A revision of genus Toxorhynchites Theobald, 1901, in the South-East Asian countries, with description of a new species Toxorhynchites (Toxorhynchites) darjeelingensis from West Bengal, India (Diptera, Culicidae)

2015·10.5 MB·

by  B K Tyagi

ISSN0973-1555(Print)ISSN2348-7372(Online) HALTERES,Volume6,13-32,2015
©B.K.Tyagi,A.Munirathinam,R.Krishnamoorthy,G.Baskaran,R.Govindarajan,R.Krishnamoorthi,
T.Mariappan,K.J.DhananjeyanandA.Yenkatesh
A
revision ofgenus Toxorhynchites Theobald, 1901, in the South-East
Asian countries, with description ofa new species Toxorhynchites
(Toxorhynchites) darjeelingensis from West Bengal, India (Diptera,
Culicidae)
B.K. Tyagi*,A. Munirathinam, R. Krishnamoorthy, G. Baskaran, R. Govindarajan,
R. Krishnamoorthi, T. Mariappan, K.J. Dhananjeyan andA. Venkatesh
Centrefor ResearchinMedicalEntomology(I.C.M.R.), 4-Sarojini Street, Chinna
Chokkikulam, Madurai-625 002, TamilNadu, India
*(e-mail: [email protected]; [email protected])
Abstract
ThegenusToxorhynchites(TribeToxorhynchitini),comprising89speciesworldwidewhichareorganized
under four subgenera (Afrorhynchus, 19 species; Ankylorhynchus, 4 species; Lynchiella, 16 species and
Toxorhynchites,50species),ischaracterizedbymosquitoesthatdonotfeedonblood; insteadtheysubsist
onvarietyofplantjuicesandhavetheirmouthpartscommensuratelydesigned.Globallythereareabout
3,543 species of mosquitoes (Family: Culicidae), of which nearly 3,061 species are culicines under
Subfamily Culicinae that is further divided into eleven tribes one ofwhich is Toxorhynchitini Lahille,
1904, represented by a solitary genus Toxorhynchites Theobald, 1901. Species of the subgenus
Toxorhynchites alone are prevalent in the southeastern Asian countries (Indonesia, 12 species; India, 9
species; Thailand, 8 species; Bangladesh, 2 species; Sri Lanka, 2 species; DPR Korea, 1 species;
Myanmar, 1 species; andNepal, 1species).Ataxonomiccomparisonismadeamongstalltaxaendemicto
these countries. Ironically no species of Toxorhynchites has ever been reported from Bhutan, Maldives
andTimor-Leste. Toxorhynchites (Tox.) splendensisthemostcommonspeciesamongstallandhassofar
been recorded from only seven countries including India which is a home for as many as ten species,
includingthecurrentTx.(Tox.)darjeelingensissp.n.collectedfromthefoothillsofDarjeelingHimalayan
Mountains in the West Bengal State. Toxorhynchites (Tox.) darjeelingensis sp. n. is described, with a
comparisonofferedwithitsclosestallies,i.e.,Tx.bengalensis,Tx.splendensandTx.tyagii.
Keywords: Toxorhynchitesdarjeelingensis sp. n., Culicinae,mosquitoes, SoutheastAsia.
Received:12February2015;Revised:21March2015;Online:4May2015;Published:5November2015.
Introduction
Mosquitoes (Family Culicidae; Order Diptera) rounded scutellum, make a very special group
are highly diverse creatures, represented by a of mosquitoes, next to Anophelini in the
monophyletic taxon (Wood and Borkent, evolutionary tree, which are generally large
1989; Miller et ak, 1997; Harbach and sized mosquitoes and essentially vegetarian,
Kitching, 1998). Culicidae is a large and deriving their nutrition requirements from
abundant group of strikingly varied species plants only with an exquisitely designed
(3,543) (Harbach and Howard, 2007; Tyagi et mouthparts for the purpose. The genus
al., 2015) that occur throughout tropical and comprises 89 species which are organized
temperate regions of the world, and well under four subgenera, namely, Afrorhynchus
beyond the Arctic Circle. Most of the (19 species), Ankylorhynchus (4 species),
mosquito species of the world (3,061) belong Lynchiella (16 species), and Toxorhynchites
to subfamily Culicinae which is subdivided (50 species). Toxorhynchites species are
into 11 tribes, including Toxorhynchitini that endemic to Asia, and the southeast region
is represented by single genus, comprisingelevencountries, whereasmanyas
Toxorhynchites. The species under 24 species occur (Tyagi et al., 2015). The
Toxorhynchitini,characterized by an evenly larvae arepredatory and opportunisticallyfeed
13
Tyagietal.
