Myrmica xavieri sp. n., a new ant species (Hymenoptera: Formicidae) from Spain

2008·0.52 MB·

by  Alexander Radchenko

©EntomologicaFennica.7March2008
Myrmica xavieri sp. n., a new ant species
(Hymenoptera: Formicidae) from Spain
AlexanderRadchenko,GrahamW.Elmes&*RiittaSavolainen
Radchenko,A.,Elmes,G.W.&Savolainen,R.2008:Myrmicaxavierisp.n.,a
newantspecies(Hymenoptera:Formicidae)fromSpain.—Entomol.Fennica
19:49–54.
HerewedescribeanewantspeciesfromSpain,Myrmicaxavieri.Weplaceitin
the Myrmica lobicornis species group of which three species are previously
knownintheIberianPeninsula:M.lobicornisNylander,M.wesmaeliBondroit,
andM.lobulicornisNylander.Ofthese,M.xavierimostcloselyresemblesM.
wesmaeli.M.xavieriislikelyanIberianendemic,arelictofthefaunaisolatedin
theIberianPeninsuladuringthePleistocene.
A.Radchenko,MuseumandInstituteof Zoology,PolishAcademyof Sciences,
64WilczaStreet,00-679Warsaw,Poland;e-mail:[email protected]
G.W.Elmes,CentreforEcology&Hydrology,CEHWallingford,Crowmarsh
Gifford, Wallingford, Oxfordshire, OX10 8BB, United Kingdom; e-mail:
[email protected]
R.Savolainen,DepartmentofBiologicalandEnvironmentalSciences,P.O.Box
65, 00014 University of Helsinki, Finland; *corresponding author’s e-mail:
[email protected]
Received19January2007,accepted12June2007
1.Introduction longscape,withscapeindexSI >0.60(seedefi-
1
nition of the scape index below). In contrast,
In the ant genus Myrmica, the shape of the an- males of the schencki-group and scabrinodis-
tennal scape is important in defining species groupspecies–queensandworkersofwhichare
groups (Radchenko 1994a). Key features ofthe mosteasilyconfusedwiththoseofthelobicornis
scapearetheshapeandorientationofanyridgeor group – have a much shorter scape, with SI <
1
dentiform lobe at the bend of the base of the 0.50.Thefemalecastesofmostlobicornis-group
scape,oftencombinedwithadegreeofbending. specieshaveaverticallobeordentonthescape
Somespecieshaveaverticallobeatthebendof bendthatneverextendshorizontally(relativeto
thescape(relativetothedorsalplaneofthehead), thedorsalplaneofthehead)asdoesthelobeor
orahorizontallobeorridge,whereasinothersthe ridgeofmostscabrinodis-groupspecies.Atone
lobeorridgeislackingorbarelyvisible.Species extreme, lobicornis-group species with large
oftheMyrmicalobicornisgroupareunambigu- lobesmaybeconfusedwithsomeschencki-group
ously defined by the combination of following species,andattheotherextreme,specieswithno
features of both the female and male castes lobesmaybeconfusedwithafewspeciesofthe
(Radchenko1994a,b):workersandqueenshave scabrinodisgroup.
antennalscapesthatarestronglycurvedandoften Three lobicornis-group species are previ-
angled at the base, and males have a relatively ouslyknownfromtheIberianPeninsula:M.lobi-
50 Radchenkoetal. (cid:127) ENTOMOL.FENNICAVol.19
cornisNylander,M.wesmaeliBondroit,andM. anteriormargin)tothemid-pointoftheoc-
lobulicornis Nylander which was raised to spe- cipitalmargin.
ciesrankbySeifert(2005).Intheyear2000,one HTL length of hind tibia, measured from its
ofus(RS)collectedanestofalobicornis-group junctionwiththefemurtothejunctionwith
species,includingsexualforms,whichappeared thefirsttarsaljoint.
distinctfromtheotherthreespecies.Afteraclose HW maximumwidthofheadindorsalviewbe-
examination of the Elmes Myrmica collection, hind(above)theeyes.
another sample, collected ten years earlier, was PH maximumheightofpetioleinprofile,mea-
detected. Individuals of the two nest samples, suredfromtheuppermostpointofthepeti-
coming from well separated sites in Spain, olarnodeperpendicularlytotheimaginary
showedthesameclearmorphologicaldifferences linebetweentheanteroventral(justbehind
from all other known species, and therefore we thesubpetiolarprocess)andposteroventral
describethemasanewspecies,Myrmicaxavieri. pointsofpetiole.
