Odonatologica21(1): 39-71 March I,1992 Biosystematics of the larvae of the genusArgia in Mexico (Zygoptera: Coenagrionidae) R.Novelo-Gutierrez Institute deEcología.A.C.,Km 2.5antiguacarretera aCoatepec, ApartadoPostal 63,C.P. 91000 Xalapa,Veracruz, Mexico Received January21, 1991 /Revised andAcceptedNovember 18,1991 DetaileddescriptionsareprovidedoflarvaeofA.fissaSel.*, A.fumipennisviolacea Hag., A. harknessi Calv.*,A. lacrimans Hag.*,A. lugens Hag.,A.oeneaHag.*, A. pulla Hag.*,A.rhoadsi Calv.*, A.tezpiCalv.*,A. ulmeca Calv.*,A.munda Calv.,A. planaCalv., A.tarascanaCalv. andA.tontoCalv.Those asterisked (*) aredescribed herefor thefirst time.Larvaeofallspp.are diagnosed,usinganewcharacterfor the genus, i.e.the6 pharatecaudal app. (cerci).Some previouslypoorlyorincompletely described spp. areredescribed. Figs ofall taxonomic characters and the ecological dataareincluded. INTRODUCTION TheNew WorldgenusArgiais oneofthelargest odonategenera(approx. 150 spp.; cf. DAVIES, 1981),and it has reached a high taxonomic complexity. In spite ofits abundanceand wide distribution, the larvae are poorly known. Up to now only 20 species (13% ofknown species) areknown intheirlarval stage: A. apicalis Say, A. moesta Hagen, A. tibialisRambur, A.fumipennis violacea Hagen (NEEDHAM, 1903);A. lugens Hagen (NEEDHAM & COCKERELL, 1903; NEEDHAM, 1904); A. fumipennis atra Gloyd (NEEDHAM, 1904);A. emmaKennedy, A. vividaHagen (KENNEDY, 1915);A. translataHagen (GAR- MAN, 1927;BROUGHTON, 1928; GEIJSKES, 1946);A. sedula Hagen (SEE- MAN, 1927);A.insipida Hagen (GEIJSKES, 1943);A. difficilisSelys,A.orichal- cea Hagen (GEIJSKES, 1946);A. sordida Selys (SANTOS, 1968);A. concinna Rambur (DONNELLY, 1970);A. nahuanaCalvert (PROVONSHA& McCAF- FERTY, 1973);A. oculata Hagen (LIMONGI, 1983);A.mundaCalvert.A.plana Calvert, A. tarascana Calvert and A. tonto Calvert (WESTFALL, 1990). 40 R. Novelo-Gutierrez NEEDHAM (1903)briefly describedA. fumipennis violacea,andNEEDHAM & COCKERELL (1903) and NEEDHAM (1904) described and illustrated A. lugens. However, these descriptions wereeitherbased on younglarvae or were poorly illustrated, making identificationimpossible. In Mexico Argia has at least46 species (PAULSON 1982),plus many more undescribedspecies. Thirteenmexican species (28%)havebeen described.Here, I describe the larvaeof 13 more species and relate these to their congeners. METHODS Larvae werecollected fromtropicalrain forests,tropicaldeciduous forests,cloudforestsandpine- -oakforests,locatedin severalstatesoftheMexican Republic,includingloticandlenticenvironments. Specimenswereobtained in twoways:(1) collectingnewlyemergedindividuals andtheircast skins, and (2) collecting maturelarvae and rearingthem insmallaquaria.Inthe latter case, larvae were fed Artemiasalina untiltheiremergence.Teneraladultswerekept alive until theyweresufficiently hardenedfor identification, and exuviae and somelarvae werepreservedin 80% ethanol. Irecorded the ecology and emergence times formost species; times werrecorded justwhenthethoraxbegan to split. Descriptionsare frompreservedfinal instarlarvae orexuviae. Terminologyofthe labium is from CORBET (1953); thus, setameanshair-like seta. Drawingswere made with the aid ofa camera lucida ona stereoscopicmicroscope. A total of 13 species and onesubspecies were