Oligoclada teretidentis spec. nov. from eastern Ecuador (Anisoptera: Libellulidae)

5 Pages·2003·0.84 MB·English

by  Rehn, A C

Odonatologica32(2):171-175 June 1,2003
Oligoclada teretidentisspec. nov. fromeastern
Ecuador(Anisoptera: Libellulidae)
A.C.Rehn
2817GStreetApartment1,Sacramento,California 95816,UnitedStates
ReceivedJune 18,2002/Revised andAcceptedSeptember3,2002
Thenew sp.isdescribed andillustrated (holotype 3,allotype 9:Ecuador,Orellana
prov., forested shore ofoxbow lagoonnearRioTiputini,approximately 1 km. NWof
BiologicalResearch Station,ParqueNacional Yasuni,11-X-200T,depositedinUMMZ,
AnnArbor,MI,USA).Speciesispeculiarinhavingalargeyellowishpatch ontheventral
mesepistemumandby discretelateralbandsofpruinosityonsynthorax(thesebandsyellow
in 29)and,inthe 3 bythe ventral,rounded tooth at 1/2lengthofcercus.
,
INTRODUCTION
BORROR (1931) treated 14 species ofOligoclada as valid inhis revisionofthe
genus.Sevenspeciesand 1 subspecies havebeendescribedsince then(seeSANTOS,
1945a, 1951;FRASER, 1947;GEUSKES, 1984; DE MARMELS, 1989, 1992;
MACHADO & MACHADO, 1993). The monotypic Podothemisnemesis Ris was
transferredtoOligoclada bySANTOS(1945b), andGEUSKES(1984)synonymized
O.raineyiRiswithO.abbreviata(Rambur), bringingthecurrent numberofspecies to
21. Thespecies describedhereinbrings thetotal to22.
OLIGOCLADA TERETIDENTISSP. NOV.
Figures1-8
Material. — Holotype9: ECUADOR;Orellanaprovince,forestedshoreofoxbowlagoonnearRio
Tiputini,approximately 1km. NW ofthe BiologicalResearch Station,ParqueNacional Yasuni, 11-X-
-2001, AndrewC.Rehn leg. — Allotype 9; samedataas holotype. — Paratype 3: samedataas
holotype.Holotypeandallotypearedepositedinthe UniversityofMichiganMuseumofZoologyinAnn
Arbor,Michigan,USA.The paratypemale isin thepersonalcollection ofthe author.
Etymology.—ThenameteretidentisisLatinfor“roundedtooth”,referringtotheventral,rounded
172 A.C.Rehn
toothlocated atmid-lengthonthe malecercus.
MALE(holotype). — Head. — Labiumwhitish-yellow except mesalmargins of
palps black; labrum, postclypeus and anteclypeus whitish-yellow with black setae;
fronsbi-colored, athin palebandjustabovefronto-clypeal suture,remainderoffrons
and vertex metallicsteel-blue;antennaebrownish-black; occiput shiny black except
forasmallposteriorpale spotoneithersideofmidline,andwithlong posteriorsetae;
rearofheadshiny black.
Thorax. — Prothorax mostlyblack, dorsumand sidesofmedianlobediffusely
darkbrown;posterior lobeerect,slightly emarginated medially withafringeoflong,
whitesetae.
Pterothoraxentirelyblackexcept foralarge, rounded,triangularyellowishpatchon
ventral 1/2andexternal 3/4ofeach mesepistemum, thispatch entirely surroundedby
brownish marginand adjacent ventrally to mesopleural (humeral) suture although
slightly obscured by pruinosity there, slightly narrowed dorsally. Lateralbands of
pruinosity as follows:oneon posteriorhalfof mesepimeron, connecteddorsally and
ventrally withsecondbandcovering muchofmetepistemum,areasurrounding spiracle
black, athirdtriangularband covering the posterior-dorsal halfof the metepimeron,
fusedwithmetepistemal bandonitsupperend(Fig. 1).
Legs black, withproximal flexorsurfacesofallfemorapruinose.
Wings. — Membranelightly smoky throughout, venationas forthegenus;analloop
comprising 10cellsinrighthindwing, 11 cellsinlefthindwing, heeland toepoorly
developed;2rows ofcellsinanalfieldatlevelofmidriborigin; discoidalfieldoffore
wing comprising 2 cell rows tobeyond levelof nodus; forewings with 9 antenodal
crossveins, right forewing with 8 postnodals, leftfore wing with 9 postnodals; hind
wings with6antenodals,right hind wing with 8 postnodals, lefthind wing with 9
postnodals. Pterostigmabrown.
Abdomen.— Black, with diffuse dorsalbands ofpruinosity on basal 1/3of
segments 1 and 2; anterior hamulesblack, extending justbeyond level ofanterior
lamina,butslightlylessprominent thanroundedgenital lobes(Fig.2), medialhooksof
anteriorhamulesdivergingcaudally, externaledgeofhamularridgedevelopedanteriorly
intosmall squarelobe (Fig.3). Cerciblack basally, darkbrownindistalhalf, longer
than segment9; inlateralview ventralmargin strongly up curvedinbasalhalf, with
oneprominent, roundedventraltoothat 1/2length (Fig.4), preceded bythreesmaller,
moreexternal teethbest seenindorsal oblique view, tips broadly pointed; indorsal
viewtipspointedandslightly divergent,innermarginsconvexatbase,becomingconcave
to3/4length,coveredwithfinewhitishsetae(Fig.5). Epiproctblack, slightly shorter
thancerci,tapered toblunt,upcurved, emarginated tip(Figs 4,6).
Measurements (mm). — Totallength25,abdomenlength17,hindwinglength21.
