Simulium (Gomphostilbia) nuwakotense Takaoka & Shrestha, 2010

Takaoka, Hiroyuki & Shrestha, Suchitra, 2010, New species of black flies (Diptera: Simuliidae) from Nepal 2731, Zootaxa 2731, pp. 1-62 : 23-27

Simulium (Gomphostilbia) nuwakotense Takaoka & Shrestha sp. nov.

Description. Male. Body length 2.5 mm. Head. Much wider than thorax. Upper eye consisting of 17 vertical columns and 18 horizontal rows of large facets. Face and clypeus dark brown, white pruinose, silveryiridecent when illuminated at certain angle of light; clypeus densely covered with yellowish-white short to medium-long hairs interspersed with several dark brown simple medium-long hairs. Antenna composed of scape, pedicel and 9 flagellomeres, dark brown except scape, pedicel and base of 1st flagellomere yellow though parts of scape somewhat darkened; 1st flagellomere elongate, 1.78 times as long as 2nd one. Maxillary palp with 5 segments, light brown, proportional lengths of 3rd, 4th, and 5th segments 1.00:1.18:2.68; 3rd segment ( Fig. 12A) somewhat widened near apex; sensory vesicle ( Fig. 12A) ellipsoidal, small, 0.29 times as long as 3rd segment, and with medium-sized opening apically. Thorax. Brownish-black to black, covered with yellowish-white short hairs (most hairs lost); scutum whitish-gray pruinose and shiny widely along lateral margins and on anterior and prescutellar areas when illuminated at certain angle of light. Scutellum dark brown, with yellowish-white short hairs (all upright long hairs as well as most short hairs lost). Postnotum dark brown, whitish-gray pruinose and bare. Pleural membrane bare. Katepisternum brownishblack, whitish-gray pruinose, covered with yellow short hairs as well as dark short hairs. Legs. Foreleg: coxa dark yellow to light brown; trochanter medium brown; femur medium brown with apical cap dark brown; tibia dark brown except median large portion on outer surface medium brown; tarsus dark brown, with moderate dorsal hair crest; basitarsus somewhat dilated, 7.22 times as long as its greatest width. Midleg: coxa dark brown; trochanter light to medium brown; femur medium brown with apical cap dark brown; tibia dark brown except basal 1/4 or little more yellow; tarsus dark brown. Hind leg: coxa medium to dark brown; trochanter light brown; femur medium brown except apical cap dark brown; tibia dark brown except from base to basal 1/5 yellow and from basal 1/5 to basal 2/5 light brown; tibia covered with yellow hairs on basal 2/5; tarsus ( Fig. 12B) medium brown except basal 1/2 of basitarsus (though base and narrow area along anterior margin medium brown) dark yellow to light brown and little less than basal 1/2 of 2nd tarsomere yellow; basitarsus ( Fig. 12B) somewhat swollen, spindle-shaped, 4.72 times as long as wide, and 0.78 and 0.75 times as wide as greatest width of tibia and femur, respectively; calcipala ( Fig. 12B) well developed, 1.10 times as long as wide, and 0.35 times as wide as greatest width of basitarsus; pedisulcus ( Fig. 12B) well developed. Wing. Length 2.0 mm. Costa with dark brown spinules as well as dark brown hairs except basal portion with patch of yellowish hairs. Subcosta without hairs. Hair tuft on stem vein yellow. Basal portion of radius fully haired. Basal cell absent. Abdomen. Basal scale dark brown, with fringe of light brown long hairs. Dorsal surface of abdomen medium to dark brown except basal 1/2 of segment 2 yellow, covered with dark brown short to long hairs; segments 2 and 5–9 each with pair of shiny dorsolateral or lateral patches, of which those on segment 2 broadly connected in middle to each other. Genitalia. Coxite in ventral view ( Fig. 12C) nearly rectangular, 1.78 times as long as its greatest width. Style in ventral view ( Fig. 12C) slender, tapered toward apex, markedly curved inward, with apical spine; style in ventrolateral view ( Fig. 12D) 0.77 times as long as coxite, somewhat wide basally (0.41 times as wide as its length), moderately tapered toward basal 1/2, then very slightly tapered toward apex. Ventral plate in ventral view ( Fig. 12C) transverse, 0.50 times as long as wide, slightly widened posteriorly, with anterior margin produced anteromedially, posterior margin somewhat concave medially (though nearly straight when viewed somewhat obliquely), and densely covered with microsetae on ventral surface; basal arms of moderate length, directed forward though slightly convergent apically; ventral plate in lateral view ( Fig. 12E) moderately produced ventrally; ventral plate in end view ( Fig. 12F) gently curved ventrally, with marked depression medially on ventral margin, densely covered with microsetae on posterior surface except both lateral areas mostly bare on dorsal 1/2. Median sclerite ( Fig. 12C,E,G) thin, plate-like, wide, connected to anterior 1/3 of ventral plate. Paramere ( Fig. 12H) slender, with several distinct hooks decreasing in length toward base. Aedeagal membrane densely setose, not sclerotized. Ventral surface of 10th abdominal segment somewhat sclerotized near base, without distinct hairs near posterior margin on each side. Cercus ( Fig. 12I,J) somewhat produced posteroventrally, with 14 or 15 hairs.

