Simulium (Simulium) huense Takaoka

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, Zootaxa 4261 (1), pp. 1-165 : 139-147

Simulium (Simulium) huense Takaoka & Ya’cob (Substitute name)

Simulium (Simulium) cavum Takaoka & Ya’cob (in Takaoka et al., 2015a) (preoccupied name): 74–79 (Male, pupa and larva).

The substitute name huense is here given for the species which was described as Simulium (Simulium) cavum Takaoka & Ya’cob, 2015 from central Vietnam ( Takaoka et al. 2015a). The name cavum is preoccupied by an African species Simulium (Metomphalus) cavum Gibbins, 1938 ( Adler and Crosskey 2016) . Thus, cavum Takaoka & Ya’cob, 2015 is a junior primary homonym of cavum Gibbins, 1938 .

Distribution. Vietnam (Lam Dong).

Remark. This species was described from Lam Dong Province, southern Vietnam ( Takaoka et al. 2015a).

Simulium (Simulium) sapaense Takaoka & Low sp. nov.

Female. Body length 2.5 mm. Head. Slightly narrower than thorax. Frons black, shiny, with bluish reflection when illuminated at certain angles, with several dark stout hairs along lateral margins; frontal ratio 1.5:1.0:1.4; frons:head ratio 1.0:3.6. Fronto-ocular area well developed, short, directed laterally, and rounded apically. Clypeus black, shiny, with bluish reflection when illuminated at certain angles, moderately covered with dark-brown medium-long hairs though mediolongitudinal portion widely bare. Labrum 0.6 times length of clypeus. Antenna composed of scape, pedicel and nine flagellomeres, dark brown, except scape, pedicel and first flagellomere yellow when viewed ventrally, but dark brown except scape, basal half of pedicel and basal half of first flagellomere yellow when viewed dorsally. Maxillary palp with five segments, medium brown except third segment dark brown; proportional lengths of third, fourth, and fifth segments 1.0:1.1:2.4; third segment ( Fig. 62 A) of moderate size, with medium-sized ellipsoidal sensory vesicle (0.3 times length of third segment) having medium-sized opening. Maxillary lacinia with 15 or 16 inner and 18 outer teeth. Mandible with 25–27 inner and 12 outer teeth. Cibarium ( Fig. 62 B) with 70 minute processes, of which several are vestigial, near posterodorsal margin. Thorax. Scutum black, shiny with bluish reflection and white pruinose when illuminated at certain angles, moderately covered with dark short fine hairs interspersed with several dark-brown long upright hairs on prescutellar area. Scutellum dark brown, covered with dark-brown upright long and short hairs. Postnotum black, shiny and white pruinose when illuminated at certain angles, and bare. Pleural membrane bare. Katepisternum longer than deep, brownish black, shiny and white pruinose when illuminated at certain angles, and bare. Legs. Foreleg: coxa yellow; trochanter yellow except dorsal surface partially medium brown; femur medium brown with apical cap dark brown, though basal portion light brown on outer surface and widely yellowish on basal half on inner surface; tibia medium brown except apical cap dark brown, with median outer surface widely white and with bright white sheen when illuminated at certain angles; tarsus black, with moderate dorsal hair crest; basitarsus greatly dilated, 5.0 times as long as its greatest width. Midleg: coxa brownish black; trochanter medium brown except base yellow; femur dark brown except apical cap brownish black; tibia dark brown except base whitish yellow and apical cap brownish black, and with whitish sheen widely on posterior surface when illuminated at certain angles; tarsus light to medium brown except basal five-sixths of basitarsus and basal half of second tarsomere whitish yellow and fifth tarsomere brownish black. Hind leg: coxa medium brown; trochanter yellow; femur medium to dark brown except extreme base yellowish; tibia medium to dark brown except base whitish yellow, apical cap brownish black, and with whitish sheen widely on posterior surface when illuminated at certain angles; tarsus medium brown except basal two-thirds of basitarsus (though base medium brown) and basal half of second tarsomere whitish yellow; basitarsus ( Fig. 62 C) nearly parallel-sided, 6.2 times as long as wide, and 0.8 and 0.6 times as wide as greatest widths of hind tibia and femur, respectively; calcipala ( Fig. 62 C) moderately developed, nearly as long as wide, and 0.4 times as wide as greatest width of basitarsus; pedisulcus ( Fig. 62 C) well developed; claw simple, without tooth. Wing. Length 2.5 mm. Costa with dark spinules and hairs; subcosta haired except near apex bare; basal section of radius bare; R1 with dark-brown spinules and hairs; R2 with dark-brown hairs; hair tuft on base of radius dark brown; basal cell absent. Halter . White except base darkened. Abdomen. Basal scale dark brown, with fringe of yellow hairs. Dorsal surface of abdomen medium brown to brownish black, with dark short hairs; tergite 2 and 6–9 shiny and iridescent when illuminated at certain angles. Ventral surface medium brown to brownish black; segment 7 with large median sternal plate. Terminalia . Sternite 8 ( Fig. 62 D) well sclerotized and bare medially, covered with 12 or 13 long and medium-long stout hairs and few short fine hairs on each side. Ovipositor valve ( Fig. 62 D) nearly triangular, rounded posteromedially, membranous except inner margin weakly sclerotized, densely covered with microsetae together with 12 or 13 short fine hairs; inner margin nearly straight or slightly concave medially. Genital fork ( Fig. 62 E) 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. 62 F) pointed posteromedially, moderately concave anterolaterally, and with strongly sclerotized anteromedial surface; seven and four sensilla on anterodorsal concave portion and anteromedial surface, respectively; paraproct in lateral view ( Fig. 62 G) somewhat produced ventrally, 0.7 times as long as wide, covered with 16 or 17 short to medium-long hairs and numerous microsetae on lateral and ventral surfaces. Cercus in lateral view ( Fig. 62 G) short, rounded posteriorly, 0.3 times as long as its greatest width, and covered with medium-long and short hairs. Spermatheca ( Fig. 62 H) ovoidal, 1.3 times as long as wide, moderately sclerotized except duct and narrow area of juncture with duct unsclerotized, without discernible reticulate surface patterns; minute internal setae present; accessory ducts subequal in thickness to each other and slightly thicker than main duct.

