Simulium (Gomphostilbia) brinchangense Takaoka, Sofian-Azirun & Hashim, sp. nov.
Creators: name: Takaoka, H.
name: Sofian-Azirun, M.
name: Ob, Z. Ya'C
name: Hashim, R.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Simuliidae
Simulium
Simulium brinchangense

description: Simulium (Gomphostilbia) brinchangense Takaoka, Sofian-Azirun & Hashim sp. nov.
Female. Body length 2.3 mm. Head. Slightly narrower than width of thorax. Frons black, slightly shiny when illuminated at certain angles, densely covered with whitish-yellow scale-like recumbent short hairs interspersed with few dark simple longer hairs along each lateral margin; frontal ratio 1.97–2.02:1.00:2.75–2.76; frons: head ratio 1.00:4.69. Fronto-ocular area well developed, narrow, directed dorsolaterally. Clypeus black, slightly shiny when illuminated at certain angles, densely covered with yellow hairs interspersed with several dark longer hairs on each side. Labrum 0.59–0.64 times length of clypeus. Antenna composed of scape, pedicel and 9 flagellomeres, dark brown except scape, pedicel, and base of first flagellomere yellow. Maxillary palp composed of 5 segments, light to medium brown, proportional lengths of third, fourth, and fifth segments 1.00:1.03–1.18:2.10–2.75; third segment (Fig. 1 A) somewhat swollen; sensory vesicle (Fig. 1 A) medium-sized (0.25–0.28 times length of third segment), with medium-sized opening. Maxillary lacinia with 9 inner and 12–14 outer teeth. Mandible with 20 or 21 inner teeth and lacking outer teeth. Cibarium (Fig. 1 B) medially forming sclerotized plate folded forward from posterior margin, with moderately sclerotized medial longitudinal ridge. Thorax. Scutum brownish-black except anterolateral calli ochreous, shiny when illuminated at certain angles, densely covered with whitish-yellow scalelike recumbent hairs except whitish hairs near anterior and lateral margins. Scutellum medium to dark brown, shiny when illuminated at certain angles, covered with whitish-yellow short hairs and dark brown long upright hairs along posterior margin. Postnotum dark brown, shiny when illuminated at certain angles, and bare. Pleural membrane bare. Katepisternum medium to dark brown, longer than deep, shiny when illuminated at certain angles, moderately covered with fine short hairs. Legs. Foreleg: coxa yellow; trochanter dark yellow to light brown; femur medium to dark brown, though extreme apex yellowish; tibia white except little more than apical 1/4 brownishblack, with whitish sheen on outer surface of basal 3/4; tarsus black, with moderate dorsal hair crest; basitarsus moderately dilated, 6.50 times as long as its greatest width. Midleg: coxa medium brown except posterior surface dark brown; trochanter yellow; femur medium brown with base and extreme tip yellowish; tibia light to medium brown except basal 2/5 whitish, covered with whitish fine hairs on basal 2/3 and white sheen on posterior surface of basal 2/3 when illuminated at certain angles; tarsus brownish-black except little less than basal 1/2 of basitarsus dark yellow. Hind leg: coxa light brown with apex yellow; trochanter yellow; femur medium brown with base yellow and apical cap dark brown, though extreme tip yellowish; tibia (Fig. 1 C) light to dark brown with basal 1/2 yellowish-white, covered with whitish fine hairs on outer and posterior surface of basal 3/4 and white sheen on posterior surface of basal 3/4 when illuminated at certain angles; tarsus dark brown to brownish-black except little less than basal 2/3 of basitarsus (though base light brown) and basal 1/2 of second tarsomere white; basitarsus (Fig. 1 D) narrow, nearly parallel-sided, 5.77 times as long as wide, and 0.72 and 0.65 times as wide as greatest widths of tibia and femur, respectively; calcipala (Fig. 1 D) slightly shorter than width at base, and 0.54 times as wide as greatest width of basitarsus. Pedisulcus (Fig. 1 D) well defined. Claw (Fig. 1 E) with large basal tooth 0.5 times length of claw. Wing. Length 2.3 mm. Costa with dark spinules and hairs except hairs on basal portion yellow. Subcosta with dark hairs except near apex bare. Hair tuft on base of radial vein whitish-yellow. Basal portion of radius fully haired; R1 with dark spinules and hairs; R2 with hairs only. Basal cell absent. Halter. White except basal stem darkened. Abdomen. Basal scale ochreous, with fringe of whitish-yellow hairs. Dorsal surface of abdomen medium brown to brownish-black except basal 4/5 of segment 2 yellow or dark yellow, moderately covered with dark short to long hairs except segment 2 with yellow fine short hairs; tergites of segments 2 and 6–8 shiny when illuminated at certain angles. Ventral surface of segment 2 entirely whitish, those