A new species of the genus Ligia (Crustacea: Isopoda: Ligiidae) from steep streams of Chichijima and Anijima Islands of the Ogasawara Islands

2011·3.5 MB·

A new species of the genus Ligia (Crustacea:
Isopoda: Ligoodae) from steep streams of
Chichijima and Anijima Islands of the
Ogasawara Islands
journal or Bulletin of the Toyama Science Museum
publication title
number 34
page range 73-79
year 2011-03-15
URL http://repo.tsm.toyama.toyama.jp/?action=repos
itory_uri&item_id=940
富山市科学博物館研究報告第34号，pP73-79；（2011）
ANewSpeciesofthegenuSL噌加（CruStacea：IS0poda：Ligiidae）
fromsteepstreamS0fChichijimaandAnijimaISlandS0ftheOga”waraISlandS＊
NoboruNunomura')，HirokoHoriguchi2)，TetsuroSasaki3)
MantaroHironaka2）andTakahikoHariyama2）
ToyamaScienceMuseuml)，LaboratoryofBiology，HamamatsuUniversitySchoolofMedicine2》‐
InstituteofBoninology3）
Nishinakano-machi，Toyama-shi，939-8084,Japan')，
1-20-1,Handayama，Higashi-ku，Hamamatsu-shi，ShizuokaPref，431−3192，Japan2)，
Miyanohamamamichi,Chichijima,Ogasawaralslands,Tokyo，’00-2101,Japan3）
小笠原諸島父島･兄島の渓流から発見されたフナムシ属（甲殻亜門：等脚目：フナムシ科）の1新種
布村昇')，堀口弘子2)，佐々木哲朗31，
弘中満太郎2)，針山孝彦2）
富山市科学博物館')，浜松医科大学生物学教室2)，小笠原自然文化研究所3》
〒939-8084富山市西中野町1-8-311)，〒431-3192浜松市東区半田山1-20-12)，
〒lOO-2101東京都小笠原村父島字宮之浜道3）
小笠原諸島父島と兄島の渓流から発見されたフナムシを新種Ljg/αro〃e""CO/αとして
記載した。本種は純粋な淡水域に生息する種としては本属で初めての記録と思われる。
本種は同じく父島の海岸に生息する〃gjaya脚α"jsﾙ〃Nunomuraともっとも類似する
が、尾肢が長いこと、顎脚髪縫合線が完全に見られること、第1小顎の基節内葉先端
に歯に鋸状のものが含まれることなどにより区別される。
Keywords：Isopoda，Ligiidae，newspecles，〃g/αro〃e""CO/α，steepstreams
Ogasawaralslands，Japan
Hitherto，thiIty-threespeclesofthete汀estrialisopodgenusL壇jaFa6"c〃sl798areknownintheworld
(Schnmaallffnnssss，,22000033))．.AAmmoonn2gtthheemmttwwoossDpeecciieess,.〃〃g宮jjαα加加""jj""ee""ssjjssNNuunnoommuurraa，ll997799aanndd〃Lp壇jjaαv”αﾉ""?αα""jなs〃ﾙ/〃NNIumnnomm,u,rraa，1l999900
havebeenrecorded廿omtheOgasawaralslands（Nunomura，1979,1983；1990,1991,Tsuge，2008）But,anyspecle真
hasnotrecorded廿omsteepstreamRecently，membersoftheLaboratolyofBiology，HamamatsuUniversitySchoOI
ofMedicine，collectedsomespeclmensofanunidentifiedspecies〃gja廿omasteepstreamofChichijimalsland，
Ogasawaralslands（Fig｣-2)，andsubmittedthosespeclmenstothesenlorauthorfbridentificationLater，additionai
speclmensinbettercondition，collected師mChichijimaandAnijimaislands，weremadeavailablebvT・Sasakifbr
smdyJnthispaper,anewspecies,L堰jaro"で""CO/α,isdescribedandillustrated､Thenewspeciesisthe価rstrepre
sentatlveofthegenusinhabitinginsmallstreamsonsteepslopes．
＊ContributionsfTomtheToyamaScienceMuseum，No.40号
７１八くＪ
Nllnomura，N・an〔lcla
ThetypematerialisdepositedintheNationalMuseumofNatureandScie､Ce,Tokyo（NSMT),ToyamaScience
