An annotated list of Odonata collected in Ghana in 1997, a checklist of Ghana Odonata, and comments on West African odonate biodiversity and biogeography

20 Pages·2001·2.4 MB·English

by  O’Neill, G

Odonatologica30(1): 67-86 March 1, 2001
An annotatedlist of Odonata collected in
Ghana in 1997, a checklist of Ghana Odonata, and
comments on West African odonatebiodiversity
and biogeography
G.O’Neill¹ and D.R. Paulson²
1 DepartmentofBiology, University ofPuget Sound, Tacoma, WA 98416,United States
(present address: 14 LehighAve., Wilmington,DE 19805,United States)
2SlaterMuseum ofNatural History, University ofPuget Sound, Tacoma, WA98416, United
States; — e-mail: [email protected]
Received August 8, 2000/ RevisedandAccepted September 4, 2000
Collections were madeat8 localities in southern Ghana duringthe summerof
1997. Three regions were sampled: coastal savanna, wooded savanna, and
rainforest. 71 spp. werecollected, 24 ofwhich are new for the country,bringing
the Ghana list to 123 spp. A list of spp. known from the country is included.
Trithemis dejouxiPinhey, 1978,is raised tospecificrank. Individual variation in
Phaon iridipennis and Palpopleura lucia is quantified. West African Odonata
biodiversity and biogeography are discussed.
INTRODUCTION
Todate, only fourstudieshavefocusedspecifically onthedragonflies ofGhana
(KARSCH,1893;NEVILLE,1960;MARSHALL&GAMBLES,1977;D’ANDREA
& CARFI, 1994). Littlehas been published about the biology ofthe species
occurring there,andnolistof speciesknownfromthecountry hasbeencompiled.
Fromthesepapersandothers, especially PINHEY(1962a),99species ofOdonata
have beenrecorded inGhanato date.
The landscape ofGhanavaries fromwet forest to drysavanna due to a sharp
rainfall gradient. The southernportion ofthecountry is covered by wet, semi-
moistandsemi-dry forests, whilefarthernorth,incentralGhana,forestgives way
to thetallgrasses, short shrubs, andscatteredtrees ofthesavanna (SAYERetal.,
1992).Terrestrialorganismsexhibitadiversitygradient along thishabitatgradient,
butto datenoonehasdoneasystematic survey ofaquatic organismsalongit. The
68 G. O’Neill& D.R. Paulson
research presented herebeganas anattempttodeterminewhetherasimilardiversity
gradient occurred in Odonata. Theoriginal intentwas to testthehypothesis that
two changes in biodiversity willoccur along the gradient as itchanges from wet
forest to savanna woodland,thefirst a declineinspecies richness ofOdonataand
the seconda shiftin species composition. Due to fieldconditions,only two sites
along thegradientcouldbesampled verywell,buttwo previous studies(NEVILLE,
1960;MARSHALL&GAMBLES, 1977) fallatdifferentplaces along thegradient
andallow furthercomparisons.
Thegradient fromwet todry inGhanaoccurs fromsouthtonorth,withincreased
distancefromthecoast,but italso occurs fromwest toeast. Ghanais oneofthe
easternmost countriesin theWestAfrican forest belt, and, moving fromwest to
east,theclimatebecomesdrierand drieruntiltheDahomey GapisreachedinTogo
andBenin. TheDahomey Gap, where the dry savannaextendsall theway tothe
coast andthereis no wet forest, represents awell-knownclimaticbarrierinWest
Africa(SAYERetal., 1992).This gaphasbiogeographic significance, becausefor
manyterrestrial wet-forest species it represents abarrier ofinhospitable habitat.
Thiscausessomespecies tooccurononlyonesideofthegap.Thepresentcollections
also contributeto an attemptto understandthe significance ofthat barrier for
Odonata.
METHODS
Field work was conductedby thefirst authoratthreesites in Ghana from June toAugust 1997.
