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Acanthochondria serrani sp. n. (Copepoda: Chondracanthidae) parasitic on Serranus auriga (Perciformes: Serranidae) from Argentinean waters

Paola E. Braicovich1,2 and Juan T. Timi1,2

1 Laboratorio de Parasitología, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata, Argentina;

2ConsejoNacionaldeInvestigacionesCientíficasyTécnicas(CONICET)

Abstract: A new species of AcanthochondriaOakley,1927(Copepoda,Poecilostomatoida,Chondracanthidae),parasiticonSer-ranus auriga(Cuvier)fromtheArgentineancoastalzone,isdescribedandillustrated.Thenewspeciesdiffersfromitscongenersbytherelativelengthoftheneckandtheprotopodofleg2.ThisisthesecondrecordofthisgenusfortheSouth-easternAtlanticandthefirstonefromaserranidhost.

Key words:parasiticcopepods,marinefish,systematics,Argentina

FOlIAPArASITOlOgICA56[4]:313–316,2009ISSN0015-5683(print),ISSN1803-6465(online)

©InstituteofParasitology,BiologyCentreASCrhttp://www.paru.cas.cz/folia/

Addressforcorrespondence:P.E.Braicovich,laboratoriodeParasitología,FacultaddeCienciasExactasyNaturales,UniversidadNacionaldeMardelPlata,Funes3350,(7600)MardelPlata,Argentina.Phone:+540223475-4060;Fax:+540223475-3150;E–mail:braicovi@mdp.edu.ar

AcanthochondriaOakley,1927isthelargestgenusofthefamilyChondracanthidaeEdwards,1840(Østergaardetal.2003).Thelatestreviewwithakeyto43validspe-ciesofthisgenuswasgivenbyHoandKim(1995).Fouradditional species were later described, A. kajikaHo etKim,1996,A. zebriaeHo,KimetKumar,2000,A. hoi Kalman,2003,andA. triangularis Alves, Luque et Para-guassú,2003;thelatterisatpresentthesolespeciesre-cordedintheSouth-westernAtlantic(HoandKim1996,Hoetal.2000,Alvesetal.2003,Kalman2003).

As result of a parasitological study, a new species of AcanthochondriawasfoundinthemarinebenthopelagicfishSerranus auriga(Cuvier)fromArgentineanwaters.

MATERIALS AND METHODSAtotalof89specimensofS. auriga, capturedoff theMar

delPlatacoast(38°08'S,57°32'W),wereexaminedforparasiticcopepods. The parasites were removed from branchial cham-bers, fixed, and stored in 70% ethanol; the appendages weredissected,clearedinlacticacid,andexaminedunderalightmi-croscope.Illustrationsweremadeusingadrawingtube.Meas-urementsaregivenas themean, followedby the range inpa-rentheses.Allmeasurementsareinmillimetres.ThecriteriaforidentifyingthenewspeciesfollowHoandKim(1995).

RESULTS Acanthochondria serrani sp.n. Figs.1–26

Female (Figs.1–15): Measurementsbasedon5speci-mens.Bodywithslenderhead,elongateneck,andstout

trunk.Totallength5.03(4.74–5.21)(fromanteriorborderof head, excluding antennules, to tip of posterior proc-esses).Headdevoidofprocesses,longerthanwide,0.90(0.87–0.93)longand0.69(0.65–0.71)wide,andbearingmedianlongitudinalsclerotizedbar.Slenderneckregionformedbyfirst and secondpedigerous somites,5 timeslongerthanwide.Trunkstout,constrictedataboutmid-length,1.85(1.50–2.11)longand1.54(1.33–1.90)wideand extended postero-laterally, forming two lobes, par-allel togenito-abdomen (Figs.1–3);posteriorprocessesextendingbeyonddistal limitofgenito-abdomen.geni-tal complex conical, attached to postero-dorsal surfaceof trunk.Abdomen globular, small, broadly fused withgenitalcomplex,carryingpairofdorsalsetules(Fig.4).Caudalramuswithspinulatedtip,probablyrepresentingfusedcaudalseta,andarmedwith3setae(1dorsaland2ventral)(Fig.5).Eggsacscylindrical,multiseriate,1.95(1.71–2.17)longand0.68(0.47–0.87)wide.

