Table Of ContentOlea. SyETHER&TrondANDERSEN
MuseumofZoology, UniversityofBergen
FIRSTAFROTROPICAL RECORDS OF
DOITHRIXAND GEORTHOCLADIUS, WITH NOTES
ON THE PSEUDORTHOCLADIUSGROV?
(DIPTERA: CHIRONOMIDAE)
Szether,O.A.&Andersen,T., 1996.FirstAfrotropicalrecordsof DoithrixznAGeorthocladius,
with notes on the Pseudorthocladius group (Diptera: Chironomidae). - Tijdschrift voor
Entomologie 139:243-256,figs 1-29 [issn0040-7496]. PubÜshed 18December 1996.
The diagnoses of the genera Doithrix Ssether et Sublette and Georthocladius Strenzlce are
emended. ToyamayusurikaSasaet Kawai is shown to be ajuniorsynonym ofGeorthocladius.
ThemaleimaginesofthenewspeciesDoithrixlongipes,Doithrixamegabei, Georthocladiuslong-
icalcaneum, and Georthocladiusamakyei, all from Ghana, are described. Eight newcombina-
tionsaregiven: Doithrixfujiseptimus(Sasa) comb, n., Doithrixtogateformis(Sasa,Watanabeet
Arakawa) comb, n., Georthocladiusasamasextus(SasaetHirabayashi) comb, n., Georthocladius
fujiquinta(Sasa)comb, n., Georthocladiusshiotanii(SasaetKawai) comb, n.,Pseudorthocladius
amamikonaseus(SasaetSuzuki) comb, n., Pseudorthocladiuskurobesugoidus(SasaetOkazawa)
comb, n.,andPseudorthocladiustogakuroidus(Sasa,WatanabeetArakawa) comb. n.
The morphological expressionsofadaptations bychironomid male imagines to tropical areas
arediscussed.Theseadaptationsoften,butnotalways,consistinconsiderablysmallersizeand
associatedlowernumberofsetae,reductionofeyeelongation,considerablyshorterantennalra-
tio,lossorreductionoftheanallobeofthewing,lossofsetaeonsquama, longercostalexten-
sion, longerfrontmetatarsus resultingin higherfrontlegratio and, atleast in orthoclads, re-
ductionoftheinferiorvolsella.
O.A.Sjether&T.Andersen,MuseumofZoology,UniversityofBergen,Muséplass3,N-5007
Bergen,Norway.
Keywords.-Chironomidae,Afrotropical,newspecies, Doithrix, Georthocladius,adaptations.
The Pseudorthocladius group consists of the four and beginning near the anteptonotum, curved Cu,
closely related genera Parachaetocladius Wiilker, andananalpointwithstrongsetaeandmicrotrichiae
DoithrixSsether et Sublette, GeorthocladiusStrenzke, to apex or nearly to apex will separate the
andPseudorthocladiusGoetghehuer.Whiletheimma- Pseudorthocladiusgroupfromotherorthocladgenera.
tures of the first of these genera, Parachaetocladius, In connection with a project in Ghana supported
liveinsprings,streamsandrivers,theotherthreegen- by the Norwegian Universities' Commitee for
eraallaresemiterrestrialtosemiaquaticlivinginava- Development, Research and Education (nufu), four
rietyofdamp habitats including mosses, hygropetric newspecies belongingto the Pseudorthocladiusgroup
regions, seepages and floodplains alongstream banks were found. These finds are interesting not only be-
&
(Strenzke 1950,S^ether Sublette 1983,Cranstonet causetheyrepresentthefirstAfrotropicalfindsofthe
al. 1989). genera Doithrixand Georthocladius, but also because
ThegenusgroupwasrevisedbySsether&Sublette their morphology indicate some common trends of
(1983) showingthatitformsawelldelineatedmono- adaptationsto tropical rain forests.
phyletic group with Metriocnemus v.d. Wulp plus
Thienemannia Kieffer as the likely sister group. The Methodsandmorphology
genus Doithrixwas emended slightly byCranston & The mounting procedure used is outlined by
Oliver (1988). Within the Pseudorthocladius group Ssether (1969). Morphological nomenclature follows
Doithrixplus Georthocladiusapparently form the sis- Scether(1980).Themeasurementsaregivenasranges
tergroup ofPseudorthocladiusplus Parachaetocladius. followedbyameanwhenfourormoremeasurements
The presence ofwell developed pulvilli, naked eyes, are made, followed by the number measured in
an apical antennal seta, acrostichals absent or long parentheses (n).
