Occurrence of Yamautidius (Coleoptera, Trechinae) in the Upper Hypogean Zone of Southwestern Shikoku, Southwest Japan

2006·4.6 MB·

by  Ueno, S-I

Elytra.T1okyo,34(2):249-256.November18.2006
Occurrenceof Yarnautidius (Coleoptera, Trechinae) in the
UpperHypogeanZoneofSouthwesternShikoku,
Southwest Japan
Shun-lobi UENo
DepartmentofZoology,NationalScienceMuseum(Nat.Hist)
3-23-l Hyakunin-cho,Shinjuku,Tokyo,169-0073Japan
and
Takao NAITo
3-4-13Ikeda,Neyagawa-shi,Osaka,572-0039Japan
Abstract Twonewspeciesoft1、etrechinegenusYa,nautldiusaredescribedfor
the first time from the upper hypogeanzoneofsouthwesternShikoku,Southwest
Japan. Bothseemtobelongtothe11ozlm1lcomplexofthegroupof「.fatipe11川s,and
arereadilydistinguishedfromY. tloz1l,nt1andfromeachotherbypeculiaritiesof the
aedeaga1apical lobe and of the copulatory sclerite. The new namesgiven are
Yamautidius (s.str)crosonand Y. .silo'no.
Twenty-four species of small delicate trechinebeetles belonging to thegenus
Yalmautidiushavebeen knownuptothepresentonly from limestonecavesandmine
aditsinthewesternpartof theIslandofShikoku,SouthwestJapan (cf.UtNo,1957,
1960, l978,1982,1990). Theyareclassifiedintotwosubgenera,Yamautidius(s.str)
andMiyamaidius(UtNo,1978),andthemembersoftheformerarearrangedintonine
complexesof threespecies-groups(cf.U直NO,1982,pp 59-61,1990). Occurrenceof
upperhypogeanpopulationshaslongbeenanticipated,butourexpectationhasnotbeen
fulfilleduntil thelastspring. Anotherexpectationunfulfilledisclarificationofsouth-
westward extension of the generic range; thepreviouslymarked southern limit of
distributionisArinoki-no-kanaudoMineinTowa-mura, locatedatthenorthernsideof
theuppermaincourseoftheShimanto-gawaRiver,whichisinhabitedbyY.uozumiiS.
UtNo(1982,pp.13,30,figs 24-26;cf.No8onfig55,inU直No,1982,p 63). Towards
thesouthwest of Towa-mura, thereisa fairlywideareadominatedby theUwaHills,
surroundedbythemiddlecourseoftheShimanto-gawaRiveranditsmaintributary,the
Yoshino-gawaontheeastandnortheast,bytheNakasujiDepressiononthesouth,and
bytheBungoChannelonthewest. Noanophthalmictrechinebeetleswerefoundinthis
areabefore, mainlybecauseof theabsenceof natural cavesandoftheprevalenceof
250 Shun-lobi UENoand Takao NAITo
graniticgroundnot favourablefor theexistenceof upperhypogean trechines.
In May of this year, thesecondauthorof thepresent paper made two tripsto
southwesternShikokuandsucceededinfindingoutthreenewlocalitiesofYamautidius
at the southeastern side of the Uwa Hills to the west of the middle course of the
Shimanto-gawaRiver. Ateachlocality,anophthalmictrechinesweredugout fromthe
upperhypogean zone,andthegeneric rangewasextendedsouthwestwardsformore
than30kminabeeline,sothatboththelong-pendingproblemsmentionedabovewere
clarifiedbythis discovery. After acloseexamination, it becameapparent that the
specimensobtainedwereclassifiedintotwonewspeciesoftheuozumii complexofthe
1atppennisgroup. Theywillbedescribedinthepresentpaperunder thenamesY.croson
andY.sucmo. Theabbreviationsusedarethesameasthoseexplainedonp7ofUtNo's
1982paper.
Yamautidius(s.str)crosonS.UtNoetNAIT0,sp
nov
(Figs.1-3)
Length: 3.35-3.60mm (fromapicalmarginofclypeustoapicesof elytra).
