Mitochondrial 12S rRNA sequences support the existence of a third species of freshwater blackfish (Percicthyidae: Gadopsis) from south-eastern Australia

2004·4.5 MB·

by  Adam D Miller

MemoirsofMuseumVictoria61(2): 121-127(2004)
ISSN 1447-2546(Print) 1447-2554(On-line)
http://www.museum.vic.gov.au/memoirs/index.asp
Mitochondrial 12S rRNA sequences support the existence ofa third species of
freshwater blackfish (Percicthyidae: Gadopsis from south-eastern Australia
)
AdamD. Miller, GretchenWaggy1 StephenG. RyanandChristopherM.Austin2
,
SchoolofEcologyandEnvironment,DeakinUniversity,POBox423,Warmambool,Vic.3280,Australia
1 Currentaddress:DepartmentofCoastalScience,CollegeofMarineScience,TheUniversityofSouthernMississippi,
703EastBeachDrive,OceanSprings,MS,USA,[email protected]
2Authorforcorrespondence:[email protected]
Abstract Miller,A.D.,Waggy,G.,Ryan,S.G.,andAustin,C.M.2004.Mitochondrial 12SrRNAsequencessupporttheexistence
ofathirdspeciesoffreshwaterblackfish(Percicthyidae: Gadopsis)fromsouth-easternAustralia.MemoirsofMuseum
Victoria61(2): 121-127.
Fish ofthe genus Gadopsis are a distinctive component ofthe freshwater fish fauna of south-easternAustralia.
GadopsismarmoratusandG.bispinosusaretheonlytwospeciesrecognisedwithinthegenus,withtheformerofuncer-
taintaxonomicstatus,asitisthoughttobecomposedofatleasttwodistinctgeographicalformsbasedonmorphologi-
calandallozymedata.TheobjectiveofthisstudywastoinvestigateDNAsequencedivergenceinGadopsis,especially
inthewesternportionofitsdistribution,usinganapproximately400basepairfragmentofthemitochondrialsmallsub-
unit12SrRNAgeneregioninordertoreassessthetaxonomyofthegenus.Individualsfrom11locationsweresequenced
andconfirmthatG.marmoratusandG.bispinosusaregeneticallydistinct,andfurtherthattheG. marmoratuscomplex
consistsoftwodivergentcladesrepresentingthepreviouslyidentifiednorthernandsouthernforms.Thedegreeofdiver-
gencebetweenthethreeGadopsiscladeswassimilar(5-6%nucleotidesubstitutions),suggestingthattheydivergedfrom
acommon ancestor at approximately the sameperiodin geologicaltime. Theseresults are consistentwithprevious
allozymestudiesandhighlighttheusefulnessofmitochondrialDNAdatacoupledwithallozymeinformationforclari-
fyingtaxonomicboundariesinmorphologicallyconservativeaquaticorganisms.
Keywords MitochondrialrRNA,taxonomy,blackfish,Percicthyidae,Gadopsis,Australia
Introduction Gadopsis marmoratus has a large geographic range that
includestributaries oftheMurray-Darlingriversystem, asfar
Fish ofthe genus Gadopsis, commonly known as theriver or north as the Condamine River in southern Queensland. The
freshwater blackfish, are endemic to south-eastern Australia speciesisalsofoundinTasmaniawithendemicpopulationsin
(including Tasmania), and carry out their entire life cycle in the north and translocatedpopulations in the Huon River and
freshwater (Jackson et al., 1996). The genus is phylogenetic- elsewhere in the south. Sanger(1986), assuming that G. mar-
allydistinctanditsevolutionaryoriginsremainuncertainasit moratus is in fact a complex of two species, suggested that
may have either evolved from a marine ancestor some 15 these taxa evolved in allopatry following the isolation of
million years ago or had a more ancient Gondwanan fresh- TasmaniafrommainlandAustralia.According tothis scenario
waterorigin(Sanger, 1984;Jerryetal.,2001). ancestral gadopsids are thought to havebeenoriginally wide-
Gadopsisbelongs to the familyPercicthyidae andcontains spreadthroughoutVictoriaandnorthernTasmaniaandthatthe
twocurrentlyrecognisedspecies, G. marmoratus(Richardson, formationofthetwospeciesmayhaveoccurredduringperiods
1848) and G. bispinosus (Sanger, 1984). Sanger (1986) ofraised sea levels which isolated Tasmanian from mainland
suggested,basedonmorphologicalandallozymeevidence,that populations. Subsequently, whensealevelswerelowerduring
G. marmoratuspotentiallyconsists ofanorthern anda south- the Pleistocene glaciation and land connections re-established
ern species. However, Sanger (1986) did not formally recog- with the mainland, the Tasmanian form of G. marmoratus
nisethenorthernandsouthernformsofG.marmoratusasthese invaded southern Victoria, consequently displacing the north-
putative species were not found in sympatry and because the ernG. marmoratus(Ovendenetal., 1988).
