phylogenyof the Anseriformes 751

(d) asymmetricallyenlarged, fenestrated;(e) enlargementre- vated,essentially parallels shaft; (b) elevated,angled distally; (c) ducedand symmetrical,or obsolete.(Thalassornis, Malacorhynchus, elevated, angled medially. CI = 0.40. Nettapus.)CI = 0.67. 27. Internaltuberosity: (a) proximallyrotated, exposing completely 7. Extrasternal,subdermal 1ooping of tracheain males(U*): (a) pres- the pneumaticforamen in anconalview, lackinga distinct,dis- ent; (b) absent. CI = 0.33. tally directedprominence; (b) produceddistally so as to largely 8. Inflatable tracheal air sacs:(a) absent;(b) present. CI = 1.0 or completelyobscure pneumatic foramen in anconalview, typ- ically with prominent,distally directed point. CI = 0.50. Skull 28. Pneumaticfossa (U): (a) open, usuallycontaining numerous bony struts;(b) closedby bonyshell except for a smallcentral opening; 9. Occipitalfontanelles: (a) absent;(b) present.CI = 1.0. (c)completely closed; (d) closedbut perforated by numeroussmall 10. Lacrymals(U): (a) not fusedto skull;(b) fusedto skull dorsally, holes.(Lophodytes.) C1 = 0.43. small,nonpneumatic; (c) fuseddorsally, moderately thick, long, 29. Attachmentsite of M. latissimusdorsi posterioris: (a) well medial ventrally directed (lacking flange), nonpneumatic;(d) fused to to externaledge of pectoralattachment; (b) in line with outer skull dorsally,and (typically)also fusedto postorbitalprocess, edgeof pectoralattachment, on anconalsurface of shaft;(c) in slightly pneumatic;(e) fused dorsally, of variable shape and line with outer edge of pectoral attachment, on raised ridge. pneumaticity,posterioventrally directed, often with flangedven- CI = 1.0. tral terminus. CI = 1.0. 30. Distal portion of anconalsurface of bicipitalcrest: (a) poorly de- 11. Supraorbitalprocess (U; bestdeveloped in adultmales): (a) absent velopedor shelflike;(b) producedmedially with distinctproximal or small,straight, essentially coplanar with dorsalsurface of skull; cuplikedepression, visible as translucent window in palmarview. (b) large, flat, medially appressedto dorsalmargin of orbit; (c) CI = 0.50. large,thick, rugose, dorsolaterally directed; (d) long,slender, dor- 31. Distal terminusof deltoid crest:(a) essentiallycontinuous with sallydirected, often curved.(Aythya, Bucephala albeola.) CI = 0.38. lateraledge of shaft;(b) producedinto prominenttuberosity on 12. Anterior terminusof premaxillae:(a) stronglyventrally hooked, palmar surfaceof shaft.CI = 1.0. typically pointed; (b) strongly ventrally hooked, moderately 32. Externaltuberosity: (a) prominent,buttressed, typically with at- rounded;(c) not ventrally hooked(directed anteriorly), rounded, tachmentsite elevated,parallel to shaft, not slopingaway with spatulate. C1 = 1.0. ancohalsurface of deltoid crest;(b) reduced,lacking buttress, with 13. Bill lamellae:(a) absent;(b) present.(Nonhomologous lamellae attachmentsite sloping and essentially flush with ancohalsurface in flamingos,vestigial in anhimids; Olson and Feduccia1980a.) of deltoid crest. (Stictonetta,Sarkidiornis, Cyanochen, Merganetta, CI = 1.0. Oxyura.)CI = 0.33. 14. Retroarticularprocesses of mandible:(a) lacking, small, or re- 33. Relativeanconal heights of ectepicondyleand entepicondyle:(a) curvedand rounded;(b) recurved,pointed, and bladelike.CI = ectepicondyledistinctly higher than entepicondyle; (b) condyles 1.0. essentiallyequally high; (c) ectepicondylelower than entepicon- 15. Quadrate,lateral view: (a) not squarish,with variablydeeply curved dyle. (Hymenolaimus.)CI = 0.40. dorsalmargin between orbital and otic processes;(b) squarish, 34. Pit for attachmentof M. flexor carpi ulnaris:(a) prominent;(b) with dorsalmargin straight.CI = 0.33. reduced to obsolete. CI = 1.0. 