Simulium (Simulium) jasmoni, Takaoka & Sofian-Azirun & Belabut, 2012

Takaoka, Hiroyuki, Sofian-Azirun, Mohd & Belabut, Daicus M., 2012, Descriptions Of Two New Species Of Simulium (Simulium) (Diptera: Simuliidae) From Tioman Island, Peninsular Malaysia, Raffles Bulletin of Zoology 60 (2), pp. 399-409 : 400-404

Simulium (Simulium) jasmoni , new species

( Figs. 1A–G , 2A–H , 3A–L )

Material examined. — Holotype: male (with associated pupal exuviae and cocoon) (preserved in 80% ethanol) reared from pupa, collected from a small stream (width 0.2–0.3 m, water temperature 25.0°C, shaded), slowly flowing in a forest, near Sungai Tedau, Tioman Island , Pahang, Malaysia, coll. D. M. Belabut, 3–7 Apr.2011.

Paratypes: 1 pharate female (with associated pupal exuviae and cocoon), 1 male pupal exuviae and cocoon, and 3 mature larvae, all preserved in 80% ethanol, same data as those of holotype .

Description. — Pharate female (dissected out of pupa). Only following features are observed: Head. Narrower than thorax. Frons shiny, bare except several stout dark hairs along each lateral margin; frontal ratio 1.30:1.00:1.06; frons-head ratio 1.00:3.37. Fronto-ocular area moderately developed, directed laterally and with pointed tip. Antenna composed of scape, pedicel and 9 flagellomeres. Clypeus moderately covered with dark stout hairs except mediolongitudinal area widely bare. Labrum 0.54 times as long as clypeus. Maxillary palp composed of 5 segments; 3 rd segment ( Fig. 1A ) moderately enlarged; sensory vesicle ( Fig. 1A ) elongate, 0.61 times as long as 3 rd segment, with medium-sized round opening. Maxillary lacinia with 11 or 12 inner and 18 outer teeth. Mandible with 28 inner and 10–13 outer teeth. Cibarium with numerous pointed minute processes near posterodorsal margin. Thorax. Scutum shiny, moderately covered with medium to dark brown recumbent short hairs interspersed with dark brown long upright hairs on prescutellar area. Scutellum shiny, with dark brown long upright hairs. Postnotum shiny and bare. Pleural membrane bare. Katepisternum longer than deep, bare, shiny when illuminated. Legs. Fore basitarsus greatly dilated, 4.29 times as long as its greatest width. Hind basitarsus nearly parallel-sided; calcipala nearly as long as width at base; pedisulcus well defined; claw ( Fig. 1B ) with minute subbasal projection. Wing. Costa with spinules and hairs. Subcosta haired except near apex bare. Basal section of vein R bare; R 1 with spinules and hairs; R 2 with hairs only. Hair tuft on stem vein dark brown. Basal cell absent. Abdomen. Ventral surface of abdominal segment 7 without pair of hair tufts. Genitalia. Sternite 8 ( Fig. 1C ) well sclerotized and bare medially, covered with 9 or 10 long and medium-long stout hairs and few short fine hairs on each side. Ovipositor valves ( Fig. 1C ) nearly triangular, rounded posteromedially, membranous except inner margins weakly sclerotized, densely covered with microsetae together with 6–8 short fine hairs; right inner margin widely concave but left one nearly straight. Genital fork ( Fig. 1D ) of inverted-Y form; stem slender and well sclerotized; arms of moderate width, each with strongly-sclerotized projection directed forwardly from lateral ridge. Paraproct in ventral view ( Fig. 1E ) pointed posteromedially, moderately concave anterolaterally, and with strongly sclerotized anteromedial surface; paraproct in lateral view ( Fig. 1F ) somewhat produced ventrally and slightly posteriorly, 0.84 times as long as wide, covered with about 20 medium-long stout hairs and numerous microsetae on lateral and ventral surfaces. Cercus in lateral view ( Fig. 1F ) short, rounded posteriorly, 0.49 times as long as its greatest width, and covered with numerous medium-long and short stout hairs. Spermatheca ( Fig. 1G ) ovoidal, 1.12 times as long as wide, well sclerotized except duct and narrow area of juncture to duct unsclerotized, without discernible reticulate surface patterns; minute internal setae present.

