The Auk 117(1):154-163, 2000

PHYLOGENY, BIOGEOGRAPHY, AND OF AUSTRALASIAN TEALS

MARTYN KENNEDY 1 AND HAMISH G. SPENCER Departmentof Zoology,University of Otago,P.O. Box 56, Dunedin,New Zealand

ABSTRACT.--Thetaxonomy of the Australasianteals has been particularly unstable. Aus- tralasianGrey Teal (Anasgracilis) and ChestnutTeal (A. castanea)are widely viewed asspe- cificallydistinct, but the taxonomyof theNew Zealandteals remains unsettled. Because con- servationstatus is affectedby taxonomicrank, it is importantto resolvethe statusof the rare subantarcticteals. To estimatephylogenetic relationships of teals,we sequencedthree mi- tochondrialDNA genes(12S, and ATPase6 and 8). The resultantphylogeny unequivocally groupsthe ChestnutTeal with the GreyTeal, rather than with the New Zealandteals as has traditionally been held (Fleming 1953). A greater level of sequencedivergence occurred within the New Zealandteals than betweenthe Grey and Chestnutteals. This diversity,to- getherwith morphologicaland behavioraldifferences, implies that the New Zealandteals shouldbe accordedspecific status as A. aucklandica,A. nesiotis,and A. chlorotis.Although it is most likely that the teal that colonizedthe AucklandIslands and CampbellIslands orig- inated in New Zealand, our data do not allow us to determine whether the ancestors of the CampbellIsland Teal came from mainlandNew Zealandor the AucklandIslands. This un- certaintyarises because, as our data show,the colonizationevents were separatedby a short period of time. Received25 November1998, accepted 16 June1999.

F•VE EXTANT TEALS inhabit the Australasian 1990).The brown-plumagedteals (i.e. all teals region and provide an interesting example of exceptthe )all existin allopatry.The speciationin insularSouthern Hemisphere wa- Auckland Island Teal (A. aucklandica)and terfowl (see Livezey 1990). Grey Teal ( CampbellIsland Teal (A. nesiotis)occur only on gracilis),which are small and drab, are wide- their respectivesubantarctic island groups (see spreadthroughout . Last centurythe Fig. 1). They are smaller and darker than the specieswas rare and localizedwithin New Zea- Brown Teal, and unlike this ,they are land, but it is now widely distributed (Mar- flightless(Marchant and Higgins 1990). chantand Higgins1990). Grey Tealare broadly The taxonomyof the Australasianteals has sympatricwith the ChestnutTeal (A. castanea) beenthe subjectof muchdebate (e.g. Dumbell in southeastern and southwestern Australia 1986,Williams and Robertson1996). Anas grac- and with the Brown Teal (A. chlorotis)in main- ilis, for example,was previouslytreated as a land New Zealand (Marchant and Higgins subspeciesof A. gibberifronsof (Live- 1990);vagrant havebeen report- zey 1991).Although now universallyaccepted ed in New Zealand on severaloccasions (Guest asseparate species (e.g. Marchant and Higgins 1992). ChestnutTeal are stronglysexually di- 1990, Turbott 1990, Livezey 1991, Christidis chromatic;the male has a greenhead, chestnut and Boles 1994), occasionaldebate has ques- breast, and dark upperparts,and the female tioned whether Grey and Chestnutteals war- closelyresembles a Grey Teal. Brown Teal are rant separatespecific status (Frith 1967) de- lessobviously dichromatic, with the female a spite their widespreadsympatry. more uniform brown than the male, which has The taxonomichistory of the brown-plum- a deepchestnut breast and a greeniridescence aged teals remains unresolved(see Dumbell on the crown and nape. Brown Teal were for- 1986). Fleming (1953) consideredthe Brown, merly widespreadthroughout North, South Auckland Island, and Campbell Island teals and Stewart Islands but are now rare and re- (the endemicNew Zealand teals)to be subspe- stricted in their distribution, with the main ciesof the ChestnutTeal, a positionaccepted by populationsin thenorth of North Islandand on Frith (1967). More recently,however, the New Great Barrier Island (Marchant and Higgins Zealand teals have been acceptedas specifical- ly separatefrom the ChestnutTeal, although I E-mail: [email protected] severaldifferent taxonomic arrangements have

154 January2000] PhylogenyofAustralasian Teals 155 AUSTRALIA'• ' N

