Table Of ContentA new species of the gnathiid isopod
crustacean from the sea off Sanriku, northern
Japan
journal or Bulletin of the Toyama Science Museum
publication title
number 21
page range 55-60
year 1998-03-30
URL http://repo.tsm.toyama.toyama.jp/?action=repos
itory_uri&item_id=712
BuⅡetmoflheToyamaScienceMuseumNo21，pp､55-60（1998？
ANewSpeciesoftheGnathiidlsopodCrustacean
fromtheSeaoffSanriku,NorthemJapan＊
NoboruNunomura
TbvamaScienceMuseum
Nishinakano-machi,『Ibyama-shi,939-8084JABﾍN
三陸沖から発見されたウミクワガタ科（甲殻綱，等脚目）のl新種
布村昇
富山市科学文化センター．
〒939-8084富山県富山市西中野町1-8-31
岩手県三陸沖から発見されたウミクワガタ（グナチア）を、新種G"α"zjtz”"r和e"sなとし
て記載した。本種はアンチル諸島から知られているG"α”αjo"""αMonod，1926と最もよ
く類似するが、(1)大顎の先端が内側に突出しないこと(2)第二触角の鞭数が少ないこと、（証
頭部前側縁が細く突出する、(4)胸脚の内縁の突起が弱いこと､(5)第2胸肢の第2節の先端に
長い剛毛がないことで区別される。
DuringabenthossurvevatOtsuchiBa孔Dr・Shm1ichilshmarucoⅡectedsomegnathiidspecimensandthey
werehandedovertomeformvstudvfOrthecourtesyofDr・Shin'ichilshimaru，KanazawaWomen1sCollege・At
closeexamhlationofmine，itprovedtobeanewspeciesofgenusG"α”α，IwatePrefecture，PaciflcSideof
NorthemJapan．
Gna的胸鎚nr汰凹enSi5nosp．
（Jap,name；Samiku-umikuwagata,new）
（Figs､1-3）
M“e"αIexa腕me。：4叡叡（1夢holotype,2．8mmmbodylength3cF1ざ'paratypes,2．4〜27.mmmbodv
length）42mmdepth,OtsuchiBay,offO1suchi,IwatcPrefccturc,conShm'ichilshimaru,Au9．2，1993．1￥
(2.8mmmbodylength)，1zuphea（L6mmmbodylength）lpraniza（1.6mmmbodylength）larva・These
femaleandlarvaspecmensarcconsideredtobethesamespecies，fortheywerecollectedmmthesame
habitat,andothergnathiidwasnotfoundaroundtherc・Holotype（TOYACr-12473),2maleparatype（Tm公Cr‐
12474〜12475),1female（Tm公Cr-12476),onezupheaspecmen(TOMヘCr-12477）andoneplaniza（TOMヘCr
-12478）aredepositedattheTbyamascienceMuseumandamaleparatype（OMNHAr-3981）isdepositedatthe
OsakaMuseumofNaturalHistory
Des””"0列of'"α/e：Bodyslender,3．6tmesaslongaswide・Colordullyellowmalcohol・Cephalon3/4
tlmeaslongaswide・Dorsalsulcuslacking･Suplaocularlobepresent・Para-ocularomamentationlackmg
Pleonalmoststraight・Pleotelsonelongatedtriangular，
Antennule．（Fig.1F）Peduncle3-segmented；eachsegmentreclangular；Hagellum5segmented，termmal
segmentwith3sctaeatthetip，Antennaalittlelongerthanantennulc，Peduncle5-segmentedFlagellum7-
scgmented,cachsegmenttrapezoid，
Mandiblc（Fig.1B）triangulaLMandibularsetaepresent・Armcdcarinalackmg・Mediofrontalprocess
lacking・
Maxnlipcd（Fig.1C）5−segmented；firstsegmm1stoulwithoutseta；secondsegmentsquarewith3plumosc
Keyword：Astacilla,Conathia,NcwSpectes,GI1athiidea,Sanriku,Japan
＊ContributionfromtheToyamaScienceMuseumNo､194
Ｆ『Ｕ
NoboruNul1omur茎
一
(cid:631)ﾐミ
Fig.1G"“hjα””放"e"szsn・sp．
A･Dorsalvicw；B・Anteriorpartofcephalon；C・Maxilliped；D・Pylopod；E,Antennule；RAntenna；G-Ko
Pcrcopodsl-5；L,Penes；M・Pleopodl；NPlcopod2；O・Uropod．（All：Holotypemalc)．
Ｆ「Ｕ
ANewSpeciesoftheGnathiidlsopodCmstaceanfromtheSeaoffSanriku,NorthemJapan
setaeoninnermargm；thirdsegmentsquarewith7segments；fburthsegmentwith8setae；tennmalsegmenl
smallandroundwithmanvfinesetacaroundthemargin；termmalsegmenttriangularwith7plumosesetae
