Simulium multistriatum
Creators: name: Takaoka, Hiroyuki
name: Sofian-Azirun, Mohd
name: Ya'Cob, Zubaidah
name: Chen, Chee Dhang
name: Lau, Koon Weng
name: Low, Van Lun
name: Pham, Xuan Da
name: Adler, Peter H.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Simuliidae
Simulium
Simulium multistriatum

description: 4) Simulium multistriatum species-group
Simulium (Simulium) daoense Takaoka & Adler sp. nov.
Female. Body length 3.0– 3.2 mm. Head. Narrower than thorax. Frons black, shiny, with several dark, long, stout hairs along each lateral margin and four or five similar hairs just above lower margin; frontal ratio 1.3– 1.7:1.00:1.5–1.7; frons:head ratio 1.0:4.5–4.6. Fronto-ocular area well developed, short, directed laterally and slightly upward. Clypeus black, white pruinose, slightly shiny when illuminated at certain angles, moderately covered with dark-brown long stout hairs except small area near upper margin or mediolongitudinal area of upper half somewhat widely bare. Labrum 0.8 times as long as clypeus. Antenna composed of scape, pedicel and nine flagellomeres, medium to dark brown except scape, pedicel, base of first flagellomere yellow when viewed dorsally, and scape, pedicel, flagellomeres 1 and 2 yellow when viewed ventrally. Maxillary palp with five segments, proportional lengths of third, fourth, and fifth segments 1.0:1.0:2.1–2.3; third segment (Fig. 48 A) of normal size; sensory vesicle (Fig. 48 A) of moderate size (0.4 times length of third segment) having opening of moderate size near apex. Maxillary lacinia with 13 inner and 14 or 15 outer teeth. Mandible with 24–26 inner and 12–14 outer teeth. Cibarium (Fig. 48 B) with blunt medial projection on posterior margin and without minute processes near base of medial projection. Thorax. Scutum black, shiny when illuminated at certain angles, densely covered with golden-yellow recumbent short hairs interspersed with several dark-brown long upright hairs on prescutellar area; when illuminated in front and viewed dorsally, scutum white pruinose with five longitudinal nonpruinose vittae (one narrow medial vitta, two wider submedial vittae and two wider sublateral vittae though sublateral vittae somewhat wider than submedial ones), all vittae united with broad transverse band on prescutellar area; when illuminated from behind, scutum having reversed color pattern. Scutellum dark brown, covered with dark-brown upright long hairs and golden-yellow short hairs. Postnotum black, white pruinose when illuminated at certain angles and bare. Pleural membrane bare. Katepisternum longer than deep, black, shiny and white pruinose when illuminated at certain angles and bare. Legs. Foreleg: coxa whitish yellow; trochanter yellow; femur yellow except apical cap medium brown on inner surface, and dark yellow except basal one-fifth yellow and apical cap medium brown on outer surface (in one female, femur light brown except base yellow and apical cap medium brown); tibia yellowish white except base yellow and apical cap brownish black, with shiny sheen widely on outer surface when illuminated at certain angles; tarsus black, with moderate dorsal hair crest; basitarsus greatly dilated, 5.5–5.9 times as long as its greatest width. Midleg: coxa brownish black; trochanter dark yellow with base yellowish white; femur dark yellow with base yellow and apical cap medium brown (in one female, femur light brown except basal half or little less yellow and apical cap medium brown, and in another female, femur light brown with apical cap medium brown); tibia white to yellowish white except apical cap medium brown, and with shiny sheen on posterior surface when illuminated at certain angles; tarsus dark brown except basal half to twothirds yellowish white. Hind leg: coxa dark brown; trochanter whitish yellow; femur dark yellow with base yellow and apical cap medium brown (in one female, femur medium brown except basal half yellow and apical cap dark brown, and in another female, femur light brown except basal one-sixth yellow and apical cap medium brown); tibia white to