of segments 3–5 light brown and those of other segments dark brown; sternal plate on segment 7 undeveloped. Genitalia. Sternite 8 (Fig. 1 F) bare medially, with 21–23 medium-long to very long hairs together with few slender short hairs on each side. Ovipositor valves (Fig. 1 F) triangular, thin, membranous, moderately covered with microsetae interspersed with 1–3 short hairs; inner margins slightly concave, somewhat sclerotized, and slightly separated from each other. Genital fork (Fig. 1 G) of usual inverted-Y form, with slender stem; arms of moderate width, moderately folded medially; lateral plate of each arm with thin lobe directed medioposteriorly and small stout projection directed anterodorsally. Paraproct in ventral view (Fig. 1 H) concave anterolaterally, with 3 or 4 sensilla on anteromedial surface; paraproct in lateral view (Fig. 1 I) somewhat produced ventrally, 0.64 times as long as wide, with 24–28 medium-long to long hairs on ventral and lateral surface. Cercus in lateral view (Fig. 1 I) short, rounded posteriorly, 0.42 times as long as wide. Spermatheca (Fig. 1 J) ellipsoidal, 1.56 times as long as its greatest width, well sclerotized except duct and small area near juncture with duct unsclerotized, and with many fissures on surface; internal setae absent; both accessory ducts slender, subequal in diameter to major one.
Male. Body length 2.5 mm. Head. Somewhat wider than thorax. Upper eye medium brown, consisting of 11 or 12 vertical columns and 13 or 14 horizontal rows of large facets. Face black, grayish-white pruinose. Clypeus black, whitish pruinose, densely covered with golden-yellow scale-like medium-long hairs (mostly directed upward) interspersed with several dark brown simple longer hairs. Antenna composed of scape, pedicel and 9 flagellomeres, dark brown except scape and basal 1/2 or little more of pedicel yellow, rest of pedicel light brown and base of first flagellomere yellowish-white; first flagellomere elongate, 1.91 times length of second one. Maxillary palp light to medium brown, with 5 segments, proportional lengths of third, fourth, and fifth segments 1.00:1.21:2.75; third segment (Fig. 2 A) slender; sensory vesicle (Fig. 2 A) ellipsoidal, small (0.21 times length of third segment), and with opening of medium size. Thorax. Scutum brownish-black to black (except anterolateral calli dark ochreous) without longitudinal vittae in 1 male, but dark brown with 5 faintly-recognized black longitudinal vittae in another male; scutum shiny on shoulders, on wide area along each lateral margin and on prescutellar area when illuminated at certain angles, densely covered with yellow scale-like recumbent hairs. Scutellum medium to dark brown, shiny when illuminated at certain angles, covered with yellow short hairs and dark brown long upright hairs along posterior margin. Postnotum dark brown to brownish-black, shiny when illuminated at certain angles, and bare. Pleural membrane bare. Katepisternum dark brown to brownish-black, longer than deep, shiny when illuminated at certain angles, moderately covered with fine short hairs. Legs. Foreleg: coxa whitish-yellow; trochanter light brown though basal extreme whitish-yellow; femur light brown with apical cap medium brown (though apical tip yellowish); tibia white except base dark yellow and little less than apical 1/3 brownish-black, and covered with yellow hairs on basal 2/3 and white sheen on basal 2/3 when illuminated at certain angles; tarsus brownish-black; basitarsus moderately dilated, 7.85 times as long as its greatest width. Midleg: coxa medium brown except posterior surface brownish-black; trochanter light brown except base yellowish-white; femur light brown with base somewhat yellowish and apical cap medium brown (though apical extreme tip yellow); tibia medium brown except basal 1/3 whitish; tarsus dark brown to brownish-black except basal 1/4 or more of basitarsus dark yellow to light brown (border not well defined). Hind leg: coxa medium brown; trochanter whitish-yellow though slightly darkened on anterior surface; femur light to medium brown with base narrowly yellow and apical cap dark brown (though apical tip yellow); tibia (Fig. 2 B) dark brown to brownish-black except basal 2/5 yellowish-white, covered with whitish-yellow hairs on little less than basal 1/2; tarsus (Fig. 2 C) medium to dark brown except basal 2/5 of basitarsus yellowish and basal 1/4 of second tarsomere dark yellow; basitarsus (Fig. 2 C) enlarged, gradually widened from base to middle, then nearly parallel-sided or slightly narrowed toward apex, 3.65–3.84 times as long as wide, and 0.95–1.00 and 1.06–1.18 times as wide as greatest width of tibia and femur, respectively; calcipala (Fig. 2 