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FIG. 1. The Australasianregion. been proposed. One arrangement considers Using morphologicalcharacters, Livezey them to be three allopatricsubspecies (Kinsky (1991) generated a phylogeny for dabbling 1970,Dumbell 1986,Turbott 1990), anotherac- that included most of the Australasian cordsall of them separatespecific status (Mar- teals(Fig. 2). Thisphylogeny suggests a pattern chant and Higgins 1990), and yet another ac- of speciationin whichthe monochromaticGrey cords specificstatus to the Brown Teal and Teal separatedfrom the commonancestor of AucklandIsland Teal but placesthe Campbell the dichromaticbrown-plumaged teals within Island Teal as a subspeciesof A. aucklandica Australia. Within the brown-plumagedteals, (Livezey 1990). the ChestnutTeal later divergedfrom the pro- genitorof theNew Zealandteals, the latter pre- A. platyrhynchos sumablyinvading New Zealand from Austra- lia. The Auckland Island Teal then diverged from the Brown Teal after colonizingfrom the A. superciliosa New Zealand mainland. In an earlier paper, Livezey(1990) presented a tree of the sameto- A. aucklandica pologythat includedonly the teal andincluded the CampbellIsland Teal as sistertaxon to the A. chlorotis Auckland Island Teal consistent with the tra- ditional hypothesisthat the CampbellIslands were colonized from the Auckland Islands A. castanea (Dumbell 1986).Alternatively, if the Auckland and Campbell Island teals are not sister taxa, A. gracilis the Auckland and Campbell Island coloniza- tionsrepresent separate events from the main- FIG. 2. Topologyof morphologicaltree for the land, with BrownTeal stock giving rise to both taxaused in this study(pruned from 59 taxa;Livezey 1991).Branch lengths are proportional to thenumber species(Turbott 1968, Dumbell 1986). Live- of changesalong the branch. Livezey's (1990) tree has zey's (1990, 1991) phylogenyimplies that the the sametopology for the tealswith the additionof strong sexual dichromatismof the Chestnut A. nesiotisas sister taxon to A. aucklandica(A. gracilis Teal representsthe ancestralstate and is thus is equivalentto A, gibberifronsof Livezey 1990). reducedin the insular forms,a patternthat tra- 156 KENNEDYAND SPENCER [Auk, Vol. 117 ditionallyhas been interpreted as the lossof an 2.5 •L of 10X Taq buffer (Promega), I mM MgC12 isolatingmechanism (i.e. dichromatismisolat- (Promega),and 200 •M of eachdNTP. Negativecon- ing the Grey and Chestnutteals). trols were included with each PCR reaction, and all mixtures were covered with mineral oil. The reaction The taxonomic status of the different teals began with denaturation(94øC for 3 min) followed has important conservationimplications for by 40 cyclesof annealing (1 min) at 55 to 57øC (for taxathat are rare or endangered.The New Zea- 12S) or 42 to 45øC (for ATPase),template extension land Department of Conservationpolicy in- at 72øC(1 min), and denaturation at 94øC(1 min). Fi- cludes taxonomic distinctiveness as one of five nal annealing (1 min) and extension (4 min) steps factorsassessed to determineconservation pri- completedthe reactions.The PCR productwas pu- orities (Molloy and Davis 1994).Within these rified using Gelase (Epicentre Technologies)and five factors,taxonomic distinctiveness is only 1 thensequenced by an automatedsequencer using ei- of 17 criteria used to assessconservation pri- ther the PCR primersor internal primers(Kennedy orities,but it is supposedto be a decidingfac- 1999).Wherever possible, both strandsof DNA were tor when new conservationprograms are sequencedfor samplesof two or more individualsof a speciesto verify theaccuracy of thesequencing and planned (i.e. all elsebeing equal more distinct control for DNA contamination (i.e. three individu- taxawill be givena higherpriority; Molloy and als for Grey Teal,one Mallard, and two for the other Davis 1994). taxa).The GreyTeal samples originated in New Zea- In an attempt to resolvethe taxonomicand land. Ambiguity codeswere used when it was not systematicstatus of the Australasianteals, we possibleto discriminatebetween alternativebases at sequencedmitochondrial DNA (mtDNA) from a site, and these sites were treated as uncertain. the membersof this group.Sequence data can Thesesites typically were bases that had little signal be used as a measure of the relative level of di- supporting either of two alternative basesrather vergenceamong the tealsand in the estimation than being strong double peaks. The ATPasese- quencefrom Ramirez et al. (1993) for the Mallard of their phylogeneticrelationships. A robust was obtained from GenBank. Unlike the ATPase se- phylogenyfor the group would allow us to quence,the segmentof 12Ssequenced by Ramirezet evaluatethe biogeographicorigin of the differ- al. (1993) differed from that used here, so we se- ent teals. quenced12S for a Mallard. Sequenceswere alignedby eye.The 12Ssequence METHODS wasaligned with referenceto the seabirddata of Pat- ersonet al. (1995)and using the secondary-structure Total genomicDNA was obtainedfor eachof the modeland conserved-motifsapproach of Hicksonet samplesusing proteinaseK followed by phenol/ al. (1995). The sequenceshave