on other mosquito larvae, and thus have the sing 24 species disseminated over eight
potential of a biological agent for controlling countries, viz., Indonesia (12), India (9),
obnoxious mosquitoes particularlythe dengue/ Thailand (8), Bangladesh (2), Sri Lanka (2),
chikungunya vectors, Aedes aegypti and Ae. DPRKorea(1),Myanmar(1) andNepal (1),is
albopictus (CollinsandBlackwell,2000). endemic to the south-east Asian countries
(Table 2). Ironically, Bhutan, Maldives and
GenusToxorhynchitesTheobald,1901 Timor-Leste are yet to record any species
despiteabundantsylvaticenvironment.
Adults ofToxorhynchites species are large
and colourful, with their body covered with
green, purple or red iridescent scales. The (ii) Taxonomiccharacteristics
distal halfofthe proboscis is slender andbent The subgenus Toxorhynchites is oneofthe
sharply downwards and backwards. The foursubgeneragroupedunderthegenusbythe
scutellum is evenly rounded (as in Anopheles same name. It is characteristically endemic to
south-east Asian countries, albeit hitherto
andBironella) and the posterior margin ofthe
unreportedfromBhutan, Maldives andTimor-
wing is distinctly emarginated opposite the
termination of vein CuA. Larvae have mouth Leste. Indonesia leads with species diversity
brushes composed of about 10 broad, flat enlisting 12 species, followed by India
boasting of ten species, two of which having
filaments thatareusedtocaptureprey, andthe
been recently discovered by the scientists of
dorsal and ventral abdominal setae occur in
groups and large sclerotized plates. The comb Centre for Research in Medical Entomology.
and pecten are both absent. The Some of the salient and distinguishing
Toxorhynchites larvae are found in plant subgeneric characters are offered in Table 3,
cavities, mainly tree holes and bamboo whereas the species-wise distinguishing
stumps, but sometimes in littered tin boxes as characteristicshavebeengiveninTable4.
well as earthen pots and even physiologically
active phytotelmata such as insectivorous IdentificationKeytotheAdultsof
pitcher plants, like Nepenthes species ToxorhynchitesSpecies
(Tsukamoto, 1989), although Munirathinam et
al. (2014) whoreported 128 speciesbelonging Adults of species under the subgenus
Toxorhynchites, species of which are
to all the three tribes, Anophelini,
organized under seven groups, can be
Toxorhynchitini and Culicini, from a variety
distinguishedfromthose ofother subgenerain
ofplantmaterialsincertainregions ofWestern
thefollowingkeycharacteristics:
Ghats, did notreport such abreedingbehavior
of a Toxorhynchites species (Table 1). The
larvae of all species are predators. They feed 1. Tarsi entirely dark; small and slender
species Tx.minimus(Theobald)
mainly on other mosquito larvae, including
their own kind when other species are few or Some tarsal segments with white
markings; largespecies 2
absent. The adults are basically forest
mosquitoes. Male and female both feed 2(1)Abdominal tergites VI-VIII with lateral
tufts 3
exclusively on nectar and sugary substances.
Due to non-blood sucking behaviour, they are Abdominal tergites VI-VIII weakly or
withoutlateraltufts 17
not of medical importance. However, the
3(2)Mesonotum with conspicuous border of
larvae of a few species have been used with
white or pale golden scales usually
some success to control medically important
extendingoverthewingroots 4
mosquitoes whose immature co-inhabit with
Mesonotumwithoutconspicuousborderof
that of Toxorhynchites in plant cavities and
palescales 11
artificialcontainers.