taxonomic significance of the genetic and morphological Sanger’s (1986) biogeographical hypothesis assumes that
divergencebetweenthetwoformswasuncertain. the two forms of G. marmoratus behave as independent
122 A. D. Miller,G.Waggy,S.G. RyanandC. M.Austin
species.Thishypothesisalso suggeststhatthetwoformshave buffer, 2.0 pMMgC12, 0.2mMdNTPs, 1 mMofeachprimerand2
comeintocontactinthepastandthereforeitmay stillbepos- units TagDNApolymerase.PCRamplificationswereperformedina
sible to find locations where both the northern and southern Corbett PC-960 Microplate Thermal Sequencer and consisted of30
formscoexistinVictoria(KoehnandO’Connor, 1990). Sanger cyclesofdenaturationat94°Cfor30sec,annealingat55°Cfor30sec,
(1986)suggestedthatthetwoformsmayoccurinsympatryin andextensionat72°Cfor30sec.Aninitialdenaturationcycleof3min
tGhleensetaltge’rsisvoerutshywsetsetm,s.anAanreaalelnoczoymmpeassstiudnygbthyeRGeylalnibertanald.a(nidn as7tt2a9°iC4n.e°dCTwhwieatshPeCutsRheidpdriaoundmducbttrhsoemwpierdroeegurvnaidmseurtaelUri-sVmedilniiagnthte.1d%wiatghaaro5semi/nTAcyEclgeelast
press) was unsuccessful in finding evidence supporting the
existence of sympatric populations of northern and southern Purification and sequencing. PCR products were purified using a
G. marmoratusinsouth-westernVictoria.However,theirfind- tQuIrAeqrsuiincsktrPucCtiRonpsu.riPfuirciaftiieodnDkiNtA(QwIaAsGqEuaNn)tiafciceodrvdiiandgirteoctthceommapnaurfiasco-n
ings were consistent with Sanger’s (1986) results indicating withDNAmarker(PromegaDNA/HAEIIImarker)ofknown con-
geneticdivergencebetweenthetwoforms inhabiting adjacent centration,againvisualizedunderUVlightina1%agarose/TAEgel
riversystemsinthisregion. containing ethidium bromide. Purified DNA was then sequenced
In addition to Sanger’s and Ryan’s allozyme studies there accordingtoAustralianGenomeResearchFacility(AGRF),University
havebeen several studiesofblackfishusingDNA-basedtech- ofQueensland,protocols.