whitish yellow except apical cap dark brown, and with shiny sheen on posterior surface when illuminated at certain angles; tarsus grayish black except basal two-thirds or little less of basitarsus and basal half of second tarsomere yellowish white; basitarsus (Fig. 48 C) nearly parallel-sided, 5.7–6.5 times as long as wide, and 0.5–0.7 and 0.6 times as wide as greatest widths of hind tibia and femur, respectively; calcipala (Fig. 48 C) moderately developed, slightly shorter than basal width, and 0.4 times as wide as basitarsus; pedisulcus (Fig. 48 C) well developed; all tarsal claws simple. Wing. Length 2.8–3.0 mm. Costa with dark spinules and hairs; subcosta haired except near apex bare; basal section of radius bare; R1 with dark spinules and hairs; R2 with hairs; hair tuft on base of radius dark brown; basal cell absent. Halter. White with basal portion darkened. Abdomen. Basal scale medium brown, with fringe of dark-brown long hairs. Dorsal surface of abdomen medium to brownish black except basal half to two-thirds of segment 2 yellowish, with short dark hairs; tergite 2 shiny, white iridescent when illuminated at certain angles, and tergites 6–8 shiny; ventral surface of segment 2 whitish and those of other segments light brown; segment 7 with median large sternal plate. Terminalia. Sternite 8 (Fig. 48 D) bare medially, with 25–35 dark medium-long to long stout hairs on each lateral surface. Ovipositor valves (Fig. 48 D) rounded posteomedially, membranous, each moderately covered with microsetae and four or five short to medium-long hairs, except portion along inner margin narrowly bare; inner margins divergent posteriorly, and so thin and transparent that they may be overlooked. Genital fork (Fig. 48 E) of inverted-Y form, with narrow well-sclerotized stem; arms of moderate width, each with distinct short and wide projection having rounded apex directed anterodorsally. Paraproct in ventral view (Fig. 48 F) nearly quadrate, densely covered with minute setae and with 32–36 short to medium-long hairs on lateral and ventral surfaces except anterolateral corner widely bare; anteromedial surface with six short sensilla; paraproct in lateral view (Fig. 48 G) much protruded ventrally beyond ventral margin of cercus, 0.7 times as long as wide. Cercus in lateral view (Fig. 48 G) short, rounded posteriorly, 0.5 times as long as wide, and with numerous short to medium-long hairs. Spermatheca (Fig. 48 H) large, nearly ovoid, 1.2 times as long as wide, well sclerotized except portion of juncture with duct unsclerotized, with no defined surface patterns, and with internal setae; accessory ducts subequal in thickness to each other, and to major duct.
Male. Body length 3.6 mm. Head. Slightly wider than thorax. Upper eye medium brown, with large facets in 18 vertical columns and in 18 or 19 horizontal rows. Clypeus black, thickly white pruinose, sparsely or moderately covered with dark-brown hairs. Antenna composed of scape, pedicel and nine flagellomeres, dark brown except scape and pedicel dark yellow to light brown, and base of first flagellomere yellow; first flagellomere elongate, 1.8–2.0 times as long as second one. Maxillary palp grayish to dark brown, composed of five segments with proportional lengths of third, fourth, and fifth segments 1.0:1.3:2.4; third segment (Fig. 49 A) of moderate size, with apex somewhat produced inward; sensory vesicle (Fig. 49 A) of moderate size (0.3–0.4 times length of third segment), ellipsoidal, and with opening of moderate size. Thorax. Scutum black, with white pruinose pattern, i.e., anterior pair of rectangular spots on shoulders extended posteriorly along lateral margins and connected to large transverse spot entirely covering prescutellar area; these pruinose areas shiny and iridescent when illuminated at certain angles; scutum uniformly and densely covered with golden-yellow recumbent short hairs interspersed with dark-brown long upright hairs on prescutellar area. Scutellum brownish black, with several dark long upright hairs and golden-yellow short hairs. Postnotum black, white