been submittedto chloroform extraction (blood for all teals, muscletis- GenBank (accession numbers AF173480 to sue for Mallard [A. platyrhynchos],and heart tissue AF173494).Analyses were conductedusing test ver- for the Grey [A. superciliosa]).Once extracted, sion4.0d64 of PAUP*,written by David L. Swofford. the DNA was amplifiedfor threemtDNA genes(12S Phylogenetictrees were constructedwith maximum ribosomal RNA and ATPase 6 and 8). We used the parsimony(using exhaustivesearches) and maxi- polymerasechain reaction (PCR) to amplify thesere- mum likelihood (usingbranch and bound searches). gionswith universalprimers for 12S (Kocheret al. To investigatethe support for our treesand the 1989) and primers for ATPase6 and 8 (seeKennedy phylogeneticsignal in our sequencedata, we used 1999). For ATPase 8 to be amplified, a new primer bootstrapping(Felsenstein 1985), decay indices (Bre- that is more suited to waterfowl, L9058 (5'- mer 1988), Kishino-Hasegawatests (Kishino and AGCCTTTTAAGCTACT-3'),was designedfrom the Hasegawa1989), and spectralanalysis (Hendy and sequenceof Ramirez et al. (1993).The prefix to the Penny1993). The bootstrapestimates statistical sup- primerindicates that it is the light (L) strandand the port for the branchesof a tree, whereasthe Kishino- numberrefers to the positionof its 3' end according Hasegawatest estimatesthe significanceof the ob- to the chickenmtDNA sequence(Desjardins and Mo- serveddifference (in likelihood or tree length) be- rais 1990). The primer pairs of L9265 and either tween any treesbeing compared.For the bootstrap H9922 or H9898 (requiredfor the BrownTeal) were analyses,1,000 replicates were performedfor parsi- used to amplify ATPase 6 (see Kennedy 1999), mony (using a heuristicsearch) and 100 for maxi- whereas L9058 in combination with either of the mum likelihood(using a fast-heuristicsearch). The heavy strand primers amplified ATPase 8 and decayindex is the differencebetween the length of ATPase 6. the parsimonytree(s) and the shortesttree(s) lacking A typical 25-•L double-strandedPCR amplifica- that node. The program Spectrum2.0 (Charleston tion contained extracted genomic DNA, 0.5 •M of 1998), which implementsspectral analysis (Hendy eachprimer, one unit of Taqpolymerase (Promega), and Penny1993), was used to further investigatethe January2000] Phylogenyof Australasian Teals 157 phylogeneticsignal in thedata. Support for a split(a A. platyrhynchos split is any bipartition of the set of sequencesand thus is equivalentto a branch)is a functionof the A. superciliosa numberof changesin characterstate that correspond to that split, and the conflictfor a split is the sumof the supportfor the splitsthat conflictwith it. Fordis- 1 oo cussionsof spectralanalysis and its use,see Lento et 251100 al. (1995)and Pageet al. (1998).The spectrumcan be computedfrom two-statesequence data, but because of difficultieshandling missingdata (Page et al. 1 O0 A. nesiotis 1998),we computedthe spectrumfrom distancema- A. chlorotis trices. We used the Tamura-Nei model to correct for A•aucklandica superimposedchanges (this model allows for un- F•c. 3. Equalweights maximum-parsimony phy- equalbase frequencies and a transition/transversion logram (tree length = 107, CI = 0.944, RI = 0.935). bias with two transition classes; Tamura and Nei Branch lengths representthe number of substitu- 1993). tionsalong each branch. The percentageof bootstrap replicates(out of 1,000) that supportedeach node RESULTS (->50%)are shown below the branches, and the decay indicesare shownabove the branches.Both weight- Our alignment gave a 394-bp fragment of ed parsimonyanalyses (i.e. with transversionsgiven greaterweight than transitions)and maximum-like- 12S,and the overlappingATPase 6 and 8 cod- lihood analyses(with transitionto transversionra- ing genesgave a 778-bp fragment. A partition- tio,the proportion of invariablesites, and the gamma homogeneitytest (Farriset al. 1995) showed shapeparameter all estimated)found the sameto- thatthere was no significantdifference in phy- pology.The bootstrapvalues were almostidentical logeneticsignal betweenthe ATPaseand 12S for weightedparsimony and were similar for maxi- sequence,so we analyzedthem as a singledata mum likelihood. set (100 replicates,P = 1.0). Of the 115 variable sites,73 of the characterswere parsimony in- formative.Both the significantlyskewed tree- port, and low or nonexistentlevels of conflict, length distribution(g• = -1.198 from 10,000 for the splitthat groups the Mallardand Grey random trees, P < 0.001; Hillis and Huelsen- Duck separatelyfrom the teals,for grouping beck1992) and a PTP test(1,000 replicates, P = theGrey and Chestnut teals, and