PL maximum length of petiole from above,
measuredfromtheposterodorsalmarginof
2.Materialandmethods petiole to its anterior edge at the articula-
tionwithpropodeum;thiscanbedifficult
Thematerialconsistedof20workers,30queens toseeandpetioleshouldbepositionedsuch
(gynes),and35malesfromtwonestseries.The thatmeasuredpointslayonthesameplane,
sampleswerecollectedbyhandinSpainin1990 andasthisisnotalwayspossiblethisvari-
and2000.Wemeasured19morphometricchar- ableisprobablysubjecttogreatermeasure-
actersofworkers,queensandmales(unlessoth- menterrorthantheothers.
erwisestated),withanaccuracy to0.01mm,as PNWmaximumwidthofpronotumfromabove
follows: indorsalview(workers).
PPH maximum height of postpetiole in profile
AH heightofalitrunk,measuredfromtheupper from its uppermost to lowermost points,
levelofmesonotumperpendicularlytothe measured perpendicularly to the linear
level of lower margin of mesopleuron component of the lateral post-petiolar su-
(queensandmales). ture.
AL diagonallengthofalitrunkseeninprofile, PPL maximumlengthofpostpetiole,measured
fromtheneckshieldtotheposteriormargin from above from its anterior to posterior
ofthemetapleurallobe(workers)andfrom margins.
the anterio-dorsal point of alitrunk to the PPW maximumwidthofpostpetiolefromabove.
posterior margin of the metapleural lobe PW maximumwidthofpetiolefromabove.
(queensandmales). SCL combinedlengthofscutumandscutellum
ESD distancebetweentipsofpropodealspines fromabove(queensandmales).
fromabove(queensandworkers). SCWmaximum width of scutum from above
ESL maximumlengthofpropodealspineinpro- (queensandmales).
file,measuredalongthespinefromitstipto SL maximum straight-line length of antennal
thedeepestpointofthepropodealconstric- scapeseeninprofile.
tionatthebaseofspine(queensandwork-
ers). Wecalculatedthefollowingindicesbasedonthe
FLW maximumwidthbetweenexternalborders abovemorphometriccharacters:
ofthefrontallobes(queensandworkers).
FW minimumwidthoffronsbetweenthefron- AI=AL/AH alitrunklengthindex
talcarinae(queensandworkers). CI=HL/HW cephalicindex
HL lengthofheadindorsalview,measuredina ESDI=ESD/ESL epinotal(propodeal)spine
straightlinefromtheanteriormostpointof distanceindex
median clypeal margin (including any ESLI=ESL/HW epinotal(propodeal)spine
carinaeorrugae,iftheyprotrudeoverthe lengthindex
ENTOMOL.FENNICAVol.19 (cid:127) Myrmicaxavieri,anewantspeciesfromSpain 51
Table1.Means±standarddeviationsofthemorphometriccharacters(seetextfordetails)inmmfortheholotype
andparatypesofM.xavieri.Numbersofindividualsmeasuredpercastearegiveninparenthesesincolumn
headings.
Character Holotype Workers(20) Queens(7) Males(9)
AH 1.106±0.034 1.062±0.038
AL 1.820 1.741±0.042 1.923±0.035 1.791±0.050
ESD 0.460 0.445±0.021 0.467±0.017
ESL 0.420 0.422±0.013 0.491±0.019
FLW 0.430 0.426±0.013 0.442±0.007
FW 0.340 0.333±0.011 0.359±0.008
HL 1.220 1.209±0.027 1.277±0.018 0.896±0.019
HTL 0.920 0.888±0.023 0.943±0.018 0.936±0.044
HW 1.080 1.053±0.030 1.121±0.026 0.847±0.021
PH 0.425 0.403±0.014 0.461±0.007 0.378±0.014
PL 0.520 0.489±0.023 0.560±0.013 0.490±0.009
PNW 0.800 0.757±0.023
PPH 0.505 0.494±0.012 0.566±0.011 0.455±0.016
PPL 0.420 0.382±0.022 0.461±0.012 0.356±0.016
PPW 0.475 0.471±0.015 0.556±0.009 0.446±0.016
PW 0.330 0.324±0.013 0.360±0.014 0.301±0.015
SCL 1.276±0.024 1.204±0.026
SCW 0.920±0.013 0.867±0.017
SL 1.000 0.976±0.019 0.993±0.010 0.839±0.018
FI=FW/HW fronsindex 1,500ma.s.l.),7.VII.1990,seriesE-117,leg.G.
