Simulium (Gomphostilbia) nanoiense Takaoka, Srisuka & Saeung, 2020

Takaoka, Hiroyuki, Srisuka, Wichai, Fukuda, Masako & Saeung, Atiporn, 2020, Twenty-one new species of the Simulium (Gomphostilbia) asakoae species group (Diptera, Simuliidae) in Thailand, with their genetic relationships, ZooKeys 950, pp. 51-152 : 51

Simulium (Gomphostilbia) nanoiense Takaoka, Srisuka & Saeung sp. nov. Figs 12 , 25J

Material examined.

Holotype: Male (with its associated pupal exuviae and cocoon) (in 80% ethanol) labeled as "Holotype: Simulium nanoiense male, QSBG col. no. 66, Thailand, 5-VIII-2017, by W. Srisuka", collected from a stream (width 1 m, depth 3 cm, bed sandy, moderate flow, pH 6.2, 19.6 °C, partially shaded, elevation 1,349 m, 18°16'40.4"N, 100°30'19.0"E), Khun Sathan Village, Na Noi District, Nan Province, Thailand, 5-VIII-2017, by W. Srisuka (Coll. No. 66).

Paratypes: One female, nine males (thoraces of two males for DNA analysis) (with their associated pupal exuviae and cocoons), and 10 mature larvae (one mature larva for DNA analysis) (in 80% ethanol), same data as for holotype.

Diagnosis. Female: small sensory vesicle 0.22-0.24 times as long as the third palpal segment (Fig. 12A ) and mandible with two teeth on the outer margin (Fig. 12B ). Male: medium number of upper-eye (large) facets in 12 or 13 vertical columns and 14 (rarely 13) horizontal rows. Larva: postgenal cleft as long as or little longer than the postgenal bridge (Fig. 12K ) and abdominal segments 1-3, 7, and 8 greyish (Fig. 25J ).

Description.

Female (N = 1). Body length 2.0 mm.

Head. Frontal ratio 1.8:1.0:2.7; frons:head ratio 1.0:5.0. Labrum 0.66 times length of clypeus. Maxillary palpus: proportional lengths of third, fourth, and fifth palpal segments 1.0:1.1:2.4; sensory vesicle (Fig. 12A ) small, ellipsoidal (0.22-0.24 times length of third palpal segment). Lacinia with ten or eleven inner and 13 outer teeth. Mandible (Fig. 12B ) with 21 inner teeth and two outer teeth at some distance from tip.

Legs. Foreleg: tibia yellowish white except apical three-tenths brownish black; basitarsus moderately dilated, 7.1 times as long as its greatest width. Hind leg: coxa light brown; tibia yellowish white on little more than basal half and light brown to brownish black on rest; tarsus brownish black except basal three-tenths (though base light brown) and basal half of second tarsomere yellowish white; 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.

Wing. Length 2.2 mm.

Abdomen. Basal scale ochreous, with fringe of whitish yellow hairs. Dorsal surface of abdomen medium to dark brown except anterior four-fifths of segment 2 ochreous.

Terminalia. Sternite 8 bare medially, with 27 or 28 medium-long to long hairs together with two to four slender short hairs on each side. Ovipositor valves each moderately covered with microsetae interspersed with two short hairs. Paraproct in ventral view with four or five sensilla on anteromedial surface; paraproct in lateral view 0.6 times as long as wide, with 19-21 medium-long to long hairs on ventral and lateral surfaces. Cercus in lateral view 0.5 times as long as wide. Spermatheca 1.5 times as long as its greatest width.

Male (N = 10). Body length 2.1-2.3 mm.

Head. Slightly wider than thorax. Upper eye medium brown, consisting of large facets in 12 or 13 vertical columns and 14 (rarely 13) horizontal rows. Antenna: first flagellomere elongate, 1.7 times length of second. Maxillary palpus: proportional lengths of third, fourth, and fifth palpal segments 1.0:1.3:2.6; sensory vesicle 0.14-0.17 times length of third palpal segment.

Legs. Foreleg: tibia whitish yellow except little more than apical one-third dark brown, and small subbasal area on inner and lateral surfaces light brown; basitarsus somewhat dilated, 7.0-7.1 times as long as its greatest width. Midleg: tarsus dark brown except basal one-fourth to one-third of basitarsus dark yellow (border not well defined). Hind leg: coxa light brown; femur light to medium brown with base yellow and apical cap brownish black (though apical tip yellow); tibia dark brown to brownish black except basal half or little less whitish yellow; tarsus (Fig. 12C ) brownish black except basal two-fifths of basitarsus and basal one-third of second tarsomere whitish yellow; basitarsus (Fig. 12C ) 3.8-4.0 times as long as wide, and 0.9-1.0 and 1.1 times as wide as greatest width of tibia and femur, respectively; calcipala (Fig. 12C ) slightly shorter than basal width, and 0.32 times as wide as greatest width of basitarsus.

Wing. Length 1.9-2.0 mm. Subcosta bare in three males but with one to seven hairs in six males.

Genitalia. Style in ventrolateral view (Fig. 12E ) slightly tapered from base to middle, then nearly parallel-sided toward apex, with truncated apex, and 0.8 times as long as coxite. Ventral plate in ventral view (Fig. 12D ) with basal arms slightly convergent apically; ventral plate in caudal view (Fig. 12G ) rounded ventrally. Cercus small, rounded, with 12 or 13 hairs.

Pupa (N = 11). Body length 2.4-2.6 mm.