aroundthemargm、
Pylopod（Fig.1，)Bigand2-segmcntcd；firstsegmentwithabout40setae；sccondsegmentsmaⅡandround
Pcreopodl．（Fig.1G)．Basisrectangular,with31ongsetaebothmargms,31ongsetaenearthedistalend
；ischiumr“tangularwithasctaatouterstemalmargmand3〜4selaeoninnermargm；merussquarewith2
〜31ongcrselaeandmanvshortcrsetaconmnermargmand21ongsctaeatouterdistalcomer；carpuswilh
smualemncrmarginbearing3sctae；propodusrectangularwith3sloulsetaeoninncrmargm；dactvlusbifid-
Pcrcopod2（Fig.1H).Basisrectangularwith4selaeonoutcrmarginand4setaconinnermargm；ischium
rcctangularwith5setaeoninnermargmand5sctaeonoutermargm；mcrusalittlcshorterlhanischiumwith
4setaeonmnermarginand3〜4sctacatouterdistalcomer；carpuswilh3sclaconmnermargmandaseta
atouterdistalcomcr；propoduslongwith5〜6selaeonmnermargm；dactylusbihd・
Pcrcop(〕d3（Fig.11)．Basisoblongwith61ongsctaconmnermarginand21ongsetaconoulcrmargin；
ischiumoblongwilh4sctaeonmnermarginand210ngsetaeonoulermargm；merusalmostsquarewithaseta
andprolubcranceonmncrmargmand2setaeatouterdislalcorer；carpusrcctangularwith3protuberanceson
mnermarginand2−3setaeonoutermargin；dactylusbim．
Percopod4（Fig.1J).Basisrectangularwith3sctaeonoutermargm；ischiumwith2〜31ongsetaeonouter
margm；meruswith2sctacalmnerdistalcomerand31ongsetaeattheouterdistalcomer，carpus3setae
mlhcdistalendofmnermargmandasetaatouterdistalcomer･propodusrectangularwith2〜3setae；
dactylusbifid，
Percopod5（FiglK)．Basisellipticalwith4setaeonoulcrmargm；ischiumalittleshorterthanbasis
with21ongselaeonoulermargmand5shortersetaeonmnermargin；merusabouthalfthelengthofbasis
with4setaeoninnermargmand3setacatouterdistalcomer，Oneofthemisverylong；carpusaslongas
mcruswith5stoulspmes，2−3setaeandanomamentedsetanearlhcdistalcomerofmnermargm；propodus
long，1．5timesaslongascarpuswith2serratedspines，2setaeonmnermargmand2〜31ongsetaeonouter
margm；dactvluslong、
Pcncs（FiglL)relativelystout・
Plcopodl（Fig.1M).Basisroundwith2setae，bothramilanceolalewith8plumosesetaearoundthcmargm
Pleopod2（Fig.1N).Endopodwithanarrowstylus,Otherpleopodsarealmostsmnarcachoth“
Uropod（Fig.10)Endopodlanceolatewith31ongplumoseselae；cxopod3/41measlongasendopodwith6
1ongplumosesetac，
Rem”ks：ThepresentncwspeciesismostclosclyalliedtoG"α”αﾉo"""αMonod,1926,whichwasreported
fTomtheAnt1lcs・ButthcfOrmerlsseparatedfTomthelattermthefOllowmgfeaturcs：（1）lessprolruded
apicalareaofmandiblc，（2）lessnumcrousflagellumofantcnna，(3)presenccofprotuberancesonantero-
lateralmargm，（4）weakerproluberanceofmnermarginsofpereopods，(5)absenceonlongselaonthesecond
segmentofpylopod．
Descγゆ"o〃Q/た'"αIeco"eaed”ge"Zerw城加IC”e〃ZaIe：Bodv2,21imesaslongaswide,widestat
pcrconite3-4､Colordullyellowmalcohol､Pleotelsontriangularo
Anlcnnule（Fig.2B）Peduncle3-segmentd；firslsegment3setaeatdistalcnd；secondsegmentwith4-5setae
ondistalmargm；thirdscgmentoblongFlagellum4-segmenledAntenna（Fig.2C)，alittlelongerthan
antelmuleﾌHagcllum6-segmenに｡、
Pereopodl（Fig.2，)．Basis；rcctangular；ischiumrcctangularwith21ongsctaeonoutermargin；mems
