Table Of ContentB76-2012-19-Dijkstra:Basteria-2010 05/12/2012 20:21 Page 133
A new Recent species of Parvamussium
(Bivalvia, Propeamussiidae) from Easter Island (Pacific, Chile)
Henk H. Dijkstra
NaturalisBiodiversityCenter(NCBNaturalis),P.O.Box9517,
NL-2300RALeiden,TheNetherlands;[email protected]
County,LosAngeles,U.S.A.(formerlyLACM);SBMNH,
Parvamussiumrainesispec.nov.isdescribedfromEaster SantaBarbaraMuseumofNaturalHistory,SantaBarbara,
Island.Itiscomparedwithsomecongenericspeciesfrom California,U.S.A.;ZMA,ZoologicalMuseumAmsterdam,
theIndo-Pacific. Amsterdam[nowpartofNCBNaturalis].
ThetypematerialofParvamussiumrainesispec.nov.is 133
Keywords:Bivalvia,Propeamussiidae,Parvamussium,newspecies, preservedinNCBNaturalis(holotypeandparatypes)and
EasterIsland. NHMLAC(paratypes)withvoucherspecimensinthepri-
vatecollectionofMrBretK.Raines.
Introduction Systematic part
EarlythisyearMrBretK.RainesandDrMarkusHuber PropeamussiidaeAbbott,1954
publishedamonographonthebivalvesfromEasterIsland PropeamussiidaeAbbott,1954:361,369.
andSalasyGómez,inwhichanewparvamussiidspecies
forEasterIslandwasrecordedanddeterminedas“Parva- Remarks.—Foranemendeddescriptionofthisfamilysee
mussiumscitulum(E.A.Smith,1885)”.RecentlyMrBretK. Mikkelsen&Bieler(2008:148).
Raineswassokindtosendmesomespecimensandinmy
opinionthismaterialwaserroneouslydetermined.Infact,it ParvamussiumSacco,1897
isanewParvamussiumspecies,whichisdescribedherein.
Acronymsandabbreviations:BKR,collectionMrBretK. ParvamussiumSacco,1897a:102.Proposedasasubgenusof
Raines,Alamogordo,NewMexico,U.S.A.;IEU,Instituteof AmussiumHerrmannsen,1846(unjustifiedemendationof
EvolutionaryBiologyandEnvironmentalStudies,Univer- AmusiumRöding,1798);nodiagnosisgiven,buttypespecies
sityofZurich,Zurich,Switzerland;NCBNaturalis, designated;Sacco,1897b:48(diagnosis).Typespecies(by
NaturalisBiodiversityCenter,Leiden,TheNetherlands; originaldesignation):Pecten(Pleuronectes)duodecimlamellatus
NHMLAC,NaturalHistoryMuseumofLosAngeles Bronn,1832;UpperMiocene,northernItaly.
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Figs1-6.Parvamussiumrainesispec.nov.,Chile,EasterIsland,offthewesterncoastlinenearTahai,27˚07’20”S,109˚26’30”W,50-80m,dead,dredged,
xii.2000.1-2,5,holotype(lv),ZMAMoll.365560,height5.2mm,width5.7mm;1,exterior;2,interior;5,closeupradialandcommarginalsculpturecen-
tralarea.3-4,6,paratype(rv),ZMAMoll.365561,height4.6mm,width4.9mm;3,exterior;4,interior;6,closeupcommarginallamellaecentralarea.
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135
Figs7-12.Parvamussiumscitulum(Smith,1885),Indonesia,EofKomodoIsland,SlawiBay,8˚36.8’S,119˚30.7’E,65m,dead,vanVeengrab,17.09.1984
(Snellius-IIstn4.075).7-8,11,lv,ZMAMoll.144629,height6.0mm,width6.1mm;7,exterior;8,interior;11,radialsculpturecentralarea.9-10,12,rv,
ZMAMoll.144629,height5.2mm,width5.0mm;9,exterior;10,interior;12,smoothcentralarea.
Dijkstra,H.H.–AnewrecentspeciesofParvamussium
B76-2012-19-Dijkstra:Basteria-2010 05/12/2012 20:21 Page 136
Remarks.—Forsynonymy,diagnosis,distributionanddis- inheight,paratypesNCBNaturalis2to5.9mminheight,
cussion,seeDijkstra(1995:25). paratypesNHMLAC2to5.8mminheight.
