Euplectus lapponicus (Coleoptera: Staphylinidae: Pselaphinae), a new species from boreal Finland

2019·0.89 MB·

by  Ivan Löbl

©EntomologicaFennica.15December2010
Euplectus lapponicus (Coleoptera: Staphylinidae: Pselaphinae),
a new species from boreal Finland
IvanLöbl&JaakkoMattila
Löbl, I. & Mattila, J. 2010: Euplectus lapponicus (Coleoptera: Staphylinidae:
Pselaphinae),anewspeciesfromborealFinland.—Entomol.Fennica21:181–
186.
AnewspeciesofthegenusEuplectusLeach,1817,E.lapponicussp.n.Löbl&
Mattila,isdescribedfromtheNorthBorealzoneofFinland.Thespeciesisdis-
tinctive,andmaybeeasilydistinguishedbythereducednumberofelytralfoveae,
incombinationwiththesizeofthebody,thepunctation,andthegenitalcharac-
ters.
I.Löbl,Muséumd’histoirenaturelle,routedeMalagnou1,CH-1208Geneva8,
Switzerland;E-mail:[email protected]
J. Mattila, Metsähallitus, Natural Heritage Services, P.O.Box 36, FI-40101
Jyväskylä,Finland;E-mail:[email protected]
Received14April2010,accepted7June2010
1.Introduction
Kurbatov,1988,1991).AccordingtoS.A.Kur-
batov(personalcommunication),E.gravisKur-
Euplectus Leach, 1817 is one of the pselaphine batov,1988,andE.rutilansKurbatov,1988were
generaassociatedwithrottenwoodofalargeva- foundinRussianborealforestsinadditiontoE.
riety of trees (e.g., Horion 1949, Kangas 1951, karstenii, E. punctatus, E. signatus, E. mutator,
Palm1959,Pearce1957).Somespeciesarealso andE.decipiens.EuplectuskarsteniiandE.sig-
found under loose bark, in leaf litter, compost, natuswereintroducedtoNorthAmericabutare
moss,inbirdnests,andmay beassociatedwith unknownfromborealtaigaofCanadaandAlaska
ants.Todate,tenofthe30speciesknowntoin- (Chandler 1997, Davies 1991, Wagner 1975).
habit Europe have been recorded from Finland Typically, the north European Euplectus, as are
(Silfverberg2004,Löbl&Besuchet2004),alloc- allotherpselaphines,MeliceriatragardhiPalm,
curring also in the boreal zone (see Ahti et al. 1938excepted,arewidely distributedandwell-
1968):E.kirbiiDenny,1825andE.nanus(Rei- knownspecies.DiscoveryofanadditionalPsela-
chenbach,1816),extendnorthtoreachtheSouth phinae species from northern Europe seemed
Borealzone,E.sanguineusDenny,1825andE. therefore improbable. Euplectus lapponicus de-
bescidicus Reitter, 1882 reach north the Middle scribedbelowshowsthatapplicationofvarious
Boreal zone, and the ranges of E. piceus Mot- samplingmethodsmayleadtounexpectedfind-
schulsky, 1835, E. decipiens Raffray, 1910, E. ings,eveninhabitatsthatexhibitlowtaxonomic
signatus(Reichenbach,1816),E.punctatusMul- diversity.
sant & Rey, 1861, E. karstenii (Reichen- The identification of European Euplectus is
bach,1816),andE.mutatorFauvel,1895extend noteasy, unless characters ofthemalegenitalia
northtoreachtheNorthBorealzone.Euplectus areused.Theexternalcharactersgiveninexisting
speciesarefoundintheRussianborealtaiga(see keys(e.g.,Jeannel1950,Kangas1951,Besuchet
182 Löbl&Mattila (cid:127) ENTOMOL.FENNICAVol.21
1974)areoftennotclearlydefined,erroneously eringmostoffronsandvertex, vertexwithme-
termed,orcomparativeanddifficulttoapplyun- dian carina. Posterior arms of U-shaped frontal
lessyouhaveaccesstoreliablyidentifiedspecies. impression shallow, indistinct but reaching
Asanexample,theheadwidthisusedasakey tentorialfoveae.Pronotumaboutaswideashead
character but usually without indication if mea- at eye margins, widest in anterior third. Elytra
suredwithorwithouteyes,thevertexalimpres- withtwobasalfoveae.Discalcarinaeontergite1
sionistermeda“fovea”,andexpressionssuchas distinct, extended beyond tergal mid-length.
