138 Journalofthe Lepidopterists' Society journaloftheLepidopterists'Society 60(3),2006,138-142 AREMARKABLE NEW RIODINID SPECIES, STALACHTIS HALLOWEENI (RIODINIDAE: STALACHTINI), FROM MOUNTAYANGANNA, GUYANA JASON W. HALL P. DepartmentofEntomology, NationalMuseumofNatural History.Smithsonian Institution.Washington,DC20560-0127, USA Email:[email protected] ABSTRACT.Anewriodinidspecies,Stalachtishalloweeni Halln. sp. (Stalachtini),isdescribedfrom MountAyanganna,atepuiinwestern Guyana. A preliminary hypothesis ofphylogenetic inter-relationships within the small genus Stalachtis Hiibner is suggested, based on an informalstudyofexternal morphologyandmalegenitalia.Three speciesgroupsareproposed, thephlegia,calliope andeuterpegroups, and S.halloweeniishypothesizedtobesistertotheremainingmembersoftheeuterpegroup. Additionalkeywords: endemism,montaneforest,morphology,SouthAmerica Situated in the Pakaraima Mountain RRaannggee of Guyanan colleagues, S. Fratello led the first western Guyana, Mount Ayanganna (2042m) is one of Lepidopteracollectingexpeditiontothe upperslopes of the easternmost tepuis in the Guiana Shield. Like the Mount Ayanganna. Among the many new taxa of other tepuis inwestern Guyana and easternVenezuela, butterflies collected there were several new species of Mount Ayanganna consists of eroded sandstone Riodinidae, including a new species of Stalachtis remnants of the Roraima Formation (MacCulloch & Hiibner, 1818 (Stalachtini), although most of these Lathrop 2001), and its isolated high-elevation habitats species were represented by only a small number of harbor significant numbers of endemic plants and female specimens. Fortunately, a second expedition to animals. During the last five years alone, several new Mount Ayanganna in 2002, by a different team that endemic species offrogs, snakes and lizards have been includedone ofthe 1999 Guyanan expedition members described from Mount Ayanganna (MacCulloch & (R. Williams), produced additional Stalachtis Lathrop 2001, 2002, 2004). specimens, includingmales. During the last tenyears, there have been numerous This new Stalachtis species is remarkable in several Lepidoptera expeditions to the upland regions of respects. It is the first new species to be described in western and southern Guyana (Fratello 1996, 2001, this small, essentially South American genus of 2003, 2005). In 1999, accompanied by several US and aposematic species for over 150 years, since Westwood (1851) described S. magdalena; it is the first known Stalachtis species to apparently occur exclusively in montane habitats; and its wing pattern differs substantially from that of its congeners. I herein describe this new Stalachtis species and attempt to establish its phylogenetic position within the genus by informally constructing a preliminary hypothesis of phylogenetic relationships for Stalachtis andproposing anewspecies-group classification. Stalachtis halloweeni Hall, new species (Figs. 1-2; 3; 4) Description: MALE: Forewing length 29.5 mm. Forewing elongate, costal and distal margins approximately straight, four forewing radial veins, discal cell elongate; hindwing rounded and slightlyelongate, hindwingveins Rs and Mj stalked. Dorsalsurface: Forewing ground color black, discal cell orange with some black scalingmedially,broadorangeraysincells2AandCu„extendingfrom (Cu.,) or near (2A) wing base to join submarginal band, orange rectangle at base ofcell Cur small orange spot at base ofcell M3, orange streaksincells M,toIU.andR„immediatelydistaltodiscal cellend,decreasinginsizefromcellM.tocellR„broadsubmarginal orange band extending from costa to tornus, with an enlarged Figs. 1—2. Stalachtis halloweeni adults (dorsal surface on rectangularorangepatchnearlyencirclingablackspotincellsM and 3 gleafnt,nav,entGruaylasnuarfa(cUeSoNnM)ri.ght2)..P1.arHaotlyopteypfeemmaallee,.MMoouunnttAAyyaann-- Catuw2i,ndigstbaalsef,riangberoblaadcko;rahnignedwsitnregagkrtohurnodugcholdoirscballaccke,llpaalnedocrelalnsgCeus,potto