16. Frontonasalregion of skull (U): (a) essentiallycontinuous with 35. Externalcondyle and brachialdepression (palmar side, distal end): profiledefined by premaxillaeand frontals;(b) enlargedinto con- (a) separatedby smoothstrip of bone;(b) connectedby rounded spicuous,laterally compressed, dorsal prominence (larger in males); ridge. CI = 1.0. (c) with rounded,pneumatic swelling (especially in adultmales). 36. Attachmentsite for externalhead of triceps:(a) immediately distal CI = 0.50. to head,typically in excavationunder head; (b) displaceddistally 17. Frontals:(a) without dorsallydirected hornlike prominence;(b) on lobe of bone and obscuresexternal terminus of capitalgroove. with small, ossified "horn" on midline. CI = 1.0. CI = 1.0. 18. Pterygoid-palatinearticulation: (a) a simpleabutment; (b) a ball- and-socketarrangement involving two extensionsof the ptery- Carpometacarpus gold. CI = 1.0. 37. Distal end of internal rim of carpaltrochlea (external view): (a) 19. Dorsumof upper bill in region of externalnares: (a) essentially with prominentswelling; (b) without prominentswelling; (c) continuous with curvature of skull to somewhat convex; (b) sub- deeplyexcavated. (Marmaronetta, Hymenolaimus, Clangula, Mergel- stantially dorsallybowed. CI = 1.0. lus,Heteronetta.) CI = 0.33. 20. Basipterygoidprocesses: (a) lacking or (in Galliformes)present 38. Externalrim of carpaltrochlea: (a) essentiallycontinuous, un- but withoutbasal supports; (b) present,lipped, almost pedicellate. notched;(b) with prominentnotch distally. CI = 1.0. CI = 1.0. 39. Dorsal surfaceof metacarpalII: (a) flattened proximally (can ap- pearangular); (b) roundedproximally. CI = 1.0. Vertebrae 40. Tuberosityof metacarpalII: (a) small;(b) prominent,spurred. CI = 21. Number of cervical vertebrae (U, V): (a) 17; (b) 18-20; (c) 21; (d) 22-25; (e) 16. (Some Tadorninae.) CI = 0.67. 41. Angle of processof metacarpalI: (a) perpendicularto or proxi- mally directedrelative to shaft;(b) angleddistally. (Plectropterus.) CI = 1.0. Humerus 42. Processof metacarpal1 (U): (a) not enlarged,length less than 22. Capitalshaft ridge: (a) prominentand directedtoward head;(b) width of trochlea;(b) an enlarged,pointed spur, longer than width prominentand directedtoward external tuberosity; (c) obsolete of trochlea;(c) enlarged,blunt, typicallywith rugose-cappedspur, proximallyor absentcompletely. (Sarkidiornis, Cyanochen, Hymeno- longerthan width of trochlea.(Plectropterus, Hymenolaimus, Lopho- laimus,Chenonetta.) CI = 0.50. netta.) CI = 0.50. 23. Capitalgroove: (a) short,essentially directed distally; (b) extend- 43. Attachmentsite of M. extensormetacarpi ulnaris (Zusi and Bentz ing laterallytoward external tuberosity, undercutting head. (Thal 1978;"flexor" of Woolfenden 1961) (U, V): (a) completelyproxi- assornis.)CI • 0.50. mal to proximalfornix of metacarpalII and III: (b) opposite,at 24. Proximo-anconalregion: (a) variably rounded by shaft; (b) tra- leastpartly, fornix; (c) completelydistal to fornix. (Tachyeres.) versedby a deep, uninterruptedtrenchlike depression from un- CI = 0.29. der head to internal edge immediatelydistal to bicipital crest. 44. Lower proximalsurface of metacarpalIII: (a) ungrooved,round- CI = 0.33. ed; (b) distinctly grooved. CI = 0.50. 25. Deltoid crest(V): (a) margin rounded,laterally flaring, concave 45. Facetsfor digits II and III (U*): (a) facet for digit III extending anconally;(b) marginangular or squared,depressed around shaft fartherdistally than facetfor digit II; (b) facetsessentially equal toward palmar side, convexanconally. (Sarkidiornis, Hymenolai- in distal extent. CI = 0.33. mus.) CI = 0.50. 46. Cuneiform fossa:(a) shallowto moderatelydeep; (b) deep, round- 26. Surface of attachment for anterior articular ligament: (a) not ele- ed, ovate, with distinct rim. CI = 1.0. 752 B•DLE¾C. LIV•E¾ [Auk,Vol. 103