“more”and“less”arefrequentlyused.Inspiteof Maletrochanterslackingobvioussexualcharac-
that,E.lapponicusmaybereadilydistinguished ters.Aedeaguswithfusedparameres,setalpatch
byitsexternalcharacters. situatedonleftparameralmargin,apicalmargin
deeplyemarginate,apophysesabsent,basalbulb
weakly elongate, dorsaldiaphragmsmall, inter-
2.Materialandmethods
nalsacbifidapically.
Description. Length 1.63–1.80 mm (males),
The terminology follows Chandler (2001). The 1.85–1.87mm(females).Bodyuniformlyrufous,
aedeagusoftheholotypeandlegsandantennaof antennaeandfemoraslightlylighter,tibiaesome-
one paratype are mounted on slides in Canada whatlighterthanfemora,palpiandtarsidistinctly
balsam,andareillustrated.Theaedeagiofthere- lighter than femora. Pubescence short. Head in
maining males are mounted in Euparal. The dorsalviewsub-trapezoidal,0.24–0.26mmlong
malesweredissectedpriortoourstudyandtheir to neck constriction (0.27–0.31 mm with neck
abdominalapicalsegmentswerelost,besidesone constriction),maximumwidth0.31–0.35mmat
specimen. The length of the body is measured posterior eye margin, with eyes 0.33–0.37 mm.
fromtheanteriormarginofthefronttotheapical Anterior margin of frons convex. U-shaped im-
marginofabdominaltergite4inmales,or5infe- pressionshallow,notclearlydelimited,withpos-
males.Arabicnumeralsaregiventoexposedab- terior arms almost indistinct, reaching vertexal
dominaltergitesandsternites. foveae.Centreoffronshardlyconvex,gradually
inflexedanteriorly.Dorsalpostantennalpitsdis-
Theexaminedspecimensaredepositedinthefol- tinct, separated from U-shaped impression.
lowingcollections: Vertexalfoveaenotinimpressions,aboutinlevel
with eye centres, interval between them about
MZH:ZoologicalMuseumoftheHelsinkiUni- twiceaslargeasfovealdiameter,smallerthatin-
versity,Helsinki,Finland tervalsbetweenfoveaeandlateralheadmargins.
MHNG:Muséumd’histoirenaturelle,Geneva, Temporashorterthaneyes,rounded.Eyesmulti-
Switzerland faceted,indorsalviewlongerthangenae.Vertex
PCJM:Privatecollectionofthesecondauthor lacking median impression, with median carina
PCEH:PrivatecollectionofEskoHyvärinen extendedto,orslightlyanterior,levelofposterior
eyemargin.Punctationdenseandfairlycoarseon
dorsum of head, puncture diameters about as
3.DescriptionofEuplectuslapponicus
large as puncture intervals, on centre of frons
sp.n.Löbl&Mattila
puncturessparse,anteriormarginoffronsfinely
punctate. Subgenal punctation very dense and
Type specimens. Holotype: male, in MZH., coarse,puncturesnarrowly separated.Antennae
carded: Finland 758084:345402 Li: Inari, Alli- (Fig.1a)withsegments1and2elongate,segment
vuotso 21.VI.–20.VII.2007 Esko Hyvärinen et 3 as long as wide, segments 4 to 8 wider than
al.leg.Paratypes:3males,2females,withsame long, segments 5 and 7 each hardly larger than
data as the holotype. One male paratype in segments 4, 6 and 8, segment 8 slightly wider
MHNG, one male paratype in PCJM, one male than segment 7, following segments gradually
paratype in PCEH, the remaining paratypes in larger, segment 11 as long as segments 8 to 10
MZH. combinedandwithoutbasalstalkabout1.6times
Diagnosis.Headwithdistinctpunctationcov- as long as wide. Pronotum0.30–0.34 mmlong,
ENTOMOL.FENNICAVol.21 (cid:127) Euplectuslapponicussp.n.fromFinland 183
Fig.1.Euplectuslappo-
nicussp.n.,male.–a.
Antenna.–b.Meso-
tibia.–c.Metatibia.–d.
Aedeagus,dorsalview.
–e.Aedeagus,ventral
view.–f.Aedeagus,lat-
eralview.Scalebara=
0.2mm,scalebarb=
0.1mm.