243
TijdschriftvoorEntomologie,volume139,1996
The holotypes ofthe new species are deposited at Ssether et Sublette sharing a synapomorphy in the
the Museum of Zoology (zmbn), University of basal swelling ofthe gonostylus. Ueno & Iwakuma
Bergen, Bergen, Norway. (1996) recorded D. villosa Ssether et Sublette from
theMiyatokomireinJapan.
DoithrixSsetheretSublette
Doithrixlongipessp. n.
DoithrixSxû\exetSublette, 1983:6.
(figs. 1-7)
Typespecies. - DoithrixvillosaS^etheretSublette, Type material. - Holotype •, Ghana: Western re-
1983: 9. gion, Ankasa Game Production Reserve, 6-
Diagnosis of male imago. - As in Ssether & 12.xii.1993, NUFU project (ZMBN No. 173). -
Sublette (1983: 6) and Cranston et al. (1989: 191) Paratypes: 3 • asholotype.
with the following emendations: Minute to moder-
ately small species, wing length 0.7-2.0 mm. Diagnostic characters. — The small size (wing
Antennal ratio between 0.2 and 2.0. Eyeswithoutor length 0.7-0.8 mm), extremely long metatarsus giv-
withveryslighteyeelongation.Antepronotum mod- ing an LR, of 1.01-1.04, the very long costal exten-
erately to well developed. Dorsocentrals extending sion, absenceofsetaeonsquamaandtheevenlywide
well forward, singleto triplein front; acrostichals ex- gonostylus will separate the species from all other
tending to one third to half the length of scutum Doithrixexcept D. amegabeisp. n. described below.
fromantepronotum;prealarsfewtonumerous,when The short antennal ratio (0.2-0.3), the subtriangular
few in anterior and posterior group. Scutellum with inferior volsella, and the shorter and less sclerotized
setae in uni - biserial transverse row. Anal lobe of phallapodeme will separate D. longipes from D.
wingwelldevelopedtoveryweak,usuallyprotruding. amegabei.
Virgaconsistingofatmostabout6veryfinespinesor
occasionallyabsent. Gonocoxitewithstrong, posteri- Male imago (n = 4 exceptwhen otherwise stated).
orly directed, apically pointed or rounded inferior - Total length 1.41-1.54, 1.47 mm. Wing length
volsella or occasionally inferior volsella broad based, 0.73-0.77, 0.74 mm. Total length / wing length
relatively low and subtriangular or reduced. Gono- 1.90-2.01, 1.98. Wing length / length ofprofemur
styluswithorwithoutexpandedbase,apicallystrong- 2.62-2.75, 2.68. Coloration pale brown with vittae,
lyattenuatetotruncateorslenderandapproximately median anepisternum II, ventral part ofpreepister-
evenlywideforitsfulllength;withafewtonumerous numandpostnotumdarkbrown.
longsetaeon innermargin. Head (figs. 1-3).AR0.23-0.27,0.25. Ultimatefla-
Included species. - In addition to the four species gellomere77-109, 87 [im long; apical seta30-45, 37
describedbySaether & Sublette (1983) and Doithrix |im long. Flagellomere2with 1 sensillachaetica, 29-
dillonaeCranston etOliverdescribedbyCranston & 36 pm long; flagellomere 3 with 2 sensilla chaetica,
Oliver (1988), Wang (1994) described Doithrix 28-36 and 33-38 pm long, the longest about 3 pm
emeiensis WangfromChina (examinedbythesenior wide. Temporal setae 8-19, 9; including3-4, 4 inner
author),andtwospeciesdescribedfromJapaninoth- verticals; 2-3, 3 outer verticals; and 2-4, 3 postor-
ergeneraclearlybelongto Doithrix, namelyDoithrix bitals.Clypeuswith6setae.Tentorium77-86,84pm
fiijiseptimus(Sasa), comb. n. describedas Pseudortho- long; 8-13, 10 pm wide. Stipes 60-71, GG pm long,
cladiusfujiseptimusmSasa (1985: 126); andDoithrix 15-23, 19 pmwide. Palpwith 5 palpomeres, lengths
togateformis (Sasa, Watanabe et Arakawa) comb. n. (inpm): 15-23, 18; 23-30, 25;45-49,47; 56-71, 62;
described as Toyamayusurika togateformis in Sasa, 75-94, 82. Third palpomere with about 6-7 sensilla
Watanabe et Arakawa (1992: 235). Both are typical clavatain2-3groups; fourthpalpomerewith0-1 api-
Doithrix, thefirstnearlyidenticalto D. emeiensisand calsensillumclavatum.
