On the systematics of the tribe Tanytarsini (Diptera: Chironomidae) – three new species from Finland

2008·3.1 MB·

by  Wojciech Giłka

©EntomologicaFennica. 7March2008
On the systematics of the tribe Tanytarsini
(Diptera: Chironomidae) — three new species from Finland
Wojciech Gilka&LauriPaasivirta
Gilka,W.&Paasivirta,L.2008:OnthesystematicsofthetribeTanytarsini(Dip-
tera: Chironomidae)—threenewspeciesfromFinland.—Entomol.Fennica 19:
41—48.
Three new chironomid species ofthe tribe Tanytarsini are describedfromFin-
land: Micropsectra malla sp. n., Paratanytarsas paralaccoplzilas sp. n. and
Tanytarsusparanigersp.n.Thenewspeciesarecomparedwiththeirclosestrela-
tives and their systematic position is discussed. As a result ofour study, the
MicropsectrarecurvataspeciesgroupSéiwedal, 1981 isregardedasunwarranted
anditsspeciesareincludedtotheMicropsectranotescensgroupSéiwedal, 1976.
TheFinnishfaunaofthetribeTanytarsini,consistingof123validspecies,isone
ofthemostspecies-richinEurope.
W. Gil/ca, Department ofInvertebrate Zoology, University of Gdansk, Al.
Marszalka Pilsadskiego 46, 81—378 Gdynia, Poland; E—mail.‘ scorpio@ocean.
aniv.gda.pl
L. Paasivirta, Raahikoskenkata I7 B 5, 24240 Salo, Finland; E—mail.‘ laari.
[email protected]
Received9February2007, accepted5Jane2007
1. Introduction Micropsectra. The new species shows a distinct
similaritytoMicropsectratoriSéiwedal, 1981,so
Chironomids ofthe tribe Tanytarsini, due to the far considered to be a member ofthe recarvata
larval habitat preferences, are particularly spe- group Séiwedal, 1981. Paratanytarsas para—
cies-richinmostlacustrineregions oftheworld. laccoplzilas sp. n. (the 16thFinnish andthe 19th
AlthoughtheFennoscandianfaunaofthetribeis European Paratanytarsus) forms a distinct spe-
one ofthebestknown, itstillyields species new cies group together with Paratanytarsas lacco—
toscience(Gilka2005,Gilka&Paasivirta2007). philas (Edwards, 1929), its closest and only
Recent studies indicate that the Finnish Tany- known group-relative (Reiss & Séiwedal 1981,
tarsini comprise at least 120 species (Paasivirta, Cranston et al. 1989). Tanytarsus niger Ander-
unpubl.), i.e. nearly 70% ofthe European fauna sen, 1937 and Tanytarsusparaniger sp. n. (the
(Saether&Spies2004,Gilka&Abramczuk2006, 9thFinnishandthe 10thEuropeanspeciesofthe
Stur&Ekrem2006). norvegicus group) are undoubtedly sibling spe-
Thispapercontains descriptionsofthreefur- cies,theyare,however, easilydistinguishableby
thernewspecies foundinFinland.Micropsectra someuniquemorphologicalfeaturesfoundinthe
mallasp.n.ofthenotescensgroupSéiwedal, 1976 newspecies.
is the 20th Finnish and the 37th European
42 Giika &Paasivirta ' ENTOMOL. FENNICAV01. 19
Table 1. Length (pm)oflegsegmentsand leg ratiosofmaleMicropsectramallasp. n.
fe tI ta ta2 ta3 ta ta LR
1 4 5
p1 685—755 505—590 645 355 255 175 105 1.26
(720,n=7) (545,n=7) n=1 n=1 n=1 n=1 n=1 n=1
p2 670—750 590—675 300—345 175—200 125—145 90—95 75—90 0.51
(705, n = 7) (620, n = 7) (320, n =4) (185, n =4) (135, n = 4) (90, n = 4) (80, n =4) (0.51, n =4)
p3 795—890 750—845 485—535 280—315 230—245 130—145 95—105 0.61—0.63