C) slightly shorter than basal width, and 0.32 times as wide as greatest width of basitarsus. Pedisulcus (Fig. 2 C) well defined. Wing. Nearly as in female except subcosta with 6–8 hairs; length 2.1–2.2 mm. Halter. Grayish-white except basal stem darkened. Abdomen. Basal scale dark brown, with fringe of light to medium brown hairs. Dorsal surface of abdomen dark brown to black except anterior 1/2 of segment 2 light brown, covered with dark brown short to long hairs; segments 2 and 5–7 each with pair of shiny dorsolateral or lateral patches; ventral surface of segment 2 whitish, and those of other segments light to dark brown. Genitalia. Coxite in ventral view (Fig. 2 D) nearly rectangular, 1.84 times as long as its greatest width. Style in ventral view (Fig. 2 D) bent inward, bluntly rounded apically and with apical spine; style in medial view (Fig. 2 F) shorter than coxite (0.76 times length of coxite), gently bent inward, nearly parallel-sided to apex, with bluntly pointed apex; style in ventrolateral view (Fig. 2 E) very slightly tapered toward apical 2/3, then nearly parallel-sided, and with truncated apex. Ventral plate in ventral view (Fig. 2 D) with body transverse, 0.61 times as long as wide, widened posteriorly, with anterior margin produced anteromedially, and posterior margin somewhat concave medially (though posterior margin slightly convex medially when ventral plate is slightly inclined), densely covered with microsetae on ventral surface; basal arms of moderate length, directed forward, then slightly convergent apically; ventral plate in lateral view (Fig. 2 G) moderately produced ventrally; ventral plate in end view (Fig. 2 H) trapezoidal, ventral margin slightly concave medially, densely covered with microsetae on posterior surface except portion near each lateral tip narrowly bare. Median sclerite (Fig. 2 D) thin, plate-like, wide. Parameres of moderate size, each with 3 distinct long and stout hooks and several smaller ones. Aedeagal membrane moderately setose, slightly sclerotized at base but dorsal plate not well defined. Ventral surface of abdominal segment 10 without distinct hairs near posterior margin. Cercus in lateral view small, rounded, with 14 or 15 hairs.
Pupa. Body length 2.6 mm. Head. Integument light yellow, moderately covered with small round tubercles; antennal sheath without any protuberances; face with pair of unbranched long trichomes with coiled apices, and frons with 3 pairs of unbranched long trichomes with coiled or uncoiled apices; 3 frontal trichomes on each side arising close together, subequal in length to one another and slightly longer than facial one. Thorax. Integument yellow, moderately covered with round tubercles except posterior 1/2 sparsely covered with round tubercles, and with 3 unbranched long dorsomedial trichomes with coiled or uncoiled apices, 2 unbranched long anterolateral trichomes (1 with coiled apex, 1 with uncoiled apex), 1 unbranched medium-long mediolateral trichome with uncoiled apex (though bifid trichome on right side in 1 pupa), and 3 unbranched ventrolateral trichomes with uncoiled apices (1 medium-long and 2 short) on each side. Gill (Fig. 2 I) composed of 8 slender thread-like filaments, arranged as [(1+2)+ (1+2) (or 3)]+2 filaments from dorsal to ventral, with medium-long common basal stalk having somewhat swollen transparent basal fenestra at base; common basal stalk medium-long, 0.68–0.70 times length of interspiracular trunk; dorsal and middle triplets share short stalk; dorsal triplet composed of 1 individual and 2 paired filaments with short primary and secondary stalks, and middle triplet composed of 1 individual and 2 paired filaments and bearing medium-long primary stalk and short secondary stalk, or 3 filaments arising at same level from medium-long primary stalk; stalk of ventral pair of filaments medium-long, 1.08–1.23 times length of common basal stalk, 1.15–1.25 and 1.15–1.25 times as thick as primary stalks of middle and dorsal triplets, respectively, and 0.71–0.83 times as thick as common stalk of middle and dorsal triplets; primary stalk of dorsal triplet lying against that of lower pair at angle of about 60 degrees when viewed laterally; 6 filaments of dorsal and middle triplets subequal in length (2.3–2.8 mm long including their own stalks and basal common stalk) and thickness to one another; 2 filaments of ventral pair subequal in length (3.0– 3.5 mm long including their own stalk and common basal stalk) and thickness to each other, and 1.32–1.60 times as thick as those of 6 other filaments when compared basally; all filaments grayish light brown, gradually tapered toward apex; cuticle of all filaments with well-defined annular ridges and furrows