pruinose when illuminated at certain angles and bare. Pleural membrane bare. Katepisternum longer than deep, brownish black to black, shiny and white pruinose when illuminated at certain angles, and bare. Legs. Foreleg: coxa whitish yellow; trochanter medium brown except base yellowish; femur dark yellow with apical cap dark brown; tibia brownish black except middle one-third light brown, though outer surface widely white except basal tip and apical cap, and with white sheen when illuminated at certain angles; tarsus brownish black, with moderate dorsal hair crest; basitarsus moderately dilated, 6.0–7.6 times as long as its greatest width. Midleg: coxa brownish black; trochanter dark brown though extreme base yellow; femur light brown except apical cap medium brown; tibia whitish yellow to yellow except apical cap medium brown, and with white sheen widely on posterior surface; tarsus dark brown to brownish black except basal onethird to half of basitarsus yellowish. Hind leg: coxa brownish black; trochanter yellow; femur medium brown except basal one-third yellow and apical cap brownish black; tibia dark brown to brownish black except basal tip yellow; tarsus (Fig. 49 B) medium to dark brown except basal half or little less of basitarsus whitish yellow (though base somewhat darkened) and basal one-third of second tarsomere whitish yellow; basitarsus (Fig. 49 B) much enlarged, spindle-shaped, gradually widened from base to apical one-third, then tapered to apex, 3.4–4.1 times as long as its greatest width, and 0.8–1.0 and 1.1 times as wide as greatest widths of hind tibia and femur, respectively; calcipala (Fig. 49 B) small, 0.8 times as long as width at base, 0.3 times as wide as greatest width of basitarsus; pedisulcus (Fig. 49 B) well developed. Wing. Length 3.0 mm. Other characters as in female except subcosta haired on basal three-fifths. Halter. White with basal portion darkened. Abdomen. Basal scale dark brown to brownish black, with fringe of dark long hairs. Dorsal surface of abdomen medium brown to brownish black, and covered with dark short hairs; segments 2 and 5–7 each with pair of silvery or bluish iridescent spots dorsolaterally, those on segment 2 broadly connected in middle to each other. Genitalia. Coxites, styles and ventral plate in ventral view as in Fig. 49 C. Coxite in ventrolateral view (Fig. 49 D) nearly quadrate, 0.9 times as long as width. Style in medial view (Fig. 49 E) spatulate dorsoventrally, 1.5 times as long as coxite, with long horn-like basal protuberance having pointed apex in form of stout spine; style in ventrolateral view (Fig. 49 F) elongate, 3.2 times as long as its greatest width at base, slightly tapered to middle, then slightly widened to apical one-fourth, and nearly parallel-sided toward apex; Ventral plate in ventral view (Fig. 49 C) with body nearly rectangular (though somewhat narrowed basally, and rounded on each posterolateral corner), covered with many minute setae on anterior and anterolateral surfaces of central portion, and several ridges on posterior surface; arms directed forward and divergent from each other; ventral plate in lateral view (Fig. 49 G) having ventromedial process somewhat curved posteroventrally and with bare round apex, and with serrated posterior margin, and moderately covered with microsetae on anterolateral surfaces; ventral plate in caudal view (Fig. 49 H) nearly triangular, with several ridges on posterior surface, having ventromedial process nearly parallel-sided. Median sclerite (Fig. 49 G, I) arising near anterior margin of ventral plate and directed dorsally, plate-like, widened from base toward apex, with round apex, brown basally, but not so well sclerotized apically. Paramere (Fig. 49 J) with several distinct hooks. Aedeagal membrane (Fig. 49 K) moderately covered with minute setae, and with weakly sclerotized dorsal plate in form of horizontal bar (Fig. 49 L). Abdominal segment 10 (Fig. 49 M, N) without distinct hair on ventral and lateral surfaces. Cercus (Fig. 49 M, N) small, rounded, with 11 or 12 distinct hairs.