ganna, Guyana(USNM). M and along anal margin, those in cells Cu, and M shorter than 3 Volume 60, Number3 139 others and that in cell Cu, joining submarginal band, small distal orangespotincellSc+Rrbroadandunevensubmarginalorangeband extending from apex to tornus, distal fringe black. Ventral surface: Forewingdiffersfromdorsalsurfacebvhavingasmallorangespotat costalwingbase, onlydistalportionoforange streakpresentin cell 2A,orangestreakincell M„joiningsubmarginalband,orangespotin cell R, replaced bv a sparse scattering ol whitish scales; hindwing differs by having averv narrow line oforange scaling at middle of costal margin, with a sparse scattering ofwhitish scales distally, a largerorangespotincellSc+R amuchlargeranddarkerorangespot 1; at wing base, and a sparse scattering of whitish scales along anal margin. Head: Firstsegmentoflabialpalpi a mixture ofblackandwhite scaling,segmenttwoblackwithabroadwhitelateralbandandsome whitescalingventrally.andthirdsegmentblack;eyesbareandblack, withamixtureofblackandwhitescalingatmargins;fronsblack,with white scaling laterally; antennae 60% offorewing length, segments black with white scaling at ventral base and narrow nudum region alonginnerventralmargin,clubsblack. Body:Dorsalsurfaceofdioraxblack,tegulablackwithdarkorange scaling at base, ventral surface of thorax black with a white band between legs and a large orange patch near base of forewing; abdomenblackdorsally,withabroadorangebandlaterally,andwhite ventrally,withnarrowblacklines oneitherside (patterningvirtually indiscernibleinFig. 1duetoacoveringofmold),alllegsblack. Genitalia (Fig.3): Uncusinlateralviewrectangularandvertically Fig.3. MalegenitaliaofStalachtishalloweeni holotypeinlat- elongate, lateral "window" anterior to uncus very narrow, tegumen eralview. Scalebar = 1mm. verynarrow, with atriangularventral margin; falces extremelylong ofsclerotizationdorsallycurvinganteriorlyintoaninvaginatedpouch andventrallydirected,withaweaklybent"elbow";vinculumnarrow, below papillae anales that is membranous except for a broad, anteriorlybowed,broadestmediallyandslightlyposteriorlyindented triangular, horizontal band of sclerotization along dorsal "roof" of near ventral tip, with a posteriorly directed triangular section of pouch (perhaps a protected resting place for extremely long male sclerotizedtissueatventral marginandnoanteriorsaccus; aedeagus genitalfalcesduringcopulation);papillaeanalesproportionatelysmall narrow,convexandolmediumlength,gradually taperingtoaslightly andround;verybroad, semicirculartuftoflong,posteriorlydirected, upturnedandfinelypointedtip,vesicaexits alongventral marginof palebrownsetaearoundposteriormarginofeighthtergite. posterior third of aedeagus, comutal patch consists of a short Types: Holotype d, GUYANA: Cuyuni-Mazaruni, Mount sclerotized rod with about six prominently curved and anteriorly Ayanganna, 1120"m, 5°22.22'N 59°57.34'W 12-16 Oct 2002 ^R. directed spines densely positioned along all but its anterior tip, Williams) (National Museum of Natural History, Smidisonian comutalpatchpositionedaboutonethirddistancefromposteriorto Institution,Washington, DC,USA[USNM]). anteriortip ofaedeagus on unevertedvesica; pedicel in lateralview Paratypes: lc5, 19, same dataas holotype. 39, GUYANA: Cuyuni- broadbasally,becomingnarrowerinangularposteriorsection,pedicel Mazaruni, Mount Ayanganna, 4500-5500 ft, 5°24.1'N 59°57.4'W, joinsaedeagusaboutonethirddistancefromanteriortoposteriortip; 13-18Apr1999(S.Fratelloetal.)(USNM). valvae in lateral view consist ofalarge rectangular basal section, a Noadditionalspecimenshavebeenlocatedinthemajormuseums narrow,posteriorlyelongateandround-tippedlowerprocess,aslightly ofEuropeandNorthAmerica(aslistedinHall 1999,2005). wbriotahdear,pomsotrereiorrelcytaanngdulaurpwaanrddlpyostceurrivoerdl,y eflinoenlgyatpeoiunptpeedrtperromciensas,l Etymology: The name is derived from the middle projection, averybroadand rounded innerprocess, slightlyshorter English word halloween, in reference to the fact that than lower process, and a pointed transtilla of medium length the wing pattern is composed ofthe traditional orange oefxtaeenddeianggupso;stnearriorrolwytbuefttwoefenlopnagi,rpoofsitnernieorrplyrodciersescetseda,ndpaalcerobsrsotwonp and black colors ofHalloween, and is reminiscent ofa setaearoundoutermarginofgenitalcapsule;eighthabdominaltergite carvedpumpkin. 