4(3)Proboscis with distinct median pale band
orwithdorsomedianpalespot 5
SubgenusToxorhynchitesTheobald, 1901
Proboscisdark 7
(1) Distributionofspecies:
5(4)Probosciswithdistinctmedianpaleband;
ThesubgenusToxorhynchites,compri-
lateral tufts on tergum VI with golden
14
ArevisionofgenusToxorhynchitesTheobald,1901,withdescriptionofanewspecies
scales, VII & VIII with brilliant orange 13(ll)Lateral tufts on tergum VI & VII with
scales Tx.sunthomiThurman orange (or) dark brown
Proboscis with dorsomedian pale setae 14
spot 6 Lateral tufts on tergum VI-VIII with
6(5) Lateral tufts on abdominal segment VII black and orange (or) white and black
darkwithbluishblackandVIIIwithdark setae 15
goldensetae Tx.biddeyiThurman 14(13)Lateral tufts on tergum VI -VIII with
Proboscis dark with few pale scales orange setae; fore and hind tarsi 3-5
dorsally at base; Lateral tufts on abdom- black; midtarsi 2-4 white andmidtarsi
inal segments VI & VIII with golden 5blackscales...Tx.auranticaudaLane
and VII black setae Lateral tufts on tergum VI white and
Tx.speciosus(Skuse) darkbrown andVII & VIII darkbrown
7(4) Each abdominal segment with two setae; mid tarsi 1-5 with white
creamy yellow bands (one broad and banding on basal half. Tx.
another thin line); lateral tufts on tergum bengalensisRosenbergandEvenhuis
VI-VIII orange and black; Knee spots of 15(13) Lateraltufts ontergumVIwhite,VII&
all legs peacock blue VIIIblacksetae; tarsomere 5 ofalllegs
Tx.quasiferox(Leicester) entirely dark scales; all femora have
Withoutthiscombination 8 three rows of short black spines
8(7) Mid and hind tarsomeres 3-5 complete Tx.magnificus (Leicester)
whiteordarkscales 9 Lateral tufts on tergum VI-VIII with
Mid tarsomeres 2-4 white; tarsi 5 dark blackandorange setae 16
scales; lateral tufts on tergum VI & VIII 16(15)Lateral tufts on tergum VI & VII black
orange and VII dark setae; VIII orange setae; sub basal on
setae Tx.manopiThurman mid tarsomere 1 with one-fourth and
9(8) Midtarsomeres 3-5 complete white; 2 with half white scales
abdominal segments III & V with in- Tx.inomatus (Walker)
complete medial pale bands; lateral tufts Lateral tufts on tergum VI with yellow
ontergumVIpaleyellow;VIIgolden& and black setae; VII with black and
VIIIorangesetae VIII with orange setae; mid tarsomeres
Tx.edwardsi (Barraud) 1-5 with white scales; fore and hind
Midtarsomeres 3-5 darkscales 10 tarsomeres 3-5 with dark scales
10(9)Lateraltufts ontergumVI&VIIblack& Tx.splendens(Wiedemann)
VIII with orange setae 17(2) Lateral tufts on tergumVI-VIII weakly
Tx.tyagiiKrishnamoorthyetal. developed; VI & VIII with pale yellow
Lateral tufts on tergum VI with three- and VII with black setae; tarsomeres 5
fourth golden yellow one-fourth black of all legs with pale and dark
setae, VII deep blue green and VIII scales Tx.albipes(Edwards)
pale yellow setae Lateraltufts ontergumVI-VIIIwithout
Tx.darjeelingensisTyagietal. tufts; proboscis dark or with pale
1l(3)LateraltuftspresentontergumVII&VIII band 18
andnotufts ontergumVI 12 18(17)Proboscis with brown scales apically
Lateral tufts present on tergum VI- and violet tinge on basal part; aring of
VIII 13 silvery scales at the site of the
12(ll)Lateral tufts on tergum VII & VIII bent Tx.christophi (Portschinsky)
orange setae; mid tarsomeres 2 & 4 Probosciswithoutpalering 19
basal half white and tarsi 3 complete 19(18)Abdominal tergum with complete or
whitescales Tx.sumatranus(Brug) incompletebands 20
Lateral tufts on tergum VII & VIII AbdominaltergiteV-VIIwithnarrow
black setae; mesonotum with narrow incomplete basal pale bands; fore and
broad decumbent greenish scales mid tarsomeres 2-4 with pale
becoming broader and bluish late- scales Tx.gravelyi(Edwards)
rally Tx.amboinensis(Doleschall) 20(19)Abdominal tergites all with basal
bands 21
15
Tyagietal.
