Acutiserolis poorei sp. nov. from the Amundsen and Bellingshausen Seas, Southern Ocean (Crustacea, Isopoda, Serolidae)

2009·4.5 MB·English

by  Angelika Brandt

MemoirsofMuseumVictoria66: 17-24(2009)
ISSN 1447-2546(Print) 1447-2554(On-line)
http://museumvictoria.com.au/About/Books-and-Journals/Journals/Memoirs-of-Museum-Victoria
Acutiserolispoorei sp. nov. from the Amundsen and Bellingshausen Seas, Southern
Ocean (Crustacea, Isopoda, Serolidae)
AngelikaBrandt
Angelika Brandt, Zoological Museum of the University of Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg,
Germany([email protected])
Abstract Brandt,A.2009.Acutiserolispooreisp.nov.fromtheAmundsenandBellingshausenSeas,SouthernOcean(Crustacea,
Isopoda,Serolidae).MemoirsofMuseumVictoria66: 17-24.
Acutiserolispooreisp.nov.,isdescribedfromtheAmundsenandBellingshausenSeas,SouthernOcean.Comparison
withthetypematerialofthemostsimilarspecies,Acutiserolisspinosa(Kussakin, 1967)revealedthatA.pooreimaybe
distinguishedfromA.spinosabybroadereyes,lessacuteandslightlyshortercoxalplatesandthesmalltuberclesthatare
irregularlyscatteredonthedorsalsurface.Additionally,nosuturedividesthefifthcoxalplateandtheheadhasaprominent
mediocaudalspinereachingtothemiddleofthethirdpereonite;theappendixmasculinaisconsiderablyshorterthanthat
ofA.spinosa,whilethepleotelsonofA.pooreiiscoveredwithsomesmalltuberclesandthemediocaudaltipisslightly
moreprominentthanthatofA.spinosa.
Keywords taxonomy,Isopoda,Serolidae,newspecies,Acutiserolispoorei.SouthernOcean
Introduction Abbreviationsusedintextandfigures:
The first significant change from the simplistic serolid Al, 2—antennula, antenna; Hy,—hypopharynx; lMd, rMd,—
taxonomy was the establishment of several new genera by left and right mandible; Mp,—mandibular palp; Mxl,
Brandt(1988) includingAcutiserolis. Thiswasrecentlyrevised 2,—maxillula, maxilla; Mxp,—maxilliped; PI-7,—pereopods
by Poore & Storey (2009) and Cuspidoserolis Brandt, 1988 1-7;Plpl-5,—pleopods 1-5;urp,—uropods
synonymisedwithAcutiserolis.Poore&Storey(2009)presented
Taxonomy
anupdatedandextensivegenericdiagnosis.
A new species has been sampled in the Amundsen and
SphaeromatideaWagele, 1989
Bellingshausen Seas, faunistically ayetunknown area ofthe
SouthernOcean,fromonboardoftheBritishRVJamesClarke
SerolidaeDana, 1853
Ross. Itisdescribedinthepresentpaper.
GenusAcutiserolisBrandt, 1988
Materialandmethods
DuringtheBIOPEARLII(Biodiversity.Phytogeny,Evolution 2009A:cu2t-i9s.erolisBrandt, 1988: 21; 1991: 131, 139.— Poore& Storey,
and Adaptive Radiation of Life in Antarctica) expedition in Cuspidoserolis Brandt, 1988: 23-24.— Brandt, 1991: 131,
2008 with RV James Clarke Ross (JR 179, for location data 138-139—.Wagele, 1994:52,59-60.
see Kaiser et ah, 2009), megabenthic faunafromthe shelfof Serolis {Acutiserolis). -Wagele, 1994: 53, 60. Not Acutiserolis.
theAmundsenandBellingshausenSeaswassampledusingan -Poore & Brandt, 1997: 152-160 (= Brucerolis Poore & Storey,
Agassiztrawlfittedwithanetofmeshsize1cm.Allspecimens 2009).
ofthe species describedhere camefrom approximately 1500 Typespecies.Acutiserolisspinosa(Kussakin, 1967)(Brandt, 1988by
mdepth. originaldesignation).