though becoming less marked apically, densely covered with minute tubercles. Abdomen. Dorsally, segments 1 and 2 not pigmented and without tubercles; segment 1 with 1 unbranched slender medium-long hair-like seta on each side; segment 2 with 1 unbranched slender medium-long hair-like seta and 5 short somewhat spinous setae submedially on each side; segments 3 and 4 each with 4 hooked spines and 1 short somewhat spinous seta on each side; segment 5 lacking spine-combs; segments 6–9 each with spine-combs in transverse row (though those on segment 9 somewhat smaller than those on segment 8) and comblike groups of minute spines on each side; segment 9 with pair of triangular flat terminal hooks of which outer margin is 3.00–3.56 times length of inner margin and crenulated (Fig. 2 J). Ventrally, segment 4 with 1 unbranched hook and few slender short setae on each side; segment 5 with pair of bifid hooks sub-medially and few short slender setae on each side; segments 6 and 7 each with pair of bifid inner and unbranched outer hooks somewhat spaced from each other and few short slender setae on each side; segments 4–8 with comb-like groups of minute spines. Each side of segment 9 with 3 grapnel-shaped hooklets. Cocoon. Wall-pocket-shaped, thinly and moderately woven, widely extended ventrolaterally; anterior margin somewhat thickly woven, with dorsal portion slightly or moderately produced anteriorly forming short bulge when viewed dorsally; 3.6–4.0 mm long by 2.9–3.1 mm wide.
Mature larva. Body length 5.2–5.8 mm. Body color yellowish to grayish-yellow except dorsal surface of abdominal segments 7 and 8 grayish; abdominal segments 5 and 6 each with faint to moderate reddish-brown Wshaped transverse band dorsally, though band on segment 6 often partially faded, being divided into 1 dorsomedial and 2 dorsolateral spots, or completely disappeared in some larvae; ventral surface of abdominal segment 7 with faint gray transverse band though disconnected medially. Cephalic apotome pale yellow; head spots faintly positive. Lateral surface of head capsule pale yellow except eye-spot region whitish; eye-brow and spots near posterior margin faintly positive; spot below eye-spot region usually indistinct. Ventral surface of head capsule pale yellow except darkened area near posterior margin on each side of postgenal cleft. Antenna composed of 3 segments and apical sensillum, somewhat longer than stem of labral fan; proportional lengths of first, second, and third segments 1.00:0.78–0.85:0.79–0.88. Labral fan with 30–34 main rays. Mandible with 3 comb-teeth decreasing in length from first to third; mandibular serration composed of 2 teeth (1 medium-sized and 1 small); major tooth at acute angle against mandible on apical side; supernumerary serrations absent. Hypostoma with row of 9 apical teeth; median tooth most prominent, somewhat longer than each corner tooth, which is somewhat longer than 3 intermediate teeth on each side; lateral margin smooth; 4 or 5 hypostomal bristles per side lying parallel to lateral margin. Postgenal cleft (Fig. 2 K) pentagonal, 1.2–1.6 times as long as postgenal bridge. Cervical sclerites composed of 2 pale small pieces, not fused to occiput, widely separated medially from each other. Histoblast of pupal gill filaments with medium-long common basal stalk. Thoracic cuticle bare. Abdominal cuticle almost bare except few posterior segments moderately covered with unbranched minute setae dorsally and last segment densely covered with colorless unbranched setae on each side of anal sclerite. Rectal scales absent. Rectal papillae compound, each of 3 lobes with 6–9 finger-like secondary lobules. Anal sclerite of usual X-form, with anterior arms subequal in length to posterior ones, broadly sclerotized at base; accessory sclerite absent. Last abdominal segment expanded ventrolaterally forming double bulges on each side, visible as large conical ventral papillae when viewed from side. Posterior circlet with 83 or 84 rows of up to 15 hooklets per row.
Type specimens. HOLOTYPE: Male (with associated pupal exuviae and cocoon) (preserved in 80% ethanol) reared from pupa, collected from a small stream moderately flowing in a natural forest (width 0.5–1.0 m, water temperature 14.5˚C, shaded, altitude 1,800 m), near the peak of Mt. Brinchang, west of Sungai Palas village, Pahang, Malaysia, 27.I.2011, by H. Takaoka and A. Takaoka. Paratypes: 1 male with associated pupal exuviae and cocoons, same data as those of the holotype; two females with associated pupal exuviae and cocoons, and 7 mature larvae, same locality as that of the holotype except date and collector: 30.III.2012, by Zubaidah Ya’cob, all paratype specimens preserved in 80% ethanol.