for grouping 0.001; Faith 1991, Faith and Cranston1991) the New Zealandteals together (Fig. 4). The showedthat the data contained significant sig- spectrum,like thedecay index, showed that the nal. With the Mallard and GreyDuck defined level of supportfor groupingthe Brown and asoutgroups and all sitesweighted equally, the CampbellIsland teals is relatively low. There resultingparsimony tree had a lengthof 107 was,however, no conflictin our data against steps(Fig. 3). We foundthe sametopology for groupingthe Brown and Campbell Island teals parsimonywhen transversionswere given together,with virtually no supportand some greaterweight than transitions, and in themax- conflict for the alternative arrangements imum-likelihoodanalysis (consequently, we groupingeither the Brown and AucklandIs- presentonly the equallyweighted parsimony land tealsor the AucklandIsland and Camp- tree). bell Island teals (Fig. 4). High decayindex values and 100% bootstrap Our equally weightedparsimony analysis values were found for three of the four internal produced one most-parsimonioustree of branches,i.e. separatingthe Grey Duck and length107 and two trees of length 109. No other Mallardfrom the teals, the sister-taxa grouping trees had a length of lessthan 123. The two of the Greyand Chestnutteals, and grouping treeswith a lengthof 109 groupedeither the theNew Zealandteals (Fig. 3). Theshort inter- Brown and Auckland Island teals or the Auck- nal branchgrouping the Brownand Campbell land Island and CampbellIsland teals.A Kishi- Islandteals had highbootstrap support (91%) no-Hasegawatest comparingall threetrees of but a low decayindex. Similar bootstrap values length109 and smallershowed that we cannot were foundfor both the weighted-parsimonyreject thesealternate topologies (P > 0.05). and maximum-likelihoodanalyses. The spec- Livezey'stopology (Fig. 2) has a lengthof 125 tral analysisalso showedhigh levelsof sup- and canbe rejectedby the Kishino-Hasegawa 158 KENNEDYAND SPENCER [Auk,Vol. 117

lengths,which are proportionalto the number of substitutions, indicate that the New Zealand tealsare as divergentfrom one anotheras the Greyand Chestnutteals. Pairwise comparisons (Table1) showthat Grey and Chestnutteals dif- fer by 0.29%,and the divergencesbetween the 0.025 - New Zealand tealsvary from 0.63 to 0.70%(Ta- ble 1). We also combined our mtDNA data set with

0.000 all otheravailable mtDNA sequencedata (more than 1,000bases each of two mtDNA genes,cy- tochrome b and ND2, obtained from GenBank; Johnsonand Sorenson 1998) to constructa phy- -0.025 - logenyfor the group.A partition-homogeneity test showedthat therewas no significantdif- ferencein phylogeneticsignal between Johnson -0.050 - and Sorenson's(1998) cytochrome-band ND2 sequenceand our ATPaseand 12S sequence; thus,we analyzedit asa singledata set of more -0.075 - than3,200 bases (100 replicates, P = 0.27).With ß support this combineddata set, we found a single [] conflict equallyweighted parsimony tree that grouped the Greyand Chestnutteals as sister taxa (boot- -0.1 O0 Split strapvalue of 100%and high decayindex, Fig. 5). TheNew Zealandteals form a monophyletic FIG.4. The support/conflictspectrum. The splits group with a bootstrapvalue of 100% and a are labeledby the taxa they group and are ordered high decayindex, and the combineddata set left to right by their (positive)support values (i.e. ex- placedthe AucklandIsland and CampbellIs- pected number of substitutionsper site), with the (negative)conflict values normalized following Len- land tealsas sister taxa. Although the bootstrap to et al. (1995). supportfor groupingthe AucklandIsland and Campbell Island teals was reasonable(76% vs. 23% that supportedgrouping the Brown and test (P < 0.0001;i.e. no significantsupport for Campbell Island teals, which was the next it in our data).Similarly, the spectrumshowed most-parsimonioustree), the decay index of no supportand extremelyhigh conflictfor the only 2 showedthat the strengthof the signal split groupingthe Chestnut,Brown, Auckland wasweak. A Kishino-Hasegawatest did notre- Island,and CampbellIsland teals(Fig. 4). jecteither of the alternativehypotheses, i.e. that Our phylogeny(Fig. 3) showsthat the Grey the Brown and CampbellIsland teals or the and Chestnut teals are sister taxa and the New Brown and Auckland Island teals are sister taxa Zealand teals are monophyletic. Branch (P > 0.05).As before,a Kishino-Hasegawatest

TABLE1. Percentsequence divergence between different taxa basedon the model of Tamuraand Nei (1993). Valuesbelow the diagonalare for our data alone,and valuesabove the diagonalare for our datacombined with those of Johnsonand Sorenson(1998).

