Description of the larva of Acanthagrion quadratum Selys, with a key to the known larvae of the genus (Zygoptera: Coenagrionidae)

2009·1.1 MB·English

by  Novelo-Gutiérrez, R

Odonatologica38(4):321-328 December 1,2009
Description of thelarva of Acanthagrion
quadratum Selys, witha key totheknown larvae
of thegenus(Zygoptera: Coenagrionidae)
R.Novelo-Gutiérrez
Systematics Network,InstitutedeEcología,A.C.,
ApartadoPostal63,MX-91070 Xalapa,Veracruz, Mexico
[email protected]
Received 18August2009/Reviewed andAccepted5September2009
Thelarvaisdescribed,illustrated,andcomparedwith otherdescribed congeneric
larvae. A. quadratumisdistinguishedfromall othersbypossessing3prementalsetae,
4setaeonlabialpalp,and caudallamellae 8-10 timeslongerthantheir widestpart.
Akey tothe9 knowncongenericlarvaeisprovided
INTRODUCTION
The neotropical genusAcanthagrion Selys, 1876comprises 40known species
(VON ELLENRIEDER & LOZANO, 2008), A. inexpectum Leonardand A.
quadratum Selysoccur inMexico(GONZAlEZ-SORIANO& NOVELO-GU-
TIERREZ, 2007). Thegenuswas redefinedby VON ELLENR1EDER&LOZ-
ANO(2008),whodiagnosedthelarvaefromthoseofOxyagrion bytheirmarkedly
lanceolatecaudallamellae, withwidth/length ratio0.18 or less, andlongerthan
abdomen(1.02ormore).Despite thespeciose natureofthegenus,larvaeofonly
eight species (20% of genus) havebeendescribed:A. ascendensCalvert(GEIJS-
KES, 1941),A. adustumWilliamsonandA. indefensum Williamson(GEIJSKES,
1943),A.fluviatile De Marmels (DE MARMELS, 1990), A. apicale Selys (DE
MARMELS, 1992), A. hildegarda Gloger(MUZON et al.2001), A. vidua Selys
(DE MARMELS, 2007), and A. aepiolum Tennessen (LOZANO et al., 2007).
WESTFALL& MAY (1996) keyed the larvaof A. quadratum, providing some
figures, butdidnot includea description. Iprovide hereafulldescription of the
larvaofA. quadratum, encompassing variabilityofmaterialfromseveral locali-
ties. Basedon comparison withdescriptions of otherlarvae of Acanthagrion a
key toalltheirdescribedlarvae isprovided.
322 R.Novelo-Gutierrez
Figs 1-5.Acanthagrionquadratum,details oflarval morphology; (1)last instar larva,dorsal view;
— (2)rightantenna,lateral view; — (3)mandibles,ventrointernal view: (a)rightmandible,(b)left
mandible;- (4)rightmaxilla,ventralview; - (5)labium: (a)prementum, dorsalview,(b)detailof
labialpalp,frontal view.
Acanlhagrionlarvae 323
ACANTHAGRION QUADRATUM SELYS, 1876
Figures 1-9
Material. - 8 exuviae(5<J, 3 9reared),22 lastinstarlarvae(146, 8 9),29youngerlarvae
(196, 109).MEXICO:Veracruz: LosTuxtlas: Balzapote,RioMaquinas(18°37’27”N,95°05’31.2”
W, 18m),31-V-1984,H.Velascoleg.(Id);RanchoDr.Moreno,roadtoPlayaEscondida(18°34’741
N, 95°03’816W,pond,20m),24-VIII-1984,R.Noveloleg.(5d.3 9);EstaciondeBiologiaTropical
“LosTuxtlas”,LagunaAzul (18°35’363N, 95°05’607W, 176m),27-VIII-1988,R.Noveloleg. (7d,
4 9); Catemaco,Coxcoapan,EjidoLopezMateos (18°26’510N,94°57’902 W,river, 174m),02-XI1-
2003,R.Arceleg.(I d).Sayula,Almagres(17°48’333N, 94°54’369 W,lagoon,30m),20-111-1999,
J.A.Gomezleg.(Id).Xalapa,BotanicalGarden(19°30’745N,96°56’619 W,pond, 1337m),08-V-