Pupa. Body length 3.0 mm. Head. Integument yellow, moderately covered with round tubercles except antennal sheath without tubercles; frons with 3 simple very long trichomes on each side; face with 1 simple or bifid very long trichome on each side; frontal trichomes slightly longer than facial ones. Thorax. Integument yellow to dark yellow, moderately covered with round tubercles, with 3 simple long trichomes with coiled or uncoiled apices dorsomedially, 2 simple trichomes (1 very long, 1 long) with uncoiled apices anterolaterally, 1 simple long trichome with uncoiled apex mediolaterally, and 3 simple trichomes with uncoiled apex (1 medium-long, 2 short) ventrolaterally on each side. Gill ( Fig. 13A,B) of inflated Y-form in lateral view (0.7– 0.8 mm long), each arm short (dorsal arm 0.3 mm long, ventral arm 0.4 mm long), with 2 short finger-like projections (0.13–0.19 mm long), 1 very short nipple-like one (0.02–0.05 mm long) and 1 thread-like filament (0.5–0.6 mm long); in addition, 6 slender thread-like filaments (2 individual and 4 paired filaments, arranged as 1+2+1+2 from dorsal to ventral) arising near base from inside surface; all 6 thread-like filaments subequal in length (0.8–0.9 mm) and thickness to one another; each inflated arm with 2 constrictions; cuticle of inflated structure grayish except basal portion blackish dorsally, very thick except somewhat swollen thin transparent organ ventrally (mostly broken) at base; cuticle of 8 thread-like filaments as well as that of inflated structure smooth and densely covered with very minute tubercles. Abdomen. Dorsally, all segments almost transparent except segment 9 yellowish; segments 1 and 2 without tubercles; segment 1 with 1 medium-long simple seta on each side; segment 2 with 1 medium-long simple seta and 5 very short setae submedially on each side; segments 3 and 4 each with 4 hooked spines and 1 very short seta on each side; segment 5 lacking spinecombs; segments 6–9 each with spine-combs in transverse row (though those on segment 9 much smaller than others on other segments) and comb-like groups of minute spines on each side; segment 9 with pair of distinct plate-like wide terminal hooks with crenulated outer margin ( Fig. 13C). Ventrally, segment 4 with 1 simple hook and few short setae on each side; segment 5 with pair of bifid hooks submedially and few simple slender short setae on each side; segments 6 and 7 each with pair of bifid inner and simple outer hooks somewhat spaced from each other and few simple slender short setae on each side; segments 4–8 each with comb-like groups of minute spines. Each side of segment 9 with 3 grapnel-shaped hooklets. Cocoon. Wall-pocket shaped, thinly woven, moderately extending ventrolaterally; anterior margin somewhat thickly woven; floor roughly or moderately woven; individual threads invisible; 3.5 mm long by 2.2 mm wide.

Female and mature larva. Unknown.

Type specimen. Holotype male (together with its associated pupal exuviae and cocoon) (preserved in 80% ethanol), reared from pupa collected from a small stream (water temperature 23.0˚C, exposed to the sun, altitude 1,811 m, 27˚81’05.7” N, 85˚25’64.5” E) rapidly flowing along the road, near Ranipauwa , Nuwakot, Nepal, 5.VIII.2009.

Biological notes. The pupa of this new species was collected from a grass leaf trailing in water. No other species was collected.

Etymology. The species name nuwakotense refers to the locality name, Nuwakot, where this new species was collected.

Remarks. The remarkable configuration of the pupal gill of S. (G.) nuwakotense sp. nov. ( Fig. 13A,B) appears to be very similar to those of S. (G.) gombakense Takaoka & Davies , originally described from Peninsular Malaysia ( Takaoka & Davies 1995; Takaoka 2000) and later recorded from Thailand ( Kuvangkadilok & Takaoka 2000), and S. (G.) sachini Takaoka & Henry , originally described from Darjeeling, India ( Takaoka et al. 2010), and newly recorded from Nepal, as noted in the present paper. However, this new species is distinguished in the pupa from these two known species by the dorsal inflated arm with two constrictions and both dorsal and ventral arms each with one small nipple-like projection as well as two short finger-like projections (dorsal arm with no constriction in S. (G.) gombakense and one constriction in S. (G.) sachini , and both arms with three short finger-like projections of similar length in both known species).

The male of S. (G.) nuwakotense sp. nov. is readily distinguished from that of S. (G.) gombakense by the ventral plate with two ventrally produced processes ( Fig. 12F) but almost indistinguishable from that of S. (G.) sachini , though the hind basitarsus of this new species is somewhat narrower than that of S. (G.) sachini , as noted under the following species.