Twenty-one new species of the Simulium (Gomphostilbia) asakoae species group (Diptera, Simuliidae) in Thailand, with their genetic relationships Author Takaoka, Hiroyuki Tropical Infectious Diseases Research and Education Centre (TIDREC), University of Malaya, 50603, Kuala Lumpur, Malaysia Author Srisuka, Wichai Entomology Section, Queen Sirikit Botanic Garden, P. O. Box 7, Maerim, Chiang Mai 50180, Thailand Author Fukuda, Masako Institute for Research Promotion, Oita University, Idaigaoka 1 - 1, Hasama, Yufu City, Oita, 879 - 5593, Japan Author Saeung, Atiporn Center of Insect Vector Study, Department of Parasitology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand https://orcid.org/0000-0003-3550-5992 atisaeung.noi@gmail.com text ZooKeys 2020 950 51 152 http://dx.doi.org/10.3897/zookeys.950.51298 journal article http://dx.doi.org/10.3897/zookeys.950.51298 1313-2970-950-51 3E805885D3354FB3AE8DFA443FAD82AE 7F08092C01585A70A7948EA57A2A8E2E Simulium (Gomphostilbia) huaimorense Takaoka, Srisuka & Saeung sp. nov. Figs 20 , 25I Material examined. Holotype . Male (with its associated pupal exuviae and cocoon) (in 80% ethanol) labeled as "Holotype: Simulium huaimorense male, QSBG col. no. 49, Thailand, 2-II-2019, by W. Srisuka", collected from a stream (width 1.2 m, depth 10 cm, bed sandy, moderate flow, pH 6.6, 17.1 °C, exposed to the sun, elevation 1,154 m, 19°03'36.8"N , 99°19'15.7"E ), at a coffee plantation, Huai Mor, Doi Saket, Chiang Mai Province, Thailand, 2-II-2019, by W. Srisuka (Coll. No. 49). Paratypes . One female, two males (thorax of one male for DNA analysis) (with its associated pupal exuviae and cocoon) (in 80% ethanol), and three mature larvae (in 80% ethanol), collected from a small stream (width 30 cm, depth 2 cm, bed sandy, moderate flow, pH 7.3, 19.8 °C, partially shaded, elevation 1,440 m, 19°54'04.1"N , 99°34'26.6"E ), at coffee plantation, Pha Lung Village, Muang District, Chiang Rai Province, northern Thailand, 30-VIII-2018, by W. Srisuka (Coll. No. 122). Diagnosis. Male: upper-eye large facets in 16 vertical columns and 17 horizontal rows. Pupa: extremely short primary stalks of the dorsal and middle triplets of filaments (Fig. 20G ) and cocoon with a short anterodorsal projection. Larva: abdominal segments 1-4 grey. Figure 20. Female, male, pupa and larva of S. huaimorense sp. nov. A female B-F male G-I pupa J larva. A mandible (right side) B hind basitarsus and second tarsomere (left side; lateral view) C coxites, styles and ventral plate (ventral view) D style (right side; ventrolateral view) E ventral plate and median sclerite (lateral view) F ventral plate (caudal view) G gill filaments (right side; lateral view) H terminal hooks (caudal view) I cocoon (dorsal view) J head capsule (ventral view). Scale bars: 1.0 mm ( I ); 0.1 mm ( B, G, J ); 0.02 mm ( C-F ); 0.01 mm ( A, H ). Description. Female ( N = 1). Body length 2.0 mm. Head. Frontal ratio 1.9:1.0:2.6; frons:head ratio 1.0:4.8. Labrum 0.67 times length of clypeus. Maxillary palpus: proportional lengths of third, fourth, and fifth palpal segments 1.0:1.2:2.3; sensory vesicle ellipsoidal, medium long (0.27-0.28 times length of third palpal segment). Lacinia with nine or ten inner and 14 or 15 outer teeth. Mandible (Fig. 20A ) with 20 inner teeth and one or two outer teeth at some distance from tip. Legs. Foreleg: Basitarsus moderately dilated, 6.5 times as long as its greatest width. Hind leg: coxa light brown; tibia yellowish white on basal two-thirds and light brown to brownish black on rest; basitarsus 6.2 times as long as wide, and 0.7 and 0.6 times as wide as greatest widths of tibia and femur, respectively; calcipala nearly as long as width at base, and 0.6 times as wide as greatest width of basitarsus; claw with large basal tooth 0.46 times length of claw. Wing. Length 2.0 mm. Abdomen. Dorsal surface of abdomen medium to dark brown except anterior five-sixths of segment 2 ochreous Terminalia. Sternite 8 bare medially, with 23 or 24 medium-long to long hairs together with three or four slender short hairs on each side. Ovipositor valve moderately covered with microsetae interspersed with two or