1991,R.Noveloleg.(2 d).Tlapacoyan,Ixtacuaco(20°01.957N, 97°07.014W,stream, 115m), 10-
VII-2002,R.Noveloleg. (29), samedatabut 30-III-2003(2 d,29).Emiliano Zapata,Miradores
(19°28’278N,96°4T197W,lagoon,930m),22-11-1997,R.Arce leg.(19);samedatabut 11-1-1998
(19);samedata but 19-VIII-2008,B.BrugandR.Noveloleg.(I d).Hidalgo:Molango,Lagunade
Atezca (20°48’293N, 98°44’535 W, lagoon,1294 m), 13-III-1988,R.Novelo leg.(3 d, 1 9); same
data but 12-11-1994 (1 d);samedata but 06-IV-1997(I d,2 9). SanLuis Potosi: Micos,cascadas
Pago-Pago(22°05’996N,99°09T43 W,stream, 154m),25-VII-1990,R.Noveloleg.(3 d, 19);San-
taFe(22°07’800N, 99°12’082 W,stream, 224m),24-VI-1998,R.Novelo leg.(1 d);Ciudad Valles,
nacimiento RioCoy(21°46’339N,99°03'602W,stream, 138m),06-VII-2004,R.Noveloleg.(6 d,
2 9). Puebla:XicotepecdeJuarez(20°15’804N,97°57’739 W,pond, 1167m),20-V-1987,R.Novelo
leg.(1 d, 1 9). Queretaro:ArroyoSeco, ElNogal(2I°20’759N,99°32’673 W, stream,642m),23-
VII-1998,R.Noveloleg.(2 d).All depositedatColeccion Entomologicadel InstitutodeEcologia,
A.C.,Xalapa(IEXA).
DESCRIPTION: Exuviae and last instar larvae (Fig. 1)yellow to dark brown
(alcoholic specimens); larvaslenderwithvery long andnarrow caudallamellae
(epiproct andparaprocts).
Head. — Almost twice as broadas long andwiderthan thoraxandabdo-
men,occipital marginwidely concave,cephalic lobesroundedandcoveredwith
short, stout, stiff setae,remainderofhead smooth; compound eyes widerthan
long, withroughly circularpale spots ondarkbackground (Fig. 1),dorsallength
ofcompound eye onethird thelength of occipital area. Antennae7 segmented
(Fig. 2),thethirdsegmentthelongest; relativelength ofantennomeres: 0.50,0.80,
1.0,0.75,0.60,0.40,0.20; scapeandbasal0.80ofpedicel lightbrown,remainder
of antenna creamy pale. Mandibles(Fig. 3)withmolarteethbut lacking molar
crest, with followingformula(sensu Watson 1956): L 1+2 345 Oab, R 1+234
5 ya.Ventralpad ofhypopharynx subrectangular, anteriormarginstraightwith
arowoflongsetae,posterior marginwidelyconvex, smooth.Maxilla: galeolaci-
nia(Fig. 4) withsix teeth, thethreedorsalteethlarge and moderatelyincurved,
theventroapical tooththelargest, the remaining two ventralteeth thesmallest,
themost internal one amerespine, arow of stiff setaepreceding bothventral
anddorsal teeth; maxillary palpincurved, sharplypointed, withsomestifflong
setaeonitsexternalsurface. Labium;prementum-postmentumarticulationrea-
ching basal half of mesosternum; prementum(Fig. 5a) longer than its widest
324 R.Novelo-Gutierrez
part, lateralmarginsmoderately divergent onbasalhalf,thenstrongly divergent
atapicalhalf andwitharow of 10-11spiniformsetae; threelong andstoutpre-
mentalsetae toeach side of midline; ligula prominent, triangular, itsborderfi-
nely serrulate withclosely setminuteclaviform setae on apex; labialpalp (Fig.
5a)withfourlong andstoutsetae,its apicallobedividedintoasquarely trunca-
te dorsalbranchcomposed offoursmall teeth(Fig. 5b) ofwhichthedorsalone
isobtuseandwithminutedenticles,anda ventralbranchwithawell-developed
endhook; internalmarginofpalpfinely serrated; movablehooklong andshar-
ply pointed.