possiblyclose to D. hamiltoniSjetheretSubletteand Thorax (fig. 4). Antepronotum with 4 setae.
D. barberiSsetheretSublette,allfoursharingsynapo- Dorsocentrals 8-11, 10; acrostichals about 6-8; pre-
morphiesin thehook-likeinferiorvolsellaeandother alars4-5, 5, including2-3, 3 posteriorand 1-3, 2an-
details; and the second probably close to D. ensifer teriorprealars. Scutellumwith4setae.
Figs 1-8. DoithrixlongipesSÇ.n.,maleimago.- 1,Cibarialpump,tentoriumandstipes;2,Thirdpalpomere;3,Flagellomere
1to5,showingthesensillachaeticaonflagellomeres2and3;4,Thorax;5,Wing;6,Analpointanddorsalaspectofleftgono-
coxiteandgonostylus;7,HypopygiumwithanalpointandlaterosterniteIXremoved,leftdorsalaspect,rightventralaspect;
8,Gonostylus,ventralaspect.
244
S^THER&Andersen: Doithrix&Geonhocladius
245
TijdschriftvoorEntomologie,volume139,1996
246
S/£THER&Andersen: Doithrix&Geonhocladius
Table 1. Lengths(in pm)andproportionsoflegsof maleimagoofDoithrixlongipessp. n.
P.
p.
p.'
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248
SyETHF.R&Andersen: Doithrix&Geonhockdius
Table2. Lengths(in pm)andproportionsoflegsofmaleimago(ÄDuithrixamegabeis^. n.
TijdschriftvoorEntomologie,volume139,1996
great to be coincidental and the two species may be ofhind tibia 34-41, 38 pm and 17-19, 19 pm long.
conspecific. G. shiotaniiisverysimilarto G. longical- Widthatapexoffronttibia21-23, 23 pm; ofmiddle
caneumsp. n. described below, sharingfor instance a tibia21-23,23pm;ofhindtibia26-28,27pm.Hind
unique synapomorphy in the triangular and curved tibial comb of 10-11, 11 setae; shortest setae 19-23,
outer heel ofthe gonostylus, and appear to form its 22 pm long; longest setae 30-34, 32 pm long.
sister species; while G. fujiquintus (asamasextus) is Lengthsandproportionsoflegsas inTable3.
close to G. amakyeisp. n., the other Georthocladius Hypopygium (figs. 20-22). Anal point 15-21, 19
describedhere.Thetwospeciesdescribedhereaswell pmlong;with9-12, 10strongsetae;laterosterniteIX
as theJapanese species all differ from previously de- with 2-3, 3 setae. Phallapodeme 45-51, 49 pm long;
scribed species in the male hypopygium. Theycould transverse sternapodeme 26-34, 29 pm long.
represent the unknown males of the subgenus Gonocoxite 109-120, 116 pm long; inferior volsella
Atelopodella, but without knowledge of the imma- triangular, with strong anteriomedially directed mi-
turessuchasubgenericplacementispremature. crotrichiae alongmedian margin. Gonostylus 54-75,
GGpmlong;withlong,slightlycurvedouterheel;dis-
tancefrombasetoapexofheel 56-75, 68 pm; toout-
Georthocladiuslongicalcaneumsp. n.
er furcation between gonostylus and heel 36-41, 40
(figs. 16-22) pm from base; gonostylus beyond heel tapering to
gioTny,peAmnaktearsiaal.G-aHmoelotyPpreodSuc,tGihoanna:ReWseesrtvee,rn r6e-- aHpVex;2.m1e9g-a2s.e9t8a,82-.1461.,9pmlong.HR1.60-2.00, 1.76;
12.xii.1993, NUFU project (zmbn No. 220).- Etymology. - From Latin, longus, long, and calca-
Paratypes: 3 (Î, asholotype. neum, theheel, as anoun in apposition, referring to
Diagnostic characters. — The small size (wing thelongouterheelofthemalegonostylus.