0.31–0.36 mm wide, widest in anterior third, beyondmetasternalbasalfourth.Elytraatsuture
graduallynarrowedbasally,lateralmarginsarcu- 0.45–0.53 mm long, maximal length 0.48–0.55
ate,basalandapicalangleswidelyrounded,basal mm,widestbeforeapicalfourth,combinedmaxi-
marginarcuate.Medianlongitudinalsulcusfairly mal width 0.46–0.54 mm. Lateral margins
deep, hardly reaching anterior sixth of disc, weaklyrounded.Lateralmargincarinaeindorsal
joined to antebasal sulcus. Punctation fairly view obsolete or hardly visible near base.
coarse,nearbasevery dense,onremainingsur- Humeral tubercles low. Each elytron with two
facesimilartothatonprevailingdorsalsurfaceof small basal foveae similar in size, inner foveae
head, with puncture diameters about as large as joinedtosuturalstria,outerfoveajoinedtodiscal
puncture intervals. Prosternum with transverse stria;anteriormarginofinnerbasalfoveaaboutin
wrinkles. Mesosternum impressed in middle. level with posterior margin or centre of outer
Metasternum with median impression starting basalfovea.Discalstriaextendedslightlybeyond
184 Löbl&Mattila (cid:127) ENTOMOL.FENNICAVol.21
Fig.2.HabitatofEu-
plectuslapponicus
sp.n.inLemmenjoki
NationalPark,Alli-
vuotso.
elytral-mid-length,hardlyvisibleindorsalview, evenly long setae (lateral view), apex broadly
distinctinobliqueview.Metathoracicwingsfully rounded, with large emargination. Membranous
developed,functional.Abdominaltergites1and structuresdistinct.Internalsacbifidapically,with
2withdiscalcarinaedivergingapically,extended leftarmslightlylongerthanrightarm.
somewhatbehindrespectivetergalmid-length,at Distribution.NorthernFinland.
basesseparatedbyintervalsaboutaslargeasfifth Habitat.Naturalborealforest,about200km
ofbasalwidthoftergum.Followingtergiteslack- north from Arctic Circle, close to forest border
ingdiscalcarinae. zone,ontheborderofthedistributionofNorway
Malesexualcharacters.Mesofemoraslightly spruce (Picea abies). The site is located in
inflated. Inner side of mesotibiae with small LemmenjokiNationalParkinFinnishLappland
subapicaldenticle(Fig.1b).MetatibiaeasinFig. (lat. 68°18,508’, long. 25°52,891’). The eleva-
1c. Trochanters and abdominal ventrites 1 to 5 tionisratherlow(290mabovesealevel).Thefo-
lackingobvioussexualcharacters.Ventrite6with restisopenwithcanopycoverof28%andvol-
apicalmarginconcave,inmiddle0.06mmlong, umeoftreesonly67m3perhectare.Thevolume
withshallowdepressioninmiddle,twoadmesal, ofScotspine(Pinussylvestris)is39m3/ha,Nor-
transverserowsofpeg-setae. Eachrowsituated way spruce21m3/ha,andDowny birch(Betula
proximally a minute transverse ridge. Left row pubescens) 7 m3/ha (Fig. 2). The site is sur-
consistingoffivebluntpegsetae,rightrowcon- roundedbymosaicofnorthernmiresandforests.
sistingofsixpegsetae,fiveofthembluntandas Thespecimenswerecollectedbytrunkwindow
in the left row, the inner peg seta narrower and traps(seeHyvärinenetal.2006).
pointed. Inner side ofventrite 6 with transverse Relationships. Euplectus lapponicus shares
apicomedian ridge. Hemisternites (morphologi- with E. validus a reduced number of elytral fo-
cal tergite IX) with right half concave mesally, veae, a moderately elongate basal bulb of the
left half sinuate mesally. Aedeagus (Figs 1d–f) aedeagus with small dorsal diaphragm, a wide
0.27–0.29 mm long. Basal bulb oval in dorsal paramerebearinglongsetaeatleftmargin,anda
view.Dorsaldiaphragmsmall,round.Parameres bifid internal sac. As these characters may be
fused,about1.5timesaslongasbasalbulb,with homoplasies,thecloserrelationshipsofthenew
remnantofleftparameresdistinct,bearingalmost speciesareunknown.