Related toY. uozumiiand identical withthelatter in thecharacteristicconforma-
tion of thebasal parts of elytra, but a little larger and dark-coloured, with
m ore
anteriorlyenlargedprothoraxandobviouslyamplerelytra. Definitelydifferent fromY.
uozumii inconfigurationofmalegenitalia,particularlyofcopulatorysclerite.
Colourreddishbrown,shiny,withinfuscatedheadandpronotum;clypeus,labrum,
palpi,antennae,venter ofhindbody,andlegspaler thanelytra. Microsculpturefine,
distinctlyimpressedonheadandpartiallydegeneratedonpronotum,mostlyconsisting
oftransversemeshes,largelyobliteratedonelytrathoughperceptiblehereandthereas
finetransverselines.
Headfairlylarge,similar tothatofY.uozumii;antennaerelativelylong, reaching
apicaltwo-fifthsofelytrain ,withpedicelaboutahalfaslongasantennomere3or4,
eachofwhichisnearly3.5timesaslongaswide,antennomeres8-10eachsubcylindrica1
and nearly three times as long as wide, terminal antennomere about as long as
antennomere3andobviouslylongerthanscape.
Pronotumwiderthanheadandalittlewiderthanlong,widestataboutsix-sevenths
from base, andalmoststraightlynarrowedposteriadtowardsante-basalsinuationof
sides;PW/HW130-1.38 (M I33),PW/PL1.03-1.10 (M1.06),PW/PA t29-1.34
(M I32),PW/PB l66-1.76(M I71);sidesratherwidelyreflexednear frontangles,
verynarrowlyborderedatmiddle,andmoderatelyreflexedinbasalarea,brieflybut
stronglyroundedin front,eitherstraightorslightlyemarginateatmiddle,shallowly
sinuateataboutbasalsixth,andthenmoreorlessdivergenttowardshindangles,which
areacuteandpostero-1atera11yprotrudent;apexmuchwiderthanbase,nearlystraightor
slightlybisinuate,PA/PBl25-1.35(MI29),withfrontanglesproducedforwardsand
roundedat theexternalsidestogetherwithanteriormost portionsof lateralmargins;
baseslightlyemarginateat middleandslightlysinuateoneachsideinsidehindangle;
UpperHypogeanYamaittldiusfromSouthwesternShikoku 251
Fig.1. Yamattttdius(s.str)croso1t S.UtNoet NAIT0,sp nov.,c,;;', fromKukiin Nishitosa-mura
basalareanarrow,withsmallbasal foveae. Lateralexpansionofpropleuranarrowlybut
clearly visible fromabove.
Elytraovateandample,muchwider thanpronotum, widestat aboutmiddle, and
almost equally narrowed towards bases and towards apices; EW/PW 1.67-1.72
(M I 69),EL/PL2.53-2.59(M2.56),EL/EW139-1.45(M I42);shouldersdistinct
252 Shun-lobi UENo and Takao NAITo
though rounded; prehumera1borders moderately obliqueand slightly emarginate,
becomingmuch finer towardsbasal pedunclebut complete to thebaseof stria5, and
devoidofbasaltubercles;sidesnarrowlybordered,gentlyarcuateatmiddle,andrather
widely roundedat apiceswithout appreciablepreapica1emargination, formingasmall
re-entrant angleatsuture;dorsummoderatelyconvexthoughwidelydepressedon the
disc inbasal third;striaesuperficial andsmooth,striae l-5moreor lessdeepened in
basal depression, 6-7 fine, 8moderately impressedbehind themiddleset of marginal
umbilicate pores; apical striole clearly impressed, free at the anterior end though
directedtostria5;stria3withtwosetiferousdorsalporesat1/7-1/6andabout1/3
frombase, respectively,stria5withasinglesetiferousdorsal poreat about 3/5 from
base;preapica1porelocatedbehindtheleveloftheterminusofapicalstricto,andmore
distant fromapexthan fromsuture. LegsordinaryforamemberofYamautldius.
