The Auk 117(1):154-163, 2000 PHYLOGENY, BIOGEOGRAPHY, AND TAXONOMY 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 Grey Teal)all existin allopatry.The speciationin insularSouthern Hemisphere wa- Auckland Island Teal (A. aucklandica)and terfowl (see Livezey 1990). Grey Teal (Anas CampbellIsland Teal (A. nesiotis)occur only on gracilis),which are small and drab, are wide- their respectivesubantarctic island groups (see spreadthroughout Australia. Last centurythe Fig. 1). They are smaller and darker than the specieswas rare and localizedwithin New Zea- Brown Teal, and unlike this species,they are land, but it is now widely distributed (Mar- flightless(Marchant and Higgins 1990). chantand Higgins 1990).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 Indonesia(Live- 1990);vagrant Chestnut teal 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 •/TasmanTasmania SouthSeaIsl •orthlslandNEWZEALAND - 45 ø S Stewart Island ,9 Auckland Islands Southern Ocean Campbell Islands 165øE I 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- ducks that included most of the Australasian cordsall of them separatespecific status (Mar- teals(Fig. 2). This phylogenysuggests 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 sumably invading 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