FLI=FLW/FW frontallobeindex W.Elmes.Thenestoftheholotypewasinopen
HTI=HTL/HW hindtibialengthindex pineforest(Pinussylvestris)withmoistsoil.The
PI =PL/PH petioleindex(1) paratypenestwasca.180kmNNWoftheholo-
1
PI =PL/HW petioleindex(2) type site in well-trampled grass on a mountain
2
PPI =PPL/PPH postpetioleindex(1) passnearapineforestinthemountainsofSoria
1
PPI =PPH/PPW postpetioleindex(2) Province,byaroadbetweenSoriaandLogroño.
2
PPI =PPW/PW postpetioleindex(3) Both nests were in soil under stones. The holo-
3
PPI =PPW/HW postpetioleindex(4) typeisdepositedintheNaturalHistoryMuseum
4
SCI=SCL/SCW scutellumindex (BMNH), London, United Kingdom, and the
SI =SL/HL scapeindex(1) paratypes, in the Institute of Zoology of Ukrai-
1
SI =SL/HW scapeindex(2) nian National Academy of Sciences, Kiev,
2
Ukraine, and in the collections of Graham W.
Elmes, UnitedKingdom, andXavier Espadaler,
3.DescriptionofMyrmicaxavierisp.n. SanCugat,Spain.
(Figs.1–3,Tables1–2) Diagnosis.Worker(Fig.1).Headlongerthan
itswidthwithslightlyconvexsidesandoccipital
Material examined. Holotype worker: Spain, margin, and broadly rounded occipital corners.
Aragón,ProvinceofTeruel,SierradeAlbarracín, Anterior clypeal margin narrowly rounded,
Fuente del Canto, ca. three km WSW of Bron- somewhat prominent, with no medial notch.
chales(40°30’N,1°37’W,1,630ma.s.l.),1.VIII. Frontalcarinaefairlystronglycurved,fronsrela-
2000,No.334/2000(seriesE-186inthecollec- tivelynarrow,thoughfrontallobesnotwidelyex-
tionofG.W.Elmes),leg.R.SavolainenandK. tended. Antennal scape strongly angled at the
Vepsäläinen.Paratypes:9workers,30gynesand base,withsmallverticallobe.
35malesfromthenestoftheholotype;10work- Alitrunk with slightly convex promesonotal
ers,Spain,CastillayLéon,ProvinceofSoria,Si- dorsum;promesonotalsutureclearlyvisiblefrom
erradeUrbion,ca.25kmNofSoria(frommem- above; metanotal groove sharp and deep.
oryElmesplacesitintheregion42°N,2°30’W, Propodealspineslong,acute,straightanddiver-
52 Radchenkoetal. (cid:127) ENTOMOL.FENNICAVol.19
Fig.1.Myrmicaxavieriworker(holotype;scalebars1
mm).–a.Head,dorsalview.–b.Scape,lateralview,
seenfrombehind.–c.Scape,dorsalview.–d.Base
ofscape,lateralview,seenfromahead.–e.Baseof
Fig.2.Myrmicaxavieriqueen(paratype;scalebars1
scape,anteriorview.–f.Alitrunkandwaistinprofile.
mm).–a.Head,dorsalview.–b.Scape,lateralview,
–g.Alitrunkandwaistfromabove.–h.Tibiaandbase
seenfrombehind.–c.Scape,dorsalview.–d.Base
offirsttarsaljointofhindleg.
ofscape,lateralview,seenfromahead.–e.Baseof
scape,anteriorview.–f.Alitrunkandwaistinprofile.
gent(seenfromabove)projectingbackwardsat –g.Alitrunkandwaistfromabove.–h.Tibiaandbase
an angle less than 45° (seen in profile). Petiole offirsttarsaljointofhindleg.
with distinct anterior peduncle, its anterior face
slightly concave, not steep, meeting the dorsal muchlongerthanthoseonheadmargin.General
surfaceatabluntroundedangle;dorsalsurfaceof colour reddish-brown, appendages somewhat
petiolarnodeslightly convex,gradually sloping lighter.
posteriorly. Postpetiole distinctly shorter than Queen(Fig.2).Likeworkerinshapeofhead,
broad,withconvexdorsum.Spursonmiddleand scape,generalcolourandpilosityofthebody,but
hindtibiaewelldevelopedandpectinate. withcoarsersculpture,especiallyonthealitrunk,
Frons with sinuous longitudinal rugae, re- petioleandpostpetiolethantheworker.Themain
mainingpartsofheaddorsumwithcoarsereticu- differenceisamoremassivepetiolethaninwork-
lation. Antennalsocketssurroundedby concen- ers, with a shorter anterior peduncle. Also the
tricrugae.Clypeuswithlongitudinalrugae,fron- propodeal spines are longer and less divergent
tal triangle coarsely striated. Sides of alitrunk thaninworkers.