The first site was near Pantan, asmall villageinthe southern coastal savanna, approximately 10
miles north ofAccra. Specimens werecollected 2-6 June at a small stream and several small
pondsin thearea(see below for habitatdescriptions). The second site was Bui National Park, a
Guinea savanna/semi-dry forest mosaicinthewestern part ofthe central region.Specimens were
collected 19June-24 July from the Djapolx,a medium-sized stream, and theBlack VoltaRiver,
a large river. The third site was Kakum National Park, a dense rainforest site in the southwestern
section ofGhana. Specimenswere collected 26-27 August at two small streams in denseforest.
Identifications were made using published literature, the unpublished keys ofVICK (1997),
and comparisons with material in the second author’s collection. All specimens have been
depositedin that collection. Notes oneye color in life, ecology, and behavior are includedfor
some species.
COLLECTION LOCALITIES
GREATER ACCRA REGION, PANTAN, 5°42’ N, 0°12’ W
— (Oya) Oyarefacoastal savannapond,0.5-1 m deep30 m wide pond,1-2 m mud surrounding,
then 1 m tallgrass, sparse trees and shrubs.
— (Dak) Dakobi stream, 1-2 m wide coastal savannastream nearroad,marshy in places, 1 m
tall grass bordering, sparse trees and shrubs.
— (Pan)Pantan coastal savannapond, 30 m wide pond, surrounded by 1-2 m tall grass, 1 m
deep water,then sparse trees and shrubs.
(a)Dawa, an open coastal savannaarea, 1-2m tall grass, nearroad.
Odonata of Ghana 69
CENTRAL REGION, SHAI HILLS GAMEPRODUCTION RESERVE, 5°52’ N,0°4’ E
— (Sha) open coastal savannaarea with 0.5-1 m tall grass, more trees on nearby steeprocky
hills,short grass nearsmall stream.
BRONG AHAFO REGION, BUI NATIONAL PARK, 8°20’ N,2°19’ W
— (Dja) Djapoli stream, 3-4 m wide stream with rocky/sandy bed, alternatingpools and
trickles, 0.05-0.30 m deepwater, bordered by 1-2m tallgrass and largetrees.
(a)Bui Camp,small farmlands surroundingvillage,0.5-1 m tallgrass with exposedareasof
soil and rock, no waternearby.
(Vol) Black Volta River, 50-70 m wide river, water 13-15 m deep,bordered by very dense
shrubs aryl trees.
CENTRAL REGION, KAKUM NATIONAL PARK, 5°22’ N, 1°22’ W
— (Kakl) small rainforest stream,meandering0.5-1 m wide trickle with sandy soil/small rock
bed through dense rainforest, sun shining throughonly in limited areas ofthinned canopy.
— (Kak2) rainforest stream, slow flowing 1 m wide stream, sandy soil/pebblerock bed with
areas of solid rock causing waterfalls/small pools, through dense rainforest, sun shining
throughonly inlimited areas ofthinned canopy.
ANNOTATEDLISTOFSPECIESCOLLECTED
Afterthespecies namesare thelocalitiesandthenumberofeach sex collected.
Thecodeforlocality referstothelist ofcollectinglocalitiesabove.Theasterisked
species arenewforGhana.Thecollectionsare summarizedinTableI, whichisalso
acomplete listoftheOdonataknownto occur inGhana.
CHLOROCYPHIDAE
(1) Chlorocypha curta(Hagen, 1853). Dja(8(3,89). — Thisspecies apparently
favorsmoreopenstreamsthanthefollowing two species, whichwerefoundtogether
atKakum.
(2) Chlorocypha glauca (Selys, 1879). Kak2(2<3).
(3) Chlorocypha selysi (Karsch, 1899). Kakl (6<3), Kak2 (1<3).