niques (Ovendenetal., 1988;Waters et al., 1994; Jerry etal., Dataanalysis.SequencechromatogramswereviewedusingEditView
2001). These studies, however, are limited by minimal sam- and edited using SeqPup software (Gilbert, 1997). Sequences were
plingofthenorthernformofG. marmoratus,especiallyinthe aligned using the Clustal X program (Thomson et al., 1997) with
westernportionofitsdistribution.Thisstudythereforeextends alignment-ambiguous regions excised prior to phylogenetic recon-
these studies by using Polymerase Chain Reaction (PCR) struction(Gatesyetal., 1993). Phylogenetic analyeswereconducted
amplification ofan approximately 400 base pair fragment of using a range of approaches implemented by the PAUP* software
the mitochondrial 12S rRNAgeneregion coupled with direct package(Swofford,1998).Phylogeneticsignalwithinthedatasetwas
DNA sequencing, in order to further evaluate the taxonomic assessedusingthegl statisticfromtherandomtreelength-frequency
status of the northern and southern forms of G. marmoratus distribution(HillisandHuelsenbeck,1992).Phylogeneticrelationships
cwihtohseenmpbheacsaiusseomnititoschwoensdtreiranldiDsNtrAibu(timotnsD.NATh)ishaasppbreoeanchfowuansd mwearxeimeustmimlaitkeedliuhsoiondgampparxoaicmhuesm.pTahresimmoonsyt,pnaerisgihmboonuiro-ujsointirneeg waansd
identified using a full exhaustive search with support for branches
to be very useful for inferring phylogenetic and taxonomic evaluated by 1,000 bootstrap replicates. Distance analysis was per-
relationships in groups oforganisms where the protein-based formedusingtheTajima-Neimodelofevolution andtheneighbour-
techniques ofallozyme electrophoresishave lackedresolution joiningoptionwiththenumberofbootstrapreplicatessetat1,000.The
orproducedambiguousresults(Hillisetal., 1996). mostappropriatemodelofevolutionforthemaximumlikelihood(ML)
analyseswasobtainedviatestingalternativemodesofevolutionusing
Modeltest(PosadaandCrandall, 1998).
Methodsandmaterials
Gadopsissamples.Tissuesampleswereobtainedfromspecimenspre-
Results
viouslycollectedbyRyanetal.(inpress).Sampleselectionwasbased
on the results ofRyan et al. (inpress) togetherwiththree reference Approximately400bpofthemitochondrial 12SrRNAcoding
sitesbasedonprevious studiesbySanger(1984) andOvendenetal. regionweresequencedfor 12individualsofGadopsisfrom 11
(1988). These three sites consisted of the MacDonald River locations. After sequence editing, 290 bp were used for sub-
(Murray-Darlingcatchment,northernG. marmoratus),theGellibrand sequent analysis (GenBank accession numbers: AF505866 -
River (south-west Victoria, southern G. marmoratus) and Cudgewa
Creek(north-eastVictoria,G.bispinosus).Theothersamplesobtained AF505872). The random tree distribution based on the entire
by Ryan et al. (inpress) included specimens ofthe G. marmoratus data set including both the outgroup taxa is significantly
complexfromeightadditionalsites.ThesesitesincludedDarlotCreek, skewedtotheleftwithgl=-0.899,P<0.01, indicating signifi-
BracknellCreek,theWimmeraRiver,andtheWannonRiver.Inaddi- cantphylogeneticinformation(HillisandHuelsenbeck, 1992).
tion DNA sequences were provided by D. Jerry, James Cook Therandomtreedistributionwithinthe ingrouptaxawas also
University,Queensland,forsamplesfromStonyCreek,Victoria,rep- significantlyskewed(gl=-0.686,PcO.Ol).
resentingbothG.bispinosus(GenBankaccessionnumber:AF294459) Percentage sequence divergences and the number of
andG. marmoratusandLittleForesterCreek(Tasmania) alsorepre- nucleotide substitutions among individuals (Table 1) indicate
senting G. marmoratus (AF294452). The remaining specimens were
theexistenceofthreeequallydistinctgroupswithinGadopsis.
fromEightMileCreekandMosquitoCreek(SouthAustralia)(Fig. 1). TheindividualsrepresentingsouthernG.marmoratus(samples
Samples ofMaccullochellapeelipeeli (Murray cod) and Bostockia
porosa (Western Australia nightfish) were included as outgroups 9-12, Table 1) differat 14-18basepositions (5-6% sequence
(sequencesderivedfromGenBank,accessionnumbers:AF295060and divergence) in comparison with northern G. marmoratus
AF295048) individuals (samples 3-8), and 15-16 base positions (5-6%
DNA extraction and amplification of mtDNA. Total DNA was sequence divergence) compared to G. bispinosus (samples 1
extractedfrommuscletissueusinganextractionprotocoldevelopedby and 2). Gadopsis marmoratus (northern) and G. bispinosus
Crandall et al. (1999). Afragment ofthe 12S mtDNAgene region differedat 15-20basepositions (5-7% sequencedivergence).
