Heteragrion tiradentense spec. nov. from the state of Minas Gerais, Brazil (Zygoptera: Megapodagrionidae)

2006·1.5 MB·English

by  Machado, A B M

Odonalologica35(1):47-54 March1,2006
Heteragriontiradentense spec. nov.
from thestateof Minas Gerais, Brazil
(Zygoptera: Megapodagrionidae)
A.B.M.Machado¹andL.C. Bedê²
1DepartamentodeZoologia,InstitutedeCienciasBiologicas, Universidade Federal deMinas
Gerais,Caixa Postal486, BR-31270-901 Belo Horizonte,Minas Gerais,Brazil
[email protected]
2Conservation International-Brazil,Av,Getiilio Vargas,1300,7°andar,
BR-30I2-021 Belo Horizonte,Minas Gerais,Brazil
ReceivedSeptember29, 2005/ReviewedandAcceptedOctober 19,2005
Thenewsp. (holotype6:Brazil,MinasGerais,Tiradentes,l-XI-1999)isdescribed
and illustrated. Itbelongsin the group 1 ofE. deSELYS-LONGCHAMPS(1862,
Bull. Acad. Belg.[II] 14:5-44)and differsfromtheotherspp. ofthegroupbyitssmall
sizeandby thecolor,shapeand size ofitsmesepisternalspot.
INTRODUCTION
The Sao Jose mountainrange ofsoutheastern Brazil has recently been pro-
claimedby theGovernmentof theStateof Minas Geraisthe“LibelulasdaSer-
ra de Sao Jose”WildelifeRefuge, the first nature reserve in Braziland perhaps
inSouth Americawiththe primary focus on theprotection of dragonflies. On
surveying the rich odonatafaunaof thisreserve (120 species) we came across a
beautifulnew speciesofHeteragrion thatis describedhereinunderthenameof
Heteragrion tiradentense. Withthisnewfinding thegenusattains43species and
1 subspecies, 16ofwhichfromtheBrazilianfaunaas reported by SELYS(1862,
1886),CALVERT(1909), SJOSTEDT(1918), WIELIAMSON(1919), MACH-
ADO(1988), GARRISON (1989) andCOSTA & SANTOS(2000). H.tiraden-
tenseisthe 6thspecies ofHeteragrion reported forthestateofMinasGerais, two
ofwhich, H. obsoletumSelys, 1886andH.petiense Machado,1988,figureamong
the Brazilian red listed Odonata(MACHADO etah, 2005). Heteragrions are
poorlystudied in Braziland thenumberofspecies is likely to increasesubstan-
tiallyasmorestudiesare made.
48 A.B.M.Machado &L.C. Bede
HETERAGRION TIRADENTENSE SP. NOV.
Figures1-5
Material. - Holotype<S and allotypeS: BRAZIL,Minas GeraisState;Tiradentes. Libelu-
las daSerra deSao Jose State Wildelife Refuge(Chafarizcreek atthe Mae D’-Agua forest). 11-XI-
1996,L.C. Bede & W.Piper leg.;21°06T6”S,44°I0'42”W. - Paratypes(2<J), same localityand
collector asthe holotype, l-XI-1999. All species depositedin A.B.M. Machado collection in Belo
Horizonte,MG, Brazil.
Etymology.— The namereferstothemunicipalityofTiradentes where thespecimenswere
collected.
MALE(Holotype): — Head (Fig.2) — Labiumyellowish white.Labrumdark
brownwiththebaseandthemarginorange.Anteclypeus, baseofmandibleand
genaeyellowish white,withatransverse dark brownbandcrossing thegenaebe-
tweentheeyesandthepostclypeus. Postclypeus black. Anteriorportionoffrons
dark brown. Top ofheadblackexcept fora lightbrownstripe between thelat-
eral ocelli andthe antennae baseandanotherbehindtheeyes. Antennaescape
andpedicel black. Rear oftheheadyellowish white.