Parvamussiumrainesispec.nov.(Figs1-6) Distribution.—EasterIsland,50-150m,finesandorsand
andrubble.Sofaronlysinglevalveshavebeensampled.It
Parvamussiumscitulum(E.A.Smith);Raines&Huber,2012:33, ismostlikelythatthepresentspeciesislivingsomewhat
fig.16A-E.NotAmussiumscitulumE.A.Smith(1885:312,pl.23figs deeper.
4,4a-b).
Comparison.—InarecentpublicationontheMolluscafrom
Materialexamined.—Chile:EasterIsland,offthewestern EasterIslandandSalasyGómez,Raines&Huber(2012:33)
coastlinenearTahai,27˚07’20”S,109˚26’30”W,50-80m,dead, incorrectlydeterminedthepresentspeciesasParvamussium
dredged,leg.B.K.Raines,xii.2000(lv,holotype,ZMAMoll. scitulum(E.A.Smith,1885).Itisanundescribedspecies.
365560;rv,figuredparatype,ZMAMoll.365561;28v, Parvamussiumscitulumisrecordedfromthe(sub)tropical
paratypesZMAMoll.365562;10v,paratypes,LACM3229); Indo-WestPacific,livingat50-300m(Dijkstra&Maestrati,
offthesouthwesterncoastnearOrongo,27˚11’58”S, 2008:94).ThetrueP.scitulum(Poppe,2011:42,pl.1016figs
109˚29’28”W,100-150m,dead,dredgedinfinesand,leg. 5-8)differsmorphologicallyfromthepresentspeciesinits
B.K.Raines,xi.2002(20v,paratypes,LACM3228). largersize,reachinguptoc.10mminheight(P.rainesispec.
Othermaterialexamined.—MataveriBay,27˚08’44”S, nov.reachesuptoc.6mm),inhavingverydelicate,closely
109˚26’46”W,80-120m,dead,dredgedinsandandrubble, spacedradialliraeontheleftvalve(P.rainesihaswidely
leg.B.K.Raines,xi.2002(10v,collectionMrB.K.Raines). spacedscalyradialriblets),andinhavingasmoothorvery
weaklyandcloselyspaced,commarginallysculptureddisc
136 Description.—Shelluptoc.6mmhigh,fragile,semi-trans- oftherightvalve(P.rainesihasprominent,widelyspaced
parent,almostcircular,inequivalve,nearlyequilateral,left commarginallirae).SimilarspeciesarecomparedinTable1.
valveveryweaklyinflated,rightvalvestronglyinflated,au- Parvamussiumrainesiissomewhatsimilarinshapeand
riclesunequalinsizeandshape,umbonalanglec.90˚,inter- sculpturetoP.cristatellum(Dautzenberg&Bavay,1912)
nalriblets10plus1-2rudimentaryorlacking,leftvalve (Poppe,2011:40,pl.1015figs2-3),recordedfromthetropi-
brightlymottled,rightvalvewhitish,dullortransparent calIndo-WestPacific,livingin194-510m(Dijkstra&Maes-
glossy.Prodissoconchc.200µmlong,smooth. trati2008:87),butdiffersinhavingbetterdeveloped,
Leftvalvesculpturedwithnumerousunevenlyspaced prominent,radialandmorecloselyspacedcommarginal
radialriblets,increasinginnumbertowardsventralmargin, sculptureontheleftvalve(P.rainesihasfewer,lesspromi-
anddelicatecommarginallamellae,intercostalandonthe nentradialribletsandmorewidelyspaced,moredelicate
radialriblets,morecloselyspacedneartheventralmargin commarginallamellae,whicharelackinginsomespeci-
thanelsewhere.Bothauricleswithcommarginallamellae, mens).Moreover,thecommarginalsculptureoftheright
moreprominentandmorewidelyspacedontheanterior valveofP.cristatellumismorecloselyspacedthaninP.
thanontheposteriorauricle.Hingelinestraight. rainesi.
Rightvalvewithwidelyspacedcommarginallirae,so- ParvamussiumrainesiismorphologicallyclosesttoP.