Pupa. Body length 3.4–3.6 mm. Head. Integument ochreous, densely and elaborately covered with small round tubercles; antennal sheath bare except basal portion covered with small tubercles; frons with two unbranched slender short trichomes (Fig. 50 A) on each side; face with unbranched slender short trichome (Fig. 50 B) on each side. Thorax. Integument dark yellow to ochreous, densely and elaborately covered with small round tubercles; thorax with three long anterodorsal trichomes (all unbranched, or two unbranched and one bifid or quadrifid, or one unbranched and two bifid or trifid, or two bifid and one trifid) (Fig. 50 C), two anterolateral trichomes (anterior trichome unbranched, medium-long, and posterior trichome unbranched or rarely bifid, long) (Fig. 50 D), one unbranched medium-long mediolateral trichome (Fig. 50 E), and three unbranched ventrolateral trichomes (one short, slender, and two others long, stout) (Fig. 50 F), on each side. Gill (Fig. 50 G) with eight slender thread-like short filaments in four pairs (though two middle pairs sharing short stalk) arising from short common basal stalk; all pairs short-stalked; gill filaments divergent basally, upper filament of dorsal pair forming an angle of 90 degrees or little more against lower filament of ventral pair when viewed laterally; filaments slightly shortened from dorsal to ventral, with upper filament of dorsal pair longest (about 2.0 mm long), and lower filament of ventral pair shortest (about 1.1 mm long); relative thickness of eight filaments from dorsal to ventral when basal portions were compared 1.0:0.8–0.9:0.8:0.6–0.7:0.7–0.9:0.6–0.7:0.6:0.6; all filaments light to medium brown, tapered toward apex (though nearly parallel-sided or slightly widened from base for short distance except upper filament of middle inner pair), with distinct annular ridges and furrows forming definite reticulate surface patterns, and densely covered with minute tubercles. Abdomen. Dorsally, segment 1 light brown and sparsely covered with minute tubercles, and often segments 2–4 each light brown narrowly along anterior margin, other segments unpigmented except basal portions of spine-combs on segment 8 yellow; segment 1 with one unbranched slender short seta (Fig. 50 H) on each side; segment 2 with one unbranched slender short seta and five unbranched short setae, of which four are stout (one is often bifid) (Fig. 50 I), on each side; segments 3 and 4 each with four distinct hooked spines and one unbranched short seta on each side; segment 8 with distinct spine-combs in transverse row on each side; segments 5, 6, 7 and 9 lacking spine-combs; segments 6–9 each with comb-like groups of minute spines on each side; segment 9 without terminal hooks. Ventrally, segments 3–9 unpigmented, each (except segment 9) with comb-like groups of minute spines; segment 4 with few unbranched slender minute setae on each side; segment 5 with pair of bifid stout hooks submedially and few unbranched short setae on each side; segments 6 and 7 each with pair of bifid inner and unbranched or bifid outer stout hooks somewhat separated from each other, and few unbranched short setae on each side. Grapnel-shaped hooklets absent on each side of segment 9. Cocoon (Fig. 50 J, K). Wall-pocket-shaped, tightly and thickly woven, ochreous, with large anterolateral window on each side, and not extended ventrolaterally; individual threads invisible; 4.3–4.9 mm long by 1.8–2.2 mm wide.