CALOPTERYGIDAE
(4) Phaon iridipennis (Burmeister, 1839). Oya (2d), Dak(3c?), Dja(26<3, 10
9),Vol(2c3),Kak1 (2c?),Kak2(1c3). — Thisspecies, widespread acrossAfrica, was
collected atnearlyevery site visited. Commonperching places includedrocks in
the streambed, vineson thewalls ofthestreambed,andin 1-2m grassbordering
thestream.Oviposition tookplace inthestemsofa20 cm tallplant next toaslow-
flowing 1.5 mwidestream atDjapoli. Many individualswereobserved feeding by
making short(5-20 cm) flights, capturing smallflying insects, andlanding onthe
original perch for consumption ofthe prey. The intensity ofthe greenthoracic
markings variedgreatly inbothmales andfemales,not apparently correlatedwith
age,and some specimens hada lightblue pruinosity ontheventral surfaceofthe
thorax. PINHEY(1961a, 1961b)discussedbriefly thevariationinthe relativesize
70 G.O'Neill & D.R. Paulson
and colorofthethoraxandthesizeandpresenceofthepterostigmainthisspecies.
Thusweanalyzed thesubstantialseriesfromGhanacollectedforthisstudy.Variation
insizewasnot especially noteworthy (Fig. 1),exceptforasinglemalefromDjapoli
streamthatfellwell belowtherangeoftheothers, withahindwing length of32.3
mm.Thismaleis dullerthanmostoftheotherspecimens, andits cerciandepiproct
arerelatively short,butotherwiseitappearsidenticaltotherest oftheseries.With
theexception oftheespecially smallmale, therangeinhindwing length of 34.4-
-37.2 mm in males (N = 35) and37.2-39.6mm in females(N = 10) seems not
especially large. PINHEY(1951, 1961a) gives therangeformalesas 37-40mm,
implying distinctlylargeranimalsin southern and eastern Africathanthosefrom
Ghana,andindeed5 males inthePaulson collectionfromKenya andZimbabwe
ranged from37.9-39.0mm. Figure 1 doesshow that pterostigma length is quite
variablein males.Thepolymorphism apparent(pterostigma vs nopterostigma) is
surely not arealpolymorphismbutinsteadrepresents continuousvariationinsize,
because thesmallest pterostigmapossible corresponds tothelength ofthecellsat
thatpoint onthe wing.Twoofthemales withthesmallestpterostigmas alsohave
relatively littlepigmentation inthecellthatwouldbe consideredthepterostigma,
andthatcell is not very welldifferentiatedfromadjacent cells. Males thatlack a
pterostigma merely lack pigment inany cell.
(5) Sapho bicolor Selys, 1853.Kakl (1c?), Kak2 (seen).
(6) Sapho ciliata (Fabricius, 1781). Kak2(56, 1$). — Thisspecies wasmore
Fig. 1. Hindwing and pterostigma lengthofPhaon iridipennisfrom Ghana.
Odonata of Ghana 71
common thanS. bicolorandwas foundatthelargerofthetwo streams inthewet
forestatKakum.All specimens collectedwere perched 1-1.5mover thestream.
(7) Umma cincta (Hagen inSelys, 1853). Kakl (19),Kak2(26). - Observed
both under theshadeofthecanopyand insun undergapsin thecanopy.
PROTONEURIDAE
(8) Chlorocnemiselongata Hagen in Selys, 1853. Kakl (66, 19). — Males
have wings suffusedwithyellow, andtheonly femalecollectedhas clearwings.
(9) * Elattoneuranigra Kimmins, 1938. Dja (8c?, 79). - Nearest previous
records Coted’IvoiretotheWestandNigeria totheEast.Fivepairs werecollected
in tandem,oneover a5 cm deep trickleandoneovera2 mwidestream.
(10) Isomecocnemis subnodalis (Selys, 1886). Kakl (19). — The specimen
collectedwas ateneral,andthespecific identificationisnot certain,butsubnodalis
is theonly speciesknown fromGhanato date.
(11) Prodasineuravilliersi Fraser, 1948. Kakl (9c?,29), Kak2 (3c?). - This
species isknown fromonly GhanaandtheCote d’Ivoire.
PLATYCNEMIDIDAE
(12) * Mesocnemisrobusta (Selys, 1886).Vol(5c?). — Thisrecordextendsthe
knownrangeofthisspecies, previously known fromNigeriato Sudan,andis the
firstrecordWestoftheDahomey Gap.Specimens collectedwere foundless than1
m over theBlackVoltaRiver, wherevegetation hung downfromthebank.