FEMALE (allotype). — Head. — Similarto holotype except facebrown, entire
vertical surfaceoffronsbrown, horizontalsurfaceof fronsand vertexasinholotype;
posterior marginofocciput emarginate, withsmalllaterallobes(Fig.-?).
Thorax. — Prothoraxasinholotypeexceptfringeoflongsetae onhindmarginof
Oligocladateretidentissp.n. 173
posterior lobegolden.
Pterothoraxsimilarto holotype exceptbrown; ventralmesepistemal patch entirely
yellow withno colorchange around margins; ventral 1/5of mesepimeron andarea
around stigma black; lateral yellow bandson mesepimeron, metepistemum and
metepimeronwhereholotype ispruinose.
Legsblack, exceptcoxaebrownish.
Wings. — Membranelightly smokythroughout; right forewing with8antenodals,
9 postnodals, left forewing with 9antenodals, 9 postnodals; hind wings with 7
antenodals,8 postnodals.
Abdomen.— Stockierthanholotype,entiredorsumofsegments2and3yellowish-
-brownabovelateralcarina,blackish-brownbelowlateralcarina; dorsumofsegment4
yellowish-brown above lateralcarinaexceptforsmallblack areaimmediately above
apical 1/5 oflateralcarina;paleareas morerestrictedandformingamid-dorsalbrown
bandon segments 5-7, this bandoccupying dorsal 1/3 ofareabetweenmid-dorsal
carinaand lateralcarinaonsegment5,anddorsal 1/4ofthesameareaonsegments6
Figs 1-8.Oligocladateretidentissp. n.,holotype i (1-6),andallotype 9(7,8):(1)synthorax,left lateral
view (lightlystippledareasindicate pruinosity); — (2)hamule, genitallobeand anteriorlamina,lateral
view; —(3)hamules,ventralview; —(4)caudalappendages,leftlateralview; —(5)caudalappendages,
dorsalview;—(6)caudalappendages,ventralview;—(7)occiput,dorsalview;—(8)abdominalsegments
8-10,ventralview.
174 A.C.Rehn
and7;remainderofsegments5-7andsegments8-10black. VulvarlaminaasinFigure
8. Stemite9convex, overlapping stemite10. Ventralcarinaof segments2-9 fringed
withlong, whitesetae.
Measurements (mm). —Totallength25,abdomenlength16,hindwinglength21.5.
VARIATIONINPARATYPE. — The single paratypemaleshows littlevariationfrom
theholotype, exceptthatthepaleposterior occipital spots areabsent.
DISCUSSION
Oligoclada teretidentisbelongs to “group IT” ofBORROR (1931) basedon the
structure ofthepenis intheparatypemale(notillustrated),although thephylogenetic
validity ofthesegroupshas never been analyzed. Thenew species is distinguished
from most othermembers ofthe genus by the large, ventral yellow patch on the
mesepistemum ofboth sexes. Mature males of no otherknown Oligoclada species
have large mesepistemal patches (O. monosticha Borrorand O. sylvia Kirby have
obscure grayish mesepistemal bands,but differgreatly inmorphology ofhamulesand
cerci).BasedonDEMARMELS’(1989)descriptionofO. hypophane andBORROR’s
(1931) discussionofO. walkeriGeijskes, femalesofthosespeciesalsohavelarge pale
antehumeralpatches. FemaleO. teretidentisare distinguished fromO. hypophane by
vulvar laminamorphology (DEMARMELS, 1989,fig 202), and are distinguished
fromO. walkeriby vulvarlaminaandocciput morphology (GEIJSKES, 1984,figs 18
& 19).
Thestructure of the male cerci in O. teretidentisis diagnostic, and while slightly
similartoO. monosticha,theventralmarginofthecercus inthatspecies is lessarched
basally, andtheventraltooth is moredistadand moreacute.Theformofthe female
occiputisdiagnosticinO. teretidentisasfarasisknown,butfemalesofseveralspecies
remainundescribed,and descriptions ofseveral othersdo notdiscuss this structure.
Oligocladateretidentisisknown only fromthe AmazonBasinofeastern Ecuador.
Allthree specimens inthetype series were collectedalong the forestedshore of an
oxbow lagooninmostlysunnyconditionsatmid-day.Themaleswereobservedperching
ondeadlogswithinseveralinchesofthewater.Thefemalewascapturedassheattempted
to oviposit along the water’s edge near the base of shorelinevegetation. Common
species flying atthesamelocationincludedMicrathyria occipita Westfall,Perithemis
electraRis, Erythemis haematogastra (Burmeister), Acanthagrion apicale Selys and
Protoneurapaucinervis Selys.
Publishedrecords ofOligoclada in Ecuador are scarce, but the genus is well-
represented there. Asingle femaleO. pachystigma Karschwas collectedalong with
thenewspecies describedinthispaper.Thefollowing additionalOligoclada species
havebeencollectedinEcuadorbyDennisR. Paulsonandothers:O. crocogasterBorror,
O.monosticha,O. stenopteraBorror, O.umbricolaBorrorandO. walkeri(D.Paulson,
pers.comm.).
Oligodadateretidentissp.n. 175
ACKNOWLEDGEMENTS
IthankROSSER GARRISON forhisencouragement to describethenewspecies andforhis helpful
comments. DENNIS PAULSON andNATALIAVON ELLENREIDERkindlyprovided review and
comments.
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