Male. Body length 2.5–3.0 mm. Head. Slightly wider than thorax. Upper eye medium brown, with large facets in 17 or 18 vertical columns and in 19 or 20 horizontal rows. Clypeus black, thickly white pruinose, silvery or bluish, shiny when illuminated at certain angles, covered with dark-brown hairs along lateral margins and near ventral margin (medial portion widely bare). Antenna composed of scape, pedicel and nine flagellomeres, medium brown to brownish black except base of first flagellomere yellowish; first flagellomere elongate, 1.7 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 1.0:1.3:2.9; third segment ( Fig. 63 A) of moderate size; sensory vesicle ( Fig. 63 A) small, ellipsoidal (0.3 times as long as third segment), and with small opening. Thorax. Scutum black, with white pruinose pattern, i.e., anterior pair of crescent spots (though not sharply pointed posteriorly) on shoulders extended posteriorly along lateral margins but disconnected near base of wings to large transverse posterior spot entirely covering prescutellar area; these pruinose areas silvery or bluish iridescent when illuminated at certain angles; scutum uniformly and moderately covered with brassy recumbent short hairs interspersed with dark-brown long upright hairs on prescutellar area. Scutellum brownish black, with several dark-brown long upright hairs. Postnotum black, white pruinose when illuminated at certain angles and bare. Pleural membrane bare. Katepisternum longer than deep, black, white pruinose when illuminated at certain angles, and bare. Legs. Foreleg: coxa yellow; trochanter light brown except base yellow; femur light to medium brown with apical cap dark brown; tibia medium brown except median large portion widely white on outer surface, and with bright white sheen widely on outer surface when illuminated at certain angles; tarsus brownish black to black, with moderate dorsal hair crest; basitarsus greatly dilated, 5.2 times as long as its greatest width. Midleg: coxa brownish black; trochanter medium brown except base yellow; femur medium brown with apical cap dark brown; tibia medium brown except apical cap dark brown and extreme base whitish yellow; tibia with white sheen on posterior surface when illuminated at certain angles; tarsus medium brown except basal three-fourths of basitarsus and base of second tarsomere whitish yellow. Hind leg: coxa dark brown; trochanter dark yellow; femur dark brown except apical cap brownish black and extreme base light brown; tibia dark brown except apical cap brownish black and basal tip yellow; tarsus ( Fig. 63 B) medium brown except little less than basal half of basitarsus (though extreme base darkened) and little less than basal half of second tarsomere whitish yellow; basitarsus ( Fig. 63 B) much enlarged, gradually widened from base to apical one-fourth, then slightly narrowed to apex, 3.9 times as long as its greatest width, and 0.9–1.0 and 1.0 times as wide as greatest widths of hind tibia and femur, respectively; calcipala ( Fig. 63 B) small, slightly shorter than wide, 0.3 times as wide as greatest width of basitarsus; pedisulcus ( Fig. 63 B) well developed. Halter . White except basal portion darkened. Wing. Length 2.1–2.5 mm. Other characters as in female except subcosta bare. Abdomen. Basal scale brownish black, with fringe of dark long hairs. Dorsal surface of abdomen brownish black to black, with dark short hairs; segments 2, 6 and 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. 63 C. Coxite in ventrolateral view ( Fig. 63 D) 0.8 times as long as wide. Style in ventrolateral view ( Fig. 63 E) elongate, 3.0 times as long as its greatest width at basal one-third, nearly parallelsided from base to basal one-third, then tapered toward middle, and slightly tapered to apex; style in medial view ( Fig. 63 F) 1.7 times as long as coxite, much produced dorsally near base forming round protuberance having several small cone-like spines on its apex. Ventral plate in ventral view ( Fig. 63 C) well sclerotized, with body subquadrate (though slightly narrowed basally, and rounded on each posterolateral corner), 0.6 times as long as wide, posterior margin somewhat concave, and with round projection directed ventrally which is covered with many minute setae; arms divergent from each other; ventral plate in lateral view ( Fig. 63 G) with posterior margin weakly serrated along basal two-thirds; ventral plate in caudal view ( Fig. 63 H) rounded ventrally, with lateral margin serrated along basal two-thirds, with numerous setae on posterior surface except most of basal portion bare. Median sclerite in lateral view ( Fig. 63 G) arising just anterior to ventral plate, directed dorsally; median sclerite in caudal view ( Fig. 63 I) plate-like, gradually widened from base to middle, then nearly parallel-sided to apex, with round apex, brown basally, but not so well sclerotized apically. Paramere in caudal view ( Fig. 63 J) with several distinct hooks and several smaller ones. Aedeagal membrane moderately covered with minute setae, and with moderately sclerotized dorsal plate in form of horizontal bar ( Fig. 63 K). Abdominal segment 10 ( Fig. 63 L, M) with three to five hairs on ventral surface and three to five hairs on lateral surface on each side. Cercus ( Fig. 63 L, M) small, rounded, with five to seven distinct hairs.