(13) * Mesocnemis singularis (Karsch, 1891).Vol (6c?). — Nearest records
from Cote d’Ivoireto theWestand Togo to theEast. Specimens were collected
only fromthe Black VoltaRiver, where the species coexisted in apparentequal
numberswithM. robusta.Bothspecies ofthegenus were coloredsimilarlyinlife,
heavily pruinose.
(14) * Platycnemis guttifera (Selys, 1886).Kakl(lc?). — Thisrecordextends
theknownrangeofthisspecies, previously known fromGuineatoCoted’Ivoire,
slightly to theEast.
(15) Platycnemis sikassoensis (Martin, 1912).Dja(6c?, 69).During copulation
the male opened its wings, then closed them when straightening the abdomen
afterwards.Threepairs werecollected intandem.
COENAGRIONIDAE
(16) * Aciagrion hamoniFraser, 1955.Dja (2c?). — NearestrecordsfromCote
d’IvoiretotheWestandtheRepublic ofCongototheSoutheast.Onemalecollected
at duskin an openarea with 0.5 mtall grass, somebare soil, andtrees 10-15m
apart.PINHEY (1972)describedtheonly maleofthisspecies heretoforereported.
72 G. O'Neill & D.R. Paulson
and thetwo specimens collectedinGhana matchhis description quitewell.
(17) Agriocnemiszerafica LeRoi, 1915.Oya (1d, 39), Dak (1d,2?).
(18) * Ceriagrion bakeri Fraser, 1941.DJa (1d). — Nearestprevious records
Coted’Ivoireto theWestandTogo to theEast.
(19) Ceriagrion glabrum (Burmeister, 1839).Dak(8c?, 39), Pan(8c?, 7 9),Dja
(4d, 19). — Five tandempairs were collected, oneofthemduringoviposition.
(20) * Ischnurasenegalensis (Rambur, 1842).Oya (1d, 1 9). — We couldfind
norecords closerthanGuineato theWestand Nigeriato theEast. Although this
species is oneofthe more ubiquitous odonates ofAfrica (PINHEY, 1962a), it is
clearly notwidespread andcommoninGhana,aswerecordeditonlyfromacoastal
pond,andneitherNEVILLE(1960)norMARSHALL&GAMBLES(1977)found
itattheirstudy sites. Itmaybe generally rare intheWestAfricanforestregion, as
itwas not reported fromtherelatively well-sampled NimbaMountainsinGuinea
and Cote d’Ivoire (LEGRAND, 1983; 1985),or at Korhogo (LINDLEY, 1974),
Lamto(LEGRAND,1982),orTai(LEGRAND&COUTURIER, 1985)intheCote
d’Ivoire.
(21) * Pseudagrion epiphonematicum Karsch, 1899.Kakl(4d). — Firstrecord
betweenGuineato theWest and Nigeria to theEast.This species is restrictedto
WestAfrica.
(22) Pseudagrion glaucescens Selys, 1876.Dak (3d). — Recordedonly from
aslow-moving coastal stream.
(23) Pseudagrion hamoniFraser, 1955.Dak (21d, 11 9),Dja (20d, 129). —
The thorax of the specimens collectedwas green dorsally and pruinose blue
ventrally. Theeyes ofmalesareblack dorsallyandred ventrally,thoseoffemales
browndorsally andgreenventrally.Thespecies emerged abundantly fromDjapoli;
eight teneralswerepreserved. Pairsoviposited intandeminthestream.
(24) Pseudagrionkersteni (Gerstaecker, 1869).Dak (1 d),Dja (9d,2 9). — The
eyes areblackdorsally and greenventrally inlife.
(25) Pseudagrion melanicterum Selys, 1876.Dja(21 d,69),Kakl (6d),Kak2
(8d,29).
(26) * Pseudagrion nubicumSelys, 1876.Oya (Id),Dak(Id). — Knownfrom
Cote d’IvoiretotheWestand Nigeria totheEast.
(27) Pseudagrion sjostedti Forster, 1906.Dja(6d, 19), Vol(4 d, 19).
(28) Pseudagrion sublacteum (Karsch, 1893).Dak (2d),Dja (1d, 1 9).