Head. Integument yellow. Thorax. Integument yellow, moderately covered with round tubercles except dorsal and dorsolateral surfaces of posterior half almost bare or sparsely covered with tubercles, though small dorsal area near posterior margin sparsely to moderately covered with tubercles.

Thorax. Gill (Fig. 12H ) composed of eight slender thread-like filaments, arranged as (3+3)+2 or [(2+1)+3]+2) or [3+(1+2)]+2 from dorsal to ventral; common basal stalk 0.7-0.8 times length of interspiracular trunk; dorsal and middle triplets sharing short stalk, and mostly composed of three individual filaments arising at same level; stalk of ventral pair of filaments variable in length, 0.9-1.1 times length of common basal stalk, and 0.7-0.8 times length of interspiracular trunk; primary stalk of dorsal triplet lying against that of lower pair at angle of 70-80° when viewed laterally; filaments of dorsal triplet subequal in length (1.6-1.9 mm) and thickness to one another; filaments of middle triplets subequal in length (2.0-2.3 mm) and thickness to one another; two filaments of ventral pair subequal in length (2.5-3.0 mm) and thickness to each other and 1.4 times as thick as six other filaments of dorsal and middle triplets when compared basally.

Abdomen. Dorsally, all segments light yellowish; segments 1 and 2 without tubercles; segment 9 with pair of wide flat terminal hooks (Fig. 12I ), of which outer margin 2.0-2.1 times length of inner margin and crenulated when viewed caudally.

Cocoon (Fig. 12J ). Light yellow, slipper-shaped, roughly to moderately woven, widely extended ventrolaterally; anterior margin not thickly woven medially, without bulge or short projection; individual threads visible or not; 2.9-3.2 mm long by 2.0-2.8 mm wide.

Mature larva (N = 9). Body length 5.0-5.6 mm. Body creamy white with following color markings: thoracic segment 1 encircled with dark grey band (though disconnected ventromedially), dorsal surface of thoracic segments 1-3 often light grey except posterior half of segment 3 light ochreous; ventral surface of thoracic segment 2 dark grey; ventral surface of thoracic segment 3 light grey on anterior one-third and light ochreous on posterior two-thirds; abdominal segments 1-3 entirely grey, abdominal segments 7 and 8 light grey dorsally, abdominal segment 4 with purplish transverse band (though often partially faded, leaving narrow band or small spot(s) dorsomedially), abdominal segments 5 and 6 each with distinct, dark purplish, W-shaped, transverse band dorsally (though that on segment 6 often faded partially, leaving one distinct round dorsomedial spot and two dorsolateral spots), dorsal and dorsolateral surfaces of abdominal segments 7 and 8 each covered with dark purplish pigment, though dorsomedial portions usually faded (Fig. 25J ).

Head. Head spots faintly or moderately positive. Antenna: proportional lengths of first, second, and third articles 1.0:0.7:0.8. Labral fan with 33-38 primary rays. Postgenal cleft (Fig. 12K ) small, rounded, 1.0-1.1 times length of postgenal bridge.

Thorax and Abdomen. Thoracic and abdominal cuticle sparsely covered with unpigmented minute setae dorsally except last abdominal segment densely covered with unbranched colorless minute setae on dorsolateral and lateral surfaces of each side of anal sclerite and on each lateral surface even down to base of ventral papilla. Rectal organ compound, each of three lobes with ten or eleven finger-like secondary lobules. Anal sclerite with anterior arms slightly longer than posterior ones. Posterior circlet with 85-88 rows of hooklets with up to 14 hooklets per row.

Etymology.

The species name, nanoiense , refers to the district, Na Noi, where this species was collected.

Distribution.

Thailand (Nan).

Discussion.

This new species is similar to S. brinchangense described from Peninsular Malaysia ( Takaoka et al. 2014b), in having a similar number of male upper-eye facets but is distinguished by the male ventral plate with its ventral margin rounded (Fig. 12G ) when viewed posteriorly (ventral margin is nearly straight or slightly concave in S. brinchangense ).

This new species is similar in larval body color to S. junkumae sp. nov. but is distinguished from the latter species by the dorsal and dorsolateral surfaces of larval abdominal segments 7 and 8 light grey (Fig. 25J ).

Figures

Figure 12. Female, male, pupa and larva of S. nanoiense sp. nov. A, B female C-G male H-J pupa K larva. A sensory vesicle (right side; anterior view) B mandible (right side) C hind basitarsus and second tarsomere (left side; lateral view) D coxites, styles and ventral plate (ventral view) E style (right side; ventrolateral view) F ventral plate and median sclerite (lateral view) G ventral plate (caudal view) H gill filaments (right side; lateral view) I terminal hooks (caudal view) J cocoon (dorsal view) K head capsule (ventral view). Scale bars: 1.0 mm (J); 0.1 mm (C, H, K); 0.02 mm (A, D-G); 0.01 mm (B, I).

Figure 25. Schematic illustrations of larval body color patterns (dorsal view). A S. teerachanense sp. nov. B S. pitasawatae sp. nov. C S. sutheppuiense sp. nov. D S. asakoae E S. klonglanense sp. nov. F S. namdanense sp. nov. G S. chaowaense sp. nov. H S. loeiense sp. nov. I S. huaimorense sp. nov. J S. nanoiense sp. nov. K S. junkumae sp. nov. L S. myanmarense M S. maewongense sp. nov. N S. phapeungense sp. nov. O S. muangpanense sp. nov. P S. maehongsonense sp. nov. Q S. thungchangense sp. nov. R S. chiangdaoense S S. inthanonense (morph 1) T S. inthanonense (morph 2).