Museum,Toyama（TOYA）KitakyushuMuseumofNaturalHistoryandHumanHistory，Kitakyushu（KMNH）and
OsakaMuseumofNamralHistory,Osaka（OMNH).Sizeofspeclmensisindicatedbythebodylength（BL）measured
homthemidpointoftheanterlormarginoftheheadtothemidpointoftheposterlormarginofthepleotelson．
’42．E
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制錨aj獅織“a“Grc”
●鋪奪鋪j“謎I霧，
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2k鰯
FiglMapshowingthesamplingsltesofZ,噌jα／o〃e""α〕/αNunomura，spnov
Fig.2AspectsofsamplingSites，
HatsImeura-gawaRiveI。，Chichijima，0雷
L壇jα”rl･“"“〃Nunomura，sp.､．
(takenbySasaki）
74
ANewSpeciesoftheGenusLjgia
TaxonomV
L増加”〃E""”〃Nunomura，Sp.n．
INewJaPaneSename：NagaI･e-hmamuShil
（Figsl-6）
M1花"α／exα”"ed：Holotype：male（BL15．5mm)，NSMT-Cr21253，upperstreamofHatsuneuraRiver，240m
加mrivermouth,Chichijimalsland,Ogasawaralslands,27。04535N，142.13.20」'E,45minaltimde，l7June2010-
coⅡT､SasakiAllotype：female（BL18．4mm)，NSMT-Cr21254,samedataasholotypeParatypes：lmale（BL8．6
mm),NSMT-Cr21255，andlfETnale（BLl50mm)，NSMT-Crsamedataasholotype;lmale（BLl32mm)，and2
fbmales（BL73−uOmm）OMNHAr-8372,samedataasholotype；lmale（BLl5」m、),TOYACr‐23271andlfe‐
male（BLl45mm）TOYACr-23272，samedataasholotype；lc7（paratype，BL62mm)，TOYACr-23273and2早
早（BL9.7〜13.8,Ⅱ､）TOYACr-23291-23292，samelocalityasholotype，23June2007,collTakahikoHarivamal
Male，KMNHIvR500，496)，lfemale（KMNHIvR500，497）
蕊
蕊繍繍 -ﾆﾆｰｰﾆﾆｰ4ﾆﾆｰｰ土ﾆ日-ｰﾖﾆｰﾆｰｰｰﾆﾆｰｰﾆﾆffｰ.ｰ』ｰ侭5弧一−二号蕗野,
霧婁
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蕊
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や露 懲,撚-溺涯蕊ﾆﾆ蕊冒 溌I『-蕊職’露 慧I蕊蕊騨
叱ﾛ'4'''''''''''''''''''''''''''1''''
瀞蝿:::職i蝿:E
Fig.3L増加”〃ell"“ﾉaNunomura，sI〕.n． Fig.4AIivestateofL噂iα”'"e""”肱
Dorsalviewofholotype（takenbySasaki） Nunomura，sp.n．inAnijima．
(takenbVSasaki)．
Non-type：lJ4早早，upperstreamofTakinoura-gawa,Amiima27oO7'012,N，142.12518'E，l60minaltimde，ll
June2010,co1TetsuroSasaki；6早早，downstreamofariverofAniiima27｡061424N，142。12518'，l50minal‐
timde，coll・TetsuroSasaki．
D“c叩"o〃Bodyoval（Figs3,4，5A)，22timesaslongaswide（excludingantennaeanduropods).Colorgener‐
allypalegray，mottledwithirregulardarkernlarkingsondorsalsurface、Evesrenifblm，eachwithabout750onnnatidia，
Distancebetweeneyesrelativelynarrow，0.5timesofeyelength、Surfaceofdorsalsurfaceofbodyalmostsmoothwith
sca枕eredmanymlnutegranules、Pleotelsonwith2pairsofrelativelyshallowconcavities；medialareaofposterlormal･‐
ginofpleotelsononlyslightlyandroundlyprotnlded、
Antennule（Fig6A）small，flrstsegmentrectangular，secondsegmentrectanguler；teIminalsegmentsmaⅡand
semlcercul“Antenna（Fig6B),reachingthemiddlepartofseventhpereonalsomlte,composedof5peduncularand25