succesfully reared or collected with skins at emergence: A.fissa, A.fumipennisviolacea, A. harknessi,A.lacrimans, A. lugens, A.munda, A. oenea,A.plana, A.pulla,A. rhoadsi,A.tarascana, A. tezpi,A.tontoandA. ulmeca. Allspecimensaredepositedin the author’scollection. DIAGNOSIS OF ARGIA LARVAE Generallystoutandshort,yellow to darkbrown;headwiderthanlong, cephalic lobes with stout spiniform setae; antennae 6 or 7-jointed, usually longer than head;labiumshortwithoutwell developed dorsoapical premental setae,butwith lateral and basidorsal spiniform setae; ligula slightly arcuate to prominent, its distalborder convex and covered with small claviform setae, two small spines near distalborderon dorsal side; palpi usually with 1-4 setae (rarely 0or 5), its externalbordercoveredwithsmallspiniform setae,internalborderslightly serra- ted, distally ending in two hooks, the inferior one the largest (Figs 29b, 38b). Thorax robust; prothorax, in dorsal view withposterolateral margins angularly produced and covered with spiniform setae. Legs short, femorapale with dark rings, clawswithpulvilliform empodium. Wingcases infullgrownlarvaeusually extending to abdominal segment 4 or 5. Abdomen short, covered with setae, spiniform setae orboth;gonapophyses well developed inboth sexes, withspini- form, claviform or hairlikesetae on theirventralborders. Gills usually laminar, but also triquetral, saccoid or a combinationofthese, and generally ending ina filamentoustip. Measurementsforthe following descriptions are given in TableI. Argialarvae fromMexico 41 Table I Measurements ofArgialarvae (mm) TToollaalllleennggtthh MMaaxxiimmuummwwiiddtthh HHiinnddffeemmuurr LLaatteerraallggiillll CCeennttrraallggiillll SSppeecciieess ((wwiitthhoouuttggiillllss)) ooffhheeaadd ((iinncclluuddiinngglliipp)) 6 9 6 9 6 9 6 9 6 9 ffilssssaa 1122..33--1144..55 1122..77--1155..33 33..Ô6--33.7J 33..66--44..00 33..77--44..11 33..77--44..00 66..44--66..66 44..00--77..00 44..88--66..UÜ 55..00--66..00 ff.vviioollaacceeaa 1111..55 1133..44--1144.2.2 33..66 44..00 33..55 33..77--33..99 55..00 SS..33--55..55 44..88 55..11 hhaarrkknneessssii 1122..00--1144..55 1122..88--1144..00 33..SS--33.9.9 33,,77--33..99 33..66--33..99 33..77--44..11 44..88 55..00--55..55 33..77 33..SS--33..66 llaacvrriimmaannss 2211..00--2211..99 1177..33--1177..66 44..22--44..66 44..00--44..55 55..00--66..77 44..55--55..00 S5..22--55..55 55..00--66..33 44..00--55..55 lIunggeennss 1144..66--1188..77 - 44..S8--55..22 - 44..77--S5..33 - 55..77--66..22 - 55..11--55..33 mmuianudlaa 1100..55--1144..77 1111..77--1133..66 33..77--33..99 33..99--44..1I 33..22--33..44 33..33--33..8S 55..00--55..11 55..00--66..00 44..55--44..S8 44..S5--55..55 ooeennecaa 1133..00 1122..33 33..77 33..66 33..00 33..22 55..88 66..77 44..55 44..55 ppllaannaa 1144..22 - 33..88 - 33..11 - 33..55 - 33..44 ppuullllaa 1100..11--1122..33 1122..99 22..99--33..11 22..99 22..99--33..11 22..99 44..88--66..00 44..55 44..66--55..33 44..11 rrhhooaaddssii I1I1.0.0-1-122..00 1100..66--1111..66 33..33 33..33--33..44 33..00--33..66 33..22 S5..22--55..44 55..44--S5..77 55..00--55..22 44..00--55..22 ttaarraassceaannaa 1111..88--1144..00 1122..55--1133..66 33..SS--33..99 33..SS--33..99 33..44--33.88 33..33--33..66 44..9966..55 44..5S--55..S5 44..00--55..00 44..44 tteezzppii 1133..11--1144..00 1122..00--1155..00 44..00 33..77--44..00 33..S5--33..77 33..S5--33..77 44..55--66..66 44..33--66..00 33..99--55..S5 44..22--44..SS ttoonnttoo 1144..88 1144..44--1166..66 44..44 44..33--44...S5 44..66 44..00--44..88 55..66 S5..55--77..44 55..44 4499--66..11 unllmmeeccaa 1144..77--1177..33 1144..33--1144..66 44..11--44..22 44..11 44..11--44..22 44..11--44..55 55..5S--77..55 44..00--55.1.1 66..11 44..11 ARGIA FISSA SELYS Figures 1,20, 32,49,66,72, 95 Material — 4larvae (2<? 