APPENDIX 1. Continued. 72. Calcaneal ridges of hypotarsus:(a) 2, lateral to midline of shaft, bordered medially by depression(deep in Anseranas);(b) 3 or 4, 47. Distal portion of internal rim of carpal trochlea: (a) of uniform situated on midline of shaft, without depressionon internal mar- thicknesswith proximal portion; (b) distinctly thickened. CI - gin. CI = 1.0. 0.50. 73. Wing on trochlea for digit lI: (a) not prominent medially; (b) 48. Internal rim of carpal trochlea(posterior view): (a) in line with medially prominent, thickened. CI = !.0. internal margin of shaft;(b) sharplydeflected laterally. (Callonet- 74. Groovein trochleafor digit II: (a) absent;(b) present,but posterior ta.) CI 1.0. terminus of groove variable in extent. CI - 1.0. 75. Anterior extent of internal and external ridgesof shaft:(a) essen- Radial carpal tially equal, no twisting of shaft about its long axis;(b) internal 49. Size and shape:(a) small, short, and blunt; (b) elongatedinto large ridge lessprominent anteriorly than external,becoming flush with pointed spur. CI - 1.0. shaft immediately distal to proximal foramen, associatedwith moderate twisting of shaft; (c) internal edge of shaft depressed Appendicular pneumaticity below level of shaftanteriorly, associatedwith strongtwisting of 50. Distal alar and pelvic elements:(a) essentiallynonpneumatic; (b) shaft. (Hymenolaimus,Merganetta, Amazonetta.) CI = 0.33. pneumatic with one or more large foramina. CI - 1.0. 76. External margin of shaft: (a) concave(in anterior profile), curving smoothly to external surface of trochlea for digit IV; (b) essen- Femur tially straight, trochlea for digit IV internally deflected. CI = 1.0. 77. Posterioropening of distalforamen: (a) directedposteriorly, flush 51. Head, relative to plane of external surfaceof shaft: (a) oriented with surfaceof shaft; (b) directed distoposterinrly,recessed in posteriorly;(b) perpendicular.CI - !.0. depressionimmediately proximal to symphysisof trochleafor 52. Anterior extent of trochanter: (a) relatively great, such that an- digits III and IV. (Anseranas.)CI = 1.0. terior-posteriordepth of trochantersubstantially exceeds depth of head; (b) reduced,such that depth of trochanteronly equals Sternum that of head. CI = 0.33. 78. Pneumaticforamen (U*): (a) open, ovoid;(b) pitted, largely oc- 53. Distal extent of internal condyle:(a) distinctlyless than that of cluded by medial bar; (c) closed (sometimesmarked by small externalcondyle; (b) equalto that of externalcondyle. CI 1.0. depression).CI = 0.25. 54. Rotular depression:(a) shallow to moderately deep, margin rel- 79. Ventral manubrial region (U*, V): (a) keel-like, laterally com- atively indistinct;(b) deep,distinctly bordered proximally. CI = 1.0. pressedmedial flange;(b) thick medial wedge;(c) lackingmedian protuberance(s);(d) long, peglike spine;(e) small lump; (f) a pair 55. Curvatureof shaft,lateral view (U): (a) straightto slight;(b) mod- of small pointed prominencesseparated at midline by a deep erate;(c) strong,subangular. CI - 0.22. excavation,typically with an ovoid pit at base;(g) a wide, mod- 56. Popliteal fossa:(a) shallow;(b) deep, typically pitted. CI -- 0.25. eratelylong, dorsoventrallycompressed flange; (h) a pair of points 57. Lobe at midpoint of posterior surfaceof shaft: (a) not prominent; partially separatedby a shallow midline excavation;(i) a small, (b) prominent. CI - 1.0. unforked, dorsoventrallycompressed flange. (Cyanochen, Hymen 58. Posteriorintermuscular line (U): (a) relatively distinct,following olaimus,Cairina, Lophonetta, Chenonetta, Polysticta.) CI = 0.50. internal edge of shaft; (b) relatively distinct, swingslaterally to- 80. Carina (keel) shape, lateral profile: (a) well developed, ventral ward trochanter; (c) indistinct. CI = !.0. margin curved throughout length; (b) reduced,ventral margin 59. Internal edge of distal end of shaft: (a) smoothly curving and essentiallystraight for posteriorhalf. CI - 0.33. continuouswith proximal portion; (b) leveled by raisedridge to 81. Posterior-lateralprocesses (U*): (a) extendwell posteriorto post- internal condyle. CI = 1.0. pectoral line of sternal plate; (b) approximatelyequal to post- 60. Posteriorintermuscular line: (a) distinguishableonly as fine etch- pectoral line in posterior extent. CI = 0.33. ing; (b) forming overhanging ridge proximally. CI = 1.0. 82. Dorsal manubrial region (U, V): (a) rounded notch; (b) rounded Tibiotarsus notch with small point on midline; (c) rounded notch with mod- erately large point on midline; (d) even shelf. (Malacorhynchus, 61. Proximal articulating surface:(a) in line with shaft, squareswith Hymenolaimus,Marmaronetta, Callonetta.) CI = 0.43. distal condyles;(b) strongly rotatedcounterclockwise about shaft 83. Abdominal plate (dense,symmetrical extension of sternal plate (proximal view). CI = 0.50. posteriorto both post-pectoralline and posterior-lateralprocess- 62. Rim of internal condyle:(a) distinctly notched;(b) lacking notch. es): (a) absent;(b) present. CI !.0. CI = 1.0. 84. Sternal notches(posterior margin of plate medial to posterior- 63. Inner cnemial crest:(a) not deflectedlaterally; (b) laterally de- lateralprocesses): (a) typicallyopen posteriorly;(b) typicallyclosed flected. CI = 1.0. posteriorly, forming fenestrae.CI 1.0. 64. Anterior extent of condyles: (a) internal distinctly greater than 85. Xiphial area:(a) posteriormargin approximatelystraight or con- external; (b) approximately equal. (Aythya.) CI = 0.25. cave;(b) with medial, irregularly shaped, roughly circular exten- 65. Inner cnemialcrest: (a) lackingdistinct ridge extendingdistally sion of thin bone (anterior to posterior-lateralprocesses). CI = along anterior surfaceof shaft; (b) continued by distinct ridge 1.0. distally along anterior surfaceof shaftto point well beyondprox- 86. Costal margin: (a) comprisesless than half of basin length; (b) imal terminus of fibular crest. CI = 0.25. comprisesmore than half of basin length. CI - 1.0. 66. Internal condyle, posterior view: (a) with relatively rounded in- 87. Carina: (a) lacking pneumatic foramen in anterior margin, appar- ternal edge;(b) flared, with squaredmedial edge. CI - !.0. ently solid; (b) with small pneumatic foramen in anterior edge, 67. External ligamental prominence: (a) essentially continuouswith but carinauninflated; (c) hollow, containingloop of trachea,with curvatureof shaft;(b) producedlaterally, ridgelike. CI = !.0. large pneumatic foramen in anterior edge. CI 1.0. 88. Intermuscularline: (a) anglesmedially to carlhal basewell ante- Tarsometatarsus rior to posterioredge of plate; (b) extendsposteriorly to posterior 68. Trochleafor digit 11:(a) approximatelyequal to trochleafor digit margin of plate. CI 0.33. IV in distal extent;(b) proximal to trochleafor digit IV. CI - 1.0. 