(approximately 400 bp) was amplified via PCR using the 12S c/d In contrast, comparison between samples within each of
primersdescribedinJerryetal. (2001).DoublestrandedPCRampli- these groups revealed much lower levels of divergence with
fications were performed in 50 ml volumes consisting of: lx PCR G. marmoratus (southern), G. marmoratus (northern) and
Mitochondrialsequencesoffreshwaterblackfish 123
Figure 1.Samplelocations: 1.MosquitoCreek,2.EightMileCreek,3.WimmeraRiver,4.WannonRiver,5.DarlotCreek,6.BracknellCreek,
7.GellibrandRiver,8.StonyCreek,9.CudgewaCreek(G.bispinosus), 10.LittleForesterCreek(Tasmania), 11.MacDonaldRiver(NewSouth
Wales).
G. bispinosus showing differences at 0-1 bp positions search with support for branches evaluated by 100 bootstrap
(0.00-0.03%), 0-8 bp positions (0-3% sequence divergence) replicates and the application of a gamma distribution shape
and 4 bp positions (1% sequence divergence) respectively. parametervalueequalto0.2293andcalculatedbasefrequency
Nevertheless, geographic variation was apparent within the andsubstitutionalratematrixvalues.Thesignificantfeatureof
northernformofG.marmoratus. Blackfishsamplesfromwest- thetreesistheclusteringofGadopsisintothreedistinctclades,
ernVictoriaandsouth-easternSouthAustralia(sites 1-4)differ representingthetwoputativenorthernandsouthernspecies of
by 7-8 base positions from the two samples from the G. marmoratusand G. bispinosus. Thesethreeclades are sup-
Murray-Darling River system (sites 8-11). Variation within ported by high confidence values in each method ofanalysis
eachofthesegroupswasminimalwithhaplotypeseitherbeing (66-100% bootstrap). Especiallynoteworthy is thatthe analy-
identicalordifferingatonlyasinglebaseposition. ses do not necessarily indicate that the northern and southern
The degree of divergence between the outgroup taxa, forms areeachother’sclosestrelative.Whilemaximumparsi-
B. porosa andM. peelipeeli, andblackfish samples was sub- monyandmaximumlikelihoodmethodsindicateanunresolved
stantial ranging between 12 and 16% (34-45 bp differences). trichotomy for the relationship between the three clades, the
This was also similar to the difference between the two out- distanceapproachsuggeststhenorthernG. marmoratusmayin
grouptaxa(10% sequencedivergence) (Fig.2).Themaximum factbemorecloselyrelatedtoG. bispinosusthantothesouth-
parsimony, distance and maximum likelihood methods gave ern G. marmoratus although the bootstrap support for this
,
similartreetopologies.TheTamura-Neimodelwaschosenfor relationship is low. The maximum likelihood and distance
the maximum likelihood analysis, involving a full heuristic analyses also highlight phylogenetic patterns within the
124 A. D. Miller,G.Waggy,S.G. RyanandC. M.Austin
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Mitochondrialsequencesoffreshwaterblackfish 125
WimmeraR(3) WimmeraR(3)
EightMileCk(2) WnnnonR(4)
MosquitoCk(1) MosquitoCk(1)
W
armonR(4) EightMileCk(2)
MacDonaldR(11) MacDonaldR (it)
StonyCk(8) StohyCk(8)
GellihrandR(7) StonyCk(bispinosus)(8)
DarlotCk(5) CudgewaCk(bispinosus)(9)
L.ForesterCk(10) L.ForesterCk(10)
BracknellCk(6) GellihrandR(7)
StonyCk(bispinosus)(8) DarlotCk(5)
CudgewaCk(bispinosus)(9) BracknellCk(6)
B.porosa
B.porosa
M.peelipeeli
M.peelipeeli
MacDonaldR(11)
StonyCk(8)
WimmeraR(3)
EightMileCk(2)
MosquitoCk(1)
WannonR(4)
GellihrandR(7)
DarlotCk(5)
BracknellCk(6)
L,ForesterCk(10)
StonyCk(bispinosus)(8)
CudgewaCk(bispinosus)(9)
M.peelipeeli
B.porosa
Figure2.Phylogenetictrees,usingthePAUPsoftwarepackage(Swofford, 1998).A,Maximumparsimony,usingafullexhaustivesearchwith
1000bootstrapreplicates.B,Distanceanalysis,usingtheneighbour-joiningoption,bootstrapreplicatessetat1000.C,Maximumlikelihood,using
theTamura-Neimodelwith100bootstrapreplicates.
