Redescription of Idotea (Pentidotea) rotundata Richardson, 1909
journal or
publication title
Bulletin of the Toyama Science Museum
number 32
page range 71‑74
year 2009‑02‑25
URL http://repo.tsm.toyama.toyama.jp/?action=repos
itory̲uri&item̲id=897
富山市科学博物館研究報告第32号， 71‑74；（2009）
RedeScriptionof〃りr （Pe"" r ） "血 Richard§0,,1909＊
NoboruNunomura ToyamaScienceMuseum
l‑8‑31Nishinakano‑machi，Toyama939‑8084，Japan
ヘラムシ属の一種，〃" （Pe" " ） 〃" "a（等脚目：甲殻類）の再記載
布 村 昇 富山市科学博物館
939‑8084富山県富山市西中野町l‑8‑3i
北海道大学の五嶋聖治博士が「環境省による知床半島沿岸域における浅海域生物相 調査の一部」の調査時に北海道知床から採取した〃brea（Pe"" reα），or"" /αを調 査した。本種は当初青森県鮫から記載されたが，従来，付属肢の形態が十分に記載さ れていなかったため知床産の標本をもとに再記載した。また，和名「マルオヘラムシ」
を提唱する。
キーワード：等脚目，ヘラムシ，再記載，マルオヘラムシ
Keywords：Isopod,Idoteidae,jじわ花a（Pe""reα）ノ℃r""rα,redescription
〃brea（Pe""/eα）γ"""Cた"αwasdescribed廿omSame，Aomori，Pac耐csideofNorthemJapanbyRichardso、
(1909)．Afterthat，Guljanova（1936）andKussakin（1974,1982）recordedthepresentspeciesButthemolphology ofalltheapendageshavenotbeendrawnyet･Recently，ProfGohimaoftheHokkaidoUniversitycollectedaserle墓 ofmarineisopodcrustaceansentitledFaunaandHorasurveyoftheshallowseaareaalongtheShiretokocoastm ShiretokoPeninsula，northNorthemJapan･Thesamplesweresenttomefbridentiflcation，andlfbundsomespeclmens of〃brea（Pe""reα）ror""raandrecdescribedthespecles・
Befbregoingfilrther,IwouldlikeexpressmyslnceregratitudetoProfSeUiGoto，HokkaidoUniversity,fbrhi葦 kindnessingivingmeachancetotheimportantspeclmens・ThissurvevwasconductedbvthefmancialsupportofthE JapaneseMinistryofEnvironment．
〃ひZea（Pe"" r ）′0m"血mRichardS0n，1909
（Jap・name：Maruo‑heramushi，new）
（Figsland2）
MJre"α/exα"'j"e鉛1c?(366mminbodylength)．TipofShiretoko‑Cape､Hokkaido，May30，2007，
Goshima2007う3早早，Chashikotsu‑zaki,nearUtoro，ShiretokoPeninsula,Hokkaido,Aug27,2007,coⅡSeiji 2exs,Chashikotsu‑zaki,nearUtoro，ShiretokoPeninsula,Hokkaido,Aug16，2008，colLSeijiGoshima；lex， Kabutoiwa,ShiretokoPeninsula,Hokkaido,Aug26，2007，collSeijiGoshima．
De "o".･Bodv（FiglAandB）slender，6．8timesaslongaswideColorpaleyellowinalcohol・
square，withasmallmedialconcavltyonarterialmargin・Eveslocatedatthemedialareaonlateralmargln・
composedofabout70ommatidia・PereonalsomltesparalleLCoxalplatesvisibleindorsalviewonpereonal
＊Contributionsfi･omtheToyamaScienceMuseum，No.36胃
coll．Se砿 Goshima・
inteItidal
Cephalon Eacheye segments
N()boruNllnoImll･壷
5‑7．Dorsaltwoperfectsumrelinesonpleotelson、Pleotelsonwithaveryshallowconcavltyatthemediolateralpart， Frontallamina（FiglC）pentagonal；clypeusshortAntennule（FiglD)：segmentlbigandoval；segment2with 4‑5setaeatdistal‑lateralangleぅsegment3aslongassegment2；tenninalsegmentwithl2‑14aesthetascsOnthedistal marginAntenna（FiglE）long，reachingthirdpereonalsomltesラpeduncle5‑segmentedandHagellum9‑segmented Rightmandible（Fig2F)：parsincisiva4‑headedうlaciniamobilisnotchitinzedand3‑headed；lOhairs；processus molariswithlaciniamobiliswideLeftmandible（F唱lG)：parsincisiva3‑headed；laciniamobilischitinzedand3‐ headed；l2hairs;processusmolariswithmorethan25setae；processusmolariswide､Maxillula（FiglH)：innerlobe with3plumosesetaeandasmallsimplesetaondistalmargln；outerlobelOsimplesetaeatthetipMaxilla（Fig ll)：innerlobewithl7setae；lnnerramusofouterlobe7withsetaeatthedistalmarglnand6setaeatthetipof outerramusofthesameMaxilliped（FiglJ)：enditerelativelynarrow,withl3‑l4plumosesetaeatthetip;palp5‐ segmented，segmentsl‑2almostsquareラsegment41ongest，withmorethan20setaeonlnnermarg1nandllsetaeon outermargln；tenninalsegmentsemicircular，withl2‑l3setaearoundthemargln；epipoditenarrowlanceolate・