2 9), 7 exuviae (3 d, 49) MEXICO:Hidalgo, Molango,Lagunade Atezca (1450m),27-VII-86, 2<3, 29. 16-XI-85, 1<5 S.Ibanez leg.;-Morelos,TemilpaViejo,Rio Yautepec(1210m), I4-III-87, 1d, 19.- Jantetelco (1190m),24-11-85,2 9.- Jiutepec,Las Fuentes (1340m), 13-X-85, 1 cf; - Puebla,La Union(580m),23-V11-87, 1 9,- Unless statedotherwise, all R.Novelo leg. description — Larvae darkbrown, body stoutand short. Head mottled (Fig. 1), wider than long, posterior border widely concave, cephalic lobes bordered with robust spiniform setae; labrum yellowish-brown. Antennae 7-jointed (Fig. 20), longer than head, scape yellow, pedicel with a pseudobasal dark ring, flagellomeres pale brown with distalends yellow, ratio oflengthsofantennomeres; 0.40,0.75,1.0,0.75,0.45,0.30,0.20.Labiumyellow- -brown to dark brown; hinge extending to anterior margin of mesostemum; prementumwith15-16lateraland5-7basidorsal spiniform setae (Fig. 32); ligula moderately prominent; palp with 3 or 3 + 1 setae, other features as statedfor thegenus. Thorax: Anterodorsalpronotum with scatteredspiniform setae. Synthorax robust, anteriorandposterior wing sheaths extending to basal 0.30 and0.60 of abdominalsegment5respectively, although variableduetopostmortempreserva- tion, with a colorpattern ofalternating pale and dark transversalbands (Fig. 1). Legs yellow, withdarkbrownrings onfemoraand tibiae;two rows ofspiniform setae on dorsalandventral surfacesoffemoradiminishing innumberandrobust- ness on meso-andmetafemora; anteriorandposterior surfacesofprofemora and anteriorsurfaceofmesofemorawithspiniform setae;protibiae withlong delicate setae onexternal surface andspiniform on internalone, both kinds ofsetae on bothsurfacesofothertibiae,numerous atapices; tarsi yellow, withlong delicate 42 R.Novelo-Gutierrez Figs 1-4.Dorsal aspectofArgialarvae; (1)A.fissa,6exuviae;- (2)A.fumipennisviolacea,ultimate instar,d;- (3)<4.harknessi, d exuviae;- (4)A.lacrimans, 9exuviae. setae on dorsumand stoutsetae on venter;claws yellow. Abdomenbrown, with a pale middorsal stripe throughout widening gra- duallyfrom segment6to rear; tergites 1-4withsmallsetae, 5-10withspiniform Argialarvae fromMexico 43 setae mainly on lateral and posterior margins, increasing in number, size and robustnessposteriorly, withlong setae onpale middorsalstripe. Sternitesbrown, 1-7 withsmall setae, 8-10 with spiniform setae,stouton posterior margin of 10. Male gonapophyses pyramidal (Fig. 49), dark, short, extending posteriorly to basal0.25of stemite 10, tipsacuteandparallel; ventralborderwith5-6spiniform setaeonbasal0.50and2-3long setae atbaseofapical0.50. Femalegonapophyses exceeding posterior margin of stemite 10 for 0.50 the length of 10; in ventral view lateralones (Fig. 66a) with long, acute and divergent tips; ventralborder with 13-15 spiniform