Thorax.- Pronotallobesblack, the medianwitha brownish yellow stripe
atits posterior border(Fig. 2). Propleuron light yellow. Pterothorax(Figs 1-2):
mesopleuron blackwithalargebiconvex lens-shaped yellowspotoccupyingabout
halfthewidthoftheposteroinferiorpartofthemesepisternum. Lowerfouthof
themesepimeron darkbrown.Metapleuronlight yellowwithalightbrownstripe
onthe metepisternum andanotherpoorly definedon themetepimeron (Fig. 1).
Legsbrownexceptfortheflexorsurfacesoffemuraethatareyellowish. Toothof
tarsal clawssmall. Wingshyaline, slightly suffusedwithyellow. Venationbrown
except for the upperpart of the arculus and nodusyellow; pterostigma brown
withanyellow linealongitsradialside.
Venation. - Postnodalsin forewing 16(66.6%), 17(33.3%),inhindwing 15
(66.6%), 16(33.3%); postquadrangular cells in fore and hindwings 2(100.0%);
Fig. 1.Heteragriontiradentensesp.n.,malephotographedalive.
Heteragrionliradenlense sp.n. 49
numberof cellsbellow thepterostigma inforewing 1/4+ 1 + 1/2, 1/2+ 1 + 1/2,
2/3 + 1;in hindwing 2, 1/2 + 1 + 1/2, 2/3 + 3/4. Fore and hindwings petiolated
beyond thebaseofthe quadrangle.
Abdomen(Fig. 1).- Segments 1-2 pale yellow, dorsally black, segment2
withamiddorsalyellow line. Segments 3-7black withbasal pale yellow rings,
ventrolateralyellowsubapical stripesandyellow middorsalline.Segment8black
withalightorange ring atthe distalfourth. Segment 9 lightorange, 10 dorsally
black, laterally lightorange(Fig. 3). Superiorappendages darkbrown, except at
theventrobasalswelling, thatisyellow mediallyand brownishyellow laterally.
Structural characters.- Posteriorprothoracic lobewiththehindmar-
ginslightly more convex onthemiddlethird(Fig. 2).Superiorappendage indorsal
view(Fig. 3)forcipatewithaprominent ventraltoothatabout2/3length, continu-
ouswithaventraldenticulatedcarinato theapexandasmallerdorsaltoothden-
ticulated proximately
andcontinuousdistal-
ly with a smoothdor-
sal carinatotheapex.
In lateral view (Fig.
4), swollen ventrally
at base, this part hol-
low. Inferiorappend-
agesabsent.
Measurements
(mm). - Abdomen with
appendages 32.0-33.4
(mean 32.5); — forewing
23.8-25,0 (mean24.6); -
hindwing24.1-25.4 (mean
24.4); - pterostigma in
forewing(costalside) 1.1-
-1.2,(radialside) 1.6;— ap-
pendages1.2.
FEMALE (allotype).
— Head (Fig. 5).
— Labium, labrum,
anteclypeus, base of
mandibles, genaeand
postclypeus as in the
male. Anterior por-
tion of frons yellow-
ish brown. Top of
headoliveyellow,red- Figs 2-5. Heteragriontiradentense sp. n., male holotype(Figs 2-4),
femaleallotype(Fig. 5):(2)head and thorax,dorsal view; — (3)ap-
dishyellowattheocel- pendages,dorsalview; - (4)same,lateral view; — (5)headand tho-
larregion, withblack rax, dorsal view.
50 A.B.M.Machado &L.C. Bede
marks as follows:alargebandattheupperportionof fronsbetweenthetwoan-
tennaebasescontinuing laterallyas alargetriangularspotthatreachestheeye. A
largetrapezoidstripelaterally black, mediallyolivebrown, connecting theeye to
theblack occipital bar.Ocelliringed withblack, thelateralones connectedwith
atransverse black occipital bar.
Thorax.-Prothoraxyellow shadding intogreyishyellowatthemedianlobe.
Amiddorsalblack stripe atthe anteriorlobeconnectedwitharound blackspot
occupying the centralthirdof the posterior lobe (Fig. 5). Pterothorax(Fig. 5):
mesepisternum witha0.35mmwideblack stripe adjoining ateachsidethemid-
dorsalcarina, thatis alsoblack. Thisstripe is continuousbellowwiththe acro-
tergal areaandabovewiththeantealarsinus. Laterallyto itthereis alongitudi-
nalyellow linefollowedlaterally by agreyish yellowandapale yellow stripe, the
latterreaching themesepimeron thatis greyishyellow witha centralblackstripe.