Pupa. Body length 2.5–2.8 mm. Head. Integument dark brown except ventral surface light ochreous, moderately covered with relatively larger tubercles having minute secondary projections on frons ( Fig. 64 A), and relatively smaller tubercles on antennal sheaths and face; frons with two pairs of unbranched short slender trichomes, of which one is shorter than other ( Fig. 64 B), arising close together; face with pair of unbranched short trichomes ( Fig. 64 C). Thorax. Integument dark brown except wing sheaths ochreous, moderately covered with relatively larger tubercles (similar to those on frons though somewhat smaller) on anterior half, and relatively smaller tubercles on posterior half, and with pit-like organ near base of each gill ( Fig. 64 D); thorax with two anterodorsal trichomes of similar or different length ( Fig. 64 E), two anterolateral trichomes ( Fig. 64 F), one mediolateral trichome ( Fig. 64 G), and three ventrolateral trichomes ( Fig. 64 H), on each side; all trichomes short and unbranched. Gill ( Fig. 64 I) with six slender thread-like filaments in three pairs (one dorsal, one middle and one ventral) arising directly from thorax and lacking common basal stalk; dorsal and middle pairs short-stalked, and ventral pair sessile; lower filament of ventral pair directed downward and somewhat backward, then curved forward, other filaments directed forward and downward, then curved forward and directed forward or somewhat upward to various extent; two filaments of dorsal pair and inner filament of middle pair subequal in length to one another (2.0 mm long), outer filament of middle pair and outer or upper filament of ventral pair subequal in length to each other (1.9 mm long) and lower filament of ventral pair shortest (1.5 mm long); relative thickness of six filaments from dorsal to ventral when compared basally 1.0:0.9:0.7:0.9:0.7:0.7; upper filament of dorsal pair gradually tapered from base toward apex, other filaments nearly subequal in thickness from base to one-half or more, then slightly tapered toward apex; all filaments dark brown, with distinct annular ridges and furrows forming definite reticulate surface patterns, and densely covered with minute tubercles. Abdomen. Dorsally, all segments unpigmented except segment 1 entirely medium brown; segment 1 with one unbranched short seta ( Fig. 64 J) on each side; segment 2 with one unbranched short seta and five minute setae, of which three are stout ( Fig. 64 K), on each side; segments 3 and 4 each with four distinct hooks and one unbranched spinous short seta on each side; segment 5 and 6 lacking spine-combs; segments 7–9 each with distinct spine-combs in transverse row; segments 6– 9 each with comb-like groups of minute spines on each side; segment 9 without terminal hooks. Ventrally, segments 3–8 unpigmented, each with comb-like groups of minute spines; segment 4 with one unbranched hook and few slender minute setae on each side; segment 5 with pair of bifid hooks submedially and few unbranched short setae on each side; segments 6 and 7 each with pair of bifid inner and unbranched outer 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. Wall-pocket-shaped, thickly woven (in particular anterior margin), medium brown, not extended ventrolaterally, and with thick anterodorsal margin; individual threads invisible; 2.5–2.7 mm long by 1.2– 1.3 mm wide.

