Discovery of a Sibling Species of Stenhomalus fenestratus (Coleoptera,Cerambycinae) from Kyusyu ,Japan

4 Pages·1991·4.1 MB·English

by  Niisato, T

Elyt・'a, Tokyo,19(2):163-166,November l5、1991
DiscoveryofaSiblingSpeciesofSterlhonlalusfenestratus
(Coleoptera,Cerambycinae) from Kyushu,Japan
TatsuyaNIISAT0
BioindicatorCo., Ltd.,Toyama l-17-4,Shinjuku-ku,
Tokyo,162Japan
and
Hiroshi MAKIHARA
TohokuResearchCenter,ForestryandForestProducts
Research Institute,Morioka.020-01Japan
Abstract A new cerambycid beetle of the obriine genus Stenho,Ila/us is de-
scribedfromthesoutherncentralmountatinsofKyushu,Japan,underthenameofS
kunlaso. It hascloserelationshipwithS e,1est1・a1llsWHITEwidelyoccurringin Con-
tinentalAsiaandTaiwan,butisclearlydiscriminatedfromthelatterbytheshapeof
eyes,lengthandmaculationofelytra,andstructureoffemaleabdomen.
The Afro-Asian genus Ste/7/10,71a/usisaspecialized assemblage of the obriine
cerambycid beetles, mainly characeterized by the well developed eyes, apically di-
lated prothorax and unique conformation of male genital organ. Seven species
of its members have hitherto been known from theJapanese Islands, andmost of
them, with theexceptionofS.,m″lea/くaand its relative, arewell knownascommon
speciesoccurringin themainislandsand/ortheRyukyus.
InJuneof1990, twospecimensof apeculiar Ste11/1oma/usspecieswerecollected
by Mr. Atsushi NAGAl on thenorthernslopeoftheKirishimaMountainsinKyushu,
andweresubmitted to us for taxonomicstudy. It looked likeS. fe,1estratusWHITE
(l853, p 243, pl 8, fig 2), aspecieswidespread in China, Taiwan, Indochinaand
India,andcharacterized by thebrownish bodywith twopalespotsoneachelytron.
Aswasexpected,ourcomparativestudyhasrevealedthatmanyfundamental features
arecommon between the Kirishimaspecimensand S fenestratus, though they are
clearlydifferent inthedistanceofeyes,shapeandmaculationofelytra,andstructure
of female abdomen. Thisseems to indicate that the Kyushu populationattains to
thespecies level. In the following lines, we are going to describe this interesting
newspeciesunder thenameofS./くumaso.
Wewish toexpress our hearty thanks to Dr. Shun-lobi UENo for his constant
guidanceand for reading themanuscript of thispaper, and to Mr. Atsushi NAGAl
forofferingtheinvaluablematerial ofthisnewspecies.
164 Tatsuya NllsAToand Hiroshi MAKIHARA
StenhomaluskumasoNIISAT0et MAKIHARA,Sp nov
[Japanesename:Usumon-medaka-kamikiri]
(Figs. I,4-5,7,9-10)
CloselyrelatedtoS.feinest1・atusandnodoubtbelongingtothesamelinea9e. Ex-
ternallydistinguished fromthelatterbyelongatebodyform, especiallybyitsIon9
elytra,widelyseparatedeyesonventerandpalercolorationofelytra.
Female. Bodylargeandelongate,withstoutandrathershortantennaeandle9S.
Colourdarkreddishbrowntodarkyellowishbrown,except forblackeyesandsome-
whatpalerpalpi,antennalsegments, legsandabdominalsternites;elytradecorated
with2pairsofoblong,paleyellowmaculationsjustbeforethemiddleandatapical
third,ofwhichtheposteriorpairarelargeandadjoiningatsuture;suturalarealon-
gitudinallyandslightlyinfuscatedinbasal2/3.
Head voluminous, wellconvex,evidentlywider than pronotum, rugoselypunc-
turedandprovidedwithafewlonghairsinfront; fronsmuchreduced,nearly3/10
thebasalwidth,with fronto-clypea1suturelongandwide, formingaquadratecon-
cavity;mandiblessimplyarcuate,moderateinlength;eyescoarselyfaceted,expanded
thoughalittlelesssothaninS. fenest1・atus, their interspacebeingnarrowindorsal
aspect but fairlywideinventralaspect,1/4and2/5thewidthofaneyerespectively.
Antennaestoutandrathershort,1.23-1.29timesaslongasbody, witharowofIon9,
erectandstoutbrownhairs;scapeelongateandarcuate,distinctlylongerthansegment
3;terminalsegmentmoderatelyarcuate.
Pronotum moderate, weakly narrowed basad, narrower than the humeral
widthofelytra,stronglyconstrictedbeforeandbehind thelateral swellingswhich