squarcwilhprolubcranccsonmncrmargm；carpussquarewithprotuberanccsonmnermargm，propoduslong
wilh5stoutsetaconm､crmarginandasctaatouterdislalcOmer；dactylusrathcrlong，
Pereopod2（Fig2E)．Basisrectangularwith3relativelylongsetaeonoulcrmargm；ischiumwith2setae
5？
Nobol･uNunomura
一
戸ジグ稲″〃●ム
〜
Fig.2FemaleconsideredtobeG"α"zjα”"r放"e"”n.sp．
A・Dorsalview；B・Antennule；CAntenna；D−H､Pereopodsl-5；I・UropodandTblson（All：Female>
Onmnermargmandalongcrselaeonouterstcmalmargm，mcrusabouthalflcngthofischium，shortwitha
setaatthemnerdistalcomerand2selaeouterdistalcomer；carpusaslongasmcruswilhatoutand3
selaeoninncrmargm；propodusaslongasbasiswith2sloulsctaeonmncrmargmandasctaatouterdislal
cOmer；dactvlusratherlong，
Pereopod3（Fig.2F)．Basis3tmesaslongaswidcwithasctaonoutcrmargm；ischium4/5aslongas
basis，withasctaonbothmargins；merushalflcnglhofischiumwith21ongsclacandastoulsetaonmner
margmandasetaatthcouにrdistalcomer，carpuSaslongasmcruswith2setaeonmncrmargin；propodus
aslongasischium，withasetaalthcmiddlearcaofmncrmargmand3setaealoutcrdistalcomcr，
dactylusrathcrlong
Pcrcopod4（Fig.2G)．Basisoblong4tmcsaslongaswith2sctaconinncrmargm,andalongersctaat
innerdistalcomcr；ischium2/3tmcaslongasbasiswithalongsctaealoulerdistalcomer，merushalf
lenglhofischiumsctaconmncrmargm，carpusas1ongasmcruswilh2〜31ongsctaconinnermargm；
propodus1．4timcsaslongascarpuswith2tubcrclcsonmncrmargm；daclvlus・
Pereopod5．（Fig.2H)．Basisrclativelvslou12.61mcsaslongaswidcwilh5sclaeonmncrmargmand6
1ongsclaconoutcrmargi、；ischiumalmostaslongasbasiswith4〜5selaeonmnermargmand21ongsctae
()noutcrmargln，merus2/5aslongasischiumwithalongsctaalinncrdistalc(〕mcrand41ongsclacat
oulerdistalcOmer；carpusalittlelongcrthanmeruswith2〜3sctacmncrmarlin；propoduslwiccaslong
ascarpus；dactvlusralherlong・
Plcopodalmostsmilarmshape、
Uropod（Fig21)．Endopodexopodlen“01alewith6sclacaroundthemargm；cxopodaliltlcshorlcrlhan
lhccndop(〕dwith9sctacaroundlhcmargin
戸隅』
ANewSpeciesoftheGnathiidlsopodCrustaceanfromtheSeaoffSanriku,NorthemJapan
/ク
一 １
》
、 １
心
、‘ １ Ｉ
。
Ｊ
i:
A
"』聯
Fig.3PranizalarvaspecimenconsideredtobcG"α的jasα"〃k"e"”n.sp．
A・lateralview；BAntennule；C・Antenna；DMandible；F-I・Pereopodsl-5；J；Uropod（All：Praniza
larva)．
D“cr”"o〃qfpγα"jzajtzr”CO"eα“〃e”的e”eわ“"ly：Bodyｳslender,4．8tmesaslongaswide・
Colordullyellowmalcohol・Cephalontwiceswideaslong・Eyesratherbigandelliptical，Cacheyecomposed
ofabout60ommatida・PleotelsonTTiangular
Antennule（F鴫3B)，reachingtheanteriorpartofpereonalsegment・Pedunclecomposedof3segments
Flagellumcomposedof5scgmentsfirstsegmentshort；secondsegmenllong，thcremaming3segmentshort，
termmalscgmenl2aesthetascsan3scgmenlsatthetip，Antenna（Fig3C）aslongasantennule・Peduncle
composedof5segments.Flagellumcomposedof7or8segments・
Mandible（Fig.3G）slender,apexwith8teelh
Pcrcopodl（Fig.3F)．Basisreclangularwithasctaonmargm；ischiumrectangular；merusalittleshorter
lhanischium，withasetaeonbothmargms，carpusaslongasmeruswith2−3setaeonmnermargm；propodus
with4setacnearthedislalcndonmnermargmandasetaeonouterdistalmargm；daclylusbifid・and