length0.7-0.8 mm), absenceofsetaeonsquama, low Remarks.- G. longicalcaneum sp. n. isverysimilar
antennal ratio (0.3-0.4), and the extremelylongout- to G. shiotaniifrom Japan in the male hypopygium
erheelofthegonostyluswillseparatethespeciesfrom and appear to form its sister species. It is, however,
allother Doithrix. onlyabouthalfthesize, havemuchlowerchaetotaxy,
lowerantennal ratio, higherLR, andVRetc., allpos-
Male imago (n = 4 exceptwhen otherwisestated). sibleadaptations toatropicalclimate.
- Total length 1.54-1.64, 1.61 mm. Wing length Distribution. -The species is known only from a
0.71-0.76, 0.73 mm. Total length / wing length rain forestin western Ghanaclose to theborderwith
2.15-2.25, 2.19. Wing length / length ofprofemur theIvoryCoast.
2.34-2.43, 2.37. Coloration pale brown with vittae,
mneudmiaanndanpeopsitsntoetrunmumdaIrI,kvbernotwrna.l part ofpreepister- Georthocladiusamakyeisp. n.
Head (figs. 16, 17). AR0.36-0.44, 0.40. Ultimate (figs. 23-29)
flagellomere 105-150, 126 |im long; apical seta 26- Typematerial. —Holotype S, Ghana: Western re-
34, 29 pm long. Temporal setae 7-12, 10; including gion, Ankasa Game Production Reserve, 6-12. xii.
3-6, 5 inner verticals; 2-4, 3 outer verticals; and 2 1993, NUFUproject (zmbnNo. 219).
postorbitals. Clypeus with 4-5, 5 setae. Tentorium Diagnostic characters. — The species is similar to
75-94,85pmlong; 15-17, 16pmwide.Stipes64-75, theprecedingspeciesinthesmallsize,lackofsetaeon
71 pm long; 15-19, 17 pm wide. Palp with 5 squama,andthelowantennalratio,butdifferinhav-
palpomeres, lengths (in pm): 15-21, 19; 21-30, 25; ingashorter, triangularouterheelofthegonostylus.
53-58, 54; 68-83, 73; 64-83, 72. Third palpomere
apicallyswollen, with about 6-7 sensillaclavata in 2- Male imago (n = 1). - Total length 1.67 mm.
3 groups; fourth palpomerewithout apical sensillum Wing length 0.79 mm. Total length / wing length
clavatum. 2.11. Winglength / length ofprofemur2.23. Color-
Thorax (fig. 18). Antepronotumwith 2-4, 3 setae. ation pale brown with vittae, median anepisternum
Dorsocentrals 11-13, 12; acrostichalsabout6-8; pre- 11, ventral part of preepisternum and postnotum
alars 5-6, 6, including2-3, 3 posteriorand2-4, 3 an- blackish brown.
teriorprealars. Scutellumwith4setae. Head (figs. 23, 24). AR 0.46. Ultimate flagellom-
Wing (fig. 19). VR 1.33-1.46 (3). Anal lobe re- ere 154 pm long, apical seta 26 pm long. Temporal
duced, not projecting. C extension 79-90, 86 pm setae 7, including 4 innerverticals, 2 outerverticals,
long. Brachiolum with 1 seta; R with 2-4, 3 setae; and 2 postorbitals. Clypeus with 7 setae. Tentorium
otherveinsbare. Squamabare. 79 pm long, 17 pmwide. Stipes 77 pmlong, 26 pm
Legs. Spuroffronttibia26-30, 29 pm long; spurs wide. Palp with 5 palpomeres, lengths (in pm): 19,
ofmiddletibia 19-26,21 pmand 17-19, 18pmlong; 26, 54, 81, 86. Third palpomere apically swollen.
250
S/ETHF.R&cAndersen: Doithrix&Geonhocladhts
Table3. Lengths(inijm)andproportionsotlogsofmaleimagoofGeorthocladiuslongicalcaneumsp. n.
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