Taxon i 2 3 4 5 6 7

1 Mallard -- 0.94 5.63 5.45 6.40 6.54 6.09 2 Grey Duck 1.75 -- 5.74 5.55 6.40 6.48 5.98 3 Grey Teal 6.09 5.64 -- 0.09 5.37 5.22 5.05 4 Chestnut Teal 5.58 5.06 0.29 -- 5.36 5.32 5.02 5 Auckland Island Teal 5.77 4.96 3.98 3.95 -- 0.92 0.84 6 CampbellIsland Teal 6.39 5.50 3.87 4.14 0.70 -- 0.77 7 Brown Teal 6.09 5.23 4.06 3.96 0.63 0.63 -- January2000] PhylogenyofAustralasian Teals 159

A. platyrhynchos of divergencebetween the SouthIsland Brown Teal and the other teals exceeded 5%. A. $uporciliosa Initially, we consideredthat a contamination event occurred,but new subsamplesof the 80 originalsshowed that this was not the case.The lOO difficultiesobtaining sequence for theseindi- vidualsand the levelof geneticdivergence be- • A. aucklandica tween the Grey Duck and Mallard versus the SouthIsland Brown Teal may be explainedif

lOO thesesequences were of nuclearorigin. Anoth- er possibleexplanation is that becausemtDNA --A. chlorotisA. nesiotis is inheritedmaternally, there was a hybridiza- FIG. 5. The equal weightsmaximum-parsimony tion event (as noted in Brown Teal; Dumbell phylogramfor the combineddata set (i.e. our se- 1986) between a female Mallard or Grey Duck quenceplus that of Johnsonand Sorenson1998). Tree and a male South Island Brown Teal, and that length = 324, CI = 0.951, and RI = 0.951. Branch lengthsrepresent the numberof substitutionsalong both of the individualswe sequencedwere de- eachbranch. The percentageof bootstrapreplicates scendantsof sucha mating.From our sequence, (out of 1,000) that supportedeach node (->50%)are we cannot tell if such a hybridizationevent shownbelow the branches,and the decayindices are would havebeen with a Mallard or GreyDuck, shown above the branches. whichhybridize extensively in the wild. rejectedthe hypothesis (P < 0.0001)that places DISCUSSION the Chestnut Teal as a sister taxon to the New Zealandteals (i.e. Fig. 2) Our phylogenyshows that the hypothesis In additionto the taxaalready discussed, we that the Grey Teal and the brown-plumaged obtained blood samplesof two South Island teals (Chestnut and New Zealand teals) di- Brown Teals (A. chlorotispeculiaris) from the vergedbefore the latter colonized New Zealand remnant population in Fiordland National (seeFig. 2) and further diversifiedis not cor- Park.Mathews (1937) proposed subspecific sta- rect. All of our resultsshow that the Grey Teal tus for South Island Brown Teal based on small- and Chestnut Teal are sister taxa, and we can er wing measurementsthan their North Island rejectthe hypothesisthat placesthe Chestnut counterparts.We sequencedthe samegenes for Teal and New Zealand teals as sister taxa. Our the South Island Brown Teal to assess its taxo- phylogenythus implies that the commonan- nomic status and phylogeneticposition. Se- cestorof all the Australasianteals divergedin quencingthese individuals proved difficult, two lineages,one in Australiaand the otherin and we were unable to sequence120 basesof New Zealand. Followingthe traditional per- 12Sbecause one of the primerswould not pro- spective,we assumethat teal from Australia vide any readablesequence. The SouthIsland colonizedNew Zealand (Falla 1953, Livezey Brown Teal sequencewas added to our data set 1990),but our phylogenycontains no evidence and analyzedusing both parsimonyand max- that the colonization must have been in this di- imum likelihood to find the best estimate of the rection.Within Australia,the teal divergedinto phylogeny.Surprisingly, rather than grouping the Grey and Chestnutteals, and giventhe di- the South Island Brown Teal with the North Is- vergencebetween the two (Table 1), the split land Brown Teal or one of the subantarctic probablyoccurred at approximatelythe same teals, the South Island Brown Teal grouped time as (or perhapsafter) the New Zealand with the Mallard and Grey Duck. This group- tealsdiverged from oneanother. ing was supportedby high bootstrapvalues Wewere unable to resolvethe topologywith- (100%for groupingwith the Mallard and Grey in the New Zealand teals. Although we ob- Duck and 96% for beinga sistertaxon to the tained good bootstrap support for grouping Mallard from 1,000 parsimonybootstrap rep- theBrown