rclativelylong．
Pereopod2（Fig.3G).Basisoblong,3tmesaslongaswith,withasetaonoutermargm；ischium2/3tme
aslongasbasis，with2setaconmncrmarginandalongsetaonthestemalpartofoutermarginandasetae
nearthelalcralpartofoutermargm；merushalflcngthofischiumwithasclaonlnnerdistalcomclanda
longsclaatlhcouterdislalcomer；carpusaslongasmeruswithalongand4shortersetacaonmner
margmandonoulcrmargm，propoduslongwith4setaonmnermargmand2selaenoutermargm；dactylus
Ｆ『Ｕ
NoboruNunomura
bihd・
Pereopod3．（Fig.3H）Basisrathcrshortwithasetaconoutermargin；ischiumrectangular；merusalittle
shorterthanischiumwithasetaonoutermargin；carpusaslongasmeruswithasetaonoulermargin；
propoduslongwith4selaeoninnermargm；dactylusbind、
Pereopod4（Fig.31)．Basis2､6tmcsaslongaswidc，with3−4setaeonoutcrmargm；ischiumalillle
shorterthanbasiswith3〜41ongsetaeonoutermargm；mcrus2−51measlongasischium；carpuswilhsela
(〕nmnermargmand3setaeatoutcrdistalcom“oneofthcmlong；propodusaslongasischiumwilh6slou倉
setaand3sctaonoutcrmargin；dactylusbim．‘
Pereopod5．（Fig3J)．Basislong,4．5tmesaslongaswidc；ischiumhalflengthofbasiswithasctaon
bolhma唱ms；mcrus3/stimeaslongaswidewilhasetaatmnerdistalcomerandasetaaloutcrdistal
comcr；carpusaslongaswidcwithasetaonmnermargin；propoduslongwithasetaatinncrdislalcomer
；dactvlusbifid，
Pleopods1−5（FigK）smilarmshapc；basislrapezoid；bothramilanccolatcwith5setae･
Uropod･Endopodlanceolatewithl()〜llsctaearoundlhcmargm．
Ackllowledgments
lwouldlikclocxpressmvsmceregratitudetoDr.，Shin'ichilshimaruoftheKanazawaWOmen1sCollege
fOrhisprovidingmethesemtercslmgspecimens．'IbDr、Ichiro’IakeuchioftheOtuschiMarineBiological
StationofthcUnivcrsitvofTbkyoandmanystaffSofthcLaboratoryfbrthcirkmdnessmhelpinghis
samplmg．
Re舵rences
CalsP.（1973）GnalhiidcsdeIAtlantiqucNordl・Problemcslicsal1anatomicctaudmorphismcscxucldes
Ganthiidcs（Crustaccalsopoda）Dcscriptiond1unelbrmcbathyaleduGo唯deGaascogne：Gnalhiatcisscri
n､sp・CahicsdcBiologiemarmcl3：511-540．
Cohen,BJ・andG.CB・Poore,1994.PhylogenyandbiogcographyoftheGnathiidae（Crustacea：Isopoda）with
descriptionsofnewgeneraandspccies，mostfTomsoulh-castemAustralia、MemoirsoftheMuscumof
Victoria54：271−397．
Holdich，，．M・andK・Harrison，1980．ThecrustaceanlsopodG"α的mLeachfromQueenslandWalcrs，with
DescriptionsofNmcNewSpecies･Aust.』､Mar・FreshwalcrRcc，31：215-240．
Monod,Th､1926.LcsGnathiidaeEssaimonographiquc（morphologie,biologic,systcmatiquc）Mem・SOC・Sci・Na1．
Marocl3：1−668．p1.1．
Nishmura,S,l968AlarvalGnathiidfromSetoJapan（Crustacea：Isopoda).PublSctoMar・BiolLab,26（1）
：7−9．
Nunomura，N,フ1981.Gα""zjα”g“〃m“"SIS，anewgnathiidisopodfromSugashima，IseBay，Cental
Japan・BullctmoflhcToyamaScicnccMusem3：19-24．
Nunomura，N・’1982．AnewgnathiidlsopodfromSaekiBaXWestcmJapan，BullelmoflheTbyamaScicnce
Museum,4：17−21．
Nunomura，N,、1982.Anewsp“iesofG“”a（Crustaccalsopoda）fromtheseaofflbaragi,cenlralJapan
BulletmoflhcToyamaScimceMuscm，12：27-28．
Nunomua,N,,1992.MarmclsopodairomAmakusaKyushu（Ⅱ).PublicationsoflhcAmakusaMarmcBiological
Laboratorvll：59−71．
6§