Thorax. - Pronotumtrapezoidal, posterolateral marginsmoderatelyangular
witharow ofshortrobustsetae,its posteriormarginstraight atmiddle.Anterior
andposterior wing pads reaching basal 0.40and0.60ofabdominalsegment 5,
respectively. Legs pale withasubapical darkring onfemora(Fig. I),short(e.g.,
hindlegsscarcely reaching posteriormarginofabdominalsegment8);dorsaland
ventralbordersandanterior(external) surfaceoffemorawithrows ofspiniform
setae;externalsurfaceoftibiaewithsparse,long, delicatesetae,internalsurface
withsparse spiniform setae,apicalends oftibiaewithtridentate, scalelikesetae.
Tworows ofshort, stout, stiffsetaeon ventral surfaceoftarsi, clawswithapul-
villiformempodium.
Abdomen. - Cylindric, lightbrown, withadistinctnetworkoftraqueo-
lesclearlyvisiblebytransparency, segments2-10withathinpale middorsalline
graduallywidening on 8-10, anarrow reddishbrown stripe toeach sideofpale
middorsalline(Fig. 1).Segments 1-10gradually narrowingposteriorly, 1-8with
alateralcarinawhichbearsarowofspiniform setae on4-8, increasinginnumber
and robustnessposteriorly; surfaceoftergites 5-10 densely coveredwithminute
spiniformsetaewhichare largeandstouton 10, mainly onitsposterior margin.
Stemites1-10withalongitudinal,central, wide, creamypaleband;ashort, narrow,
longitudinal, darkmidlineonapicalmarginofstemites 1-7.Malegonapophyses
sharply pointed, in ventral viewwidely divergent, reaching basal0.30the leng-
th ofsternite 10, witharow of4-5 spiniformsetae on ventralmargin, intermin-
gled withsomelong, white, delicatesetae (Fig. 6). Femalegonapophyses yellow
(Fig. 7),exceeding posterior marginofsternite 10,lateralvalvaesharply pointed
(Fig. 7a) witha ventralrow of 4-5robust spiniform setae increasing in size and
robustnessposteriorly, apices slightly divergent inventralview(Fig. 7b), central
valvaeslightly shorterthanlateralvalvae.Malecercias in Figures6and8. Cau-
dallamellae(epiproctandparaprocts) withacomplex colorpattern, slenderand
extraordinarily long,0.77the length of therest of the body (Fig. 1),8-10times
longer than theirwidestpart, lanceolate, apex acuminateandsometimes witha
very shortfilament(Fig. 9),withalongitudinal carinaalong basal0.53on both
sidesoflamellae, whichbearsarow of20-22spiniform setaeon externalcarina
and 10-11spiniform setae on internalcarinaofparaprocts, carinaeon bothsi-
desofepiproct with arow of 13-14spiniform setae;dorsalandventral margins
Acanthaghonlarvae 325
ofparaprocts witharow ofshortspiniform setaeonbasal0.30and0.53 respec-
tively, spiniform setae on basal0.52 on dorsalandventral margins ofepiproct,
remainderof margins on epiproct and paraprocts mostly smooth, with some
sparse, white, delicatesetae; nodushardly visible, butdelimitedby apical end of
lateral carinaeand ventralrow ofspiniform setaeon paraprocts.
Measurements (inmm;averagein squarebrackets). - Onlylastinstar larvae: Totallength
(excludingcaudal appendages)9.8-13.9, [11.6](N=13); abdomen 6.4-9.5,[7.8](N=13); maximum
width ofhead2.7-2.9,[2.8](N=13);hind femur(dorsal)2.4-2.7,[2.5](N=13);epiproct6.1-1.5,[7,1]
(N=6);paraprocts 1.0-1.1,[7.3](N=12);nodus onepiproctatbasal 51,4-54.2,[53.1](N=6);nodus
Figs6-13. Details ofthe morphologyofAcanthagrionspp. larvae. Figs6-9: A. quadratum,Figs 10-
11:A.adustum. Fig. 12:A. vidua,Fig. 13:A. ascendens:(6)abdominal segments 9-10,showingmale
gonapophysesandcerci: (a)ventralview,(b)lateralview; - (7)abdominal segment10showingmale
cerci;(a)dorsalview,(b)laterodorsal view; - (8)abdominalsegments9-10,showingfemalegonapo-
physes: (a)lateralview,(b)ventral view; - (9)leftparaproct, externallateral view; - (10)head; -
(ll)leftparaproct; - (12)distalendofparaproct; - (13)idera.- [Figs 10-13redrawn fromGE1JS-
KES (1943),Fig. 12fromDE MARMELS(2007)and Fig. 13 fromGEIJSKES(1941)].