three short hairs; inner margins nearly straight or slightly sinuous, Paraproct with four sensilla on anteromedial surface; paraproct in lateral view 0.6 times as long as wide, with 24 or 25 medium-long to long hairs on ventral and lateral surfaces. Cercus in lateral view 0.5 times as long as wide. Spermatheca ellipsoidal, 1.3 times as long as its greatest width. Male ( N = 3). Body length 2.0 mm. Head. Slightly wider than thorax. Upper eye dark brown, consisting of large facets in 16 vertical columns and 17 horizontal rows on each side. Antenna: first flagellomere elongate, 1.9 times length of second. Maxillary palpus: proportional lengths of third, fourth, and fifth palpal segments 1.0:1.2:2.2; sensory vesicle small, ellipsoidal, 0.22 times length of third palpal segment. Legs. Foreleg: coxa whitish yellow; trochanter light brown; femur light brown except apical tip yellowish; tibia whitish yellow except inner and lateral surface of basal one-fifth light brown and little more than apical one-third dark brown; basitarsus 7.0-8.0 times as long as its greatest width. Midleg: trochanter light brown except base yellow; femur light to medium brown with base yellowish and apical cap dark brown (though apical tip yellow). Hind leg: coxa light brown except apical one-third whitish yellow; femur medium to dark brown with basal tip yellow and apical cap brownish black (though apical tip yellow); tibia dark brown to brownish black except little less than basal half whitish yellow and subbasal small portion somewhat dark yellow; tarsus (Fig. 20B ) brownish black except little less than basal half of basitarsus (though its border not well defined) and basal one-third of second tarsomere whitish yellow; basitarsus (Fig. 20B ) 3.6-4.0 times as long as wide, and 0.9-1.1 and 1.0-1.1 times as wide as greatest width of tibia and femur, respectively; calcipala (Fig. 20B ) 0.31 times as wide as greatest width of basitarsus. Wing. Length 2.0 mm. Subcosta bare or with two hairs. Abdomen. Ventral surface of segment 2 white, those of segments 3 and 4 light brown although sternal plates medial brown, and those of other segments medium to dark brown. Genitalia. Coxite in ventral view (Fig. 20C ) nearly rectangular, 1.8 times as long as its greatest width. Style in ventral view (Fig. 20C ) with round apex; and in ventrolateral view (Fig. 20D ) tapered from base to basal two-fifths, then nearly parallel-sided, with round apex. Ventral plate in ventral view (Fig. 20C ) with posterior margin somewhat concave medially, and lateral margin emarginated medially; basal arms of moderate length, slightly divergent, then convergent apically; ventral plate in caudal view (Fig. 20F ) trapezoidal, with ventral margin nearly straight medially. Cercus with 12-16 hairs. Pupa ( N = 4). Body length 2.5 mm. Thorax. Integument yellow, moderately covered with round tubercles except dorsal and dorsolateral surface of posterior half sparsely covered with tubercles. Gill (Fig. 20G ) composed of eight slender thread-like filaments, arranged as [3+(1+2)]+2from dorsal to ventral; common basal stalk 0.7 times length of interspiracular trunk; dorsal and middle triplets sharing short stalk, and dorsal triplet composed of three individual filaments arising at same level, middle triplet composed of one individual and two paired filaments with extremely short secondary stalk; stalk of ventral pair of filaments medium-long, 1.4 times length of common basal stalk, and nearly as long as interspiracular trunk; primary stalks of dorsal and middle triplets extremely short, 0.3 and 0.6 times length of their common stalk, respectively; primary stalk of dorsal triplet lying against that of lower pair at angle of 90° when viewed laterally; filaments of dorsal and middle triplets subequal in length (2.1-2.3 mm) and thickness to one another; two filaments of ventral pair subequal in length (3.0-3.5 mm) and thickness to each other, and 1.3-1.4 times as thick as six other filaments of dorsal and middle triplets when compared basally; all filaments light brown. Abdomen. Dorsally, all segments light yellowish; segments 1 and 2 without minute tubercles; segment 9 with