Abdominal tergites few (II - VI) with having a capacity of 4 lit., at an altitude of
basalbands 24 100-150m. Specimens were individually
21(20)Firstjoints ofpalpialittle shorter;third reared to the adult stage for species
a little longer than second; venter of identification, using keys by Barraud (1934).
abdomen without median purple Chaetotaxy of the associated larval and pupal
strip Tx.klossi (Edwards) exuviae were examined following Harbach
Abdominaltergites withnarrowblue or andKnight(1980).
honeyyellowbands 22 Three legs from one side of one paratype
22(21) Abdominal tergites each with narrow specimen were used for molecular analysis.
basal blue band; sub-basal white ring From the homogenized material a whole
ontarsalsegment 1 ofalllegs 23 genomic DNA was extracted following the
Abdominal tergites each with rose techniques described by Dhananjeyan et al.
purple scales, banded with honey (2010). The genomic DNA isolated was used
yellow expanding laterally into to amplify the mitochondrial Cytochrome C
triangular patches; mid and hind Oxidase subunitI(COI) genefollowingSimon
tarsomeres dark covered with brilliant et al. (1994). The amplified PCR product was
metallic scales visualized on a 1.2% agarose gel using a gel
Tx.metallicusLeicester documentation system (Vilber Lourmet,
23(22)Mid tarsomeres 2-5 white scales; France) (Fig. 1). The product was sequenced
stemite IV with large median purple commercially (Eurofins India Pvt. Ltd., 183,
spot Tx.leicesteriTheobald Gayathri Tech Park, EPIP - II Phase
Mid tarsi 4 and large part of 5 white Whitefield, Bangalore-560066, Karnataka,
scales; sternite IV with purple scales in India).
middle Tx.kempi(Edwards) The nomenclature and chaetotaxy used in
24(20)Abdominal tergites II-VI with small thedescription ofnew species, Toxorhynchites
lateral yellowish scales; tergite I with (Tox.) darjeelingensis, were described
deep blue scales dorsally; sternites IV following Harbach and Knight (1980, 1982)
yellowish scales interrupted medially andBickleyandWard(1989).
by purple scales; ocular setae (4pairs)
amber to brownish; basal half of mid Description
tarsi 1 & 2 with white band Female: Wing: 5.7mm, proboscis 5.9mm, fore
Tx.acaudatus(Leicester) femur 4.1mm, abdomen 5.3mm. Head: (Fig.
Abdominal tergites II-V with small 2): Integument blackish, scales ofvertex light
lateral white scales; tergite I with brown and with broad distinct violet orbital
goldenscalesdorsally; sternitesIVwith line; proboscis bluish; maxillary palpus bluish
silvery white scales interrupted purple, scattered pale scales on dorsum,
medially by brownish scales; ocular comprised of4 palpomeres with equal length;
setae (3pairs) dark brown; basal one- antennal pedicel with a large conspicuous
fourth of mid tarsi 1 & 2 with white dense patch of silvery scales, scales of
band Tx.coeruleus(Brug) flagellomeres 1-6 dense with many small
hairs. Thorax(Fig. 2): Integument darkbrown
Toxorhynchites(Toxorhynchites) or blackish, mesonotum densely covered with
darjeelingensisTyagietal.,sp.n. rather dull bronzy scales with bluish-green
tinge, scales slightly narrower on disc than on
urn:lsid:zoobank.org:act:16DC9A08-2E48- sides, with whitish yellow scales with blue
4D23- >90-E4E37DBAEE5D tinge patches over wing root to scutellum;
antepronotumwith6-8 minutehairsalongwith
MaterialsandMethods bluish scales, postpronotumwithsilvery scales
Larvae and pupae of Tx. (Tox.) along with 4-5 setae, pleural and coxal scales
darjeelingensis, sp. n. were collected from silvery; one weaklower mesepimeral seta and
Ghadhalar Kurthi, Matha Bhanga block, usual row of caudal mesepimeral setae.
