A New Species of the Genus Malthinus (Coleoptera, Cantharidae) from Kitadaito Island far off Southwest Japan

2006·2 MB·

by  Takahashi, K

Elytra,Tokyo,34(2):353-356,November l8,2006
A NewSpeciesof theGenusMalthinus (Coleoptera,Cantharidae)
from Kitadaito Island faroffSouthwest Japan
Kazuhiro TAKAHAsHI
239-11, Nagamochi,Hiratsuka,259-1217Japan
Abstract AnewcantharidofthegenusMalthinusisdescribedfromKitadaito
IslandoftheDaitoIslandsfaroffSouthwestJapanunderthenameofMnakanishiisp
nov. Thisisthefirst recordofaJapanesecantharidbeetle fromoceanicislanddistant
fromthemainland.
Introduction
Kitadaito Islandlieson thenorthwesternPacificOcean to theeast of theRyukyu
Islands. It isbasedonaraisedatoll,anddidnotjoinanycontinentsinceithadbeen
formedasavolcanicislandaboutfiftymillionyearsago(KAwANA,1988). Onsuchan
isolatedisland,occurrenceofendemicspeciesisexpectedasinthecaseoftheOgasawara
Islandsof Japan.
Recently,Mr.MotooNAKANIsHIofMatsusakacollectedaremarkablebeetlewhen
hevisitedtheislandinApril,2005,whichisobviouslyacantharidprobablybelongingto
thegenusMalthinus. Thisdiscoveryisveryimportantbecauseit isthefirst recordofa
cantharidbeetlefromtheoceanicisland. Thisspecimenwassenttomeforexamination
through the courtesyof Messrs. Katsumi AKITA and Hiroshi OToBE. Besides, ad-
ditionalspecimenscollectedby thesamemanandhiswifeat thesameplaceinApril,
2006,werealsosent tome. Afteracarefulexamination, itbecameclear thatthereare
nocloserelativesinthegenusMalthinus. Therefore,Iconcludethat it iscertainlyanew
species,andamgoing todescribeit inthepresentpaper.
Before going further, I wish to express my cordial thanks to Messrs. Motoo
NAKANIsHIofMatsusaka, KatsumiAKITAofTsuandHiroshiOToBEofTsu for their
kindhelpinprovidingmewithvaluablematerials,andtoDr.MasatoshiTAKAKUwAof
the KanagawaPrefectural Museumof Natural History, 0dawara for his critically
readingthemanuscript ofthispaper.
Material and Method
Themalegenitaliaexaminedweretreatedwith10%KOHsolutionat90°C for
about 10minutes, andsketched in50%glycerin.
Theabbreviationsusedin the text areasfollows: HW: width of head:PW: widthof
354 Kazuhiro TAKAHAsHI
pronotum;PL: lengthof pronotum;EW:widthofelytra;EL: lengthofelytra
Description
Malthinusnakamshiisp nov.
(Figs.l-5)
M ale. Body largelybrownishblack;headbeforeeyes,apicalportionsofelytra
and posterior and lateral marginsof 2nd to 7thsternites yellow; fore femora, basal
halvesofmeso-andmetafemoraandpronotumexcept foranterior blackmarginand
anteriormedian longitudinalblackishmaculationyellowishorange.
Headweaklyconvexindorsalaspect,denselycoveredwithsmallpuncturesthough
relatively largebehindeyes; neckgradually constricted posteriad. Antennae filiform,
obviouslyexceedingtheelytra1apices;comparativelengthsofeachsegmentasfollows:
1.67: 1.00:1.14: 1.23 :1.45: 1.34: 1.30: 1.30: 1.25: 1.20: 1.31. Eyesprominent; in-
ter-ocular distancebroad, 3.41 timesaswideasan eye. Mandibleprovided with a
distinct inner tooth. Terminal segmentsof maxillary and labial palpi simple, not
extendedapicad. Gularsuturedistinct;gulaverynarrowandconcave.
Pronotum nearly slightly broader than long, widest at middle;