pair of wide flat terminal hooks (Fig. 20H ), of which outer margin 2.9 times length of inner margin and crenulated when viewed caudally. Cocoon (Fig. 20I ). Light yellow, slipper-shaped, moderately woven, widely extended ventrolaterally; anterior margin thickly woven medially, with short projection; individual threads not visible; 3.5 mm long by 2.5 mm wide. Mature larva ( N = 3). Body length 4.5-5.3 mm. Body creamy white with following color markings: thoracic segment 1 encircled with distinct reddish brown band (though disconnected ventromedially), thoracic segments 2 and 3 ochreous on ventral surface; abdominal segments 1-4 entirely grey, abdominal segments 7 and 8 light grey on dorsal and dorsolateral surfaces; abdominal segments 5 and 6 each with distinct reddish brown, W-shaped, transverse band (of which central and dorsolateral parts marked) along posterior margin of dorsal and dorsolateral surfaces (though band on abdominal segment 6 often partially faded, leaving one round dorsomedial spot and two larger dorsolateral lateral spots); abdominal segments 7 and 8 covered with reddish brown pigments on dorsal and dorsolateral surfaces (though central portion often faded out to varying extent) (Fig. 25I ); abdominal segments 5-7 each with pair of reddish brown spots ventrally (though often faded). Head. Head capsule yellow except eye-spot region whitish, sparsely covered with minute setae (though moderately on dorsal surface); head spots faintly to moderately positive. Antenna: proportional lengths of first, second, and third articles 1.00:0.72-0.75:0.75-0.82. Labral fan with 24-26 primary rays. Postgenal cleft (Fig. 20J ) rounded or slightly triangular anteriorly, 0.8-1.0 times length of postgenal bridge. Abdomen. Rectal organ compound, each of three lobes with 11-13 finger-like secondary lobules. Anal sclerite: anterior arms nearly as long as or slightly longer than posterior ones. Posterior circlet with 86-92 rows of hooklets with up to 14 hooklets per row. Etymology. The species name, huaimorense , refers to the locality name, Huai Mor, where this species was collected. Distribution. Thailand (Chiang Mai and Chiang Rai). Discussion. Simulium huaimorense sp. nov. is similar to S. myanmarense described from Myanmar ( Takaoka et al. 2017b ) in that both species share the high number of male upper-eye large facets and cocoon with a short anterodorsal projection (Fig. 20I ). However, this new species is distinguished in the male by the upper-eye large facets in 16 vertical columns and 17 horizontal rows (14 or 15 vertical columns and 15 or 16 horizontal rows in S. myanmarense ), relative length of the hind basitarsus against its greatest width, which is 3.6-4.0 in this new species versus 4.3-4.4 in S. myanmarense , in the pupa by the extremely short primary stalks of the dorsal and middle triplets of filaments (Fig. 20G ), which are 0.1-0.3 and 0.6-0.7 times as long as their common stalk (the dorsal and middle primary stalks are nearly as long as their common stalk in S. myanmarense ), and in the larva by abdominal segments 1-4 grey (abdominal segments 1 and 2 grey in S. myanmarense ). This new species is distinguished from S. maewongense sp. nov. and four other related species (noted under S. maewongense sp. nov.), which have a cocoon with a short anterodorsal projection (Fig. 20I ), by the higher number of the male upper-eye large facets. This new species is similar in the higher number of male upper-eye facets and the arrangement of the pupal gill filaments to S. kiewfinense sp. nov., and S. junkumae sp. nov. from Thailand and S. hongthaii from Vietnam ( Takaoka et al. 2014a ) but is distinguished from the latter three species by the cocoon with a short anterodorsal projection, and from S. junkumae sp. nov. by larval abdominal segments 1-4 being grey (Fig. 25I ) (larval abdominal segments 1-3 grey in S. junkumae sp. nov.). This new species is distinguished from S. doisaketense from Doi Saket, Chiang Mai Province ( Jitklang et al. 2008 ), by the primary stalks of the dorsal and middle triplets of gill filaments much shorter than their common stalk (much longer in S. doisaketense ).