AESHNIDAE
(29) * Anaxephippiger (Burmeister, 1839).Pan (Id). — Known from Cote
d’Ivoireto theWestand Nigeria totheEast.Recorded only fromthecoastalarea.
(30) * Gynacantha cylindrata Karsch, 1891.Dja (29). — KnownfromCote
d’Ivoireto the West and Benin to the East. This species was collected at dusk
flyingoveranareaofbaresoil40mfromthestream.
Odonata of Ghana 73
(31) Gynacantha manderica Griinberg, 1902.Dja (Id, 19). — This species
was collectedat dusk.
GOMPHIDAE
(32) * Crenigomphus reneiFraser, 1936.Dja(Id). — KnownfromCoted’Ivoire
totheWestand Nigeria totheEast.
(33) * Gomphidia madi Pinhey, 1961.Dja (1 d), Vol (2d, 19). — ThisWest
Africanspecies waspreviously knownonlyfromCoted’Ivoire,Nigeria,andUganda.
(34) Ictinogomphusferox (Rambur, 1842).Dak (1 d).
(35) Lestinogomphus africanus (Fraser, 1926).Vol (Id). — Collected20 m
fromalarge river in 1 mtallgrass.
(36) * Paragomphus genei (Selys, 1841).Dja (2d),Vol(19). — Knownfrom
Coted’IvoiretotheWestandNigeria totheEast,aswellas muchmoreextensively
on thecontinent.Theeyes are greendorsally andlightblue ventrally.
(37) * Paragomphus nigroviridis (Cammaerts, 1969).Kak2 (1d). — Known
fromCoted’IvoiretotheWestandCameroonandZairetotheEast,itappearstobe
aspecies ofwet forest, unlike theprevious species, whichis distributedwidely
overAfrica.
CORDULIIDAE
(38) Phyllomacromia bifasciata Martin, 1912.Dja(1 d).
(39) * Phyllomacromia pseudafricana Pinhey, 1961.Dja(1d). — Knownfrom
Coted’IvoiretotheWestandNigeria totheEastandfairlywidespread throughout
WestAfrica.
(40) * Phyllomacromia sp. Dja (19). — Thisfemalehasnot beenidentified,
butit is surely notany ofthe species knownfrom thecountry, including thetwo
species listedaboveaswellas P.melania(Selys),andP.sophia (Selys). Itdoesnot
appeartofitineitherthepicta orsophia groupsas definedby GAMBLES(1979).
Itisasmall(abdomen38.6mm,hindwing 36.5mm)species withthreeconspicuous
stripes oneach sideofthethorax. Thefaceis brown,with asmallyellow spot at
eachendofthepostclypeus, thefronsmetallicblue-violetabove.Theabdomenis
mostly black, withthefollowing yellow markings: large squarelateralmarksand
pair oftransversely orientedmiddorsalspots on 1;fine yellowrings atbases and
paired dorsal spotsatmiddlesofsegments3to6, becoming smallertorear; anda
conspicuous yellow bandonthebasalthirdofsegment7.The vulvarlaminaeare
small(0.7 mm), narrow, andpointed.
LIBELLULIDAE
(41) Acisomapanorpoides Rambur, 1842.Dak (2c?, 19),Pan (19).
74 G. O'Neill & D.R. Paulson
(42) * Aethriamantarezia Kirby, 1889.Dak (1c?). — Recordedonly fromthe
coastal area. KnownfromCoted’Ivoireto theWestandNigeria totheEast.
(43) * Brachythemis lacustris (Kirby, 1889). Vol(5c?, 89). — Knownfrom
Coted’IvoiretotheWestand Nigeria totheEast.Recordedonly fromalargeriver.
This species was foundinhigh populations amongthe smallshrubsthatgrew on
islands nearthebank oftheriver.
(44) Brachythemis leucosticta (Burmeister, 1839).Oya(7<?,29),Dak(2c?), Vol
(1c?). — Recordedfromthecoastalareaandonalarge river.
(45) Bradinopyga strachani (Kirby, 1900).Sha(2c?, 1?).This genusis usually
associatedwith rocky areas, andthe Shai Hillshave abundantrock outcrops.