The sampled fauna was fixed in 96% ethanol. In the Generic remarks. The genus diagnosis ofAcutiserolis Brandt,
laboratory, megabenthic isopods of the BIOPEARL 2 1988 had been referred to by Poore and Brandt in 1997 and
expedition were kept in ethanol permanently and dissected, recently been revised by Poore and Storey (2009) who have
identifiedandillustratedusingaLeicaMZ12stereomicroscope designated Cuspidoserolis to be a junior synonym of
equippedwithacameralucida. Acutiserolis. As Poore and Storey provided a very extensive
18 A. Brandt
genericdiagnosisofAcutiserolis,theirconceptisfollowedhere about twice as long as first one, third one longest, first and
exceptforthefactthatpereonite6is dorsallynotfusedwith7 secondarticlewithsmallfeather-likeseta.47flagellararticles;
andpleonite 1 becauseinA.pooreiatleastasuturelineofthe first flagellararticle longest. From flagellararticles 15 to last
segmentisclearlyvisible. but one article one aestetasc each and 1-3 long simple setae.
Last flagellar article without aesthetasc, but with 6 simple
Acutiserolispooreisp.nov. (figs. 1-4) setaeandonefeather-likeseta.
Holotype.Femaleof24mmlength,13.03.2008,RVJamesClarkeRoss, A2 of paratype female (fig. 2) with 19 flagellar articles.
AmundsenSea,PineIslandBayslope,71°15'S 109°98'E, 1515-1530m Firstpedunculararticlevery short; secondpedunculararticle
depth,ZMH-K42212. slightly longerthanthirdwithoutsetae; thirdarticlewithfew
Paratypes.maleof28mmlength,femaleof22mmlength(laterally mediodistalandlateralshortsetules;fourthpedunculararticle
partlydamaged),andfemale(damagedafterpereonite3,anteriorpart little shorter than fifth, but slightly broader, with several
only),27.02.2006,RVJamesClarkeRoss,BellingshausenSea,northwest longitudinal rows of groups of 5-7 simple setae; fifth
of Alexander Island, 68°38'S 75° 87'E, 1469-1497 m depth peduncular article also with groups of setae. All 20 flagellar
ZMH-K-42213;femaleof24mmlength,twoMancaIIof19mmeach, articles with groups of 1-4 distolateral simple setae and one
13.03.2008, RVJames ClarkeRoss,Amundsen Sea, Pine Island Bay onopposite side.
slope,71°15'S 109°97'E,1515-1530mdepth,ZMH-K-42214. P2 ofparatypefemale (fig. 2) basis bearing threefeather-
Diagnosis. Head with long mediocaudal acuminating spine like setae, and long ischium with only distal simple setae.
reaching mid of third pereonite in dorsal view. Eyes 0.3 as Merus 0.5 of ischium and 0.9 of carpus, carpus with some
broad as long, dorsal side ofbody with scatteredtubercles on ventral simple setae and some distodorsal ones. Propodus
allpereonites,pleonitesandpleotelson.Tipsofcoxalplatesnot proximally as broad as distally. Ventrallythe propodus bears
quiteasacute,butshorterandlesscurvedcoxalplateslaterally rows oflong simple setae. Dactylus 0.4 as long as propodus,
totheirpereomers. Thecoxal plates weredirectedcaudallyto withshortdorsal setules,ashortandsmall claw.
alargerextentthaninthetype species. Pereonites 6and7not Additionaldescriptionofparatypemale(figs 1-4).
fused mediodorsally or medioventrally. Uropods inserted Mandibles ofparatype male (fig. 2): Pars incisiva ofrMd
withinproximolateralcaudallydirectednotch(smallerandless narrower than of left. Lacinia mobilis of rMd much smaller
distinct than in the type species). Male appendix masculina andnarrowerthan pars incisiva, onetooth accompaniedby a
twice as long as endopodite (possibly the male is subadult). small, similarly long blunt, spine-like structure, pars molaris
Pleotelson covered with some small spine-like tubercles and lacking. First palp article as broad as second, second one
caudally rounded, mediocaudal tip is slightly acute (slightly longest (slightly longer than first), with a distolateral row of
morethanthatofA.spinosa). more than 27 spines. Last article shortest and laterally bent,
with a ventral row of smooth spines (detail in fig. 2). Pars
Distribution.AmundsenSeaandBellingshausenSea. incisiva of lMd (fig. 2) 1.2 as broad as of rMd, with broad
Etymology. Named afterGary Poore, who loves to workwith cutting surfaceandone shallowincision,laciniamobilis with
Serolidae and related species. Besides being a very good onebroadsurfaceandaccompaniedbyasinglespine(rudiment
isopodologistheisaverygoodfriend. ofthespinerow),parsmolarisabsent.
Lateral endite of Mxl of paratype male (fig. 2) distally
Description of female holotype (fig. 1) and paratype (fig. 2): curved medially, apically with 10 strong cuticularized teeth.