ENTOMOL.FENNICAVol.21 (cid:127) Euplectuslapponicussp.n.fromFinland 185
4.Discussion
of Euplectus in two subgenera, Euplectus s. str.
andDiplectellusReitter,1909,basedonthepres-
Members of Euplectus usually have elytra with enceorabsenceofavertexal“fovea”(infactan
fourbasalfoveae.EuplectusbonvouloiriReitter, impressionatposteriormarginofthevertex)and
1882 may have the number of basal foveae re- ontheparameresthatmaybeseparatedorfused.
duced,andE.validusBesuchet,1958possesses He(Jeannel1956)establishedfortheNorthAfri-
onlytwobasalfoveae.E.lapponicus,whichalso canspeciestwoadditionalsubgenera,Diplectidi-
hasonlytwofoveaeatthebaseofeachelytron, usandEuplectinus,basedontheinternalsac.Ac-
wouldkeyoutinBesuchet(1974)asE.validus. cordingtoJeannel(1956),Diplectellusisdefined
E.lapponicusalsoshareswithE.validusamod- bythebifidinternalsac.Inaddition,Jeannel(l.c.)
eratelyelongatebasalbulboftheaedeagus,witha placedthespeciesofthesesubgenerainanumber
small dorsal diaphragm, parameres fused and ofinformalgroups.Wagner(1975)andChandler
wide, lacking apophyses, setal patch situated at (1997) listed Diplectellus as a valid subgenus,
leftparameralmargin,andtheinternalsacbifid andWagner(1975)recognizedinformalspecies
apically. E. lapponicus may be readily distin- groupsfor theNearcticspecies, whileKaraman
guishedfromE.validusbytheheadbehindeyes (1962)usedonlytheinformalspeciesgroups,and
about as wide as the pronotum (while it is dis- Besuchet(1974)listedJeannel’ssubgenera,asa
tinctlynarrowerthanthepronotuminE.validus), number of other genus-group names, in synon-
the pronotal punctation coarser than the elytral ymywithEuplectus.SubsequentworkersonPa-
punctation, the lateral contours of pronotum laearctic Euplectus (Kurbatov 1988, 1991, Sa-
rounded(obliquenearbaseinE.validus),andthe bella1998)ignoredboth,thesubgenera,andthe
elytrawiththeinnerbasalfoveaesituatedcloseto informalspeciesgroups.E.lapponicuspossesses
thebasalmargin(inE.validustheanteriormargin characters used to define Diplectellus, but does
of the inner basal fovea is situated in or behind notprovideevidencesupportingthemonophyly
levelofposteriormarginofouterfovea).Besides, ofthatgroup,norsupportsitasavalidsubgenus.
the male mesofemora are notably swollen, the
mesotibialdenticleisapical,andtheparamereis Acknowledgments.EskoHyvärinensetthewindowtraps
notapicallynotchedinE.validus. togetherwithMiaVuomajoki,JariKangasniemiandPet-
teri Polojärvi from Metsähallitus’Natural Heritage Ser-
ThefunctionalmetathoracicwingsinE.lap-
vices.JKandPPemptiedthetrapsduringtheseason.Esko
ponicus provide evidence that the reduction of
Hyvärinenprovidedphotographsofthesiteandgavecom-
wings is not necessarily correlated with the re- mentsonthemanuscript.DonaldS.Chandler,Durham,
ductionofthenumberofelytralfovea,asstated commentedanearlierdraftofthepaper.Informationon
byBesuchet(1974). distributionofEuplectusinborealRussiawaskindlypro-
videdbyS.A.Kurbatov,Moscow.
Thelengthofthediscalcarinaeontheabdom-
inaltergite1and/or2isoneofthekeycharacters
used by authors (e.g., Jeannel 1950; Kangas, References
1951,Besuchet1974)foridentificationofWest
Palaearctic species of Euplectus. These carinae
Ahti,T.,Hämet-Ahti,L.&Jalas,J.1968:Vegetationzones
are not clearly visible in all species and their
andtheirsectionsinnorthwesternEurope.—Annales
lengthmayvarywithinaspeciesasitmayappear BotaniciFennici5:169–211.
tobedifferentdependingontheangleofobserva- Besuchet,C.1974:24.Familie:Pselaphidae.Pp.305–362.
tionandonoptics.Whilethesecarinaeextendde- —In:FreudeH.,HardeK.W.&G.A.Lohse(eds),
DieKäferMitteleuropas.Band5StaphylinidaeII(Hy-
cidedly posterior to the respective tergal mid-
pocyphtinaeundAleocharinae)Pselaphidae.Goecke
lengthinE.validus,theyarelessclearlyseenin
&EversVerlag,Krefeld,381pp.
E.lapponicus.Ifconsideredasnotextendingpos- Chandler,D.S.1997:AcatalogoftheColepteraofAmeri-
terior to the tergal mid-length, the new species canorthofMexico.Family:Pselaphidae.—United
maykeysoutasE.punctatusinBesuchet(1974), StatesDepartmentofAgriculture,ix+118pp.
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