setae onbasal 0.75 and two long setae at base ofapical 0.25;inlateralview asFigure66b.Centralgonapophyses smooth,slightlyshorter thanlateralonesand concolours. Gillslaminar(Fig.72), narrow atbase, ending in afilamentoustip; colorpattern mottled;laterals(Fig. 72b)threetimes as long as wide, with an external lateral carina close and parallel to ventral border, extending over basal 0.60 of gill and covered with spiniform setae; dorsaland ventralborderswithspiniform setaeonbasal0.17and0.66respectively, remainder ofborders withdelicatewhitesetae. Centralgill (Fig. 72a) twiceas long as wide, withoutlateralcarinae; dorsaland ventralborders with spiniform setae onbasal 0.50 and 0.18 respectively, remainderof borders as for lateral lamellae. Male cerci enlarged, bluntly pointed (Fig. 95 a-e), slightly concave ventrally. Remark. - Someindividualshave apoorly defined darkringon antennalpedicel. ecology. - Larvae inhabitlagoons, streams and rivers, where they cling to roots,submerged or floatingvegetation, or decayedleavesandtwigs accumulated atbackwaters ofstreams andrivers. Specimens collected atHidalgo were found withA.rhoadsi. Adults are year-round atleastin Morelos(GARCIA, 1987)and Hidalgo, andemergence probably occurs throughout theyear. Emergence in the laboratory occurred between 11:41 and 13:08h. DISCUSSION. -Afissa belongs to thegroupwithligula moderately prominent, they show closeresemblance tothoseofA.tarascana described by WESTFALL (1990) andreared by myself (cf. below). Bothare similarinthemottledgeneral appearanceofthe body, 3 setae onpalpus andshape ofmaleandfemalegonapo- physes. They differin size andin shape and colorpattern of gills,as well as in shape ofmale cerci. In this last featureA.fissa resembles A. rhoadsi. ARGIA FUMIPENNIS VIOLACEA HAGEN Figures 2, 19,38,56,69, 77,87 Material. - 13larvae(4<5,7Ç), 2exuviae (Ç) MEXICO:Durango,LaMichilîa,arroyo Corralitos, 23-VIII-87, 1(5; 9-XII-87, 1 d;- arroyo ElTemazcal, 10/12-XII-87,2d, 10Ç. - All R.Novelo &E.Gonzâlez leg. description. - Larvae brown, body stout and short (Fig. 2). H ea d as in A.fissa; apale triangular spot on each side ofmedianocellus. Antennae 7-jointed (Fig. 19), longer than head, pedicel dark but pale atbase. 44 R,Novelo-Gutierrez Figs 5-8. Dorsal aspect ofArgia larvae: (5)A.lugens,ultimate instar, cf; - (6)A.munda, ultimate instar,d;- (7)A.oenea,9exuviae (gillsdetached);- (8)A.plana,6 exuviae. Argia larvae fromMexico 45 otherantennomeresyellow,ratiooflength ofantennomeres: 0.50,0.75, 1.0,0.98, 0.65,0.40,0.20.Labiumwithhinge extending posteriorlyto0.50ofmesostemum; prementumlongerthan wide(Fig.38), with 11 lateraland7basidorsal spiniform setae;ligula barely prominent;palpus with3 long setae (Fig.38b),otherfeatures as inA.fissa. Thorax: Pronotumas inA.fissa: Synthorax stout, wing sheaths extending toabdominalsegment6.Legs yellow,otherwisesimilartoA.fissa; tibiaedensely covered with intercalatespiniform setae and long setae;tarsi yellow, spiniform setae on under side and delicate setae on dorsum; claws yellow. Abdomen-brown, witha broadmiddorsalpale stripenarrowing suddenly on 10(Fig. 2),a dark spot on eachside ofthis stripe on 4-9; sides and dorsum of4-10and ventroposterior margin of7-10 with spiniform setae increasing in number, size, and thickness posteriorly; posterior