Male. Body length 2.0 mm. Head. Somewhat wider than thorax. Upper eye medium brown, consisting of 16 vertical columns and 17 horizontal rows of large facets. Face brownish-black to black, greyish-white pruinose and shiny when illuminated at certain angle of light. Clypeus black, whitish pruinose, covered with several dark brown simple longer hairs along each lateral margin. Antenna composed of scape, pedicel and 9 flagellomeres, dark brown except base of 1 st flagellomere somewhat dark yellow; 1 st flagellomere elongate, 1.56 times as long as 2 nd one. Maxillary palp greyish-brown, with 5 segments, proportional lengths of 3 rd, 4 th, and 5 th segments 1.00:1.22:2.33; 3 rd segment ( Fig. 2A ) widened apically; sensory vesicle ( Fig. 2A ) globular, small (0.22 times as long as 3 rd segment), and with small opening. Thorax. Scutum black, with distinct white markings which are shiny when illuminated at certain angle of light: i.e., large spot on each shoulder and large spot on prescutellar area, both of which approaching each other along each lateral margin but do not connect; scutum moderately covered with brassy short hairs mixed with several dark brown long upright hairs on prescutellar area. Scutellum brownish-black to black, with dark brown upright long hairs. Postnotum black and bare. Pleural membrane bare. Katepisternum longer than deep, black and bare. Legs. Foreleg: coxa yellowishwhite; trochanter yellow except apical portion light brown; femur medium brown; tibia dark brown to brownish-black except median large portion of outer surface white, and with median large white sheen when illuminated at certain angle of light; tarsus brownish-black to black with moderate hair crest; basitarsus moderately dilated, 6.43 times as long as its greatest width. Midleg: coxa brownish-black; trochanter medium brown except base dark yellow; femur dark brown to brownish-black; tibia brownish-black except base yellowishwhite; tarsus light brown except basal 3/4 of basitarsus and basal tip of 2 nd tarsomere yellowish-white. Hind leg: coxa brownish-black; trochanter yellow; femur dark brown with apical cap brownish-black and base yellow; tibia brownishblack to black except basal tip yellow; tarsus ( Fig. 2B ) medium brown except little less than basal 1/2 of basitarsus and little more than basal 1/2 of 2 nd tarsomere yellowishwhite; basitarsus ( Fig. 2B ) enlarged, wedge-shaped, 3.86 times as long as wide, and 0.83 and 0.73 times as wide as greatest width of tibia and femur, respectively; calcipala ( Fig. 2B ) nearly as long as wide, and 0.27 times as wide as greatest width of basitarsus. Pedisulcus ( Fig. 2B ) well defined. Wing. Length 1.5 mm. Costa with dark brown spinules as well as pale hairs. Subcosta bare. Hair tuft on stem vein dark brown. Basal portion of radius bare; R 1 with dark spinules and few pale hairs; R 2 with hairs only. Basal cell absent. Haltere. White except basal stem darkened. Abdomen. Basal scale dark brown, with fringe of light to medium brown hairs. Dorsal surface of abdomen medium black, covered with dark brown short to long hairs; segments 2 and 5–7 each with pair of white dorsolateral or lateral patches which are brilliantly shiny when illuminated at certain angle of light; ventral surface brownish-black to black. Genitalia. Coxite in ventral view ( Fig. 2C ) nearly quadrate, 1.15 times as long as its greatest width, and covered with stout hairs along posterior margin. Style in ventral view ( Fig. 2C ) 1.67 times as long as coxite, slightly divergent and moderately tapered from base toward apical 2/5, then convergent and very slightly widened to round apex, and with apical spine; style in ventrolateral view ( Fig. 2D ) with outer margin nearly straight and inner margin sinuous, somewhat produced outward at basal 1/3 and slightly so at apical 1/4; style in medial view ( Fig. 2E ) gently curved dorsally, with short basal protuberance furnished with 8–10 distinct cone-like spines. Ventral plate in ventral view ( Fig. 2C ) with body quadrate, though very slightly narrowed posteriorly, with anterior and posterior margins nearly straight, and basal arms of moderate length, directed forward and slightly divergent; ventral plate in lateral view ( Fig. 2F ) with ventrally produced hairy process; ventral plate in end view ( Fig. 2G ) rounded ventrally, with lateral margins weakly toothed on basal 2/3, and moderately covered with microsetae on posterior surface except lateral areas of basal 2/3 widely bare. Median sclerite ( Fig. 2H ) gradually widened from base to apex, plate-like, and well sclerotized basally; base of median sclerite located apart from anterior margin of ventral plate ( Fig. 2C, F ). Paramere wide basally, with several distinct long and stout hooks. Aedeagal membrane moderately setose; dorsal plate well defined in form of horizontal bar. Abdominal segment 10 with 3 or 4 hairs on each posterolateral surface. Cercus small, rounded, with 8 or 9 hairs.