Mesinfrepistemum greyishyellow. Metapleuron paleyellow withtwo greyishyel-
low longitudinal stripes on the metepisternum and metepimeron respectivelly.
Legs as in themale. Wings hyaline slightly suffusedwith yellow. Upper part of
thearculus andnodusyellow, pterostigma yellowish brown.
Venation.-Postnodalsin forewing 17, in hindwing 14; postquadrangu-
larcellsin foreand hindwings 2;numberof cellsbellow thepterostigmainfore-
wing 3, in hindwing 2; fore and hindwings petiolated beyond thebase of the
quadrangle.
Abdomen.- Segments 1-6as inthemale,exceptthattheventrolateralyel-
lowstripes ofsegments3-7extendall theway betweenthe proximalyellowand
the distalblackrings. Segment 8 darkbrownwitha yellow ventrolateralstripe,
anda yellowish anterolateralround mark.Segment 9 yellow withtwo dorsola-
teral, notconfluent, darkmarks. Segment 10yellow, dorsallydark.Appendages
conical, darkbrownwiththeproximal thirdyelowish. Ovipositors yellowish.
Measurements (mm).- Abdomen 31.0; - forewing26.5; - hindwing26.3; - pterostigma
inforewing(costalside) 1.1,(radialside) 1.6; —Appendages0.6.
DISCUSSION
By having thewingspetiolated beyond thebaseofthe quadrangle, by thedor-
sumof head, the prothorax andthe mesopleuron largely blackand absence of
the inferior appendages, H. tiradentensebelongs in species groupI (H.flavovit-
tatum)ofSELYS(1862). TableIshowsthemaindifferencesseparating themales
in species ofthis group.Basedon the size, two subgroups can be distinguished,
onecontaining verylargespecies, H.muryenseCosta& Santos, 2000andH. ova-
tumSelys, 1862andanother withmuch smaller species, H. petiense Machado,
1988,H.fiavovittatum Selys, 1862andH. tiradentensesp.n. . Indeed,withanab-
domenof 32-33.4mm H. tiradentensefits among thesmallestspecies ofthege-
nus, together withH. breweriDe Marmels, 1989, H. icterops Selys, 1862andH.
Heleragriontiradentensesp.n. 51
TableI
Characters separatingthemalesofgroup IHeteragrionspecies
CChhaarraacctteerrss ** HH..ttiirraaddeenntteennssee HH..ppeetliieennssee HII..ffllaavvoovviittttaattuumm HH..oovmattuumm HH..mmuurryyeennssee
AAbbddoommeenn lleennggtthh 3322,,00--3333..44 3322..11--3388..00 3322..00--3355..00 4444 4455
HHWWlleennggtthh 2244..11--2255..44 2255..22--2277..00 2277..00--2288..00 3311 3344
PPoossttnnooddaallssiinnFFWW 1166--1177 1166--1188 2200 2200 2233
MMeesseeppiisstteerrnnaall
ssppoott::ccoolloorr YYeellllooww WWhhiittee AAbbsseenntt YYeellllooww YYeellllooww
MMeesseeppiisstteerrnnaall
ssppoott::sshhaappee BBiiccoonnvveexx SSuubbrreettaanngguullaarr AAbbsseenntt OOvvaall TTrraappeezzooiiddaall
lleennss--sshhaappeedd
MMeesseeppiisstteerrnnaall SSmmaallll,,hhaallff LLaarrggee,,ffuullll AAbbsseenntt AAbboouutthhaallff AAbboouutthhaallff
ssppoott::ssiizzee wwiiddtthh ooff wwiiddtthhooff wwiiddtthhooff wwiiddtthh ooff
mmeesseeppiisstteerrnnuummmmeesseeppiisstteerrnnuunn mmeesseeppiimmeerroonnmmeesseeppiisstteerrnnuumm
MMeeddiiaall tteeeetthhooff DDoorrssaall ttooootthh DDoorrssaallttooootthh DDoorrssaallttooootthh ?? DDoorrssaallttooootthh
tthheeaappppeennddaaggee mmuucchhsshhoorrtteerr ssuubbeeqquuaallttoo ssuubbeeqquuaallttoo mmuucchhsshhoorrtteerr
iinnddoorrssaallvviieeww tthhaannvveennttrraall vveennttrraallttooootthh vveennttrraallttooootthh tthhaannvveennttrraall
ttooootthh ttooootthh
*dataobtained fromthe literature.