borders of each tergite with stoutspiniform setae;middlepart ofdorsumof 1-4 withtuftsoflong whitesetae. Male gonapophyses pyramidal (Fig. 56), reaching posteriorly to 0.70 length of stemite 10, tips acute and divergent; ventral border with 8-9 stout spiniform setae. Female gonapophyses (Fig.69)justsurpassing stemite 10; inventralview, laterals(Fig. 69a) with tips acute andslightly divergent; ventralborderwith 12- -15 stout spiniform setae and 2-3 long setae at base ofapical 0.33 (Fig. 69b); central gonapophyses smooth, shorter than lateral ones. Gills laminar, ovate, brown withouta definitepattern,twice as long as wide,narrowed atbase,apex widelyroundednot attenuatedattip; dorsaland ventralborderswithintermingled spiniformandlong hair-likesetae,exceptatapex; laterals(Fig. 77a) withalateral carina on external surface extending over 0.75 the total length of gill, carina covered with spiniform setae. Central gill (Fig. 77b) with one carinaeach side extending over 0.55 length of gill and similarly covered with small spiniform setae. Male cerci enlarged, bluntly pointed (Fig. 87a, b, d); in posterior view notably wider than high, with a small concavity on venter, and dorsal margin sigmoid (Fig. 87c). ECOLOGY. -Larvaeare typical stream-dwellers, preferring sites wherebackwa- ters are formed, clinging under rocks, among gravel and submerged grasses. Emergence occurred between 10:09- 1:53h in thelaboratory. DISCUSSION. - A.f. violacea belongs to the group with a slightly prominent ligula; it differs from the description ofA.f. atra Gloyd (NEEDHAM, 1904) from Florida in having 3 long well developed setae on palpus and 7-jointed antenna,whileNeedham cites2+l setae and6-jointed antennae;they agree in all othercharacters.A.f. violacea sharesthefollowing characters(otherspecies in parentheses): antennal pedicel darker than remaining antennomeres (fîssa, plana, rhoadsi); threepalpal setae(apicalis, rhoadsi,tarascana);broadmiddorsal pale stripe onabdomen(emma,fissa, lacrimans, nahuana,pulla, rhoadsi); shape ofmalegonapophyses (lugens, munda,tonto); shape ofgills (munda, nahuana); shape ofmale cerci (pulla). 46 R. Novelo-Gutierrez Figs9-12, Dorsal aspectofArgialarvae: (9)A. pulla, <iexuviae; - (10)A.rhoadsi,i exuviae; - (11)A.tarascana, ultimateinstar,9;- (12)A.tezpi, 6exuviae. Argialarvae from Mexico 47 ARGIA HARKNESSI CALVERT Figures 3, 18,37,45,58,73,96 Material — 22 larvae (12 d, 109). 2exuviae (d), MEXICO: Morelos, Vicente Aranda, Rio Atnacuzac (800 m),23-1-82,3 <5, 2 9,R.Arce leg.; 1l-XII-82,4rf, 29, G.Rodriguezleg.; 12-11- 83, 5 d, 5 9, G. Cardoso leg.; - Cuautla, Las Tazas (1320 m); 19-11-86, I d, R. Novelo leg.; - Tehuixtla, Rio Atnacuzac (750m), 19-IV-86, 1 d, 1$,R. Novelo leg. DESCRIPTION. - Larvae pale brown, body stout andshort (Fig. 3), H ea d-as inA.fissa; labrumred-brown.Antennae7-jointed (Fig. 18),slightly longerthanhead,scape yellow, pedicel slightly darkerthanbrownflagellomeres; ratiooflengths ofantennomeres; 0.45, 0.60, 1.0, 0.75, 0.45, 0.20,0.10. Labium withhinge extending toposterior margin ofprostemum; prementumlonger than wide (Fig. 37), with 17-23lateral and 7-10 basidorsal spiniform setae; ligula prominent:palp withoneshortseta,externalborderdark, coveredwith spiniform and claviform setae, internalandapical borders as in other species. Thorax.