326 R.Novelo-Gutierrez
onparaproctatbasal 50-54.3,[52.7](N=12).
REMARKS. — Acanthagrion spp.inhabitin bothlotic andlenticwater bodies.
GEIJSKES (1941)reported larvaeofA. ascendensinrice fieldsand ditches,and
thoseofA.adustumandA. indefensum fromtheaquatic plant Cabombaaquatica
Aubl.(GEIJSKES, 1943). DE MARMELS(1990) foundlarvaeof A. fluviatile
on grassesinafloodedsavannah,andthoseofA. apicalein astagnantpool (DE
MARMELS, 1992). MUZON etal.(2001)recorded A. hildegardafromstreams,
whileDEMARMELS(2007)collectedlarvaeofA. vidua “instagnantandslow-
lyflowing water”.Acanthagrion quadratum inhabitsopenareasinbothloticand
lenticsystems; wheninloticsystems theyare usually foundclosely associatedto
roots ofherbaceousriparian vegetation growing in backwaters. Larvae usually
climbon emergentgrassesandaquatic phanerogams.
DISCUSSION
Dueto theshapeofthelarvalheadPESSACQ etal.(2005) consideredthespe-
cies A.adustum, A.fluviatileand A. indefensum to berelated. Iagree,and these
species mayconformanaturalgroupsharing otherfeaturessuchasantennae6-seg-
mented, onepremental setae,and caudallamellaewithapexnearly rounded.A
second groupoffourapparently closely relatedspecies includesA. ascendens,A.
apicale,A. aepiolum andA. vidua, sharing amongothercharactersthecombina-
tionof2or2+1premental setae and4palpal setae. A. hildegarda andA. quadra-
tum do notappeartobeclosely relatedto any oftheotherspecies mentioned.
Nevertheless, the larva of A. quadratum shares some featuresas follows: an-
tennae 7-segmented andcephalic lobesrounded(apicale. ascendens, hildegarda.
vidua); palpal setae 4(adustum, aepiolum, apicale, ascendens, indefensum, fluvia-
tile, vidua); premental setae3 (hildegarda); shapeof caudallamella(adustum, in-
defensum,fluviatile).
Akey to thelarvaeknown todateis presented herebasedexclusively uponthe
descriptions provided in literature; no specimens were closely examinedexcept
thoseofA. quadratum.
KEY FOR THEKNOWN LARVAE OF ACANTHAGRION
1 Posterior lobes ofhead angledand beset with spines(Fig. 10);onelargepremental seta on
each side ofmidline;antennae 6-segmented;caudal lamellae with the apex nearlyrounded
(Fig. 11) 2
1’ Posteriorlobes ofheadrounded (Fig. 1);twoormorelargeprementalsetaeoneach side ofmid-
line;antennae7-segmented(sometimes6in A.aepiolum);caudal lamellae with apexacuminate
orprolongedintoashort terminal filament(Figs.9,12) 4
2 Posteriormarginofhead almoststraight;nodusonlaterallamella (paraproct)atbasal0.55;total
lengthoffull-grownlarva excludingcaudal lamellae 11.5-13mm adustum
2’ Posteriormarginofhead concave; nodusonlateral lamellae (paraproct)atbasal 0.57ormore;
totallengthoffull-grownlarva excludingcaudallamellae less than 10,5mm 3
Acanthagrionlarvae 327
3 Scapeandpedicelofantennanearlyofthesamelength,darkerthanremainder antennomeres;
nodusonparaproctatbasal 0.58,lessthan20 and10spinesonprenodalventraland dorsalseries
respectively fluviatile
3’ Scapeclearlyshorter thanpedicel,scapedark,pedicelpalewithadark,subapicalring,remainder
ofantennomerespale;nodus onparaproctatbasal 0.57, 20and 15 spinesonprenodalventral