obsoletum Selys, 1886.Itcanbe readily separated from H.flavovittatum by the
absenceofa mesepisternalpale spoton thisspecies. Thus, thecloserspecies to
H. tiradentenseis H. petiense. Thetwo species canbe readily separated by the
characteristics of thepale mesepisternal spot: white,subrectangular and occu-
pyingallthewidthofthemesepisternum in H.petiense whilein H. tiradentense
,
itis yellow,biconvex lens-shaped andoccupying only halfwidthofthis sclerite.
TableIIshows thecharactersseparating thefemalesof groupI,confirming that
thecloserspecies to H. tiradentenseisH. petiense.
ECOLOGY AND CONSERVATION
H. tiradentensespecimens were collectedonNovember 11, 1996and Novem-
ber 1,1999 attheChafarizcreekinthe “LibelulasdaSerradeSao Jose”Wildlife
Refuge. Although fourmoreindividualswere seenin November 1999,the five
attempts to findthatspecies, betweenDecember 1996through March 1997and
in January 1998,wereunsuccessful. TheChafarizcreekisashadedslow-flowing,
narrow (1-2m wide)andshallow(10-40cm deep)firstorderstream, withapre-
dominantlymuddy-sandy substrate.Itrunsthroughanold, semideciduousforest
area, locally known as theMaeD’-Agua (mother ofthe water)forest, adjacent
to the town of Tiradentes.Atthisplace H. tiradentenseindividualswere more
frequently foundperched on themarginal vegetation ofthe creek(Fig. 1).The
Sao Josesierra was recently declaredaStateWildlifeRefuge forthe protection
52 A.B.M.Machado & L.C. Bede
TableII
Charactersseparatingthe females ofgroup IHeteragrionspecies
CChhaarraacctteerrss HH.. ttiirraaddeenntteennssee HH..ppeettiieennssee HH..ffiiaavvoovviittttaattuumm HH.. mmuurryyeennssee
LLaabbrruumm DDaarrkkbbrroowwnnwwiitthh YYeelllloowwwwiitthh OOrraannggee BBllaacckk((??))
tthheebbaasseeaannddmmaarrggiinn aacceennttrraall
oorraannggee bbrroowwnnbbaanndd
TTooppooffhheeaadd OOlliivveeyyeellllooww DDuullllyyeellllooww OOrraannggee BBllaacckk
ddoommiinnaannttccoolloorr
MMeesseeppiisstteerrnnuumm DDoommiinnaannttlylyppaallee DDoommiinnaannttlylyppaallee DDoommiinnaannttllyybbllaacckk DDoommiinnaannttllyybbllaacckk
wwiitthhaabbllaacckk wwiitthhaabbllaacckk wwiitthhaappaallee wwiitthhcceennttrraallppaallee
mmiiddddoorrssaallssttrriippee mmiiddddoorrssaallssttrriippee aaddjjaacceennttttootthhee ccuurrvveeddlliinnee
aannddaayyeelllloowwssttrriippee aannddaayyeellllooww hhuummeerraallssuuttuurree
nneeaarrtthheehhuummeerraall lliinneenneeaarrtthhee
ssuuttuurree hhuummeerraallssuuttuurree
PPtteerroossttiiggmmaa BBrroowwnn DDaarrkkbbrroowwnn YYeellllooww BBrroowwnn
AAppppeennddaaggeess DDaarrkk bbrroowwnn;; BBrroowwnniisshhoorraannggee YYeellllooww,,ddaarrkkeenniinngg BBrroowwnniisshhyyeellllooww
yyeelllloowwiisshhaatttthhee ddaarrkkeenniinnggaattttiipp aattttiipptthheeiiss wwiitthhtthheeaappeexxbbllaacckk,.