2a8ndmFsmEt.eMrAnDiiLtsEeta:rlecfDtoiafrnfegewurlisanrgf.rmoamrgmianlceoninvefxo.llWoiwnignsg:wOayrsa:ngFeoroenwbiontghlweinnggtsh NerSiyassteBmoaitsidcuvpall,ac1e8m3e6n)tiasntdhediasoglneosgise:nuSstalcauclrirteinst(l=y veryslighdypaler, medial blackscalingin forewingdiscal cell more treated in the tribe Stalachtini. The familv-group name prominent,severalforewingpostdiscalorangespotsdonotextendas was proposed by Bates (1861), as a subfamilv, for an farproximallytocellbases,orangerayinventralforewingcellM„does undefined numberofgenerawhose species possesseda notdistallyjoinsubmarginalband. Head: Second palpal segment slightly more elongate, third "pupa not flattened beneath, secured rigidlybv the tail segment about twice as long; nudum region on antennal segments in an inclined position, without girdle", a set of slighdylarger. characters quickly discovered bv Bates (1868: 368) Genitalia (Fig.4): Corpusbursaesomewhatnarrowandelongate, withapairofsmall, sclerotized,invaginatedspine-like signa; ductus himself not to be phvlogeneticallv informative in die bursae consists ofa large, creased, hardened swelling immediately context of the higher classification of the Riodinidae. posteriortocorpusbursaecontainingaboutfourpiecesofrectangular Stichel (1910-11) used the Stalachtini as a tribal name sclerotization,ashortmembranoussectionposteriorly,drenalongand twistedlightlysclerotizedsection,followedbyashort,concaveventral forthe firsttime (as the Stalachtidi). and followed Bates section ofsclerotization; membranous ductus seminalis exits ductus (1868) in including only Stalachtis within it. Most bursae dorsally immediately anterior to ventral section of recently, Harvey (1987) defined the monotvpic sclerotization;ostiumbursaeindorsalviewconsistsofasmall,round, sclerotizedentrancehole,withabroadandprominentlyconvexband Stalachtinibythepresenceofatuftoflongsetae around 140 Journalofthe Lepidopterists' Society the posterior margin of abdominal segment eight in males and, to a greaterextent, females, and mentioned that its species are unusual in the Riodinidae in having M hindvving veins Rs and stalked rather than arising { separately from the discal cell end (Bates 1S68; Stichel 1910-11). Additional unique characters that are universal within the Stalachtini include extremely long and weakly bent (i.e. ventrally directed) falces, a complex arrangement of inner valve processes, and a long straight comb of prominently curved, anteriorly directed spines on the aedeagal vesica in the male genitalia (Hall unpubl. data). The new Stalachtis species, S. halloweeni, possesses all of the above characters. Traditionally, Stalachtis has been treated as containing eight species (e.g. Stichel 1910-11, 1930-31), althoughsomeauthors havelistedas manyas ten species (D'Abrera 1994; Bridges 1994). However, the genus is now justifiably recognized to contain only sixspecies (Callaghan& Lamas 2004). Hemming(1964, 1967) selected the type species of Hiibner's (1818) Stalachtis to be S. phaedusa (Hiibner, [1813]). It is worth mentioning that the name Stalachtis funereus albulus Lathy, 1958, which occasionally appears in the riodinid literature (e.g. Rebillard 1958; D'Abrera 1994; Bridges 1994), actually refers to a pericopine moth (Arctiidae) (Hall unpubl. data). Stichel (1910-11, 1930-31) divided Stalachtis into two sections, the "Adiorati" for S. calliope (Linnaeus, 1758) and S. magdalena Westwood, 1851, in one subgroup and S. phlegia (Cramer, 1779) (+ S. susanna (Fabricius, 1787)) and S. euterpe (Linnaeus, 