arestronglyprominent;discstronglyconvex,providedwithweakswellings,somewhat
rugoselypuncturednearapexandbase,sparselypuncturedelsewhere,denselyclothed
withpalerecumbent pubescence throughout,andalsowitha few longerect brown
hairs. Scutellum small, clothed with pale pubescence. Elytravery long, 2.51-2.63
timesaslongasthehumeralwidth,3.52-3.38timesaslongaspronotum;sidesalmost
parallel inbasalhalf, thenweaklyarcuatetoapiceswhichare rounded; discnearly
flattenedabove, providedwithrather largepunctures thoughhardly visibleinapical
1/3, clothedwithdensepalepubescenceanderect hairs, andalsosupplementarily
withlongerectyellowishhairsonbasal halves. Legsstoutandmoderatelylong.
AbdominalsternitelVweaklyandarcuatelyemarginateondisc,providedwith
denseyellowish pubescencealong theemargination; sternite VI hardly concave at
middle,sparsely clothedwithbrownishhairsat thesides;sterniteV11thinlyclothed
with brownishhairsinthecentre.
Male. Unknown.
Measu1・ements (in mm). Body length 7.2 (holotype ) and 8.5 (paratype ).
Head:widthacrosseyes135and163, widthacrossocciput0.9and1.1; frons:length
0.16and 0.20, basal width: 0.53and0.6, apical width: 0.45and 0.5; eyewidth 0.6
and0.7 in dorsal view, 0.55and0.7 inventral view; antennae: total length8.9and
NewSte,the/,talusfromKyushu 165
.
2
3 4 5
8 9 10
Figs. 1-12. Ste'1/10/Ila/tls kutnaso N1lsAToet MAKIHARA, sp nov., tron、 the Kirishima Mts.
inKyushu,Japan(Figs.1-2,4,6-7)andS.fe,1est1・atusWHITE(Figs 3,5,8-10fromTaiwan,
11-12 from northern Thailand). - 1, Fore body; 2-3, ventralsideof head,showing
interspacebetweeneyes;4-5,femaleabdominalsternites;6-12,elytra1maculations.
11.0,segment I 0.73and1.03, II 0.15and0.2, III 0.5and0.7, IV0.80and 0.88, V
0.85 and 1.13, XI 0.8 and 1.13. Pronotum: length125 and160, maximum width
1.15 and 125, apical width 0.95and 1.15, basal width 0.9 and 1.1. Elytra: length
4.4and5.4, humeral width175and2.05.
Typese・t1es. Holotype and 1 paratype, 0beno(about 550m in alLitude),
northern slope of the Kirishima Mts., Ebino-shi, Miyazaki Prof., Kyushu, Japan,
June10,1990, A. NAGAl leg. Theholotypeispreserved in thecollectionoftheNa-
tional ScienceMuseum (Nat. Hist), Tokyo, and the paratype is in theprivatecol-
lectionof T. NIIsATo.
Notes. ThediscoveryofasiblingspeciesofS. fe11est,・atusfrom Kyushuisvery
interesting inseveral respects. It is almost doubtless that the ancestor of S fe'1es-
t,・atus originated somewhere in Continental Asia and on the way of enlarging its
range, reached Kyushuacross theEast ChinaSea. Thissmall population became
specialized later insomeexternal features; forinstance,theeyesbecamewidelysep-
166 Tatsuya NllsAToandHiroshi MAKIHAR^
arated below andtheelytrabecamelonger,whereasall thelocalpopulationsofS
fe,nestratushaveretainedapproximateeyesandbroadelytra. Thisseems toSug9eSt
that theKyushupopulationhaslongbeenisolatedfromitsmotherstock. Anyway,
thediscoveryof theeighthandexoticmemberofthegenusintheJapanesefaunaiS
mostunexpectedandworthyofparticularattention.
Thetype localityof thisnewspeciesliesat the foot of Mt.Shiratori of the
Kjrjshima Mountains. Thecollectingsitewasattheedgeofanopenforestwithpine
treeslocatednearanevergreenbroadleavedforestalongthevalleyoftheNagaeRiver.
AccordjngtoMr.NAGAl, thecollector, twofemalespecimensofthetypeserieswere
takenatthesametimefromnewlycut branchesofapinetree.
要 約
新里達也・眞t 原 : 九・用から発見されたョツポシ ダカカミキ1' に近縁の新極. - ヨツポシメ
タカカミキりは, 中国および台湾, インドシナ, インドなどから分11111の知られる属の基準種で, 上地
のfiE紋パタンにわずかな地理的変異が認められるものの, これまで単一の極として扱われてきた. こ
のたび, 九州の?奏i'島lllで採集された ダカカミキ、)は, 明らかにこの種に類縁の近いものであるが, 複
限が下面で近接しないことや, 長くて平行な上 , 大きく発達するがやや不鮮明な上地黄白色紋,
. , 順部の構造の形態的相速などにより, 重sのレベルで区別される そ れで 新 種ウスモン ダカカミキ
リとして本論文で記,做命名した. この新極は, 日本の-11ミキリ相に子期されなかった木属の8番目の
種重であり, 大陸に直系の起源をもちながら, I:1本列島に侵入したのちに孤立・分化した, 本属では数
少ない例として注Flに値する.
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