and CampbellIsland teals, there was licates) and by low levels of divergencebe- a low decayindex and low supportfrom spec- tween the SouthIsland Brown Teal and Grey tral analysisfor thatrelationship. The spectrum Duck (1.09%) and Mallard (1.17%). The levels (Fig.4) showedthat the high bootstrap support 160 KENNEDYAND SPENCER [Auk, Vol. 117 that groupedthe Brownand CampbellIsland greenhead (Marchantand Higgins 1990).The tealsresulted from a lack of signalin the data third of the characters(42) is the cranialborder for any alternativegroupings. of the speculum,formed by the tips of the cau- Monophylyof theGrey and Chestnut teals.--The dal-most row of greater secondarycoverts. finding that the Grey and Chestnutteals are Thischaracter has four states (not contrastingly sistertaxa is extremelywell supportedby both colored,black, white, and buff or rufous) and bootstrappingand decayindices (Fig. 3) and by also may have been miscodedbecause the the spectralanalysis (Fig. 4). Other molecular brown-plumagedteals are supposedto share evidence,including DNA (Sraml et al. 1996, the buff or rufousstate, but this stateappears Younget al. 1997,Johnson and Sorenson1998) to be sharedby only the New Zealand teals and allozymes(Daugherty et al. 1999), indi- (Marchant and Higgins 1990). The Chestnut catesthat the Grey Teal and ChestnutTeal are Teal sharesthe white statewith the Grey Teal sistertaxa (althoughthe UPGMA and neigh- (Marchantand Higgins 1990).The last of the bor-joiningtrees constructedfrom the allo- characters(82) is the presenceor absenceof a zyme data differ somewhatand have poor subrectangularwhitish patch surroundedby bootstrapsupport for this grouping).More- dark areas on the flanks of males in alternate over, the morphologicalsimilarity of the fe- plumage.This characteris related to dichro- male,juvenile, and eclipsemale ChestnutTeal matismand eithermay be convergentor needs and Grey Teal and behavioral information to be reassessedin terms of the possiblesub- (Marchantand Higgins 1990) support group- sequentloss of dichromatismin Grey Teal (see ing thesespecies. Display bouts,for example, Omland 1997). distinguishGrey Teal from any other species Other morphologicalcharacters that are not apart from ChestnutTeal (Marchantand Hig- related to male breeding plumage are more gins1990). The similarityof the malebreeding consistentwith the Grey Teal and Chestnut plumagesof thebrown-plumaged teals has had Teal being sistertaxa. Both specieshave red a major influenceon their taxonomy,over- eyes,whereas New Zealand teals have brown whelmingother evidence that supportsgroup- eyeswith a white eye ring (character104 of ing the ChestnutTeal and Grey Teal (Daugh- Livezey1991; Daugherty et al. 1999).Similarly, erty et al. 1999). head shapeand underwingpatterns are very Livezey's(1991) phylogeny (Fig. 2) hasfour similarin the Grey Tealand ChestnutTeal and charactersthat group the ChestnutTeal with distinguish them from New Zealand teals the New Zealandteals. Given the weightof ev- (Marchantand Higgins 1990). idencegrouping the Grey and Chestnutteals, Phylogeneticand biogeographicimplications.- these characters need to be reevaluated, and We couldnot resolvethe patternof divergence possiblyeither recodedor consideredas con- within the New Zealand teals with confidence. vergenttraits. The first of Livezey's(1991) char- Becauseof prevailingwinds and the relative acters(26) is the presenceor absenceof a chest- positionand sizesof the differentislands (Fig. nut wash on the sides,belly, and breast.This 1), it is implausiblethat the teals colonized character is linked with dichromatism in the mainland New Zealand from Australia via the group,with onlythe males having the chestnut subantarctic islands. If we assume that the teals wash (Marchant and Higgins 1990). Dichro- are monophyleticand that mainlandNew Zea- matismmay havebeen lost repeatedlywithin land wascolonized from Australia,our phylog- the dabblingducks (Omland 1997), and thusit eny suggeststhat teal from the mainlandfirst is possiblethat monochromatism is the derived reachedthe AucklandIslands and then shortly statein GreyTeal (vs. dichromatism in theoth- afterward via a second