with moderately coarse sinuous longitudinal Male (Fig. 3). Head somewhat longer than
rugae,pronotumwithcoarserrugaeandreticula- broad, with slightly convex sides and occipital
tion. Petiole and postpetiole with fairly coarse margin,andgraduallyroundedoccipitalcorners.
longitudinally-concentricrugae,moresinuouson Anterior clypeal margin narrowly rounded and
thenodesofdorsum.Surfacebetweenrugaeon slightlyprominentwithnomedialnotch.Anten-
thebodysmoothandshiny. nal scape very long and strongly curved at the
Headmarginswithabundant,semierecthairs; base.Antennae13-segmented,with3-segmented
alitrunk dorsum and waist with numerous hairs club, second funicular segment about twice as
ENTOMOL.FENNICAVol.19 (cid:127) Myrmicaxavieri,anewantspeciesfromSpain 53
Etymology. This species is dedicated to the
Spanishmyrmecologist,Dr.XavierEspadaler.
4.Discussion
Differential diagnosis. The female castes of M.
xavieri clearly differ from those of the other
lobicornis-groupspeciesbytheabsenceofame-
dialnotchintheiranteriorclypealmarginwhich
isnarrowlyroundedandprominent.Alltheother
specieshaveadistinctmedialnotchintheante-
riorclypealmarginwhichisbroadlyroundedand
not prominent. Superficially M. xavieri may be
confused with M. lobulicornis and especially
withM.wesmaeli.TheworkersofM.xavieridif-
fer from both, however, by their distinctly nar-
rowerfrons(meanFI0.32vs.0.34and0.37,re-
spectively). When the 20 specimens measured
here (Table 2) were compared with a randon
sampleofM.wesmaeli(whichincludedthelecto-
Fig.3.Myrmicaxavierimale(paratype;scalebar1
type and several paralectotypes) in a linear
mm).–a.Head,dorsalview.–b.Antenna.–c.
discriminantanalysis,FIalonewassufficientto
Alitrunkandwaistinprofile.–d.Alitrunkandwaist
produce 100% discrimination between the two
fromabove.–e.Tibiaandfirsttarsaljointofhindleg.
samples(lineardiscriminantfunctionswere2905
FI–534forM.wesmaeliand2487FI–391for
longasthethirdone. M.xavieri).InclusionofSI andHTIsomewhat
2
Alitrunkfairlylong,scutumslightlyconvex, improvedthediscrimination(thethreeindicesare
scutellum not projecting dorsally above scutum morphometricsstandardisedforsizebydividing
when seen in profile. Propodeum with blunt byHW).
rounded tubercles. Petiole rather massive, rela- M.xavierihasdistinctlymoreextendedfron-
tively high, with straight anterior face and tal lobes than M. wesmaeli (mean FLI 1.28 vs.
rounded dorsum of node; postpetiole distinctly 1.18), but less extended frontal lobes than M.
longer than its width, with weakly convex dor- lobulicornis(meanFLI1.34).M.xavierialsodif-
sum. fersfromM.lobicornisandM.lobulicornisbyits
Headdorsumwithstriationanddensepunc- distinctly longer propodeal spines (mean ESLI
tures.Scutumwithdenselongitudinally-concen- 0.40vs.(cid:1)0.30)andbythedifferentshapeofthe
tricrugae,scutellumwithcoarserandlessabun- petiole:theanteriorpeduncleofthepetioleisvery
dantrugae.Pro-andmesopleurawithfinerugae, short in M. lobicornis and M. lobulicornis, and
propodeum with coarser rugae. Petiole and the anterior face of the node (seen in profile) is
postpetiolefinelybutnotdenselypunctured,peti- flat and steep, meeting the dorsal surface at a
oleadditionally hasfinerugulae, centralpartof right-angle or even more acutely. In M. xavieri
petiolar and postpetiolar dorsum smooth and thepeduncleislonger,itsanteriorfacemorecon-
shiny.Surfaceonalitrunkbetweenrugaesmooth cave, meeting the dorsal surface with a blunt
andshiny. roundedangle.
Headmargins,alitrunkandwaistwithabun- Liketheworkersandqueens,themalesofM.
dant,relativelyshortsemierecthairs.Scape,tib- xaviericlearlydifferfromallotherspeciesofthe
iaeandtarsiwithshortsubdecumbenttosuberect lobicornisgroupbytheirnarrowlyroundedand
hairs. General colour of body dark brown to unnotchedanteriorclypealmargin.Theyalsodif-
black,appendagessomewhatlighter. fer by having a distinctly longer antennal scape
54 Radchenkoetal. (cid:127) ENTOMOL.FENNICAVol.19
Table2.Means±standarddeviationsoftheindicescalculatedfromthemorphometriccharactersofTable1(see
textfordetails)fortheholotypeandparatypesofM.xavieri.Numbersofindividualsmeasuredpercasteare
giveninparenthesesincolumnheadings.