Biological notes. The pupae and larvae of this new species were collected from dead tree leaves in the water. Associated species were Simulium (Nevermannia) caudisclerum Takaoka & Davies, 1995, S. (N.) feuerborni Edwards, 1934 and S. (Simulium) brevipar Takaoka & Davies, 1995.
Etymology. The species name brinchangense refers to the name of Mount Brinchang, because this new species was collected from a stream near the peak of this mountain.
Remarks. In Malaysia, the asakoae species-group was represented by six species, i.e., S. (G.) asakoae Takaoka & Davies, 1995, S. (G.) hoiseni Takaoka, 2008, S. (G.) izuae, S. (G.) lurauense Takaoka, Sofian-Azirun & Hashim, 2011, S. (G.) roslihashimi Takaoka & Sofian-Azirun, 2011, and S. (G.) sofiani (Takaoka et al. 2013b).
The female of S. (G.) brinchangense sp. nov. is similar to that of S. (G.) roslihashimi in having the mandible without teeth on the outer margin, a medium-sized sensory vesicle (Fig. 1 A), and the hind tibia yellowish on the basal 1/2 and darkened on the apical 1/2 (Fig. 1 C). However, both species are separated from each other by the relative width of the hind basitarsus to the hind femur (0.65 in this new species versus 0.53 in S. (G.) roslihashimi).
The male of S. (G.) brinchangense sp. nov. appears to be most closely related to S. (G.) asakoae in having the haired subcosta as well as a similar number of enlarged upper-eye facets, but is readily distinguished from the latter species by the medium brown upper-eye facets (cf., vermilion in S. (G.) asakoae), and the much darker hind tibia and basitarsus (Figs. 2 B, C) (cf., the dark portions of the hind tibia and basitarsus are limited on the apical 1/ 2 in S. (G.) asakoae).
Simulium (G.) brinchangense sp. nov. is similar in the pupa to S. (G.) asakoae, S. (G.) roslihashimi and S. (G.) lurauense in the arrangement of the gill filaments (Fig. 2 I) but is easily distinguished from S. (G.) asakoae by the dorsal surfaces of the abdominal segments 1 and 2 which are not darkened and lack minute tubercles (cf., dorsal surfaces of abdominal segments 1 and 2 dark gray and covered with minute tubercles according to pupae of S. (G.) asakoae recently collected from Sungai Palas, Cameron’s Highlands, the type locality of S. (G.) asakoae), and also from the remaining two species by the relatively longer outer margin of the terminal hooks (Fig. 2 J) (i.e., the length of the outer margin relative to that of the inner margin is 3.0– 3.5 in this new species but 2.3–2.8 and 1.15–2.43 in S. (G.) roslihashimi and S. (G.) lurauense, respectively). On the other hand, S. (G.) brinchangense sp. nov. is readily distinguished in the pupa from the three other species as follows: from S. (G.) hoiseni by the number of gill filaments (8 versus 6), from S. (G.) izuae by the stalk of the ventral pair of filaments longer than the common basal stalk (Fig. 2 I) (cf., the stalk of the ventral pair of filaments is shorter than the common basal stalk in S. (G.) izuae), and from S. (G.) sofiani by the length of the common basal stalk of the gill (medium-long versus long).
The larva of S. (G.) brinchangense sp. nov. is similar to that of S. (G.) izuae in having indistinct head spots and a medium-long postgenal cleft (1.2–1.6 times the length of the postgenal bridge– Fig. 2 K) but is distinguished from the latter species by the reddish-brown marking on the dorsal surface of abdominal segments 5 and 6 (cf., no reddish-brown marking on abdominal segments 5 and 6 in S. (G.) izuae – Takaoka et al. 2013b). Some larvae of S. (G.) asakoae have a medium-long postgenal cleft but are distinguished from this new species by distinct head spots and darkened areas surrounding the postgenal cleft (Takaoka & Davies 1995). The larvae of S. (G.) roslihashimi, S. (G.) lurauense and S. (G.) sofiani differ from this new species by having a longer postgenal cleft, more than twice the length of the postgenal bridge (Takaoka et al. 2011a, b).
Simulium (G.) brinchangense sp. nov. is distinguished from 13 known species of the asakoae species-group from other countries as shown in the keys.
description: Published as part of Takaoka, H., Sofian-Azirun, M., Ob, Z. Ya'C & Hashim, R., 2014, Two new species of Simulium (Gomphostilbia) (Diptera: Simuliidae) from Cameron's Highlands, Peninsular Malaysia, with keys to 21 species of the Simulium asakoae species-group in Zootaxa 3765 (1), DOI: 10.11646/zootaxa.3765.1.3, http://zenodo.org/record/227648