colonization reached er taxa).The secondof the characters(30) is the the CampbellIslands (thus, the Brown Teal and presenceor absenceof a generalized,poorly CampbellIsland teal are sistertaxa). The level differentiatedgreenish postorbital iridescence. of bootstrapsupport for this groupingis high This charactermay have been miscoded. Rather (91%),but this reflectsa lackof conflictingsig- than being sharedby all of the brown-plum- nal in our data for either of the otherpossible agedteals, this characterappears to be shared bifurcatingpatterns within thesethree taxa. We by only the New Zealandteals, because male couldnot rejectthe alternativehypotheses that Chestnut Teals (like Mallards) have a fully either the CampbellIsland and AucklandIs- January2000] PhylogenyofAustralasian Teals 161 land teals or the Brown and Auckland Island (i.e.a singleevent colonizing both subantarctic teals are sister taxa. island groups)and may prove very difficult to The analysesof Johnsonand Sorenson(1998) resolve with confidence. Future lines of evi- and Younget al. (1997)place the CampbellIs- dencethat may help infer relationshipsamong land and Auckland Island teals as sister taxa, New Zealand teals include additional sequence thus supportingthe traditional colonization dataand comparisonswith othersimilarly dis- hypothesis.The combined data set grouped the tributed taxa. If thesecomparisons showed a Auckland Island and Campbell Island teals as consistentpattern of colonization,support for sistertaxa (Fig. 5), but the amountof change a particularhypothesis may be inferred.Para- alongthe internalbranch of the treewas insuf- sites would be an additional source of infor- ficientto allow us to rejecteither of the alter- mationif theyhave cospeciated with teals(e.g. native topologies. Patersonet al. 1993, Page et al. 1998). For ex- Threepossible biogeographic scenarios are ample, lice have been shown to have an in- apparentfor the colonizationof the subantarc- creased rate of mtDNA compared tic islandsby teal. First, our sequencedata sug- with their hosts(Page et al. 1998),so it may be geststwo colonizations,with flighted main- possible to confidentlyresolve the parasite land teal first colonizingthe AucklandIslands phylogenyand thusinfer teal phylogeny. and thenlater colonizingthe CampbellIslands Irrespectiveof the pattern of colonization, (Turbott 1968). Second,the combineddata set flightlessnessprobably evolved separately in favorsthe traditionalhypothesis of a mainland the subantarcticteals (contra Livezey 1990). Be- taxoncolonizing the AucklandIslands, which causemany of the changesin morphologyof in turn colonizedthe CampbellIslands before thesespecies probably are related to loss of becomingflightless in both the AucklandIs- flight (Livezey1990), morphological similarity lands and Campbell Islands (Dumbell 1986). of the CampbellIsland Teal and the Auckland Third, the allozymedata of Daughertyet al. IslandTeal is to be expectedand thusmight be (1999) provide a low level of support for an af- the resultof convergence. finity betweenthe Brown Teal and Auckland Is- Taxonomicstatus.--Our sequence data show land Teal which suggeststwo colonizationsof that the threeNew Zealandteals are morege- the subantarcticislands, the first reachingthe neticallydivergent from one another(0.63 to CampbellIslands and the secondthe Auckland 0.70%) than the Grey Teal and ChestnutTeal Islands(Turbott 1968).We cannotdistinguish arefrom eachother (0.29%), a resultthat agrees betweenthese three options with our sequence with allozymedata (Daugherty et al. 1999).For data or with the combinedsequence data. The the combineddata set (i.e. includingJohnson short internal branchesgrouping the Brown and Sorenson1998), we found that the level of and CampbellIsland teals (i.e. with the decay divergencebetween the Grey and Chestnut indexof 2; Fig. 3) andthe AucklandIsland and tealswas 0.09%, whereas divergences between CampbellIsland teals (i.e. with the decayindex the New Zealand teals varied from 0.77 to of 2; Fig. 5) suggestthat howeverthe teals 0.92% (Table 1). reached the subantarctic islands, the coloniza- Levelsof divergencein the sequencedata (al- tion eventswere separatedby