Pupa. Body length 2.2 mm. Head. Integument ochreous to yellowish-brown, moderately or sparsely covered with small round tubercles on frons ( Fig. 3A ) but almost bare on ventral surface and sparsely covered with smaller tubercles on both lateral surfaces; antennal sheath without tubercles; frons with 2 pairs of simple medium-long trichomes with uncoiled apices ( Fig. 3B ) (on left side of 1 pupal exuviae, 2 frontal trichomes are short and 1 of them bifid –– Fig. 3C ); face with pair of simple medium-long trichomes with uncoiled apices ( Fig. 3D ), nearly as long as or longer than frontal trichomes. Thorax. Integument ochreous to yellowish-brown, moderately covered with round tubercles on anterior 2/5 of dorsal and dorsolateral surfaces but rather sparsely covered with smaller round and cone-shaped tubercles on posterior 3/5 of dorsal surface, with 1 simple medium-long trichome with uncoiled apex anterodorsally ( Fig. 3E ), 1 similar trichome mediodorsally, 2 simple trichomes with uncoiled apices (1 medium-long and 1 short) anterolaterally ( Fig. 3F ), 1 simple or bifid short trichome with uncoiled apex posterolaterally ( Fig. 3G ), and 3 simple trichomes with uncoiled apices (2 medium-long and 1 short; or 1 medium-long and 2 short) ventrolaterally ( Fig. 3H ) on each side. Gill ( Fig. 3I ) composed of 6 slender thread-like filaments, arranged in 2+2+2 filaments from dorsal to ventral, with very short common basal stalk having transparent organ ventrally; common basal stalk hidden below produced cuticle of thoracic integument when gill is viewed dorsally; all pairs with very short or short stalk; dorsal and ventral filaments lying at angle of 90 degrees or little more when their basal portions are viewed laterally; all filaments ochreous or light brown, gradually tapered toward apex, subequal in length (0.8–1.0 mm long including their own stalks and basal common stalk) but differing in relative thickness, i.e., relative thickness of 6 filaments from dorsal to ventral 1.00:0.82:0.97:0.80:0.89:0.69; cuticle of all filaments with annular ridges and furrows though becoming less marked apically, and densely covered with minute tubercles. Abdomen. Dorsally, segments 1 and 2 not pigmented and without tubercles; segment 1 with 1 simple slender short hair-like seta on each side; segment 2 with 1 simple slender short hair-like seta and 5 very short somewhat spinous setae submedially on each side; segments 3 and 4 each with 4 hooked spines and 1 very short somewhat spinous seta on each side; segments 5 and 6 lacking spine-combs; segments 7–9 each with spine-combs in transverse row (though those on segments 7 and 9 slightly smaller than those on segment 8) and comb-like groups of minute spines on each side; segment 9 with pair of small round terminal hooks ( Fig. 3J ). Ventrally, segment 4 with 1 simple hook and few simple slender very short setae on each side; segment 5 with pair of bifid hooks submedially and few very short simple slender 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 very short simple slender setae on each side; segments 4–8 with comb-like groups of minute spines. Each side of segment 9 without grapnel-shaped hooklets. Cocoon. Wallpocket-shaped, thinly woven, not extended ventrolaterally; anterior margin somewhat thickly woven, posterior 1/2 with floor roughly or moderately woven; individual threads slightly visible; 2.2–2.9 mm long by 1.0– 1.2 mm wide.