Mature larva. Unknown.

Type material. HOLOTYPE: Male (with its associated pupal exuviae and cocoon) in 80% ethanol, labeled in a vial as [ UMSRP: Vietnam 0 43, Holotype, Simulium (S.) sapaense , Male, coll. Vietnam, 20-XII-2014, Takaoka et al.], reared from a pupa collected from a small stream (width 0.5–1.0 m, depth 7 cm, bottom rocky, water temperature 9.0˚C, partially shaded, elevation 1,680 m, 22˚22’05.320”N/103˚47’34.403”E), slowly flowing from a secondary forest, Sapa , Lao Cai Province, northern Vietnam , 20-XII-2014, by H. Takaoka, M. Sofian-Azirun, Z. Ya’cob, C.D. Chen & K.W. Lau. PARATYPES: One female, one pupal exuviae, same data as those of the holotype, labeled in each vial as [ UMSRP: Vietnam 0 43, Paratype, Simulium (S.) sapaense , coll. Vietnam, 20-XII-2014, Takaoka et al.]; one male labeled in a vial as [ UMSRT: Vietnam 0 43, Paratype, Simulium (S.) sapaense , Male, coll. Vietnam, 20-XII-2014, Takaoka et al.] reared from a pupa collected from a stream (width 0.5 m, depth 10 cm, streambed rocky, water temperature 11.0˚C, exposed to the sun, elevation 1,750 m, 22˚21’43.110”N/ 103˚47’19.221”E) moderately flowing in a secondary forest, Sapa , Lao Cai Province, northern Vietnam , 20-XII- 2014, by H. Takaoka, M. Sofian-Azirun, Z. Ya’cob, C.D. Chen & K.W. Lau.

Biological notes. The pupae of this new species were collected from dead tree leaves in the current. Associated species were S. (M.) nigrofilum sp. nov., S. (N.) tayense sp. nov., S. (S.) laocaiense sp. nov., S. (S.) giayense sp. nov. and S. (S.) turgidum sp. nov.

Distribution. Vietnam (Lao Cai).

Etymology. The species name sapaense refers to the name of the district, Sapa, where this new species was collected.