northern form of G. marmoratus. The samples from south- the same way as other data to address issues concerning the
easternSouthAustraliaandwesternVictoria(sites 1-4)forma identification of taxonomic boundaries. Thus, finding that
well supported clade (78-100% bootstrap support) as do the thedegreeofnucleotidedivergencebetweenG. bispinosusand
individuals from Stony CreekandtheMacDonaldRiverfrom thenorthernformofG. marmoratusis similartothatbetween
the Murray-Darling River system (99-100% bootstrap G. bispinosusandthesouthernform(5-7%), andsubstantially
support) (Fig2.) greater than that observed within these groupings (0-3%),
strongly suggests that each represents a distinct taxonomic
entity.
Discussion
Thedegreeofdivergencebetweenthenorthernandsouthern
Thetaxonomicvalueofmoleculargeneticdataiswidelyappre- forms ofG. marmoratus and G. bispinosus is very similar to
ciated (Hillis et al., 1996) and they canbe used in essentially thosereportedbyJerryetal. (2001).Theseauthorsexamineda
126 A. D. Miller,G.Waggy,S.G. RyanandC. M.Austin
560bpfragmentofthe 12Sgeneregionforasingleindividual (22% fixed differences) and between the northern and the
representingeachofthethreegeneticformsofblackfishaspart southern forms of G. marmoratus (11% fixed differences)
of phylogenetic study on Australian members of the family (Ryanetal.,inpress).Itisnoteworthythatwhiletheallozyme
Percichthyidae. It is also noteworthy that Jerry et al. (2001) variation between the northern and southern forms is low
reporteddivergencelevelsofasimilarorsmallermagnitudefor relativetothatbetweenG. marmoratusand G. bispinosus,the
a number of congeneric percichthyid species that are con- extent of these differences are far greater than that detected
sideredgoodbiologicalspecies.Thistogetherwiththefactthat between samples within the northern and southern groupings.
G. bispinosusandG.marmoratusareknowntobehaveasgood Significantly,findingthesamepatternofgeographicallyabrupt
biologicalspeciesbasedontheirmaintenanceofgeneticdiffer- geneticdiscontinuitybetweensamplesofblackfishfromwest-
ences in sympatry (Sanger 1986), suggests that the northern ernVictoriainbothmitochondrial DNAand allozymes (Ryan
and southern forms of G. marmoratus also represent distinct etal.,inpress),providessubstantialsupportfortherecognition
biologicalspecies. of distinct northern and southern species. Further, results
Additionalsupportforthevalidityofnorthernandsouthern reportedby Ovendenet al. (1988) are entirely consistentwith
forms of G. marmoratus as discrete species derives from an the findings ofthis study based upon restriction digest ofthe
examination of intra- and interspecific levels of divergence. wholemitochondrialgenome.
Overall,theintraspecificcomparisonsaveragewas 1.2%,com- An outcome of this study, which was not apparent from
pared with an average of 5.2% divergence for interspecific allozymeanalysesorOvenden’sstudy (1988),isthefindingof
comparisons. The largest intraspecific comparison is 2.8% geographic variation in mitochondrial 12S rRNA sequences
divergencebetween samples ofnorthern G. marmoratus from withinthenorthernformofG. marmoratus.Specifically,based
Eight-MileCreekinSouthAustraliaandtheMacDonaldRiver upon the six samples analysed, it appears that Gadopsis from
inNewSouthWales.Findingthisdegreeofintraspecificdiver- westernVictoriaand south-easternSouthAustralia (sites 1-4)
gence is not surprising given that the samples come from form a monophyletic group distinct from those of the
independentdrainagesover1000kmapart.Conversely,finding Murray-Darling drainage system (sites 8 and 11). While the
that the Wannon River sample differs from the Darlot creek degree ofdivergence amongthesetwo groups is considerably
sample by 14 base positions (6%) and are less than 100 km lessthanthatseen amongthenorthernandsouthern G. maro-
apartstronglysuggeststhateitherabiologicalorgeographical moratusand G. bispinous, they neverthelessrepresentdistinct
barrierhas limitedorcompletelyimpededmigrationofblack- diagnosable lineages. It is noteworthy that Jackson et al.