Antennulecylindrical,with2ventralspinesonanteriormarginand3subterminalsetaeandtippedwith8nakedsetae(5longand3short)andsmallknob(Fig.6).Antenna2-segmented,terminalsegmentresemblingrecurvedhookwithstriatedringnearmid-length,withoutaccessoryan-tennule(Fig.7).labrumwithfinespinulesonposteriormargin(Fig.8).Terminalbladeofmandiblewith22–24teethonconvexsideand20–23smallerteethonconcaveside(Fig.9).Paragnathasmallfleshylobearmeddistallywithspinules(Fig.10).Maxilluleresemblingsmalllobetippedwith2unequalsetae(Fig.11).Maxilla2-segment-

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Figs. 1–15. Acanthochondria serranisp.n.,female.Fig. 1.Habitus,ventralview.Fig. 2. Habitus,dorsalview.Fig. 3. Habitus,lat-eralview.Fig. 4. genito-abdomen,ventralview.Fig. 5.Caudalramus,ventralview.Fig. 6.Antennule.Fig. 7. Antenna.Fig. 8. La-brum.Fig. 9.Mandible.Fig. 10.Paragnath.Fig. 11.Maxillule.Fig. 12. Maxilla.Fig. 13. Maxilliped.Fig. 14.leg1.Fig. 15. Leg 2.Scalebars:Figs.1–3=1mm;Fig.4=0.25mm;Fig.5=0.03mm;Figs.6,14,15=0.01mm;Figs.7,9,11–13=0.05mm;Figs.8,10=0.025mm.

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ed, first segment robust and unarmed, second segmentarmedwith2setaeatbasalportion(onelargeandothersmall)andwithrowof9teethoninneredgeofterminalprocess(Fig.12).Maxilliped3-segmented,firstsegmentrobust and unarmed, second segmentwith lobate distalendbearingrowsofspinulesoninneredge,terminalseg-mentsmall,claw-likewithdenticleatdistalthirdofcon-caveside(Fig.13).Twopairsofbiramouslegspresent.leg1short,bilobed,situatedonneck,shortdistance tohead,protopodbearingouterseta;exopodlargerthanen-dopod;bothwithterminalpatchesofspinules(Fig.14).leg2withshorterbasalportion,andendingin2roundedlobes; protopodwith small outer seta, carrying rows ofspinules,exopodlongerthanendopod;bothwithterminalspinules(Fig.15).legs1and2similarinlength.

Male(Figs.16–26): Measurementsbasedon5speci-mens.Body0.50(0.47–0.52)longand0.22(0.20–0.25)wide; cephalothorax comprisingmore thanhalf of totalbody length; metamerism of body indistinct (Fig. 16).Main body flexure located between second pedigeroussomiteandgenito-abdomen.genitalcomplexwithpairofventralridgesmarkingmarginsofpairedgenitalapertures(Fig.17).Abdomenbroadlyfusedwithgenitalsomiteandindistinct.Caudalramuspilose,armedwith3nakedsetae(1dorsalatbaseand2ventro-lateral).

Antennulesmall,with3lateralshortsetae,1subtermi-nallongsetaandtippedwith6setae(4longand2short)

(Fig.18).Antenna2-segmented,robustterminalsegmentuncinatewithoutaccessoryantennule(Fig.19).labrumwithdenticlesalongposteriormargin(Fig.20).Terminalbladeofmandiblewith 11 teeth along convex side and4–5smallerteethonconcaveside(Fig.21).Maxilluleinformofnaked small lobebearing2 elements (Fig. 22).Maxilla2-segmented,firstsegmentrobustandunarmed,second segment armed with 2 setae (1 large and othersmall)atbasalportion,andterminalprocesswithoutteeth(Fig. 23).Maxilliped 3-segmented, first segment robustandunarmed,secondsegmentwithlobatedistalendbear-ingspinulesoninneredge,terminalsegmentasmallclawwithdenticleonconcaveside(Fig.24).Twopairsofre-ducedbiramouslegspresent,bothlobate;leg1(Fig.25)withprotopodbearing1outerseta.Exopodlobate,bear-ing1terminalseta;smallendopodconicalandunarmed.leg2(Fig.26)smallerthanleg1,withprotopodbearing1outerseta.Exopodtippedwith1seta.Ty p e h o s t : Serranus auriga(Cuvier,1829)(Actinopterygii,

Serranidae).Ty p e l o c a l i t y : Mar del Plata coastal zone (38°08'S,

57°32'W),Argentina.D a t e o f c o l l e c t i o n : May–JulyandOctober2007;Janu-

aryandMarch–June2008.S i t e o f i n f e c t i o n : Innersideofoperculum.P r e v a l e n c e : 19%(17fishinfectedof89examined).M e a n i n t e n s i t y : 1.2.

Figs. 16–26. Acanthochondria serrani sp. n., male. Fig. 16. Habitus, lateral view. Fig. 17. genito-abdomen, ventral view.Fig. 18. Antennule.Fig. 19. Antenna.Fig. 20. labrum.Fig. 21. Mandible.Fig. 22. Maxillule.Fig. 23.Maxilla.Fig. 24.Maxilliped.Fig. 25.leg1.Fig. 26.leg2.Scalebars:Figs.16,17,19,24=0.05mm;Figs.18,20,22,23=0.03mm;Figs.21,25,26=0.01mm.