1758) in another subgroup, and the "Diaphanes" for S. phaedusa (+ S. zephyritis (Dalman, 1823)) and S. lineata (Guerin-Meneville, [1844]). Based on a study of wing pattern and male genitalia characters in all six Stalachtis species, an alternative species-group classification and preliminary hypothesis ofphylogeneticrelationships forthegenusis proposedhere. As S. calliope, S. magdalena, S. euterpe, S. phaedusa and S. lineata all share a pair oflarge, rounded, inner valve processes, with an elongate, pointed transtilla extendingposteriorlybetween them and across the top ofthe aedeagus, S. phlegia is hypothesized to be sister tothe remainingspeciesinthegenus. Stalachtisphlegia has a much smaller pair of inner valve processes, without the intervening transtilla, and has the least derived wing pattern, with a full complement ofwhite basal, postdiscal and submarginal spots. Stalachtis calliope and S. magdalena, like S. phlegia, but unlike any odier Stalachtis species, have a complete row of Fig. 4. FemalegenitaliaofStalachtishalloweeniparatype in dorsalview. Scalebar= 1 mm submarginal white spots on the forewing, an orange patch at the base ofthe dorsal forewing and hindwing, Volume 60, Number 3 141 and an entirely checkered black and white hindwing into three species groups, the phlegia group for S. fringe. Theirsimilarwingpatterns, with mottledorange phlegia, the calliope group for S. calliope and S. markings atthebaseoftheforewingandparallelorange magdalena, and the euterpe group for S. halloweeni, S. bands on the hindwing, shared possession ofan upper euterpe, S. phaedusa and S. lineata. Thus, only two of valve process that is broadest medially (instead of Stichel's (1910-11, 1930-31) three proposed species basallvin S. phlegia and distallv in the remaining three groups for Stalachtis appeartobe monophyietic. species), and parapatric geographic ranges strongly Biology: This newspecies appearstobe restrictedto suggestthattheyaresisterspecies. Stalachtiseuterpe, S. lower montane forest habitats, where it is currently phaedusa and S. lineata appearto form a monophyietic known from between about 1100 and 1700 m. group, as all three species share similarly positioned Specifically, the type series was collected in wet, low white wing markings that are consistently formed into (canopyapproximately 10-15 m), evergreen high-tepui rays instead ofspots, the absence ofan orange patch at forest, a vegetation type that was described and the base of the dorsal forewing and hindwing, the illustrated by Maguire (1970), Huber et al. (1995) and absence ofa complete row ofsubmarginal white spots MacCulloch & Lathrop (2001). on the forewing, largely black wing fringes, and an Steve Fratello (pers. comm.) observed approximately upper valve process that is broadest distallv. As ten individuals of S. halloweeni on Mount Ayanganna, Stalachtis phaedusa and S. lineata both have elongate most ofwhich were probably females, judging by the hvaline rays on both wings they are probably sister factthatallindividuals capturedwere ofthatsex.Within species. the forest, these individuals consistentlyflew at about 5 m Stalachtis halloweeni appears to exhibit external to 7 above the ground, although two individualswere pattern characters that are somewhat intermediate observed flying only 2 to 3 in above the ground over a between those ofmembers in the calliope andeuterpe patch of low tepui scrub at 1700 m. Individuals were groups. Itshareswiththetwocalliopegroup speciesthe seen flyingover awide area from mid-morningto mid- presence oforange markings at the base ofthe dorsal afternoon,witharatherslow, steadyflight, andwerenot forewing, andwith S. magdalena theabsenceofalateral observed alighting or resting. No other Stalachtis whiteline aboveaswellasbelowthe lateralorangeband species were seen flying in the same habitats as S. on the abdomen. It shareswith the threeeuterpe group halloweeni, but S. phaedusa, S. calliope and S. euterpe