(46) Chalcostephiaflavifrons Kirby, 1889.Dak (4c?), Pan(3c?).
(47) Crocothemisdivisa Baumann,1898. Dja-a(2), Sha (It?). — As withthe
species of Bradinopyga, thisspecies is typically associatedwithrocky areas, and
bothlocalities whereitwas takenhadexposed rocks.
(48) Crocothemiserythraea (Brulle, 1832). Dak (19). — Recordedonly from
thecoastal area.Thisspecies is very widespread and commonthroughout Africa,
and it is surprising that it was nowhere commonat the sites visited duringthis
study in Ghana. UnlikeIschnura senegalensis, ithas been foundata numberof
WestAfricanforestsites.
(49) * Eothemiszygoptera Ris, 1909.Kakl (2c?). — Recordedonly fromwet
forest. KnownfromCoted’Ivoireto theWestand Nigeria totheEast.
(50)Hemistigmaalbipuncta (Rambur, 1842). Dak (3c?), Pan(29).
(51) * Nesciothemispujoli Pinhey, 1971.Dak (6c?), Pan(19). — This species
wasdescribedfromtwo malesfromtheCentralAfricanRepublic(PINHEY, 1971)
andhas notbeendiscussedsubsequently. Ourspecimens matchPinhey’s description
quitewelland differfromaseriesofmaleN. farinosa (Forster, 1898)examined(2
fromKenya, 1 fromMalawi,4fromZimbabwe,2fromSouthAfrica).Thedifference
inthe hamulesis readily apparentin theshape ofthe outerhamule, broaderand
less deeply indentedinpujoli, narrower andwith a deep longitudinal groove on
the outer surface infarinosa. Although Pinhey notedthatpujoli differedfrom
farinosa inbeing darkly pruinose, we suspect this might havebeen an artifactof
preservation, as the Ghana specimens as preserved show a shade oflight blue
pruinosity identicalto thatoffarinosa. The extentofabdominalpruinosity may
furnish anotherspecies difference:the six pujoli males are pruinose to thetip of
segment3 orextremebaseof4;twoKenyafarinosaarepruinose tothetip orjust
shortofthetipof4; andtwo ZimbabweandoneMalawifarinosa arepruinose to
thetipof5. PINHEY (1951)stated thatthe basal4-6segmentsofmalefarinosa
became pruinose, but there is no indication of the geographic source of the
specimens from which he came to this conclusion. In addition, the malepujoli
have entirely black labia, whilethe labiaofthe malefarinosa examinedare pale
(thetwofromKenyahaveblackonthemedianedges ofthepalpi). Thelabrumand
legs ofpujoliare entirely black,unlikethoseofN. minorGambles, 1966,asimilar
Odonata of Ghana 75
butsmallerspecies.ThesinglefemaleNesciothemiswas takenatadifferentlocality
fromthe malesbutisassociatedwiththembecauseofhersize, wing venation,and
general appearance. She appears tobe quite mature, dark all over with light
pruinosity on the thoraxand three basalabdominal segments.Unlike the males,
herentirefaceandlabiumare lightbrown,asare theouter surfacesofherfemora
andtibiae.Thefoliationson abdominalsegment8 are shaped as infarinosa and
are pale with dark borders. As the two species are superficially very similar, it
wouldbeofinteresttore-examineall specimens of ‘farinosa”fromWestAfrica,
whereitisconsideredwidespread(PINHEY, 1962a).
(52) * Olpogastra fuelleborni Ris, 1912.Vol(Id, 1$). — Thisrecordextends
theknown rangeofthisspecies, previously known fromNigeria to SouthAfrica
andKenya, andisthefirstrecordWestoftheDahomey Gap.Recordedonly froma
large river.Theeyes weregreeninlife.Thefemalecollectedwas a teneral,perched
2 mabovethewater.
(53) Olpogastra lugubris Karsch, 1895. Dak (Id, 19), Vol (7d, 19). —
Recordedfromthecoastalareaandalargeriver.Amatingpair perched0.5mabove
thewateron abranchapproximately 15mfromthebankof theriver.
(54) Orthetrumbrachiale (P. deBeauvois, 1805).Pan-a(Id).