Hagellarsegments、
Rightmandible（Fig6C）withincisorprocess3-toothed;laciniamobilis4-toothed；8，enicilsbehindlaciniamobilis3
molarprocesswideLehmandible（Fig6D）withincisorprocess3-toothedラlaciniamobilis2-toothedう6penicilsbehind
laciniamobilis；molarprocesswide・Maxillula（Fig.6E）with3penicilsondistalmarginofinnerendite；outerendite
withlOteethうinnergroupof6teethslenderandsawlike，outergroupof4setaestouterandsmallerinnerteeth，Max‐
illa（Fig6F）bilobed；innerlobewithroundapicalmargln；outerlobewithnumeroushairMaxilliped（Fig6G）with
enditebearinglOplumosesetaeondistalmargln；palp5-segmented；segments2-4withshortsetaedenselyonlnner
marglnandl−3setaeatdistalpartonoutermarglnぅtenninalsegmentsmall，withshortsetaearoundmargm・
Pereopodl（Fig6H）withbasisrelativelystout,with3-7setaeoneachmarginうischiumO,7timesaslongasbasia
75
Nllnomura，N、tln(lelal
／
'
一/惑一一一(cid:631)ﾍ》、
i､rニゴポー
一 、 ｛
！》：
’
名1
瓢》TV'” 5mm 2IYT和
−
N 8−鮒
Fig.5Z噌jα”〃ell"co〃Nunomura,sp.､．
A，habitus，dorsalview；B，penes，ventralviewうC，endopodofpleopodl；Dexopodo菅
thesame；E，lehmalepleopod，ventralview2ラF，rightendopodofpleopod2，ventral
vlewぅG，exopodofthesame，ventralview；H，endopodrightplexopodofexopod3-
ventralviewラIexopodofthesame；J，endopodofleflpleopod4，ventralview；
K，exopodofthesame；L，endopodofpleopod5，ventralview；M，exopodofthesameo
ventralviewラN，lefturopod，dorsalview；O，posterlormarginofpleotelson，dorsalview
(A-E,H-O,Holotypemale;F-G,paratypefemale)．
with5setaeonmnermarglnandlsetaatouterdistalangle；merus0．8timesaslongasischium，with2-3setaeon
1nnermargln；carpusL2timeslongerthanmerus，with2setaeonlnnermargm；propodusslightlylongerthancarpu＆
with9-lOsetaeonlnnermargmandll-l2shortsetaeonoutermarginラdactyluswithoutanyprotuberance、
Pereopod2（Fig61)withbasis26timesaslongaswide;ischiumO､7timesaslongasbasis,with3setaeonouter
marglnラmenlsslightlyshorterthanischium,with2groupsof5−6setaeonlnnerdistalpartandouterdistalangle)今
calpus1．3timesas］ongasmerus，bearing4setaeonlnnermargin，slightlybecomingthickerinbasalpart；propodus
O,8timesaslongascarpus，with6-7setaeonoutermarg1n、
Pereopod3（F喝6J）withbasis31timesasIongaswide,with5setaeonlnnermarglnandlOshortsetaeon
outermargin；ischiumhalflengthofbasis，with7−8setaeonlnnermarglnand4setaeincludingalongeroneonouter
margln；merusl,ltimeslongerthanischium，with4setaeonlnnermarginand3setaeincludingalongeroneonoutel・
marglnondistalpartofoutermarg1,；carpus1．2timeslongerthanmerus，withlsetaonmnermarglnand5−6setae
onoutermargln；propodusO､9timesaslonEascarpus，with5−6setaeonlnnermarglnandaboutlOsetaeonouter
margm．
76
ANewSpeciesoftheGenus〃9m
B1‘A,C−G H−I
Fig.6L増jα”〃e""“〃Nunomura，sp.､．