Mature larva. Body length 3.9–4.2 mm. Thorax and abdomen blackish-brown except each intersegmental area from thoracic segment 3 to abdominal segment 5 whitish in dorsal view, and whitish in ventral view except blackishbrown transverse band connected to that on dorsal surface of thoracic segment 1, large blackish spot on each of thoracic segments 2 and 3, blackish-brown transverse band connected to that on dorsal surface on each of abdominal segments 1–4, blackish-brown transverse band on each of abdominal segments 6 and 7and light blackish-brown mediolongitudinal line from abdominal segment 1 to abdominal segment 6. Cephalic apotome whitish-yellow to yellowish-brown, with medial area along posterior margin somewhat darkened; head spots faintly positive except posterolateral spots often indistinct and anterior or posterior spot of mediolongitudinal spots sometimes indistinct. Lateral surface of head capsule yellow or somewhat dark yellow except eye-spot region whitish; eyebrow distinctly defined; spots below and posterior to eye-spot region indistinct. Ventral surface of head capsule ( Fig. 3K ) medium to dark yellow except wide area along each lateral margin of postgenal cleft yellowish-brown to light brown; transverse spot on each side of postgenal cleft indistinct or negative; basal area on each side of postgenal cleft dark brown as usual. Cervical sclerite composed of 4 slender pieces (anterior piece dark brown and long, posterior one light brown and short, on each side), not fused to occiput, moderately separated medially from each other. Antenna composed of 3 segments and apical sensillum, much longer than stem of labral fan; proportional lengths of 1 st, 2 nd, and 3 rd segments 1.00:1.10–1.19:0.78–0.87. Labral fan with 40–42 main rays. Mandible with mandibular serrations composed of 2 teeth; major and longer tooth at obtuse angle to mandible on apical side; comb-teeth decreasing in length from 1 st tooth to 3 rd one. Hypostoma ( Fig. 3L ) with 9 anterior teeth (though 1 tiny tooth is present on outer side of corner tooth on each side in 1 larva, as shown in Fig. 3L ); median tooth and each corner tooth prominent, nearly subequal in length to each other, followed by outer and inner teeth of 3 intermediate teeth, and middle tooth of 3 intermediate teeth shortest of all; lateral margins moderately serrate subapically; 4–6 hypostomal bristles divergent posteriorly from lateral border on each side. Postgenal cleft ( Fig. 3K ) arrow-head shaped, deep (5.80–6.25 times as long as postgenal bridge), relatively wide (greatest width in middle 0.91 times as long as postgenal cleft and 0.36–0.40 times as wide as head capsule), very slightly widened from base to middle, with somewhat pointed or rounded apex. Thoracic cuticle almost bare. Abdominal cuticle almost bare except each side of anal sclerite and each lateral bulge moderately covered with short colorless setae. Rectal scales appearing to be absent. Rectal organ compound, each lobe with 7 or 8 finger-like secondary lobules. Anal sclerite X-shaped, with broadened anterior arms 0.7 times as long as posterior ones, with wide thinly-sclerotized extension between anterior arms; basal juncture area without unscleotized median incision opening posteriorly; 4–8 sensilla posterior to posterior arms. Last abdominal segment on each side with large bulge laterally and small one ventrolaterally, appearing to be small ventral papillae when viewed laterally. Posterior circlet with 70–82 rows of hooklets with up to 16 hooklets per row.

Biological notes. — The pupae and larvae of this new species were collected from stalks and leaves of grasses trailing in the water. Associated species were S. (S.) tiomanense , new species, and S. (G.) sp.

Etymology. — The species name jasmoni is in honour of Tan Sri Prof. Dr. Ghauth Jasmon, Vice Chancellor, University of Malaya, who kindly invited HT to University of Malaya for studies of black flies in Malaysia.