square, very
PW/HW 0.87, PW/PL 1.07;surfacerather convex,somewhat rugu1ose,entirelycov-
2
Figs. l-2. HabitusofMalthin1lsnaka川shitsp nov. - 1,Male(holotype);2, female
Malt/1inus from Kitadaito Island 355
3 a b c
4
Figs.3-4. 3. MaleeighthsterniteofMalt11inlisnakantshiisp nov. (Scale:0.25mm). - 4. Male
genitaliaofMalthintlsnakanlshitsp nov.;a,ventralveiw;b, dorsalview;c,1atera1view. (Scale:
0.25mm).
Fig.5. FemalegenitaliaofMalthinustlakanlshllsp nov.; pp,paraproct;c,coxite;v,valvifer. (Scale
0.25mm).
eredwithsmallpunctures. Legsslender;eachclawsimple. Elytraabbreviated,densely
coveredwithlargepuncturesthoughimpunctateatapicalyellowportions;eachpunc-
ture somewhat lined longitudinally in the middle; two obscure carinae observed;
EW/PW 1.35; EL/EW 1.91.
Abdomen with severalposteriorsegments visibleindorsal view; eighthsternite
rather short and broad, withapex distinctly emarginate (Fig. 3). Male genitalia
elongateand complicated;basalpieceprobablyoriginated fromtenthstemite, rather
elongateandleaf-shaped; innerbasal pieceprobablyoriginated fromeleventhsternite,
visiblein lateralandbasalportions;centrophyse, thetermfirstusedbyBRANcuccI,
1980,probablyoriginatedfromtenthtergite,cylindricallydepressed,providedwithwide
and longitudinal furrow indorsal view; penisoval inoutlinewithverycomplicated
structure,locatedonthecentrophyse(Fig.4).
Length:3.1(2.8-3.3)mm;breadth:1.0(0.9-1.0)mm
356 Kazuhiro TAKAHASH1
Female. Similar tomale though wider and larger; eyes smaller; antennae
shorter than thoseofmale. Pronotumreddishorangeexcept for anteriormarginand
longitudinalmedianblackishmaculation. Femoraentirelyinfuscate.
GenitaliaasshowninFig 5. Coxiterather triangular;basenotelongate,connected
with base of paraproct. Paraproct separated into two pieces; eachpiece triangular,
entirely furnishedwithrather longhairs. Valvifer thickandstout.
Length: 3.6-4.0mm; breadth: 1.1-l 4mm.
Typeseries. Holotype: Nagahagu(Sotohagu),KitadaitoIs.,OkinawaPref.,9-
,
IV-2006,MotooNAKANIsHIleg.Paratypes:l 1早,samedataasfortheholotype; l
, ,
sameplaceanddateasfortheholotype,MutsukoNAKANIsHIleg;1早,sameplaceasfor
theholotype,10-IV-2006,MotooNAKANIsHIleg; l早,sameplaceasfortheholotype,
8-IV-2005,MotooNAKANIsHlleg;1早,Nagahagu(Uchihagu),KitadaitoIs.,Okinawa
Pref.,25-III-2006, K.TAKAHAsHI leg.
Typedepositories. Theholotype isdeposited in thecollection of the Kanagawa
PrefecturalMuseumofNaturalHistory, 0dawara. Theparatypesarepreservedin the
collection of mine.
Distribution. Japan(KitadaitoIs., Daito Isis)
Remarks. Thepresentnewspeciesiseasilydistinguishedfromtheotherspeciesof
thegenus Malthinus distributed in Japan and itsadjacent areas including East and
SoutheastAsiabythepeculiarcolorpatternonthebodyandtheconformationofmale
genitalia.
要 約
高橋和弘:北大東島産のMalthin,,s属の1新極. - ;lヒ大東‘? (大東諸島) 産の標本に基づき,
ジョウカイポン科のl新種Malthinusnaka川s/111spnov.を記11?した. 本種は, 大東者島から初め
て記録されるジョウカイポン科の極で, 著な色彩パターンから,Malthlnus属の他種とは容易に
識別が可能である.
References
BRANcUcc1, M., l980.Molphologiecomparee,evolutionetsystematiquedosCantharidae (Insecta:Cole-
optera).Ent basil.,5:215-388.
KAwANA,T.,1988.LandformoftheRyukyuIslands.127pp.Shinsei-Tosho,Naha. (InJapanese)