(55) Orthetrumchrysostigma (Burmeister, 1839).Dak(3d),Pan(Id),Sha(6d),
Dja(ld,39).
(56) Orthetrumhintzi Schmidt, 1951.Pan (Id).
(57) Orthetrumjulia Kirby, 1900. Dja (2d, 29), Kak2 (Id). — Oneofthe
femalescollectedwas ovipositing, guarded by amale.
(58) Orthetrumstemmale (Burmeister, 1839).Dak (1d). Pan(1d), Dja(12d,
129),Vol(Id). — Theeyesofthisspecies areblueinlife.Onepairwascollected
intandem.Anotherpairwas collectedwhilematingin1mtallgrass.Sevenfemales
werecollectedwhileovipositing atDjapoli. Allovipositionoccurredby thefemale
dipping the tipofherabdomeninto smalltrickles andpools. Thisis the species
listed previously in WestAfrican publications as O. brachiale kalai Longfield,
1936(PINHEY,1979).
(59) Palpopleura deceptor (Calvert, 1899). Sha(Id).
(60) Palpopleura lucia (Drury, 1773).Dak (lOd, 39), Pan(3d,69),Sha(6d,
49),Dja(13d,69),Vol(Id). — This commonand verywidespread species was
collectedateverysiteexceptthewetforest.Twofemaleswereobservedovipositing
atDjapoli whilethemalehoveredoverthefemale.Ofthe33malescollected,only
two fromDjapoli wereof theformportia,withmuchreducedwing markings. The
situation with these two forms remains one of the more puzzling cases of
polymorphism in theOdonata. Bothtypes apparently occur throughout therange
ofthe species, yet at some localities, only one ofthem isreported. Differences
between the forms in extentof wing markings, although long known, have not
been quantified, andwe attempted thatby examining 58 male specimens in the
PaulsoncollectionfromSierraLeone(2),Liberia(1),Coted’Ivoire(1), Ghana(35),
76 G. O'Neill & D.R. Paulson
Fig. 2. Size and wing markings ofPalpopleura lucia from Africa,
Congo (2), Uganda (1), Kenya (3), Malawi(1), Zambia(1), Zimbabwe(10),and
SouthAfrica(1). Theblackcolorationinthehindwing is typically widest distalto
the nodusandnarrowest at orjustproximal to thenodus.Thewidthoftheblack
was measured at both of these points, and the differencebetween them (the
“indentation”) was taken as a measure oftheextent oftheblack. This was then
expressed as aproportion ofthehindwinglength, totakethedragonfly’s size into
account. Thesemeasurements are showninFigure2.Itcanbeseenthatthespecimens
aredistributedbimodally, corresponding totheformslucia(indentation/hindwing
<0.2) andportia (indentation/hindwing>0.2). Twopoints areapparenthere. (I)
Thetwo formsoverlapinsize,althoughportiaaveragessmaller, asusuallydescribed
(PINHEY, 1951).(2)WestAfricanspecimens ofluciahavewings moreextensively
markedwithblack,ontheaverage,thanthosefromEastandSouthAfrica; PINHEY
(1961a) noted that the black extended farther out the wing in West African
specimens. Although the specimens examined here clearly fall intotwo distinct
groupsbasedon wing markings, intermediatesareknown(PINHEY 1984),andthe
erectionofportia to specific statusby GAMBLESetal.(1998) ispremature,with
nonew informationaboutthebiology ofthetwo forms.
(61) Pantalaflavescens (Fabricius, 1798).Dak (2c?, 29),Pan(1c?), Sha(3c?,
49),Dja(2c?, 49),Vol(1c?). — Thisvery widespreadspecies was observedflying
in large numbers over an open area at Shai hills. One pair was collectedwhile
copulating 15m fromthestream atDjapoli.
(62) Tholymis tillarga (Fabricius, 1798).Dja (3c?, 29). — The eyes ofthis
species are red dorsally and blue ventrally in life.Four ofthe specimens were
collectedinlow flightat dusk nearthestream.
(63) Trameabasilaris (P. deBeauvois, 1805).Sha (19).