89. Foramina of basin (U*): (a) limited to midline and anterior mar- 69. Anterior (of two) ligamental passagesbetween trochlea for digits gin; (b) essentiallyabsent; (c) present on anterior margin, mid- III and IV (in distal wall of distal foramen) (V): (a) obscured from line, and scatteredacross plate (often among transversebony view anteriorly by bone; (b) largely or completely exposedante- striatinns). CI = 0.50. riorly becauseof reductionof bony covering.CI - 0.25. 90. Midpoint of coracoidalsulcus: (a) solid; (b) having oval pneu- 70. Internal calcanealridge of hypotarsus:(a) slightly to moderately matic foramen. CI = !.0. exceedsother calcanealridges in posteriorextent; (b) greatly ex- Costae ceedsother (more external) calcanealridges. CI - 0.50. 71. Facet for metatarsalI: (a) deep; (b) obsolete.CI - 1.0. 91. Uncinate processes:(a) present; (b) absent. CI - 1.0. October1986] Phylogenyof the Anseriformes 753

Coracold 118. Dorsolateral crests:(a) distinct to caudal margin of pelvis; (b) be- comesobsolete cranial to caudal margin. CI = 1.0. 92. Procoracoidal foramen: (a) present (variable in Chauna);(b) ab- sent. CI = 1.0. 119. Anterior terminus of shield (posterior terminus of fusion of me- 93. Pneumatic foramen on dorsal surface anterior to sternal facet: (a) dian dorsal ridge): (a) cranial to acetabula;(b) essentially coinci- dent with acetabula; (c) well caudad to acetabula. CI = 0.67. present;(b) absent.CI = 1.O. 120. Recessusiliacus (Baumel 1979; a pneumatic pocket at caudal ter- 94. Dorsal sternalfacet: (a) with anterior border essentiallysmoothly minus of renal depression):(a) present;(b) absent.CI = 1.0. curving;(b) with prominentcircular internal lip. CI = 1.0. 95. Brachialtuberosity (U): (a) essentiallywithout foraminaunder posterioredge; (b) with small foramina under posterioredge; (c) with small foramina,typically containedwithin larger foramina, under posterior edge. CI = 0.50. 96. Depressionon ventral surfaceanterior to sternal facet (U*): (a) present,typically deep;(b) absent.(Anseranas.) CI = 0.25. 97. Furcular facet:(a) with posteriormargin completeor slightly re- duced;(b) posteriormargin deeplynotched. CI = 1.0. APPENDIX 2. A Linnean classification of the Recent 98. Angle of head:(a) coplanarto slightlyventral to plane of blade; genera of Anseriformes.I follow the conventions (b) distinctlyventral to plane of blade.CI = 1.0. of Wiley (1981), with the exceptionof the provi- 99. Sternocoracoidalprocess: (a) wide, long, and rounded flange, ex- sional recognition of the paraphyletic "Anatini" tending farther laterally than sternal facet; (b) variably shaped, (annotated ).I have retained, where rounded or angular process,approximately equal to sternal facet possible,the names and taxonomic ranks of pre- in lateral extent;(c) long pointed process,extending farther lat- erally than sternalfacet. CI = 0.67. vious classifications.Names of subtribesare given 100. Ventral (external) sternal facet (V): (a) anterior margin moderately endingsof -eae after the namesfor the "sections" raised or continuouswith blade; (b) anterior margin with distinct of Boetticher (1952) and are derived from the old- buttress. CI - 0.33. est included genus.Sedis mutabilis follows taxa in which the order of included groupsis unresolved. Furculum * = two subfamiliesmay be in reverseorder; ** = 101. Coracoidaltuberosities (U*): (a) present; (b) obsolete.CI = 0.25. subtribespossibly are sistergroups; *** = probable 102. Furcular process:(a) a flattened point; (b) variable, but reduced, sister