(840, n = 7) (785, n = 7) (505, n = 3) (295, n = 3) (235, n = 3) (140, n = 3) (100, n = 3) (0.62, n = 3)
2. Material and methods 3.1.2. Description
The material examinedwas collectedin Finland Adult male (n = 10, unless otherwise stated).
withasweepnet, Malaise— andemergencetraps. Wing length 1.61—1.81 m(1.69, n=7). Color-
The specimens caught were dissected and ation. Pedicel, tentorium, scutal stripes, post-
mountedinCanadabalsamorEuparalonmicro- notum and sternum dark brown; antennal
scope slides. The wing was measured from the flagellum, scutellum,backgroundofthorax, legs
arculus to thetip; lengths ofleg segments, spurs and abdomen greenish-brown; halter and wing
andcombswereroundedofftothenearest5 um; pale. Head. Antennawith 13 flagellomeres; AR
palpomeresH—Vweremeasuredtonearest 1 um; 0.61—0.73 (0.67, n = 5); frontal tubercles absent
antennalandlegratios(ARandLR,respectively) orrepresentedonlybysmallswellingsofintegu—
wereroundedoffto 0.01. When3 ormorespeci- ment;lengthofpalpomeresH—V(urn,n=6):40—
mens were measured, the dimensions are re- 48 (44), 95—110 (104), 111—135 (120), 167—171
portedasrangesfollowedbythemean(inparen- (169); clypeus with 9—15 setae. Thorax chaeto-
theses). The morphologicalterminology andab- taxy:Ac 15—20,Dc9—10,Pa2—3(usually2),Scts
breviationsfollowSacther(1980). Thetypesdes- 8—10 (usually 8 setae placed in regular row).
ignatedwere depositedatthe Department ofIn- Wing. Membrane covered with macrotrichia in
vertebrate Zoology, University of Gdansk, distal 1/2, dense macrotrichia in cells r m
4+5” 1+2”
Gdynia (DIZUG) and in the Museum andInsti- m andunder veins Cu1 and An; veins Sc, M,
RM:
tute ofZoology ofthe Polish Academy of Sci- proximalhalfofCuandshortproximalsec-
ences, Warszawa(MIZPAS), Poland. tionofR andM1+2bare, otherveinswithdense
4+5
macrotrichia; R4+5 ending slightly distal ofM3+4
andwellproximal ofM1+2= FCu ending distal of
3. Results RM. Legs. Foretibiawith straight spurc. 10—15
urn long; combs ofmid and hind tibiae fused,
3.1.Micropsectramallasp. n. teethc. 10um(midtibia)to 10—15 urnlong(hind
tibia), spurs absent; ta1 ofp2 bearing 1—2 hook-
3.1.]. Diagnosis shapedsensillachaetica(n=4);lengthoflegseg-
ments andlegratios inTable 1.
Adult male. AR 0.61—0.73 (0.67). Gonostylus Hypopygium. Gonostylus 130—165 umlong,
slender, tapering to tip. Anal point slender with regularlytaperingtoslendertip.Analtergitewith
pointed tip or broadened in distal part and api- 1—5 median setae andbands ofV-type fused on
cally blunt. Superior volsella finger-shaped. elevatedhump atbaseofanalpoint; lateralteeth
Digituslongandstout,extendingbeyondapexof simple; analpointmoderately long, regularlyta-
superiorvolsella. Stem ofmedianvolsella long, peringtopointedtiporslightlybroadenedindis-
slightly curved and directed laterally, bearing tal part and apically blunt, crests separated, 2—4
large spoon-shaped lamellae. Inferior volsella lateralsetaeoneachsideofanalpoint(Fig. 1a—b).
stout and short, broadened in median part, with Superior volsella finger-shaped, with apex
roundedapex. rounded and directed medially, armedwith 2—3