Braicovich,Timi:NewspeciesofAcanthochondria

16 17 18

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20 2122

23 24

25 26

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Alves D.R., luque J.l., PARAguAssú A.R. 2003: Acanthochon-dria triangularis sp.nov.(Copepoda,Poecilostomatoida,Chon-dracanthidae) parasitic onUrophycis brasiliensis and U. mys-taceus (Osteichthyes, Phycidae) from the Southern Braziliancoastalzone.ActaParasitol.48:19–23.

DoJiRi M., Ho J.s. 1988:TwospeciesofAcanthochondria (Cope-poda:Poecilostomatoida)parasiticonfishesofJapan.rep.SadoMar.Biol.Stn.NiigataUniv.18:47–56.

Ho J.s. 1970: revision of the genera of the Chondracanthidae,a copepod family parasitic on marine fishes. Beaufortia 229:105–218.

Ho J.s., KiM i.H. 1995:Acanthochondria (Copepoda:Chondra-canthidae)parasiticonfishesofSadoIslandintheSeaofJapan,

with a preliminary reviewof thegenus.rep.SadoMar.Biol.Stn.NiigataUniv.25:45–67.

Ho J.s., KiM i.H. 1996:CopepodsparasiticonfishesofWesternNorthPacific.Publ.SetoMar.Biol.lab.37:275–303.

Ho J.s., KiM i.H., KuMAR A.B. 2000:ChondracanthidcopepodsparasiticonflatfishesofKerala,India.J.Nat.Hist.34:709–736.

KAlMAn J.e. 2003: Acanthochondria hoi, a new species of parasitic copepod(Poecilostomatoida:Chondracanthidae)ontheCalifor-niahalibut,Paralichthys californicus fromSantaMonicaBay,California,withanamendedkeytothegenusAcanthochondria.Proc.Biol.Soc.Wash.116:811–819.

ØsteRgAARD P., BoxsHAll g.A., quicKe D.l.J. 2003:Phylogenywithin the Chondracanthidae (Poecilostomatoida, Copepoda).Zool.Scr.32:299–319.

M a t e r i a l d e p o s i t e d : Holotype No. 26.209 (female),allotypeNo.26.210 (male), andparatypes (2 femaleseachwithattachedmale)No.26.211aredeposited in theCarci-nological Collection of theMuseo de la Plata (CHMlP),laPlata,Argentina.TwoadditionalparatypesaredepositedintheInstituteofParasitology,AcademyofSciencesoftheCzech republic, České Budějovice, Czech republic (Cat.No.Cr-10).

E t y m o l o g y : Thespecificnameisderivedfromthegenericnameofthefishhost,Serranus auriga.

Remarks. Byhavingtheneckregionlongerthanwideandconsistingoffirstandsecondpedigers,femaleofthenewspeciescanbedistinguishedfrommostcongenersin-cludedinthekeyprovidedbyHoandKim(1995).Twooftheremainingspecies,A. diastemaHoetDojiri,1988andA. uranoscopiHoetKim,1995,haveavery longneck(at least 8 times longer thanwide),whereas thosewithamoderatelylongneck,A. tchangiYü,1935,A. platyc-ephali Heegaard, 1940 andA. inimiciYamaguti, 1939, differfromthenewspeciesbyhavingleg2withanex-tremelylongprotopod(TypeEsensuHoandKim1995)(HoandKim1995).Among the speciesdescribedafterHoandKim(1995),bothA. zebriae and A. kajikahavetheneckregionwiderthanlongandconsistingoffirstpe-diger only in A. zebriae,whereasitincludesanarrowfirst

pedigerandamuchwidersecondpedigerinA. kajika (HoandKim1996,Hoetal.2000). Acanthochondria trian-gularis differsfromthenewspeciesbyhavingleg2withanextremelylongprotopod(TypeEsensuHoandKim1995)(HoandKim1995,Alvesetal.2003)andA. hoi differsfromthenewspecies,aswellasfromallitscon-geners,bythecombinationofaTypeB-VantennuleandTypeAleg2(Kalman2003).

Maleofthenewspeciesshowsthecharacteristicfea-turesofthegenus,whichdonotshowspeciesdifferences(Ho 1970), the exception being A. zebriae, with leg 2missingandleg1reducedtoaspiniformseta(Hoetal.2000).

On the basis of the differences listed above, a newspecies, Acanthochondria serrani, isproposed.Thisdis-coveryrepresentsthesecondrecordofthisgenusfortheSouth-easternAtlantic and thefirst one froma serranidhost.

Acknowledgements. The authors wish to thankMr. robertoMazellaandMr.HugoMazellafromthefishmarketAlbatros,Mar del Plata, for kindly providingfish samples.The presentstudy was funded by grants from CONICET (PIP No. 112-200801-0024),ANPCYT (PICT No. 02199) and UniversidadNacionaldeMardelPlata(EXA442/08).

received 1October 2009 Accepted 16November 2009

REFERENCES