Malegenitalorganratherlightlysclerotized,basicallysimilar to that ofY.uozumii
butmarkedlydifferent inconfigurationofaedeaga1apical lobeandofcopulatorypiece,
thelatterofwhichresemblesthatofY eosS.UtNo(1982,pp.13,38,figs 32-33) from
Hoshigataki-no-iwayaCaveatYokokura-yama. Aedeagusone-thirdaslongaselytra,
tubular, slender, andgentlyarcuate, withsmallbasalpart and relatively short apical
lobe; basalpartmoderatelycurvedventrad,shallowlyemarginateat thesidesofsmall
basalorifice,andwithhyalinesagittalaileron; viewedlaterally,apical lobefairlyshort,
straight,parallel-sided,andnarrowlyroundedattheextremity;vieweddorsally,apical
lobelightlycurvedtotheright,graduallynarrowedapicad,andbluntat theextremity;
ventralmarginshallowlyemarginatebeforemiddleinprofile. Innersacscalythoughthe
scales are not sclerotized; copulatorypiecenearlyahalfaslongasaedeagus, twisted,
fairlybroad inproximal three-fifthsbutbecomingnarrowerapically,andblunt at the
apex. Styleswithnarrowapicalparts, leftstyleobviouslylonger thantheright,each
bearingthreeapicalsetae.
Typeseries. Holotype: , allotype:早(founddead);paratypes: 2 ,3早早(all
founddead),4-V-2006,T.NAIT01eg;1早(tenera1),26-VIII-2006,T.NAIT0leg. All
deposited in thecollectionof theDepartment ofZoology, NationalScienceMuseum
(Nat. Hist),Tokyo.
Type locality. Kuki, 290m inaltitude, inNishitosa-muraof Kochi Prefecture,
southwesternShikoku,Southwest Japan.
Nlotes. It wasmost unexpected that themalegenitaliaof Y. croson resemble in
manyrespectsthoseofY eosoccurringattheeasternperipheryof therangeofgeneric
distribution (cf. No. 13on fig 55, inU直NO, 1982,p 63), about 68kmdistant to the
northeast in a beeline from the type locality of the present species. In external
morphology,however,Y.crosonissimilartoY.uozumii, whosetypelocalityisabout21
kmdistant tothenorth-northeast inabeeline. It isprobablethat parallelmodification
of aedeaga1innerarmature tookplacebetween thecomponentspecies of theuozumii
complexand oftheeos complex, resulting in formation ofcloselysimilar copulatory
sclerites in two remotely relatedspecies. Thisinferenceisalsosupportedby theclose
similarityof copulatoryscleritesbetweenY. sucmo (tobedescribedon the following
Upper HypogeanYa,na1ltldiusfromSouthwesternShikoku 253
3
、 /
/、一一 /
'
0
5
Figs 2-5. Malegenitaliaof Yamautldiusspp;left lateralview (2, 4), andapicalpart ofaedeagus,
dorso-apical view (3, 5). - 2-3. Y. croson S. UtNo et NAIT0, sp nov., from Kuki in
Nishitosa-mura. - 4-5. Y. sucmo S. UENoet NAIT0, sp nov., from the Shimo-no-tani at
Shimosukain Sukumo-shi
254 Shun-Ichi UENoand Takao NAIT0
pages) andY basisquamatus, the former belongingto theuozum11complex andthe
latter totheeoscomplex. Thetypelocalityofthe latter isabout 70kmdistant to the
north-northeast inabeeline from that of the former.
ThetypespecimensofY.crosonwerefoundonthenorthernslopeoftheHoke-ga-
moriRidge,themainsoutheastwardbranchoftheUwaHills. All thespecimenswere
dugout fromascreedepositedinagullyabout 300mbelow thewatershed. Unfortu-
nately,onlyonematuremalewascollectedalive;alltheotherswereinfectedwith fungi
andfounddead,thoughtheallotypeisinafaircondition.
Thespecificname“croson” isderived fromaLatinizedspellingof Kuroson,since
the type localitybelongsto theKuroson-gawadrainageareawell known toJapanese
entomologistsasagoodcollectingsiteofvariousinsects.