Remarks. — Simulium (S.) jasmoni , new species, is characterised by the female tarsal claw with a minute subbasal projection ( Fig. 1B ), which departs from the original definition (i.e., the tarsal claw is simple) of the tuberosum species-group of the subgenus Simulium by Rubtsov (1956). However, this new species is assigned to the tuberosum species-group because it agrees with the diagnostic characteristics such as the bare basal portion of the radial vein in both female and male, the unpatterned scutum in the female, the scutum with shiny pruinose pattern, the style with a short basal protuberance bearing spines, and the ventral plate quadrate when viewed ventrally and with toothed posterolateral margins in the male, and the gill with six slender filaments and the simple cocoon in the pupa, as defined by Rubtsov (1956).

This new species is very similar in the adults to S. (S.) tani originally described from Peninsular Malaysia (Takaoka & Davies, 1995), recorded from Thailand (Takaoka & Saito, 1996), Sumatra ( Takaoka et al., 2000), China and Vietnam (Adler & Crosskey, 2011), and S. (S.) rangjungense Takaoka & Somboon, 2008 described from Bhutan (Takaoka & Somboon, 2008) in many morphological characteristics including the elongate female sensory vesicle ( Fig. 1A ), the female tarsal claws each with a minute subbasal projection ( Fig. 1B ), and the numbers of the vertical columns (16) and horizontal rows (17) of enlarged male upper-eye facets, but differs in the pupa from the latter two known species by having the medium-long mediodorsal trichome on the thoracic integument (similar to anterodorsal trichome –– Fig. 3E ) and the gill filaments divergent at an angle of 90 degrees or slightly more ( Fig. 3I ) (the mediodorsal trichomes in S. (S.) tani and S. (S.) rangjungense are short and very short, respectively, and the gill filaments are moderately divergent at an angle of 45–60 degrees in both known species).

The female of this new species is also similar to that of S. (S.) keningauense from Sarawak and Sabah ( Takaoka, 2008b) in sharing the tarsal claw with a minute subbasal projection but is distinguished from the latter species by the elongate sensory vesicle (the sensory vesicle is 0.42–0.48 times as long as the third maxillary palpal segment in S. (S.) keningauense ). The pupa of S. (S.) jasmoni , new species, is easily distinguished from that of S. (S.) keningauense by the round tubercles on the thoracic integument (most tubercles are cone-shaped and with pointed apices in S. (S.) keningauense ).

Figures

Fig. 1. Female of Simulium (Simulium) jasmoni, new species. A, 3rd segment of left maxillary palp showing elongate sensory vesicle (front view); B, tarsal claw with a minute subbasal projection (lateral view); C, 8th sternite and ovipositor valves (ventral view); D, genital fork (ventral view); E, F, paraprocts and cerci (right side; E, ventral view; F, lateral view); G, spermatheca. Scale bars = 0.02 mm for A, C–G; 0.01 mm for B.

Fig. 2. Male of Simulium (Simulium) jasmoni, new species. A, 3rd segment of left maxillary palp showing small sensory vesicle (frontal view); B, basitarsus and 2nd tarsomere of left hind leg showing calcipala and pedisulcus (outer view); C, coxites, styles, ventral plate and median sclerite (ventral view); D, E, styles (D ventrolateral view; E, medial view); F, ventral plate and median sclerite (lateral view); G, ventral plate (end view); H, median sclerite (ventroposterior view). Scale bars = 0.1 mm for B; 0.02 mm for A, C–H.

Fig. 3. Pupa and larva of Simulium (Simulium) jasmoni, new species.A–J pupa; K, L larva.A, tubercles on frons; B, and C, frontal trichomes (B, simple medium-long; C, simple short and bifid short); D, facial trichome; E–H, thoracic trichomes (E, anterodorsal; F, anterolateral; G, posterolateral (simple and bifid); H, ventrolateral); I, right gill filaments (outer view); J, spine-combs, groups of minute spines and terminal hooks on 9th abdominal segment (dorsal view); K, head capsule showing mitre-shaped postgenal cleft (ventral view); L, hypostoma (ventral view). Scale bars = 0.1 mm for I, K; 0.04 mm for J; 0.02 mm for A–H, L.