groups. essentiallycontinuous with curvatureof clavicles;(c) swollen truncate lobe. CI = 1.0. Order Anseriformes 103. Clavicularsymphysis: (a) without foramina;(b) with medial fo- Suborder Anhimae ramina. CI - 1.0. Family Anhimidae 104. Clavicles:(a) roughlycircular in cross-section;(b) distinctlyflat- Genus Anhima tened antero-posteriorly.CI = 1.0. Genus Chauna 105. Lateral surfacesof clavicles: (a) smooth, unperforated; (b) with Suborder Anseres depressionscontaining several small foramina; (c) with depres- Family sion containinglarge pneumaticforamen. CI 0.50. Genus Anseranas 106. Regionof clavicularsymphysis: (a) a continuoussmooth curve; Family Anatidae (b) markedlyextended posterodorsally, forming a U-shapedac- Subfamily Dendrocygninae commodationfor trachealloop and associatedmodification of ca- rina. CI = 1.0. Genus Dendrocygna SubfamilyThalassorninae* Genus Thalassornis Scapula Subfamily Anserinae* 107. Coracoidal articulation: (a) flush with blade; (b) base protruding Tribe Anserini ventrallyas roundedhump. CI = 1.0. Genus Cereopsis 108. Taper (profile) of blade (U): (a) of uniform width or tapering Genus Anser continuouslythroughout length; (b) width maximalat midpoint; Genus Branta (c) width maximal at terminus. (Cygnus,Olor.) CI = 1.0. Tribe Cygnini 109. Coracoidalarticulation: (a) equal to acromionin proximal extent; Genus Coscoroba (b) distinctlydistal to acromion.CI = 1.0. Genus Cygnus 110. Internal surface,immediately posterior to glenold facet:(a) essen- Genus Olor tially smooth;(b) having deepdepression. CI - 1.0. Subfamily Stictonettinae 111. Anterior edge (U*): (a) containing pneumaticfossa; (b) without Genus Stictonetta pneumatic fossa.(Cairina.) CI = 0.25. Subfamily Plectropterinae 112. Dorsal surfaceof neck: (a) marked by single distinct raised at- Genus Plectropterus tachmentscar; (b) markedby two prominentraised attachment Subfamily Tadorninae scars. CI 1.0. Tribe Sarkidiornini Genus Sarkidiornis Pelvis Tribe Tadornini sedis mutabilis 113. Preacetabulariliac fossa:(a) smoothly curved surface;(b) contain- Subtribe Tadorneae ing a deep, irregularly shapeddepression. CI = 1.0. Genus Tadorna 114. Caudal margin: (a) ischium extending well caudadto ilium; (b) SubtribeMalacorhyncheae variable, but ischiumand ilium roughly equal in caudal extent, Genus Malacorhynchus forming an obliquely sloping margin, with elementstypically SubtribeChloephageae sedis mutabilis separatedposteriorly by a distinctnotch. CI - 1.0. Genus Alopochen 115. Body of pubis (V): (a) concavedorsally (rarely almost straight); Genus Neochen (b) convexdorsally. CI = 0.50. Genus Chloephaga 116. Orientation of postischiacpubis: (a) directed posteriorly;(b) di- SubtribeCyanocheneae** rectedventrally. CI = 1.0. Genus Cyanochen 117. Shapeof postischiacpubis: (a) of uniform width or evenly wid- SubtribeMerganetteae** ening caudally;(b) widened into roughly circularflange, espe- Genus Hymenolaimus cially extensiveanteroventrally. CI = 1.0. 754 BRADLEYC. LIVEZE¾ [Auk,Vol. 103

APPENDIX 2. Continued APPENDIX 2. Continued

GenusMerganetta Tribe Mergini Genus Tachyeres GenusPolysticta SubfamilyAnatinae Genus Somateria [Tribe] "Anatini" incertaesedis Genus Histrionicus Genus Pteronetta GenusCamptorhynchus Genus Cairina Genus Melanitta Genus A/x GenusClangula GenusLophonetta GenusBucephala* * * Genus Nettapus GenusMergellus*** Genus Anas GenusLophodytes Genus Callonetta GenusMergus Genus Chenonetta Tribe Oxyurini Genus Amazonetta Genus Heteronetta Tribe Aythyini GenusNomonyx Genus Marmaronetta GenusOxyura Genus Rhodonessa Genus Biziura Genus Netta Genus Aythya