Yamautidius(s.str )slicmoS. UtNoet NAIT0,sp nov
(Figs 4-5)
Length: 3.35-3.70mm (fromapicalmarginofclypeustoapicesofelytra).
Externally veryclose toY. croson, but distinguished fromit bynarrowerelytra.
Strikinglydifferent fromY. croson inconfigurationofmalegenitaliaincludingcopula-
torypiece.
Colour and microsculpture as in Y. croson. Head and pronotum practically
identicalwiththoseofY.croson;PW/HW l 25-1.31,PW/PL1.06-1.12,PW/PA t27-
1.31, PW/PB 165-1.73, PA/PB 129-1.32. Elytra obviously narrower than in Y.
croson;EW/PW160-1.64,EL/PL2.73,EL/EW152-1.58;basalpartsasinY. croson;
sidesmore feeblyarcuateatmiddleandmorenarrowly rounded at apicesthan inY.
croson;striationandchaetotaxyasinY.croson.
Malegenital organrelativelylarge though lightlysclerotized, basicallysimilar to
that ofY. crosonbutstrikinglydifferent inconfigurationofaedeaga1apical lobeandof
copulatorypiece,thelatterofwhichresemblesthatofY basisquamatusS.UtNo(1982,
pp.13,41,figs36-37) fromTashiro-no-anagamiPotholeatNakatsuofYanadani-mura.
Aedeagus about two-fifths as long as elytra, gently compressed, hardly arcuate at
middle,withventrallycurvedbasalpartandlongapical lobe;basalpart fairlyelongate,
stronglycurvedventrad,withsmallbasalorificedeeplyemarginateatthesides;sagittal
aileronnarrowandhyaline;vieweddorsally,apicalpartgraduallynarrowedintoalong
apical lobe, which isinclined to theright anddilated into asubpentagona1terminal
portion;viewedlaterally,apicallobenarrow,parallel-sided, andblunt at theextremity;
ventralmargin nearlystraight in profile. Inner sacscaly, though thescalesarenot
sclerotizedanddonot formany teeth-patch;copulatorypieceverylargeandelongate,
four-seventhsas longasaedeagus, longitudinallyduplicate, and twisted from ventro-
proxima1todorso-apica1parts,withnarrowlyroundedapex. Stylesnarrowed towards
apices, leftstyleobviouslylargerthantheright,eachbearingtwoorthreeapicalsetae.
Female unknown.
Typeseries. Holotype: ,paratype: l 5-V-2006, T. NAIT01eg. Depositedin
,
UpperHypogeanYa,na1ltldiusfromSouthwesternShikoku 255
thecollection of theDepartment ofZoology, NationalScienceMuseum (Nat. Hist),
Tokyo.
Type locality. Shimo-no-tani, 150m inaltitude, atShimosukaofSukumo-shi in
KochiPrefecture,southwesternShikoku,SouthwestJapan.
Furtherspecimenexamined. 1 Kozu,150malt.,Sukumo-shi, Kochi Prof.,20-
,
V-2006,T. NAIT01eg. (NSMT).
Notes. Thisisan interestingspeciesvery closelysimilar toY. croson inexternal
morphologybut incrediblydifferentfromitingenitalicfeatures. Itstypelocalityisonly
9.2kmdistant tothesouth-southwestinabeelinefromthatofY.crosot1, thoughlying
near thesoutheastern foot of theSasa-yamaRidgestretchingon theother sideof the
Matsuda-gawaValley. The twospecimensof the typeserieswere found in aclayey
depositofmudstoneandsandstonegravelatadepthofabout60cm.
ThesinglemalespecimentakenatKozu(3.40mminthelengthofbody)perfectly
agreeswiththetypeserieswiththeexceptionoftheaedeaga1apicallobe,whoseterminal
portionisgentlydecurved. Thisis,however,regardedasanindividualvariation. The
standard ratiosin thisspecimenareas follows: PW/HW 136, PW/PL l.14, PW/PA
1.30, PW/PB182, PA/PB140, EW/PW 156, EL/PL 2.70, EL/EW 152.