Cooch Behar district in the foothills of Abdomen (Fig. 3): Terga largely bluish or
Darjeeling mountains (West Bengal, India), greenish, tergum I with blue-green scales in
during May-June 2012. Specimens were the middle and brownish yellow scales
collected from littered battery chambers, laterally; tergumIIwith blue-green scales in
16
ArevisionofgenusToxorhynchitesTheobald,1901,withdescriptionofanewspecies
600bp
~530bp
Figure 1.Gelpictureshowingtheamplificationof~530bp
ampliconofTx.darjeelingensissp.n.
themiddleandgoldenscaleslaterally; tergaIII entirely pale; hind tarsomere lwith lA whitish
& V with deep green scales in center and yellow basal band, hind tarsomere 2 with
apico-lateral broad golden scales visible from broad basal pale band, tarsomere 3-5 of all
above; tergumIV withdeep-green scales; with legsdark.
75% ofgoldenyellowand25% ofblacklateral Male: Generally similar to female. Head:
hair-tufts; tergum VII with 90% deep blue- Integument blackish; maxillary palpus slightly
green andremainingyellowhairtufts; tergum longer than proboscis; antenna verticillate,
VIIIwithabunchofpaleyellow setae; sternaI flagellomeres 1 with few white scales and
& II completely with broad white scales; numerous black scales. Legs: All tibia dark;
sternum III mainly broad white scales with foretarsuscompletelydark; midfemorawitha
narrow median dark line; sternum IV longitudinal pale line, mid tarsomere 1,2 with
completely broad black-scaled; creamy white basalpalebandand3-5 completelydark; hind
scales are present in major area in sternum V tarsomere 1 with few scattered white scales
and VI along with black scales forming a ‘V’ posteriorly, 2 with broad white band and 3-5
shape medially; sternumVII withblack scales completely dark. Genitalia (Fig. 5):
forming narrow line in the median, remaining Gonocoxite 0.55 mm, gonostylus 0.52 mm,
area with broad white scales; sternum VIII gonostylar claw 0.05 mm. Gonocoxite with
mainly black-scaled with few scattered white numerous microsetae; gonostylus withasingle
scales, andwith golden yellow tuft. Legs (Fig. sub apical gonostylar claw; medial margin of
4): Fore femur with wide basal yellow ring, gonostylus with about 14 micro-setae
mid femur black with pale scales, hind femur distributed evenly from base to apex. Basal
70% with golden yellow, remaining black; mesallobe (BML) withonestoutandlongseta
fore andhindtibiae dark, mid-tibiawith white length0.30mm, medial surfacewithnumerous
longitudinal stripe; fore tarsomere 1 mainly short simple setae, less than half length of
pale, narrowly dark at base, fore tarsomere 2 longest. TergumIXwithabout25 simple setae
with !/3 white basally; mid tarsomere 1 with arrangedondorsolateralandlateralmargins.
broad basal pale band, mid tarsomere 2
17
Tyagietal,
Hind
Figure5.MalegenitaliaofToxorhynchitesdarjeelingensis,sp.n.
Figure3.AbdomenofToxorhynchitesdarjeelingensis,sp.n. A.Dorsalaspect;B.basalmesallobe,C.tergumIX
18
ArevisionofgenusToxorhynchitesTheobald,1901,withdescriptionofanewspecies
Figure7.Terminalabdominalsegmentsofthelarvaof
Toxorhynchitesdarjeelingensis,sp.n.
19
Tyagietal.
Pupa: Abdomen 5.1 mm, trumpet 0.9 mm, (Fig.7) and the range of variation shown in
paddle 1.4 mm. Chaetotaxy as an illustrated Table 6. Antenna: Concolorous with head
(Fig.6), and the range of variation shown in capsules. Thorax: Setae, tubercles and plates
Table 5. Cephalothorax: Moderately stronglypigmented; seta7-P,Tdouble,barbed,
pigmented; seta 1-CT single, very long, stiff; seta 10-P,M,T single, thin, barbed; seta
barbed; seta 2-CT with 2 branched; setae 3-4, 13-M with 2 branches, stiff and barbed.