anddorsal series respectively indefensum
4 Premental setae2or2+1(two setaelarge,thethirdoneahalfthelengthoftheothersorless)to
each side ofmidline;palpalsetae4 5
4’ Premental setae3ormore;palpalsetae4ormore 8
5 Nodusnotreachingbasal0.50thelengthofcaudallamellae 6
5’ Nodusbeyondbasal0.50thelengthofcaudallamellae 7
6 Caudal lamellae with tipsprolongedintoaterminalfilament(Fig. 12);nodus atbasal 0.42 the
lengthofcaudal lamellae;3rdantennomeretwiceaslongasscape; female gonapophysesreach-
ingwell beyondposteriormarginofabdominal segment10 vidua
6’ Caudal lamellae with tipsshort anacute notprolongedintoaterminal filament(Fig.13);nodus
atbasal 0.48 thelengthofcaudal lamellae;3rdantennomerenottwiceaslongasscape; female
gonapophysesreachingtojust behind posteriormarginofsegment 10 ascendens
7 Nodusatbasal 0.53 thelengthofcaudallamellae apicale
T Nodusatbasal 0.60 thelengthofcaudal lamellae aepiolum
8 Palpal setae5-6 hildegarda
8’ Palpalsetae4 quadratum
ACKNOWLEDGEMENTS
IthankDr R.ARCE-PEREZfor collectingpart ofthematerialused hereforthedescriptionof
the larva ofA.quadratum.DrsN. VONELLENRIEDER andJ.MUZON, and Lie. F. LOZANO
helpedmewithliterature. SpecialthanksareduetoDrN.vonEllenrieder forherinvaluablecriticism
which improvedsubstantiallythe finalmanuscript.
REFERENCES
DEMARMELS,J.,1990.Notasobredos“formas”enAcanthagrionfluviatile(DeMarmels, 1984)
yunadescription dela nayade(Odonata:Coenagrionidae).Boln Ent. venez.(N.S.) 5(15);
116-22,
DEMARMELS,J., 1992. Caballitos del Diablo (Odonata)delasSierrasdeTapirapecoyUnturan,
enelextreme surdeVenezuela. Adahiol. venez.14(1):57-78.
DE MARMELS, J.,2007. Thirteen newZygopteralarvaefrom Venezuela (Calopterygidae,Poly-
thoridae,Pseudostigmatidae,Platystictidae, Protoneuridae,Coenagrionidae).Odonatolo-
gica36(1):27-51.
GEIJSKES, D.C.,1941. NotesonOdonataofSurinam,2.Sixmostlynewzygopterousnymphsfrom
thecoastland waters. AnnlsEnt. Soc. Am.34(4):719-734.
GEIJSKES, DC, 1943. Notes onOdonata ofSurinam,4. Nine neworlittle known zygopterous
nymphsfromtheinland waters. AnnlsEnt. Soc. Am. 36(2): 165-184.
GONZALe’z-SORIANO,E.& R.NOVELO-GUTIERREZ, 2007.OdonataofMexico revisited.
In:B.K. Tyagi,[Ed.], Odonata: biologyofdragonflies,pp. 105-136.Sclent. Publishers/India,
Jodhpur.
LOZANO,E,A.GARRE &P.PESSACQ, 2007.Descriptiondel ultimoestadiolarval deAcantha-
grionaepiolum(Odonata:Coenagrionidae).RevtaSoc. ent. argent.66(1/2): 1-4.
MUZON,J.,N.VONELLENRIEDER &P.PESSACQ,2001.Description ofthe lastlarvalinstar
328 R.Novelo-Gutierrez
ofAcanthagrionhildegarda(Odonata:Coenagrionidae).RevtaSoc. ent. argent. 60(1/4):95-
98.
PESSACQ,R,J.MUZON&N.VONELLENRIEDER,2005. Descriptionofthelastlarvalinstarof
Acanthagrionablutum Calvert(Zygoptera:Coenagrionidae).Odonatologica34(1);73-76.
VON ELLENRIEDER,N.&F.LOZANO, 2008.Blues fortheredOxyagrion: aredefinition ofthe
generaOxyagrionSelys, 1876and AcanthagrionSelys, 1876(Odonata:Coenagrionidae).Int.
J. Odonatol. 11(1):95-113.
WESTFALL,M.J.& ML.MAY, 1996. DamselfliesofNorthAmerica. Scient, Publishers,Gaines-
ville/Florida.