Anterolateral angles ofhead slightly elongatelaterally (fig. 1); Medialenditesmallrudiment,withoneshortapical seta.
head frontally slightly narrower than mediocaudally. Two Mx2 of paratype male (fig. 2): Inner endite with many
shallow rounded elevations on head, sculptured by small slendersetae,medianenditewithtwolong setae, outerendite
concave and small convex structures, a mediocaudal spine also with two long setae: setae of median and outer endite
reaching mid of third pereonite. Body surface irregularly setulatedattips(detailinfig. 2).
covered with tubercles (only illustrated on pleotelson). Sixth Mxp of paratype male (fig. 2) with large quadrangular
coxalplatelongest, slightlylessthanhalfaslongasthelength epipodite, strong endite, 1.3 as long as epipodite. Endite
oftheanimal,measuredfromheadtopleotelson.Theepimera apicallywithtwostrongspines,nocouplinghookspresent,but
ofthesecondandthirdpleonitesdonotreachasfarbackasthe mediolateralsurfaceofenditecoveredwithsimplesetulesand
apex of the sixth coxal plate, and also do not surpass the setae. Palpusual.
pleotelson(theyreachabouttwothirds ofpleotelsoniclength), PI of paratype male (fig. 3): Basis to merus without any
firstpleonitewithslightlylongerepimerathansecond.Pereonite spines or setae, carpus with two strong sensory spines.
7 small, without coxal plates. Pereonites 2-4, and 7 with Mediolateralsurfaceofpropoduswithonelongrowofsensory
caudolateral small spines, strongest and most pronounced in spines,the sensory setadividesthe spinedistally.Alternating
pereonite 7, pleonites 2 and 3 also with caudolateral small tothesesensory spines shorterandbroaderonesoccur,which
spines. Pleotelson with one long elevated medial keel and are densely covered with small setules andwhich also beara
proximolateral triangular elevations on each side ofthis keel, sensory setawithadistalpore. Dactyluswith small and short
tips caudally directed. Pleotelson with two small shallow dactylarclaw.
frontolateralspinesandsmallspinesandtuberclesscatteredon P2 ofparatype male (fig. 3) with long basis and ischium,
dorsal surface.Tipofpleotelsonslightlyacuminating(fig. 1). ischiumwithfewsimplesetae.Merusandcarpusaboutsubequal
A1 ofparatype female (fig. 2): second peduncular article inlengthwith someventral simple setae and some distodorsal
Acutiserolispooreisp.nov.fromtheAmundsenand BellingshausenSeas,SouthernOcean(Crustacea, Isopoda,Serolidae) 19
Figure1.Acutiserolispooreisp.nov.,holotypefemaleindorsal(A)andlateral(B)view,pleotelsonofparatypemale(C)andventralpartofparatype
male(D).
20 A. Brandt
Figure2Acutiserolispooreisp. nov.,paratypefemale,headventrally(A);paratypemale,incisorofleftandrightmandibleandmandibularpalp,
maxillulaandmaxilla;paratypefemale,antennula,antenna,pereopod2andpleopod2.
Acutiserolispooreisp.nov.fromtheAmundsenand BellingshausenSeas,SouthernOcean(Crustacea, Isopoda,Serolidae) 21
Figure3Acutiserolispooreisp.nov.,paratypemale,pereopods1-5,pereopod7.
22 A. Brandt
Figure4Acutiserolispooreisp.nov.,paratypemale,pereopod6,pleopods1-5,uropod.
Acutiserolispooreisp.nov.fromtheAmundsenand BellingshausenSeas,SouthernOcean(Crustacea, Isopoda,Serolidae) 23
Figure 5. Photograph ofAcutiserolis spinosa (Kussakin, 1967) (Zoological Museum of St. Petersburg) # 46416, holotype male of32 mm
length.
ones. Propodus only 1.1 broadenedinthelowerpart, aboutas veryshort,quadrangular,fewmedial setae.
broadasathirdofthelengthofthepropodus,distallynarrower. Plp5 of paratype male (fig. 4) with short sympodite
Propoduswiththreerowsoflongsimplesetaeindistalthirdof (damagedduringdissection,notillustrated).Exopoditewith2
the article besides distally setulated proximal ones. Dactylus short distal plumose setae, endopodite smooth, as long as
less thanhalfas long as propodus, withthree dorsal setules, a exopodite,bothramiwithtransversefusionline.