Kozuisasmallvillagelyingonthesamehill3.8kmsoutheastfromthetypelocality
of Y. sucmo. Thesinglespecimenknownwasdugout fromadeposit of fairly large
flakesofshaleat thesideofa forestry road.
Thespecificname“sucmo” isderived froma LatinizedspellingofSukumo, the
southernmostknownlocalityofYamautidius.
要 約
上野俊一・内藤隆夫: 四国南西部で発見された地下1層ｷ性のケ ฀ネ(cid:18287)クラチビゴ(cid:18285)(cid:18286)シ .
四国南西部の字和山地を中心とする地域からは, これまで無aR、のチビゴミムシ類がまったく知ら
れていなかった. しかし今年の春になって, この地域の南東部の3力所で, 地ト1 居ﾀ性のケ ฀
メクラチビゴミムシが発見され, 検11の結果, アリノキメクラチビゴミムシ系列の2新硬j に分類
されることが判ったので, クロソンメクラチビゴミムシYamautidiuscrosonS.UtN0etNAIT0お
よびスクモメクラチビゴミムシY.sucmoS.UtNoetNAIT0という新名を与えてこの論文に記載
した. ケムネメクラチビゴミムシ目r1属の既知極は22極知られているが, いずれも石1J1.洞か鉱山の
iJi道から見つかったもので, 地下1層ｷ性の和1ﾀは今回はじめて報告されることになる生物地理学
的に重要な分布の空白域からの発見であるとともに, 洞麻生物学的にも重要な新発見である.
References
UtNo,S.-I.,1957. StudiesontheJapaneseTrechinae(VI)(Coleoptera,Harpalidae). Me,n. Coil. ScI. Univ.
Kyoto, (B),24:179-218,pl.1.
- 1960. Occurrence of Yama1ltldlus in two limestone caves of western Shikoku (Coleoptera
Harpalidae). :「rans.Shikok11ent.Soc.,Matstlyama 6:67-75.
- 1978. TwonewtrechinebeetlesfrommineaditsinnorthwesternShikoku,Japan. Billinatn.Sci
256 Shun-Ichi UENoand Takao NAIT0
Mils., Tokyo, (A).4:197-205.
UE、'o,S.-I.,1982. Yama11tldius(Coleoptera,Trechinae),anexampleofremarkablegenitalicdifferentiation
J.speleo1.Soc.Japan,7:5-65.
- 1990. A ne、v anophthalmic trechine beetle o「the genus Ya,nautidi1ls 「rom western Shikoku
SouthwestJapan. Ibid.,15:22-25.
Elyt・ta.Tokyo 34(2):256,November18.2006
TheStaphylinidBeetles (Coleoptera) Newly Recorded from the
Islandof Tosa-okinoshimain Kochi Prefecture,Japan
Yasuaki WATANABE
LaboratoryofInsectResources,TokyoUniversityofAgriculture,
Atsugi, Kanagawa,243-0034Japan
Onelyonespecies,Stertaesthetussun1oidesSHARP,hashithertobeenreportedbyWATANABE
(2005, p640) from the Island of Tosa-okinoshima in Kochi Prefecture. Examining the
staphylinid beetles deposited in the collection of the Laboratory of Insect Resources, Tokyo
University of Agriculture, I have found three unrecordedspecies from thisisland. They are
recordedbelowwiththecollectingdata.
1. Isocheilusstaphylinoldes (KRAATz)
1c11;l,28-VI-l955, Y.WATANABEleg.
2. ScopaeusvlrlffsSHARP
E,. 3c1?o?,1・28-VI-1955 Y WATANAB leg
3. Phi1or1thus(s.str)gastralisSHARP
l早,29-VI-1955,Y.WATANABEleg.
Reference
WATANABE, Y.,2005. Occurrenceo「StetlaesthetussltntoldesSHARP(ColeOptera,Staphylinidae) f「omthe
IslandofTosa-okinoshimaof「southwesternShikoku,Japan.Elytra,Tokyo,33:640.