fish between the two adjacent drainages. Decoupling of (1996),withoutgoingintoanygreatdetailexpressedtheview
geneticdivergenceandgeographicseparationbetweensamples thatblackfishfromsouth-easternSouthAustraliamaypossibly
indicates thatthe twoformsrepresentgoodbiological species be taxonomically distinct, therefore it will be important to
and suggests that if they do come into contact they are investigatethispatternofvariationingreaterdetailanddeter-
unlikelytointerbreed. mine if blackfish from this region may deserve taxonomic
The application of the biological species concept to recognition.
allopatricpopulationshas,however,beenwidelycriticizedand Independent of the consideration of taxonomic status of
is considered a persistent problem for taxonomic studies of Gadopsis spp.,itis apparentthatfourevolutionary significant
freshwater fish (McDowell, 1972). Some authors have called units (Waples, 1995) can be recognised in Victoria. If sup-
forthe abandonmentofthebiological species concept andits portedby additional sampling, eachoftheseunitswillrequire
replacement with lineage or genealogically-based concepts the development of appropriate management strategies ifthe
suchasthephylogeneticspeciesconcept(Claridgeetal., 1997; blackfishbiodiversityistobeconservedandprotected.Inaddi-
Avise and Walker, 1999; Shaw, 2001). An advantage of the tion to loss ofpopulations due to habitat deterioration, trans-
phylogenetic and related species concepts is that they allow locationsassociatedwithaquaculture,stockingofprivatewater
recognition of species in sympatry or allopatry because bodies and the use of Gadopsis as live bait, are factors that
genealogicalrelationshipscanbedeterminedindependentlyof could threaten the integrity of local blackfish stocks. The
geographical status (Shaw, 2001). While there are also oper- genetic hazards oflocal translocations are well illustrated by
ational difficulties in the application oflineage-based species therapidgeneticdisplacementofafreshwatercrayfishspecies
concepts (Avise and Wollenberg, 1997; Sites and Crandall, in the south-west of Western Australia as a result of an
1997), the three distinct clades ofblackfish identified in this inadvertent translocation of a closely related species (Austin
study, via all three methods of phylogenetic analysis, would andRyan,2002).
qualify for recognition as distinct species when applying a Themajordifferencebetweentheresults ofthis andprevi-
lineage-basedspeciesconcept. ousallozymestudiesisthattheallozymedataappeartounder-
Itisunwisetobasethedeterminationofspeciesboundaries estimate the degree of divergence between the northern and
on a single source of information such as mitochondrial southernforms.Infact,therelationshipsamongthethreeputa-
sequences from a single gene region. Support for the taxo- tiveGadopsisspeciesremainanopenquestion.Theparsimony
nomic conclusions of this study comes from studies of and maximum likelihood analyses suggest an unresolved tri-
allozyme and morphological variation (Sanger, 1986; Ryan et chotomy(seealsoOvendenetal., 1988),thedistanceanalysis
al.,inpress)andrestrictiondigestsofthewholemitochondrial suggests that the northern form of G. marmoratus is more
genome (Ovendenet al., 1988).Allozyme dataindicated sub- closelyrelatedto G. bispinosus, although withpoorbootstrap
stantialdifferencesbetweenG. marmoratusandG. bispinosus support, Jerry et al. (2001) supports a closer relationship
Mitochondrialsequencesoffreshwaterblackfish 127
betweenthesouthernformandG.bispinosus,andtheallozyme Gilbert,D.G. 1997.SeqPupsoftware.IndianaUniversity.
data suggests that the northern and southern G. marmoratus Hillis,D.M.,andHuelsenbeck,J.P. 1992.Signal,noise,andreliabili-
species are the most closely related. These inconsistencies ty in molecular phylogenetic analyses. Journal ofHeredity 83:
leave the phylogenetic relationships among these species 189-195
unresolved, and therefore also their possible evolution and Hillis,D.M.,Mable,B.K.,Larson.A.,Davis,S.K.,andZimmer,E.A.