mewhatmorenarrowlyspacedinlategrowthstagethan squalidulumDijkstra,1995,recordedfromthesouthwestern
earlier.Anteriorauriclewithdelicate,closelyspacedcom- Pacific,livingin260-523m(Dijkstra,1995:32,figs47-50;
marginallirae,posteriorauriclewithdelicatecloselyspaced Dijkstra&Maestrati2008:94),butP.squalidulumdiffers
commarginallamellae. mainlyinreachingamuchlargersize,uptoc.14mmin
Dimensionsoftypematerial:Holotype(NCBNaturalis) height(P.rainesiuptoc.6mm),inhavingsomewhatcoarser
5.2mminheight,figuredparatype(NCBNaturalis)4.6mm andmorestronglydevelopedradialandcommarginal
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P.rainesi P.scitulum P.cristatellum P.squalidulum
height uptoc.6mm uptoc.10mm uptoc.10mm uptoc.14mm
shape circular subcircular subcircular subcircular
convexitylv veryweaklyinflated veryweaklyinflated weaklyinflated veryweaklyinflated
convexityrv stronglyinflated moderatelyinflated moderatelyinflated moderatelyinflated
radialsculpturelv c.3permm c.6permm c.1-2permm c.3permm
incentralpart incentralpart incentralpart incentralpart
commarginalsculpturelv weak,widelyspaced absentor weaknarrowly weak,widelyspaced
weaknarrowspaced towidelyspaced
commarginalsculpturerv prominent,widelyspaced absentorweak,narrow prominent,narrowspaced weak,widelyspaced
spaced
colour brightlymo7ledlv mo7ledlv mo7ledlv brightlymo7ledlv
whitishrv whitishrv whitishrv whitishrv
Table1.Comparedmorphologicalcharacters.
sculptureontheleftvalve,inhavingamoreweaklyinflated References
rightvalve(P.rainesihasastronglyconvexrightvalve,and
inhavingmoreprominentcommarginallamellarsculpture Abbott,R.T.,1954.Americanseashells:i-xiv,1-541.NewYork.
ontheanteriorauricleoftherightvalve(P.rainesihasmore Dautzenberg,P.&Bavay,A.,1912.Leslamellibranchesdel’expédition 137
closelyspaced,moredelicatelamellae)andinhavingmore du“Siboga”.PartieSystématique.I.Pectinidés.In:M.WEBER,ed.,
irregularlyspacedinternalriblets(ribletsequallyspaced Résultatsdesexplorationszoologiques,botaniques,océanogra-
anddevelopedinP.rainesi). phiquesetgéologiquesentreprisesauxIndesNéerlandaisesOrien-
talesen1899-1900,àbordduSiboga[…].Monographie53b:1-41.
Etymology.—NamedafterBretK.Raines,researchassoci- Leiden.
ateattheNaturalHistoryMuseumofLosAngelesCounty, Dijkstra,H.H.,1995.BathyalPectinoidea(Bivalvia:Propeamussiidae,
whoachievedhisresearchtripstoEasterIslandintheyears Entoliidae,Pectinidae)fromNewCaledoniaandadjacentareas.In:
1998,2000and2002tosamplemarinemolluscs,including P.BOUCHET,ed.,RésultatsdesCampagnesMUSORSTOM,14.—
thepresentparvamussiidspecimens,bydivinganddred- MémoiresduMuséumnationald’Histoirenaturelle167(Zoologie):
ging. 9-73.
Acknowledgements Mikkelsen,P.M.&Bieler,R.,2008.SeashellsofsouthernFlorida:living
marinemollusksoftheFloridaKeysandadjacentregions.Bivalves:
IammuchindebtedtoMrBretK.Raines(NHMLAC)for i-viii,1-503.Princeton.
providingthepresentmaterialforstudypurposes.Iamalso Poppe,G.T.,2011.Philippinemarinemollusks4.Bivalvia2:1-676,pls1-
gratefultoDrAlanBeu(GNS)forhisvaluablesuggestions 1315.Hackenheim.
andcorrectionsofthetext.ThanksarealsoduetoDrDaniel Raines,B.K.&Huber,M.,2012.Biodiversityquadrupled-Revisionof
Geiger(SBMNH)forprovidingtheSEMmicrographsandto EasterIslandandSalasyGómezbivalves.—Zootaxa3217:1-106.
MrBretK.Rainesforproducingthecolourimages.DrBas Sacco,F.,1897a.ImolluschideiterreniterziariidelPiemonteedella
Kokshoorn(NCBNaturalis)isacknowledgedformounting Liguria.Part24.BollettinodeiMuseidiZoologiaedAnatomiacom-
theplates. paratadellaRealeUniversitadiTorino12(298):101-102.
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Sacco,F.,1897b.ImolluschideiterreniterziariidelPiemonteedella Challengerduringtheyears1873-76.In:ReportoftheScientificRe-
Liguria.Part24(Pectinidae):1-116,pls1-21.Torino. sultsoftheVoyageofH.M.S.“Challenger“duringtheyears1873-76
Smith,E.A.,1885.ReportontheLamellibranchiatacollectedbyH.M.S. […].Zoology13(35)1-341.London.
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