species a similar pattern of rays at the base of the have been commonly collected in neighboring lowland forewingandparticularlythehindwing, evenifthese are areas ofGuyana (Fratellopers. comm.). orange instead ofwhite, the absence ofa complete row Stalachtis is one of the most well known groups of ofsubmarginal white spots on the forewing, and black aposematic riodinids (Seitz 1916-20; DAbrera 1994). wing fringes. Based on the above characters, and the Given that the known caterpillars are gregarious and factthat S. halloweeni has the full complementofinner aposematic (Callaghan 1986), and members ofat least valve processes and an upper valve process that is some of the known foodplant families (e.g. broadest distally, this new species is tentatively Simaroubaceae) contain toxic phytochemicals (e.g. suggested to be the most basal member ofthe euterpe Morettietal. 1982; Polonskyetal. 1984), itseemslikely group. The male genitalia of Stalachtis species are that some or all ofthe Stalachtis life stages are to some rather homogeneous, with the most significant extent distasteful to predators, and adults may thus be interspecific variation exhibited by the upper and, to a predominantly Mullerian rather than Batesian mimics. lesser extent, lower valve processes. Although S. However, I am notaware ofanysympatricbutterfliesor halloweeni appears to be most closely related to S. moths that specificallycloselyresemble S. halloweeni. euterpe, its male genital valvae are probably most Distribution: Stalachtis halloweeni is eurrentiy similar to those of S. phaedusa, but its upper valve known only from the middle slopes of Mount process does not have such a prominent ventral Ayanganna, in the uplands of western Guvana. protrusion attheposteriortip, andtheposteriormargin However, the geographic range ofdiis species probably extends at about a 45° angle instead of vertically. extends to neighboring highland areas in Guvana and Elsewhere in the euterpe group, S. euterpe can be extreme eastern Venezuela. There continues to be characterized by its dorsal as well as ventral swelling to debate aboutwhether most Guiana highland endemics the distal tip ofthe upper valve process and atypically are relicts of a widespread pantepui fauna or smallandstraightterminalprojection, andS. lineata can descendants of lowland ancestors (e.g. Mvers & be characterized by its broadly triangular instead of Donnelly 1996; MacCulloch & Ladirop 2001). Given narrowerrod-shaped lowervalve process. that all six described Stalachtis species have entirely In conclusion, Stalachtis seems to be best divided lowland distributions, the ancestor of S. halloweeni 142 Journalofthe Lepidopterists" Society presumably colonized Mount Ayanganna from the Hepburn&Sons Ltd., London,UK. surroundinglowlands. . 1967. The generic names of the butterflies and their type species (Lepidoptera: Rhopalocera). Bull. Brit. Mus. Nat. Hist. Acknowledgements Hube(rE,nt.O).,SuGp.pl.Gh9a:r1b-a50r9r.an & V. Funk. 1995. Vegetation map of I thankThe National Science Foundation (DEB #0103746) Guyana.CentrefortheStudyofBiological Diversity, University forfinancial support; G. Lamas and S. Fratello forcarefullyre- ofGuyana,Georgetown,Guyana. viewingthe manuscript; S. Fratelloand R. Williams forcollect- H0BNER, J. 1818. Zutriige zur Sammlung exotischer Schmettlinge ing and donating Stalachtis specimens to the USNM; and S. [sic], bestehend in Bekundigung einzelner Fliegmuster neuer Fratello for generouslyproviding notes on the ecology ofSta- oder rarer niehteuropaischer Gattungen. 1: 1—49. J. Hiibner, lachtishalloweeni fromhis arduous andhighlyproductive 1999 Augsburg,Germany. MountAyangannaexpedition,whichwas funded inpart bythe MacCulloch,R.D.&A.Lathrop.2001.AnewspeciesofArthrosaura Smithsonian Biological DiversityoftheGuianas Program. (Sauria:Teiidae)fromthehighlandsofGuyana. Carib.J. Sci.37: 174-181. Literature Cited . 2002. 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