only a shortpe- beit low; Table1) suggestthat the BrownTeal, riod of time (i.e. hundreds or thousandsvs. Auckland Island Teal, and Campbell Island hundredsof thousandsof years).An additional Teal should be accorded the same taxonomic hypothesis,that the three New Zealand teals statusas the Grey Teal and ChestnutTeal. In representseparate colonizations by Chestnut additionto the divergencedata, severalother Teal (Williams et al. 1991), can be rejectedbe- lines of evidencesupport the speciesstatus of causeit receivesno supportfrom the phylo- thesetaxa. Diagnostic allozyme characters al- geneticrelationships of the taxa (i.e.the Chest- low thesetaxa to be separatedunder the phy- nut Teal is not a sistertaxon to any of the New logeneticspecies concept (see Daugherty et al. Zealand teals). 1999). Some behavioral charactersdiffer be- With the substantial combined data set we tweenthe mainland and subantarctic teals (e.g. wereunable to resolverelationships among the territoriality, voice, precopulatorybehavior; New Zealandteals with certainty.Thus, the re- Marchantand Higgins 1990), and substantial lationshipappears to be closeto a trichotomy morphologicaldifferences occur between the 162 KENNEDYAND SPENCER [Auk,Vol. 117 taxa (Livezey 1990, Marchant and Higgins ysis of phylogeneticdata. Bioinformatics14:98- 1990).Only superficialplumage similarities ar- 99. gue againstthe speciesstatus of the New Zea- CHRISTIDIS,L., ANDW. E. BOLES.1994. The taxonomy land teals. and speciesof of Australiaand its territo- ries. Royal AustralasianOrnithologists' Union, Conservationimplications.--Along with sev- Melbourne. eral recentworkers (e.g. Daugherty et al. 1999) DAUGHERTY, C. H., A. CREE, J. H. HAY, AND g. B. we suggestthat the Brown Teal, AucklandIs- THOMPSON.1990. Neglected taxonomy and con- land Teal and CampbellIsland Tealbe accord- tinuing extinctions of tuatara (Sphenodon).Na- ed specificstatus, which warrants separate con- ture 347:177-179. servationstrategies. We cannot comment on the DAUGHERTY, C. H., M. WILLIAMS, AND J. M. HAY. taxonomic status of the remnant South Island 1999. 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CRANSTON. 1991. Could a clad- Zealand teals (as it has in the tuatara [Sphen- ogramthis shorthave arisenby chancealone? odon];Daugherty et al. 1990),and it is possible On permutationtests for cladisticstructure. Cla- distics 7:1-28. that morphologicaldifferences in the SouthIs- FALLA,g. A. 1953. The Australian element in the avi- land BrownTeal are correlatedwith important fauna of New Zealand. Emu 53:36-46. geneticdifferences. FARRIS, J. S., M. K•LLERSJ•), A. G. KLUGE, AND C. BULT.1995. Constructinga significancetest for ACKNOWLEDGMENTS incongruence.Systematic Biology 44:570-572. FELSENSTEIN,J. 1985. Confidence limits on phyloge- We thankM. Williams(New ZealandDepartment nies:An approachusing the bootstrap.Evolu- of Conservation)and B. Evansfor providing sam- tion 39:783-791. pies;J. Fraser,R. Gray,I. Southey,and M. Williams FLEMING, C. A. 1953. Checklist of New Zealand for helpful discussions;and C. Daugherty,M. Wil- Birds. A. H. and A. W. Reed, Wellington,New liams, J. Hay, K. Johnsonand M. Sorensonfor ad- Zealand. vancecopies of theirwork. The manuscript benefited FRITH,H. J. 1967.Waterfowl in Australia.Angus and from the commentsof three anonymousreviewers, Robertson,Sydney. A. Baker,A. Paterson,M. Roy,I. Southey,and H. Su- GUEST,g. 1992. Rare bird reports in 1991. Notornis ter.Genetic work was carried out in theEvolutionary 39:319-321. GeneticsLaboratory of G. Wallis,with the assistance HENDY,g. D., ANDD. PENNY.1993. Spectral analysis and advice of T. King and L. Wallis. The initial of phylogeneticdata. Journal of Classification10: ATPaseprimers were designedby A. Baker and O. 5-24. Haddrath of the RoyalOntario Museum.The pro- HICKSON,R. E., C. SIMON, A. COOPER,G. S. SPICER,J. gramsused for the analyseswere written by D. L. SULLIVAN, AND D. PENNY. 1995. Conserved se- Swofford(PAUP*), M. A. Charleston(Spectrum 2.0), quencemotifs, alignment,and secondarystruc- and T. Eriksson and N. Wikstr6m (AutoDecay 3). ture for the third domain of 12S rRNA. 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