shortandsmallclawaswellasashortventral setule. Urp of paratype male (fig. 4) with elongate trapezoidal
P3-7ofparatypemale(figs.3,4)similar,P7shortest.Long sympodite, bearing a mediodistal simple seta. Exopodite 0.6
basis with 0-3 feather-like setae. Ischium 0.6-0.8 as long as length of endopodite, both rami with short distal and
basiswithonlyveryfewshortsimplesetae,especiallydistally, mediolateralmarginal,plumose setae,moreonendopodite.
distodorsally a simple seta. Ventrally few setae present on
ischiumandsomemoreonmerus,mostoncarpusandpropodus. Remarks.Acutiserolispooreisp.nov.caneasilybedistinguished
Distodorsallyofmerus,carpus, andpropodus atransverserow from other species of the genus by the long mediocaudal
oflongsimplesetae,mostoncarpusandpropodus.Distodorsal acuminating spine on head reaching mid ofthird pereonite in
regionofpropodussimilartothatofcarpus,butwithlongerand dorsalview.Thedorsalsideofbodybearsscatteredtubercleson
more simple setae. Dactylus very small and slender, only allpereonites,pleonitesandpleotelson,butmuchlessthaninA.
slightlylongerthanthedistalsetaeofthepropodus,withavery luethjei (Wagele, 1986). Pereonites 6 and 7 not fused
shortapicalclawand 1-3 shortsetules. mediodorsally inA. poorei which is most similar to the type
Plpl of paratype male (fig. 4) sympodite bearing three speciesAcutiserolis spinosa (Kussakin 1967) sampled at Ob-
proximomedially setulated setae, distally of these setae a station,ScottIsland,PacificOcean(67°21'S;179°53'E)between
setulated tuft (similar to a brush). Endopodite smaller than 500-900 m depth. Three specimens were collected in the
exopodite. Bellingshausen Sea and another four from the slope of Pine
Plp2 of paratype male (fig. 4) with sympodite similar to Island Bay, Amundsen Sea. The new species can be
thatofPlpl,slightlysmallerandonlywithtwoproximomedial distinguishedfromA.spinosainhavinglessacute,shorterand
setae.Appendixmasculinaabouttwiceaslongasendopodite, less curved coxal plates, scattered tubercles on the dorsal
withshortandbluntmedial spine-likestructures. surface(onlyillustratedonpleotelson)whicharelackinginA.
Plp3 ofparatypemale (fig. 4) similartoPlpl,bearingtwo spinosa being characterised by a smooth dorsal surface.
proximomedially setulated setae. Endopodite smaller and Moreover,A.pooreihasamediocaudalspineoftheheadwhich
moreroundedthanexopodite. reachestomidofthirdpereonites andnotofsecondpereonite
Exopodite ofPlp4ofparatype male (fig. 4) medially with asinA.spinosa.LikeinA.spinosa,nosuturedividedthecoxal
transverse fusion line, with a lateral row of short marginal plates ofthe fifths coxafrom the body inA. poorei which is
plumose setae. Endopodite smaller without setae; sympodite visible at pereomers 2 to 4, however, the male appendix
24 A. Brandt
masculina of A. poorei is shorter than that of A. spinosa Brandt,A.(1991):ZurBesiedlungsgeschichtedesantarktischenSchelfes
(however, this could be due to the fact that we might have am Beispiel derIsopoda (Crustacea, Malacostraca). Berichte zur
sampledonly asub-adultmale). Thecomparisonofthetypeof Polarforschung98: 1-240.
A. spinosa revealed some slight differences to the photographs Bruce (2009): New genera and species ofthe marine isopodfamily
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Acutiserolis gerlachei (Monod, 1925) has an acuminating shoresoftheSouthShetlandIslandswithremarksontheirnatural
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((E2i0g0h9t)s,sh18o3w3e)dctohnastistCsaecoofsesrevoelriaslncorvyapeticcalsepdeocniieasea(nPdooBrreuc&e Kaise(red,s):S.A,ntBaarrcnteisc,BiDo.loKg.yiAn.,aGSlaonbdasl,CCo.nJt.ex&t, 1A3.5-B1r3a9n.dt (2009):
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AntarcticSurvey,Cambridge,formakingthepreciousmaterial Antarctique Beige, 2e note preliminaire. Bulletin du Museum
fMorroimtzthSetaAblmeurnwdhsoensoratneddtBheelmlaitnegrsihaaluisnentheSefarsamaevwaiolrakbloef,hitso PoorNea,tiGo.naCl.dB’Hi&stoAi.reBNraatnudrtel(l1e9,97P)a:riCsr4u:st2a6c9e-a29I9s.opoda Serolidae:
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