6-9-CTsingle, seta5-CTwith5-7(7)branches; Abdomen: Setae 10,12,13-1 on single plate,
seta 10-CT with 4,5 (5) branches, seta 11-CT seta 11-I on separate plate; seta 3-1 slightly
with 3,4 (3) branches and seta 12-CT with 1,2 longerthan setae 1- 1and4-1; seta3-IIdouble,
(1) branches. Trumpet: Dark orange-brown, barbed, 3-III-V single, long, barbed; setae6-II-
heavily pigmented, almost twice as long as V and7-1-IV double, long, barbed; setae 1,3-
wide at apex. Abdomen: Bright brown, VII long, strongly barbed; seta 1-VIII
moderately pigmented, large setae darker than distinctly separate from large sclerotized plate
integument; seta 6-VII single, bifid at the and without tubercle; seta 2-VIII simple with
center; seta 7-VII single, forked at the center; two branches; seta 3-VIII origin with single at
paddle pigmented, more or less rounded, very the end with three branches; setae 4,5-VIII
wide, width about 0.65 of length, and similar single, long, barbed. Siphon: Index about 1.68;
asinTx. tyagii, midribcomplete, distal0.57 of seta 1-S with 6 branched. Segment X:
outer and inner margins with long fine hair- Uniformly darklypigmented; saddle withlong
like spicules; setae 1,2-Paabsent. spicules oncaudolateralmargins; ventralbrush
Larva: Head 1.21 mm, siphon 0.87 mm, (seta 4-X) with 8 pairs of setae.
saddle 0.76 mm. Chaetotaxy as illustrated
Tx.spp USA PennsylvaniaGU9081
88
66.ibbTx.spp SA AF425850
OPi^Tx.splendens Thailand HQ398877
100
,—.001
0.032 Tx.tvaaii JX436102
100 0—006
* Tx.splendens Kerala EU259307
0.091 0.003
m Tx. newspp. WB16
0.035
Tx.rutilus SAAF425849
0.126
Ae.albopictus KeralaGU299768
0.117
—I 1 1 1 1 1
0.10 0.08 0.06 0.04 0.02 0.00
Fig.8.PhylogenetictreeshowingthepositioningofToxorhynchitesdarjeelingensissp.n.
(WB16)alongwithotherassociatedtaxaofthegenusToxorhynchites
Molecularcharacterization
notidentifiedto species level; one collectedin
For phylogenetic analysis mitochondrial Pennsylvania, USA (GU908123) and another
Cytochrome C Oxidase subunit I gene
collected in South Africa (AF425850). The
sequences of six species of Toxorhynchites fifth COl gene sequence belong to Tx. tyagii
were included that were retrieved from
GenBank. The GenBank Accession Numbers (JX436102), isolated in Nilgiri hills, Tamil
Nadu, India and identified and reported as a
ofeach sequence is showninthephyletic tree. newspeciesbyCRME, India (Krishnamoorthy
Of the six sequences utilized for the et al., 2013). The 6th sequence is ofTx. rutilus
phylogenetic tree construction, 2 sequences (AF425849) fromSouthAfrica. TheCOIgene
belonged to Tx. splendens from Thailand
sequence of Aedes albopictus (GU299768)
(HQ398877) and India (EU259307). Two
from Kerala, India has been included in the
sequencesofToxorhynchitesgenus,whichare
20
ArevisionofgenusToxorhynchitesTheobald,1901,withdescriptionofanewspecies
Phylogenetic tree construction as an 4 lit., at an altitude of 100-150m from
outgroup. Ghadhalar Kurthi, Matha Bhanga block,
The evolutionary history of Cooch Behar district in the foothills of
Toxorhynchites darjeelingensis sp. n. (WB16) Darjeeling mountains (West Bengal, India) in
was inferred using the Neighbor-Joining May-June, 2012. Larvae ofTx. darjeelingensis
method (Saitou and Nei, 1987). The bootstrap were found in association with Armigeres
consensus treeinferredfrom 1000replicates is (Leicesteria) magnus, Stegomyia
taken to represent the evolutionary history of (Heteraspidion) annandalei, Aedes albopictus
the taxa analyzed (Felsenstein, 1985). The andTripteroides(Rachionotomyia) aranoides.
percentage of replicate trees in which the
associated taxa clustered together in the Etymology: This species is designated name
bootstrap test (1000 replicates) is shown next after the place ofits discovery, the Darjeeling
tothebranches. hillsinWestBengalState,India.