pprrooxxiimmaalltthhiirrdd pprroovviiddeeddwwiitthh pprroovviiddeeddwwiitthh ttiippwwiitthhssttiiffff
wwiitthhnnoohhaaiirraattttiipp ssttiiffffhhaaiirrss((??)) ssttiiffffhhaaiirrss hhaaiirrss
AAbbddoommeenn((mmmm)) 3311..00 3311..44 3322..00 4422..00
HHiinnddwwiningg((mmmm)) 2266..33 2255..22 2288..00--3300..00 3344..00
of dragonflies (Minas GeraisState DecreeNo.43.908/04ofMay 11,2004). Itis
hometo anexceptionally richOdonatafauna; sofar 120species (76 Anisoptera
and44Zygoptera) havebeenrecorded, andmore discoveriesare expected as as-
sessments are undertakenthroughout thereserve’s 3,717 hectares.TheRefuge is
thefirstofitskindin Brazilandoneofafewin theworldwithaprimaryfocus
on dragonfly conservation.
Regarding the history of forest habitatchange in the region, it is generally
known that analmost complete deforestationof thesouthern slopes ofthe si-
erra followedthegold rush inthe early 18th centuryand the succeeding exten-
sive cattleranching uptorecent times(MACHADO& HARGREAVES,2000).
Interestingly, the most preserved forest patch pointed out by these authors, the
MaeD’Aguaforest, harborsthespringsof theChafarizcreek, sofarthetheonly
sitewhereH. tiradentensewas found, out of42sampling sites(systematically as-
sessed betweenNovember 1996andFebruary 1998)throughout theRefuge and
itssurroundings.
TheMaeD’Agua area constitutesanemblematicexampleoffreshwatercon-
servation throughforestprotection. Abarocpublic waterfountain, dated 1749,
fedby theChafarizcreekthrough anaqueduct, has beenoneofthetown’smain
sourcesofpotablewater sincecolonialtimes.As inthecaseofseveralotherHet-
eragrion species, H. tiradentenseis likely to be a habitatspecialist of upstream
reachesand has certainly benefitted from theprotection of such a valuablewa-
tersource.
Heteragriontiradentense sp.n. 53
Currently,twoHeteragrionspecies, H.obsoletumandH.petiense figureamong
theBrazilianredlistedOdonata(MACHADOetal.,2005), apparentlywithrath-
er small distributionranges. Withregards to H. tirudentense,thelack ofamore
extensiveeffort to detectitandevaluateits conservation status inforest streams
ofthe region,werecommendthatitshould beplaced underlUCN’s DataDef-
ficientthreatcategory andthatfurtherresearch is madewiththis purpose.
Thewell-knownroleofdragonfliesas indicatorsofwetlandhealth(OSBORN,
2005) ledthem tobe called “Guardiansofthewatershed”(CLAUSNITZER &
JODICKE, 2004). Indeed, many odonatesand specially Heteragrion are very
sensitiveto changes in water quality. A Heteragrion species was shown to have
disappeared froma creekin aprotected areatwo monthsafterthe initiationof
miningactivitiesnearitsupstreamcourse outsidethereserve(MACHADO etal.,
1988). Thus, dragonflies are idealflagship candidatesforrisingpublic awareness
ofthelinkbetweendragonfly habitatprotection andconservationof freshwater
resources. Thisisapromising aspect tobeemphasized inthecontextoftheSao
Josesierra,itsoutstandinglyrich Odonatafaunaanditsstatusasaprotected drag-
onfly area, taking advantage ofthe region’s touristattractivenessforthe scenic
beauty ofthesierraand, atitsfoot, thecolonialtown ofTiradentes.
ACKNOWLEDGEMENTS
Wethank MYRIAN MORATODUARTE for thedrawingsthat illustrate thisarticle. Wealso
thankWERNERPIPERforhissupportand companyinthefieldresearch thatallowed thediscov-
eryofthisspecies andalsoforthephotographofthealive H.tiradentense specimen.
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