Pereopodl（Fig2A)：basisrectangular,2.ltimesaslongaswide;ischiumO､6timesaslongasbasis;merusrec‐ tangularラcarpusshort，with9‑lOstoutsetaeandseveralsmallsetaeonlnnermargm；propodusrectangular，withmore
than20setaeoninnermarg1,．
Pereopod2（Fig2B)：basisrectangular，rectangular，21timesaslongaswide；ischiumO､4timesaslongas wide；merusrectangular；camusshort；propodusrectangular，withl2‑l4setaeonlnnermargln，
Pereopod3(Fig2C)：basis28timesaslongaswide;ischiumO4timesaslongaswide;merusO2timesaslong asbasis，withaseriesofshortsetaeonlnnermargm；camusalittlelongerthanmerus，withmanyshortsetaeonlnner margl､；propoduswithbasalpartprotruded，bearing3stouterandseveralshortersetaeonlnnermargm，
Pereopod4(Fig2D)：basis24timesaslongaswide,with5‑lOrelativelyshortsetaeonbothmargins；ischium halfthelengthofbasis，with6−7setaeonlmermargln；merus0.7timesaslongasischium，with4−5setaeonmner
野鼠３ 一
鯉
剛／
M
い
1．1i" （Pe"" r ） "血raRichardS0n，l909
Dorsalview；B：Lateralview；C：Clypeusandffontallaminaうり：Antennule；E：Antennta；F：Rightmandible Leftmandible；H：MaxillulaうI：MaxillaﾗJ：Maxilliped；K:Penes（All:maleftomShiretoko)．
９ＡＧ
●色■且Ｆ ７−
RedescriptionofIdotea（Pe""故)/eα）rOnmdicaudaRichardson，1909
marglnうcalpusaslongasmems，with4‑5setaeonmnermargln；propoduswith3stoutsetaeonbasalhalfofinner
margln、
Pereopod5（Fig2E)：basis21timesaslongaswideラischiumO4timesaslongasbasis；melus65％aslong asischium；carpusshort；propodus3/4aslongaspropodus，with4stoutsetaeonbasalhalfofinnermargln・
Pereopod6(Fig2F)：basistwlceaslongaswide；ischium2/3aslongasbasis；merus35％aslongasischium：
calpusshortandaslongasmerus；propodusQ7timesaslongasbasisうdactylusO､6timesaslongaspropodus・
Pereopod7（Fig2G)：basisrectangular，l9timesaslongaswide；ischium45％aslongasbasis,merus,alittle shorterthanischium，withmanvsetaeonlnnermargln；carpusshort；propodusalittleshorterthanbasis，with3stout setaeonbasalhalfofinnermargin；dactylushalfthelengthofbasis、
Penes（Fig.1K）pairedラeachpenis5timesaslongaswide・
P1eopodl(Fig2H)：bothramlrectangular,withmanvshortsetaeondistalhalf
Pleopod2(Fig21)：bothrami3､7timesaslongaswide；stylus20％exceedsbevondthetipofendopod Pleopods3‑5（Fig2J‑L)：basissmall；bothramielongated
Uropod（Fig2M)：basislong，75％ofthewholelength;bothramlrectangula正
l 心 一 ー
A
一
、
1〈
︲︲．●．●●ｊｊｊ宮室﹁〆乙︐ノ
− b
C
G 己彦
吸 い
'1m噸
I、、
Fig.2.〃b舵a（Pe"" r ）JW"" Richardson，l909
A−G：Pereopodsl‑7；H‑L：Pleopodsl‑5ラM：Uropod（All：AmalefTomShiretoko）
Nob()I･uNunomur擢
References
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GuIjanova,E，1936．Ravnonogiedalnevostochnvkhmorei・""αSR,Rakoo〃αz"ye，7(3)：1‑279（inRussian)． Kussakin,OGl974FaunaandEcologyofisopods（Crustacea）ftomtheintertidalzoneoftheKurillslands・刀α"s‐
αc"o"so/γ〃e4cα火"Wo／Scje"ceQ／rheU＆S,R,Ft〃E ／Ce加既I"s/""/eQ／M1""eBjO/O〃l：222‑275
（inRussian)．
Kussakin，0．G. 1982．MarineandbrackishlsopodaofcoldandtemperatewatersofthenorthemhemisphereⅡ，sub‑
orderValviたra,Anthuridea,etc・AC S USS・尺，Le"腕9,α 1‑462（InRussian)．
Richardson，H･1909．IsopodscollectedinthenorthwestPacificbytheU．S・bureauoffisheriessteamer1'Albatross in1906．P,oc，US.M砿M ，37（1701)：75‑129
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