Mature larva. Body length 6.0– 6.2 mm. Body light brown except thorax dark gray to grayish black. Head. In one larva, cephalic apotome (Fig. 51 A) yellowish white on anterior two-fifths and yellow on posterior three-fifths, with darkened narrow area along posterior margin; head spots faintly positive though posterior spot of posterolateral spots on each side obscured; lateral surface of head capsule yellow except eye-spot region yellowish white and eyebrow darkened and area between eye-spot and posterior margin somewhat darkened; spots in front of posterior margin obscured or faintly negative except one small spot faintly positive; one small spot below eye-spot region faintly positive; ventral surface of head capsule (Fig. 51 B) yellow except submedian areas somewhat darkened longitudinally; spots on each side of postgenal cleft faintly positive; in another larva, cephalic apotome yellowish white on anterior half or little more, and light brown on rest with darkened narrow area along posterior margin; head spots obscured though anterior spot of mediolongitudinal spots and both mediolateral spots faintly positive; lateral surface of head capsule light brown except eye-spot region yellowish white and area between eyespot region and posterior margin somewhat darkened; spots in front of posterior margin obscured, and one small spot below eye-spot region moderately positive; ventral surface of head capsule light brown except postgenal bridge yellow; spots on each side of postgenal cleft obscured. Head capsule sparsely covered with minute setae on dorsal, lateral and ventral surfaces. Antenna composed of three articles and apical sensillum, slightly longer than stem of labral fan; length ratio of three articles (from base to tip) 1.0:1.3–1.4:0.7. Labral fan with 42 primary rays. Mandible (Fig. 51 C) with serration composed of two teeth (one medium-sized, one small); main tooth at obtuse angle against mandible on apical side; supernumerary serrations absent; comb-teeth decreasing in length from first to third. Hypostoma (Fig. 51 D) with nine anterior teeth, of which median and corner teeth subequal in length to each other; three intermediate teeth on each side shortest; lateral margins moderately serrate apically; five or six hypostomal bristles per side divergent posteriorly from lateral margin. Postgenal cleft (Fig. 51 B) large, rounded, 3.2 times as long as postgenal bridge; sheath of subesophageal ganglion weakly pigmented, forming indefinite patterns. Cervical sclerites on each side composed of one medium-brown elliptical piece, not fused to occiput. Thorax and Abdomen. Histoblast of pharate pupal gill with eight short filaments. Thoracic and abdominal cuticle moderately covered with minute colorless setae interspersed with short similar setae, which are much longer than minute setae (Fig. 51 E), dorsally and dosolaterally; last segment of abdomen moderately covered with short colorless setae on each side of anal sclerite. Rectal scales present. Rectal organ compound, each lobe with 17–22 finger-like secondary lobules. Anal sclerite X-shaped, with short broad anterior arms with forked apices, 0.7 times as long as posterior ones and junction with deep unsclerotized incision posteriorly; 10–15 sensilla on base of anal sclerite; nine sensilla posterior to posterior arms. Last abdominal segment lacking ventral papillae. Posterior circlet with 88–93 rows of hooklets with up to 16–18 hooklets per row.
Type material. HOLOTYPE: Female (with its associated pupal exuviae and cocoon) in 80% ethanol, labeled in a vial as [UMSRP: Vietnam 0 38, Holotype, Simulium (S.) daoense, Female, coll. Vietnam, 22-XII-2014, Takaoka et al.], reared from a pupa collected from a small shallow stream (width 0.5 m, bottom of pebbles, water temperature 7.0˚C, partially shaded, elevation 1,315 m, 22˚23’03.208”N/103˚50’58.990”E) moderately flowing from a forest, Sapa, northern Vietnam, 22-XII-2014, by H. Takaoka, M. Sofian-Azirun, Z. Ya’cob, C.D. Chen & K.W. Lau. PARATYPES: Eight females, two males (all reared from pupae), two pupae, one pupal exuviae and two mature larvae, in 80% ethanol, same data as those of the holotype, labeled in each vial as [UMSRP: Vietnam 0 38, Holotype, Simulium (S.) daoense, coll. Vietnam, 22-XII-2014, Takaoka et al.].
Biological notes. The pupae and larvae of S. (S.) daoense sp. nov. were collected from grass leaves and roots trailing in the current. Associated species were S. (G.) hongthaii, S. (S.) sapaense sp. nov. and S. (S.) phuluense sp. nov.
Distribution. Vietnam (Lao Cai).
Etymology. The species name daoense refers to the land in which the Dao tribe lives.
Remarks. Simulium (S.) daoense sp. nov. is assigned to the S. multistriatum species-group of the subgenus Simulium, redefined by Takaoka and Davies (1996), based on the female scutum with five longitudinal vittae, female ovipositor valves thin and unpigmented along inner margins (Fig. 48 D), male style with elongate basal protuberance (Fig. 49 E), pupal gill with eight filaments (Fig. 50 G), and cocoon with an anterolateral window on each side (Fig. 50 J, K).