ENTOMOL. FENNICAVol. 19 ° NewchironomidspeciesfromFinland 45
short, with broadly rounded apex, flake-shaped abruptly narrowed gonostylus inP. laccopnilus,
crests arrangedtypically forParatanytarsus and is a reliable diagnostic character separating the
separated by subapical knob, 3—5 long lateral two species. Anadditionalfeaturethatdistinctly
setaeplacedoneach side ofanalpoint. Superior separatesthesespeciesisthesizeandshapeofthe
volsellaoval, slightlyelongatedanddirectedme- medianvolsellaanditslamellae.Paratanytarsus
dially, with 5—6 dorsal setae, 2 setae in antero- laccopnilus has a very short, medially directed
median position and single seta at base; digitus stemofthemedianvolsellabearing shortfoliate
slender and sharply pointed, extending far be- lamellae(Fig 10inReiss&Séiwedal 1981),while
yondapexofsuperiorvolsella(Fig. 2a). Stemof P.paralaccopnilushas alongerposteromedially
median volsella 25—30 um long, apically swol- directed stem with long, subuliforrn lamellae
len, bearing dense setiform and 5—6 slender (Fig. 2). Due to the latter character, P.
subuliform lamellae (Fig. 2b). Inferior volsella paralaccopnilus will key out to couplet 4
straight and stout, with thin butwell pigmented (penicillatusgroup)inthekeytoParatanytarsus
dorsomedian ridge and bilobed apex bearing species groupsby Cranston etal. (1989), andto
elongatedprotuberance(Fig. 2a). the next couplet (laccopnilus group) when the
elongatedlamellaearedisregarded.Themorpho-
3.2.3. Typematerial logical features ofP. paralaccopnilus indicate
that thepenicillatus and laccopnilus groups are
Holotype. Male slide-mounted in Euparal: Fin- closely related, but as a result ofour discussion
land,Inaridistr., Sarmiarea,Vanhapaanmorosto, above, we would argue for a placement ofP.
c. 13 km west ofthe Russian border (68°40’N paralaccopnilusinthelaccopnilusspeciesgroup.
28°17’E), 14.Vl.—10.VIH.2005, Malaise and Adult males of Paratanytarsus paralacco—
emergencetraps, leg. J. Salmela(DIZUG). philuswerecollectedbetweenmid-Juneandmid-
Paratypes.288asholotypeslide-mountedin AugustwiththeMalaiseandemergencetrapsset
Canadabalsam(1 DIZUG, 1 MIZPAS). atsmallspringbrooksinaeutrophicswampyarea
inFinnishLapland. Theywerecollectedtogether
3.2.4. Derivation ofthename with Parapsectra chionopnila (Edwards, 1933)
and P. nana (Meigen, 1818), known as cold
The specific name refers to Paratanytarsus stenothermic inhabitants ofsprings, streams and
laccopnilus, thepresumed closestrelative ofthe moorlandpools.
newspecies.
3.2.5. Discussion 3.3. Tanytarsusparanigersp. n.
The adult male of Paratanytarsus paralacco— 3.3.]. Diagnosis
philusisveryeasilyseparablefromallotherspe-
cies of the genus by characters in the male Adult male. Anal point with granulose apex,
hypopygium. The oval, elongated and medially armed with spinulae and small dense tubercles
directedsuperiorvolsella,theslenderandsharply placed between crests. Superior volsella robust,
pointed digitus, the long stem of the median withlargeandstronglycurvedposterolateralcor-
volsellaarmedwith subuliformlamellae andthe ner,bearingadistincthook-shapedventralprotu-
bilobedinferiorvolsellawithprotuberanceonits berance in posteromedian position; ventral sur-
apex create the unique character combination. faceofsuperiorvolsellawrinkled,posteriormar-
Theclosestrelative,Paratanytarsuslaccopnilus, ginbare, onlywithafewfinetubercles.
hasasimilarstructureoftheanaltergiteincluding
the analpoint, the shape ofthe superiorvolsella 3.3.2. Description
andthedigitus, aswellastheinferiorvolselladi-
vided into two lobes. However, a slender Adult male (n = 10, unless otherwise stated).
gonostylus,regularlytaperingtoitspointedapex Wing length2.31—2.91 m(2.58, n=7). Color-
inP.paralaccopnilus as opposedto the apically ation. Antennal flagellum, halter and proximal

48 Giika &Paasivirta ' ENTOMOL. FENNICAVol. 19
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