A，rightantennule，dorsalviewラB，rightantenna，dorsalview；C，rightmandible，ventral
view；D，lehmandible，ventralview；E，lefimaxillula，ventralviewラF，lefimaxilla，ven-
tralview；G，leftMaxilliped，ventralview；H，leftpereopodl，廿ontalviewぅ1−N，right
pereopods2-7inmale，廿ontalview（All；Holotypemale)．
弓Ｉ
Nunomura．N，an〔leial
Pereopod4（Fig6K)withbasis24timesaslongaswide,with2setaeonlnnermarginand2setaeonoutermar‐
gin；ischiumO､6timesaslongasbasis，withl2setaeonlnnermarglnandlsetaonoutermargm；merussligh[ly
shorterthanischium，with8setaeonlnnermarginand5setaeonouterdistalangleラcamusO､9timesaslongmerus・
with6setaeonlnnermarg1nand2−3setaeonouterdistalangle；propodus1．2timeslongerthancarpus，with9-10
setaeonlnnermarginand8setaeonoutermarg1n，
Pereopod5（Fig6L）withbasis25timesaslongaswide,with4-7shortsetaeoneachmargin;ischiumO,7times
aslongasbasis，with5−6setaeonlnnermarginandlsetaonoutermargln；merusslightlyshorterthanischium，with
3setaeondistalmargmラcamus1．6timeslongerthanmerus，with6−7setaeon1nnermarginand2setaeonouterdis‐
talangleラpropodus1．2timeslongerthancaIpus，with6setaeon1nnermarglnand4-5shortsetaeonoutermargln、
Pereopod6（Fig6M）withbasis2．5timesaslongaswide,with6-7setaeonoutermargin；ischiumO7timesaslong
asbasis，withstrongsetaatouterdistalangle；memsO､8timesaslongasischium，with2-3setaeon1nnermargln
andouterdistalangle；carpus1．6timeslongerthanmerus，with8-lOsetaeon1nnermarginand4−5setaeonouterdis‐
talangle；propodus1．2timeslongerthancal･pus，withll-l2setaeonlnnermarginandaboutadozenshortsetaeon
outermargln・
Pereopod7（Fig6N）withbasis35timesaslongaswide,with2setaeondistalpartofinnermarginandlseta
onoutermargin；ischiumalmostaslongasbasis，with3setaeonlnnermarglnandl−2setaeonouterdistalangle；
merus0.7timesaslongasischium，with6setaeonlnnermarginand4setaeonouterdistalangle；carpus1.7times
longerthanmerus，with8−lOsetaeonlnnermarginandll-l2setaeonoutermargln；propodus1．3timeslongerthan
carpus，with5setaeonlnnermarginandll−l4setaeonoutermargln・
Penes（Fig5B）pairedeachpenisabout80timesaslongaswide,apicalparttaperlngtowardthetip,withmuch
hairondistalDart・
Pleopodlwithendopod（Fig5C）pentagonal,withsetaemuchhair;exopod（Fig5D）rounded,with3-4setae
P1eopod2（Fig5E）withendopodstraightanditsapicalareaslightlyrounded；exopodround,with4setaearound
themargln･
Pleopod3withendopod（Fig5H）pentagonalうexopod（Fig51）semicircular,with24-25setaeonmargln
Pleopod4withendopod（Fig5J）rectangular;exopod（Fig.5K）roundlytriangular,bearingl9-27setae・
PIeopod5withendopod（Fig5L)；exopod（Fig5M）roundlytriangularbearinglO-23setaeonmargln
Uropod（Fig5M）q8timesaslongasbodylengthDistalhalfofpeduncleblackincolor,Peduncleoframiin