Character Holotype Workers(20) Queens(7) Males(9)
AI 1.740±0.039 1.688±0.062
CI 1.130 1.149±0.014 1.139±0.017 1.058±0.018
ESDI 1.095 1.056±0.056 0.952±0.044
ESLI 0.389 0.401±0.016 0.438±0.014
FI 0.315 0.316±0.009 0.320±0.004
FLI 1.265 1.281±0.023 1.231±0.023
HTI 0.852 0.843±0.019 0.841±0.023 1.105±0.051
PI 1.224 1.214±0.028 1.215±0.020 1.296±0.033
1
PI 0.481 0.464±0.018 0.500±0.012 0.579±0.015
2
PPI 0.832 0.772±0.035 0.815±0.021 0.781±0.013
1
PPI 1.063 1.048±0.032 1.020±0.025 1.022±0.025
2
PPI 1.439 1.455±0.041 1.546±0.066 1.481±0.046
3
PPI 0.440 0.448±0.010 0.496±0.013 0.527±0.024
4
SCI 1.387±0.030 1.390±0.022
SI 0.820 0.807±0.013 0.778±0.013 0.937±0.020
1
SI 0.926 0.927±0.018 0.886±0.023 0.991±0.022
2
(SI >0.90,SI >0.95vs.<0.85,<0.90)andthus castes and the exceptionally long scapes of the
1 2
the male may be confused more easily with M. males,however,wellseparateM.xavierifromall
rubra(L.)orM.ruginodisNylander.Thescapeof otherknownspeciesofthatgroup(ca.20known
thelattertwospeciesis,however,gentlycurved species).ItismostprobablyanIberianendemic,a
atthebase,whereasthatofM.xavieriisstrongly relictofthefaunaisolatedintheIberianPeninsula
angled. duringthePleistocene.
Notes. We also identified two additional
workers and two males (probably fromasingle Acknowledgements.WearegratefultoCedricA.Colling-
nest)ca.65kmSEoftheholotypesite,collected wood for providing us with material, and Kari Vepsä-
by Cedric A. Collingwood in Spain (Aragón, läinen,BernhardSeifert,andJudithWardlawformaking
usefulcommentsonthemanuscript.Thisworkwassup-
Province of Teruel, Sierra de Javalambre, Java-
portedbythegrantoftheMinistryofHighEducationand
lambre, 1,500–1,800 m a.s.l. (inferred from
SciencesofPoland(No.2P04C06429)toAR,andthe
maps),June1986,seriesE-178inthecollection AcademyofFinlandtoRS.
ofG.W.Elmes)asM.xavieri.Themalesarein-
distinguishablefromthosedescribedabove.The
workersaresimilar,butexhibitminordifferences
intheshapeofpetioleandbyoneworkerhavinga References
smoother, the other a coarser sculpture than the
workersdescribedabove,andbydistinctlymore Radchenko,A.G.1994a:Taxonomicstructureofthege-
extended frontal lobes (FLI 1.35–1.36). In the nusMyrmica(Hymenoptera,Formicidae)ofEurasia.
discriminant analysis (above) the two workers CommunicationI.—ZoologicheskiyZhurnal73:39–
51 [in Russian; English translation Entomol. Rev.
fellwithintheM.xaviericluster,indicatinglarger
1995,74:91–106].
morphological variation of M. xavieri than ob-
Radchenko,A.G.1994b:Surveyofthelobicornisgroup
servedinthetwotypeseries.Topreventpossible
ofthegenusMyrmica(Hymenoptera,Formicidae)of
confusioninthefuture,wedidnotincludethese the Central and Eastern Palaearctic. — Zoologi-
specimensinthetypeseries. cheskiyZhurnal73:81–92[inRussian;Englishtrans-
WeplaceM.xavieriinthelobicornisspecies lation,Entomol.Rev.1995,74:133–146].
group,becausemanyofthefeaturesofboththe Seifert,B.2005:RankelevationintwoEuropeanantspe-
cies: Myrmica lobulicornis Nylander, 1857, stat. n.
femaleandmalecastesbestmatchthoseofthat
andMyrmicaspinosiorSantschi,1931,stat.n.(Hyme-
groupcomparedtoanyotherspeciesgroup.The
noptera: Formicidae). — Myrmecologische Nach-
absence of a notched clypeal margin in both richten7:1–7.