1996. Nucleic acids IV: sequencing andcloning. Pp. 336-339in:
biogeographichistory(Sanger, 1986).
Hillis,D.M.,Moritz,C.,andMable,B.K.(eds),Molecularsystem-
Given the vulnerability of Gadopsis from a conservation
atics(2ndedn).SinauerAssociates:Sunderland.
perspective, the relatively high degree of genetic diversity Jackson, P.D., Koehn, J.D., Lintermans, M., and Sanger,A.C. 1996.
found in this study, and the unresolvedphylogenetic relation- Family Gadopsidae, freshwater blackfishes. Pp. 186-190 in:
ships among the three major Gadopsis lineages, it becomes McDowall, R.M. (ed.), Freshwater fishes of south-eastern
apparentthatfurtherresearchisimportant.Giventherelatively Australia.A.H.andA.W.ReedPublishing:Sydney.
slow evolutionary rate of the mitochondrial 12S rRNA gene Jerry, D.R., Elphinstone, M.S., and Baverstock, P.R. 2001.
region,itissuggestedthatgeneticvariationwithinandbetween Phylogenetic relationships ofAustralian members of the family
Gadopsis populations using more rapidly evolving gene Percichthydae inferred from mitochondrial 12S rRNA sequence
regionsisdeterminedtofullyresolvegeographicalpatternsof data.MolecularPhylogeneticsandEvolution 18(3):335-347
Koehn,J.D.,andO’Connor,W.G. 1990.Biologicalinformationforthe
geneticdiversityinthesetaxonomicallydistinctgroupsandthe
management of native freshwater fish in Victoria. Victorian
phylogenetic relationships among them. Further, the geo- GovernmentPrinter:Melbourne. 165pp.
graphic sampling of Gadopsis for taxonomic and population McDowall,R.M. 1972.Thespeciesprobleminfreshwaterfishesand
genetic analysisneeds tobeexpanded, especially withrespect the taxonomy of diadromous and lacustrine populations of
to populations in the eastern part of Victoria for which our Galaxiiasmaculatus(Jenyns).JournaloftheRoyalSocietyofNew
geneticknowledgeislimited. Zealand2(3):325-367.
Ovenden,J.R., White, R.W.G., and Sanger,A.C. 1988. Evolutionary
Acknowledgments relationships of Gadopsis spp. inferred from restriction enzyme
analysisoftheirmitochondrialDNA. JournalofFishBiology32:
Wethankallthosewhocontributedtothis study.Manythanks 137-148.
to Dr Dean Jerry from James Cook University, Townsville, Posada,D.,andCrandall,K.A. 1998.MODELTEST:testingthemodel
Queensland, for supplying G. bispinosus samples, and Daniel ofDNAsubstitution.Bioinformatics 14: 817-818.
Ierodiaconou from the School of Ecology and Environment, Ryan,S.G.,Miller,A.D.,andAustin,C.M.inpress.Allozymevariation
DeakinUniversity, Warmambool, for GIS support. We would and taxonomy of the river blackfish, Gadopsis marmoratus
also like to thank Dr Christopher P. Burridge from the Richardson,inwesternVictoria.ProceedingsoftheRoyalSociety
ofVictoria.
Molecular Ecology and Biodiversity Laboratory, Deakin Richardson,J. 1848.Ichthyology.In:ZoologyoftheVoyageofH.M.S
University,Warmambool,forhiscontributiontotherevisionof Erebus andTerror, Under the CommandofCapt. SirJ. C. Ross,
thismanuscript, andtotheteamattheMolecularEcologyand R.N. During the Years 1839 to 1843. Longman, Brown and
BiodiversityLaboratoryfortheirassistanceinthefieldandthe Longmans:London.
laboratory. Sanger,A.C. 1984.DescriptionofanewspeciesofGadopsis(Pisces:
Gadopsidae) from Victoria. Proceedings ofthe Royal Society of
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