length；endopodof1．6timeslongerthanpeduncle．
Fセ脚α/e､Generallysimilartomaleexceptfbrpleopod2：Endopodoffemalerectangular（Fig5F)．
HabitatThepresentnewspeciesdwellsinsteepmountamtorrentofupperareaofsmaⅡ廿eshwaterstreams（Fi9
5，6)．
Re脚”伽Thepresentnewspeciesismostcloselyalliedto〃gjaya碗α"jsh",ashoredwellerofChichijimalslan｡，
Ogasawaralslands（Nunomura，1990),inhavingsimilarbodycolor-palegray,mottledwithirregulardarkermarkings
ondorsalsurface，swollenapicalpartofstylusonmalepleopod2，andabsenceofmaIenrstpereopod・ButL
ro〃e""CO/αissepal･ated廿omL・yamanishiibythefbllowingfeatures：maxillipedalpalpofiscompletedsegmented、
whereaslncompleteinLVa版α"jsh"うantennaofL，torrenticolaislongerandreaches7thpereonalsomlteandnageⅡum
composed25segmentsLro〃e""CO/α，whereasthelatterreachesmedialpartofumodalbasisandcomposedof32
HagellarsegmentL．yα"2α"jsﾙ〃；teetharepresentontheouterenditeofmaxillulastronglyserratedinL．yα〃α"jsﾙ"・
ratiooframitobasisofuropodis1.9〜2.4mL，／o〃e""CO/α，whereas0.7〜1.5inL.yα脚α"/sﾙ",．presenceof5stronger
saw-like5teethonthemaxillulaareinL．ro〃e""CO/α，whereasonly3teethinL．yα"”"isﾙ"・
L／C〃e""CO/αisalsoalliedtoanotherOgasawara-species,L6o""e"”（Nunomura，1979）inhavingswollenapl‐
calpartofstylusonmalepleopod2andabsenceofmale耐stpereopod，however，thefbrmerlsseparated侭omthe
latterbythefbllowingfeamres：longerandreaching7thpereonalsomlteandhaving25HagellarsegmentinL
ro〃e""CO/α，whereasatmostreaching5thpereonalonly22HagellarsegmentsZ,．加"加e"sjs；ratiooframitobasisof
uropod1.9〜2.4inL・ro〃e""CO/α，whereas1.6〜l7inL加"加e"s/s,．deeperconcavityofposterlorendofpleotelsonin
７−
ANewSpeciesoftheGenusL壇"
LIC〃e""CCIα,itsdepthtopleotelsonwidthis5％,whereas,3.5％inL加""7e"‘”teethonouterenditeofmaxiⅡula
islOtorrenticola，whereas6inLbo"加e"sjs，andeachtoothofthenewspecies2､OtimesaslongasthatofL
加""7e"s/s；onlylrowofsmalldenticlesonapicalpartofendopodofmalesecondpleopodinLro〃e""CO/α，whereas
6-7rowsofdenticlesinL・加"加e"s/s；ratiooflengthtowidthofpenesinthenewspeciesis1.7timesaslongas
thatofL・加""7e"s/s；numberofpenicilsofbothmandiblesofL．／o"で""CO/α11−12，whereas6inL・加"脚e"s噸
E""'0/o邸ﾉ.Thespecincepithetisana町ective,acombinationoftheLatin”torrentis”（＝roarlngstream）andⅧcola”
(＝dwellers)．Thisspeciesdwellsabsolutely廿omtheroarlngstreamofChichijima,Ogasawaralslands
Acknowledgements
WewouldliketoexpressourslnceregratitudetoMsShokoUmehara（InstituteofBoninology）fbrherhelpin
coⅡectingthesematerials,toM胆MasaakiTakiguchi，Dr､HideakiMori，MmHideyukiChiba（JapanWildlifeResearc雲
Center)，Mr､RiichiroTatsuta（MinistrvoftheEnvironment）fbrtheirofferingusefUlinfbmlationisabouttheAnijima
lsland．
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ワー