This new species is characterized by the bare basal portion of the radial vein of the female wing, ellipsoidal male sensory vesicle (Fig. 49 A), unbranched mediolateral and ventrolateral trichomes of the pupal thorax (Fig. 50 E, F), pupal gill filaments divergent at an angle of about 90 degrees when viewed laterally (Fig. 50 G), and cocoon with an enlarged window on each side (Fig. 50 J, K).
This new species is similar in the arrangement of the pupal gill filaments to the following species but is distinguished from them by the following characters (those of other species in parentheses); from S. (S.) xialongtanense Chen, Luo & Yang described from Hubei, China (Chen et al. 2006) by the male upper-eye facets in 18 vertical columns and in 18 or 19 horizontal rows (in 12 vertical columns and 12 horizontal rows), male style with a basal protuberance without minute spines (Fig. 49 E) (with spines), and spine-combs on pupal abdominal segment 8 (spine-combs on pupal abdominal segments 7 and 8); from S. (S.) bifengxiaense Huang, Zhang & Chen described from Sichuan, China (Huang et al. 2013) by the female cibarium without tubercles (Fig. 48 B) (with about 15 tubercles) and male ventral plate with its posterior margin nearly straight when viewed ventrally (Fig. 49 C) (posterior margin round); from S. (S.) chongquingense Zhu & Wang from Chong Quing, China (Zhu and Wang 1995) by yellow hairs on the male scutum (dark hairs); from S. (S.) uncum Zhang & Chen from Guizhou, China (Zhang and Chen 2001) by the male upper-eye facets in 18 vertical columns and in 18 or 19 horizontal rows (in 16 vertical columns and 13 horizontal rows); from S. (S.) chainarongi Kuvangkadilok & Takaoka from Thailand (Takaoka and Kuvangkadilok 1999) by the male ventral plate with its posterior margin nearly straight when viewed ventrally (Fig. 49 C) (posterior margin round) and wall-pocket-shaped cocoon (Fig. 50 J, K) (shoeshaped cocoon); from S. (S.) demolaense Takaoka & Somboon from Bhutan (Takaoka and Somboon 2008) by the ellipsoidal male sensory vesicle (Fig. 49 A) (globular), male hind basitarsus with its greatest width at apical onethird (Fig. 49 B) (greatest width at the middle) and ventral plate covered with many minute setae (Fig. 49 C) (a few setae); from S. (S.) hirtinervis Edwards from Peninsular Malaysia (Takaoka and Davies 1995) by the bare basal portion of the female radial vein (haired); from S. (S.) malayense Takaoka and Davies from Peninsular Malaysia (Takaoka and Davies 1995) by the pupal head densely covered with tubercles (bare) and cocoon with a large anterolateral window on each side (Fig. 50 J, K) (without such a window); and from S. (S.) sakishimaense Takaoka from the Ryukyu Islands, Japan (Takaoka 1977) by the male upper-eye facets in 18 or 19 horizontal rows (in 15 horizontal rows) and spine-combs on pupal abdominal segment 8 (spine-combs on pupal abdominal segments 7 and 8).
Four related Indian species, S. (S.) barraudi Puri, S. (S.) dentatum Puri, S. (S.) digitatum Puri, and S. (S.) novolineatum Puri (Puri 1932b, 1933a), differ from this new species by the shape and hairlessness of the male ventral plates.
The remaining species of the S. multistriatum species-group have the pupal gill filaments much diverged at an angle of about 120 degrees when viewed laterally, or shoe-shaped cocoons, or enlarged basal fenestra at the base of the pupal gill, all differing from those of this new species.
description: Published as part of Takaoka, Hiroyuki, Sofian-Azirun, Mohd, Ya'Cob, Zubaidah, Chen, Chee Dhang, Lau, Koon Weng, Low, Van Lun, Pham, Xuan Da & Adler, Peter H., 2017, The black flies (Diptera: Simuliidae) of Vietnam, pp. 1-165 in Zootaxa 4261 (1) on pages 108-116, DOI: 10.5281/zenodo.571608