The Phylogenetic tree was linearized Discussion
assuming equal evolutionary rates in all Adults of Toxorhynchites (Tox.)
lineages (Tekezaki et al., 2004). The tree is darjeelingensis sp. n. are superficially similar
drawn to scale, with branch lengths (next to to Tx. (Tox.) bengalensis, Tx. (Tox.) splendens
thebranches) inthe same units as those ofthe and Tx. (Tox.) tyagii. However, the diagnostic
evolutionary distances used to infer the characters for larva, pupa, adult (mesonotum,
phylogenetictree. abdomen, wing, legs and male genitalia) of
The evolutionary distances were these species clearly distinguish Tx.
computed using the Kimura 2-parameter darjeelingensis sp. n. fromtherestas shownin
method (Kimura, 1980) and are in the units of Table 6. These distinguishing characters are
the number of base substitutions per site. All summarizedbelow:
positions containing gaps and missing data (i) Adult mesonotum with broad pale yellow
were eliminated from the dataset (Complete scales over wing root to scutellum are
deletion option). There were a total of 392 present in Tx. darjeelingensis and Tx.
positions in the final dataset. Phylogenetic tyagii but absent in Tx. bengalensis and
analyses were conducted in MEGA4 software Tx. splendens.
(Tamuraetal.,2007). (ii) The lateral tufts of VI-Te in Tx.
darjeehngensis is two-third deep blue,
Type material: Holotype female (coded withremainingblackbut in Tx. tyagii it is
A#1793) with associated larval (Le#851) and two-third black and remainder only is
pupal (Pe#829) exuviae mounted on yellow; white and dark brown in Tx.
microscopic slides with the following bengalensis, and yellow and black in Tx.
collection data: INDIA, West Bengal, splendens.
Jalpaiguri district, Darjeeling hills, 21st May (iii)Adult of Tx. darjeelingensis is a rather
2012, collected as larva from littered battery smallsizedmosquito,nexttoTx. minimus.
chambers at an altitude of 150m, collected by (iv)In male genitalia, BML with one stout
CRME
R. Govindarajan, deposited in the apicalsetapresentinTx. splendensandTx.
Museum, ICMR, Madurai, Tamil Nadu, India. darjeehngensis compared to two stout
The allotype male (coded A#1794) with apical setapresentinTx.bengalensis and
associatedlarval (Le#852) andpupal (Pe#830) Tx.tyagii.
exuviae, and 2 paratype males with Le and Pe (v) The pupa ofTx. darjeelingensis can easily
mounted on microscopic slides, have the be separated on the basis of 10-C with 5
collection data same as that of the holotype. branches, whereas others have lesser (Tx.
AllarealsodepositedintheCRMEMuseum. bengalensis) and more (Tx. tyagii) (cf.
Distribution: Known only from the type Table6).
locality in Jalpaiguri district, West Bengal, (vi)LarvaofTx. darjeelingensis appearscloser
to Tx. splendens and Tx. tyagii, but the
India.
new species can be quickly distinguished
Bionomics: The immature stages of Tx. on the basis of seta 7-M with 3 branches,
darjeelingensis sp. n. were collected in a and 13-Mdoubleinthoracicregion.
litteredbattery chambers, having a capacity of
21
Tyagietal.
Table 1.PreferenceofdifferentToxorhynchites (Tox.)speciesinselectinghabitatsforbreeding
intheSouth-EastAsiaRegioncountries
bamboo Coconut Discarded Discarded Leaf IVIctsl Mud Pitcher Rocky Sintex Small Tree Resting
S"ecies/Habitat Stump husks container battery axil j)ar^re|sj pot plants pool Tank wells hole collection
Tx.acaudatus
Tx.albipes
Tx.amboinensis
Tx.
auranticauda
Tx.bengalensis
Tx.biddeyi
Tx.coeruleus
Tx.christophi
Tx.edwardsi
Tx.gravelyi
Tx.inornatus
Tx.kempi
Tx.leicesteri
Tx.magnificus
Tx.manopi
Tx.metallicus
Tx.quasiferox
Tx.speciosus
Tx.splendens
Tx.sumatranus
Tx.sunthorni
BHIIIII
Tx.tyagii
22