-Anterodorsalportion ofpronotum withsetaeandspiniform setae. Synthorax robust,anteriorwing sheathsextending toposterior marginofabdomi- nal segment 4, posterior ones slightly longer, yellow-brown with diffuse pale spots on extreme base andnodus. Legs yellow, femoraflattened; otherfeatures as inA.fissa. Abdomen.- Yellow on 1-4,5-10red-brown, aprominent subquadrangular dark spot oneachsideofpale midlineon 2-5, less conspicuous on6-8 inmature individuals; pale midlinewidening notably on 8-10; lateroventralportions of 1- 6 with dark spots comprising total length of 1-2 andapical halfof 3-6.Tergites 1-4 withminutesetae,5-10with spiniform setae increasing in number, sizeand thickness posteriorly, mainly atsides and on posterior margins; middlepart of tergites2-10withtuftsoflongsetae. Stemitesyellow,2-7withadarksubtriangular spot on each side of midline; posterior margin of7 and stemites 8-10 with spiniform setae;middlepartof8with abundantclaviformsetae. Malegonapophy- ses spatulate (Fig. 45), extending posteriorly to basal 0.75 of stemite 10, tips roundedand divergent; ventralborder with22-24 stout claviform setae. Female gonapophyses exceeding posterior margin of 10by 0.25 length of 10; laterals, in ventral view (Fig. 58a), with apices blunt, ventral border with 26-29 stout claviform setae on basal 0.80; in lateral view as in Figure 58b; central ones smooth and slightly longer than lateralones. Gills mainly laminar, but a little inflatedat extreme base (Fig. 73); lateralones littlemore than twice as long as wide,witha sma'l tip atapex(Fig. 73b); colorationobscure onbasal0.75, white on apical 0.25;dorsalborder with a few spiniform setae on basal 0.12; apical 0.33 of both borders with delicate white setae, remainder of borders smooth. Centraloneless thantwiceas long aswide,colorationasinFigure 73a,otherwise as in lateralones. Malecerci short, globulous (Fig. 96c),roundly pointed (Fig. 96a). 48 R.Novelo-Gutierrez Remark.- Great variation existsin gillpigmentation,primarilyin young instars. ECOLOGY. - Larvae are typical ofopen stream habitats; individualswere taken clinging amongthephanerogam Ceratophyllum demersumL„ whichis characte- ristic ofrapid water flow. Adults are year-round in Morelos (GARCIA, 1987) and emergence probably occurs throughout the year. Emergence in laboratory was observed at 12:17and 12:41 h. DISCUSSION. - A. harknessibelongs to the groupwith a very prominent ligula and one palpal seta. They are similar to GEIJSKES’ (1943) description ofA. insipida, being similaringeneral appearance,proportion ofantennomeres,shape and coloration of gills and in male and female gonapophyses, but males are unique inhavingspatulate gonapophyses. Thesespecies differonly by thecolora- tionofthe antennomeres and thegreater length ofthemale gonapophyses ofA. insipida A. harknessi resembles A. oenea in shape ofmale cerci. Figs 13-14.Dorsal aspectofArgialarvae:(13).A.tonto,ultimateinstar,cf; -(14)A.ulmeca, 9exuviae. ARGIA LACRIMANS HAGEN Figures4,24, 39,52,61,74,97 Material. - 7 larvae (46, 39), 2 exuviae (tj, 9). MEXICO:Hidalgo, Cacala(2000 m), 15-XI- -85, 2<S, 1 9,- Tepeoco(1750m), 29-VII/1-VIII-86,2<5, 2 £- Morelos,Tepoztlan(1705m),8- XI-86, 1 9, 11-87,1 6. - All R.Novelo leg. DESCRIPTION.- Larvae brown, body stout (Fig. 4).