Remarks. Simulium (S.) sapaense sp. nov. is assigned to the S. tuberosum species-group of the subgenus Simulium , based on the male genitalia ( Fig. 63 C). This new species is characterized by having the pit-like organ on the thoracic integument near the base of the gill ( Fig. 64 D). Seven species of the S. tuberosum species-group, i.e., S. (S.) brevipar Takaoka & Davies from Peninsular Malaysia and Thailand, S. (S.) tiomanense Takaoka , Sofian- Azirun & Belabut from Peninsular Malaysia, S. (S.) tianchi Chen, Zhang & Yang from China, S. (S.) sigiti Takaoka & Hadi from Java, S. (S.) yuphae Takaoka & Choochote from Thailand, and S. (S.) huense Takaoka & Ya’cob (substitute name for cavum ) and S. (S.) lowi sp. nov. from Vietnam, have a similar pit-like organ ( Takaoka and Davies 1995; Takaoka et al. 2012b, 2015a; Takaoka and Choochote 2005d; Takaoka and Hadi 1991; Chen et al. 2003b). This new species is distinguished in the male from S. (S.) tianchi and S. (S.) huense by having the uppereye facets in 17 vertical columns (in 15 vertical columns in S. (S.) tianchi and 21 vertical columns in S. (S.) huense ), and in the pupa from S. (S.) brevipar , S. (S.) huense , S. (S.) lowi sp. nov., S. (S.) sigiti , S. (S.) tiomanense and S. (S.) yuphae by the vicinity of the pit-like organ covered with tubercles ( Fig. 64 D) (vicinity of the pit-like organ is bare in the latter five species), and also from S. (S.) tianchi and S. (S.) sigiti by having six gill filaments of different length and thickness ( Fig. 64 I) (six gill filaments are subequal in length and thickness to one another in the latter two known species). Although whether its pupa has a similar pit-like organ is not known, S. (S.) nigrifacies Datta from India ( Datta 1974) differs from this new species by lacking spine-combs on abdominal segment 7.

Simulium (Simulium) lowi Takaoka & Adler sp. nov.

Simulium (Simulium) brevipar (not Takaoka & Davies): Takaoka et al., 2014a: 365 .

A chromosome analysis reveals that the species previously reported from Tam Dao National Park, northern Vietnam as S. (S.) brevipar from Malaysia consists of two distinct species: S. (S.) yuphae from Thailand ( Takaoka and Choochote 2005d) and S. (S.) sp., which is clearly distinguished chromosomally from S. (S.) brevipar from Malaysia (Adler et al. 2016). Our DNA analysis using the COII gene shows that the specimens from Vietnam are distinct from S. (S.) brevipar from Malaysia (Low et al. unpublished data). A subsequent morphological reexamination of two females and one male, together with their associated pupal exuviae, on which the record of S. (S.) brevipar from Vietnam was based, shows that they are almost identical to those of S. (S.) brevipar but are distinguished from the latter by a few features such as the shape of the female frons, relative size of the female labrum against the clypeus, and shape of the male ventral plate and style. Based on the results from morphological, molecular and chromosomal analyses, this species is here described as new.

Female. Body length 2.0 mm. Nearly similar to that of S. (S.) sapaense sp. nov. except following characters. Head. Frontal ratio 1.4–1.5:1.0:1.3–1.4; frons:head ratio 1.0:3.4–3.5. Labrum 0.7–0.8 times length of clypeus. Proportional lengths of third, fourth, and fifth segments 1.0:1.0:2.2; sensory vesicle medium-long (0.2–0.3 times length of third segment) having small or medium-sized opening. Maxillary lacinia with 14–17 inner and 16–18 outer teeth. Mandible with 26 inner and eight or nine outer teeth. Cibarium with 67 minute processes, of which several are vestigial, near posterodorsal margin. Legs. Foreleg: trochanter yellow; femur dark yellow basally, becoming darker toward apex with apical cap dark brown, though widely yellowish on basal half on inner surface; basitarsus greatly dilated, 4.8 times as long as its greatest width. Midleg: tarsus light brown except apical tips of basitarsus and second tarsomere yellowish white and fifth tarsomere dark brown. Hind leg: tarsus medium brown except basal seven-tenths of basitarsus (though base slightly darkened) and basal half of second tarsomere whitish yellow, and fourth and fifth tarsomeres dark brown; basitarsus ( Fig. 65 A) nearly parallel-sided, 6.1 times as long as wide, and 0.7 and 0.6 times as wide as greatest widths of hind tibia and femur, respectively. Wing. Length 1.9 mm. Subcosta haired except apical one-fourth bare. Terminalia . Sternite 8 well sclerotized and bare medially, covered with six to nine long and medium-long stout hairs and few short fine hairs on each side. Ovipositor valve densely covered with microsetae together with seven to 15 short fine hairs. Paraproct in ventral view with six sensilla on anteromedial surface; paraproct in lateral view 0.8 times as long as wide, covered with 19 short to medium-long hairs and numerous microsetae on lateral and ventral surfaces. Cercus in lateral view short, rounded posteriorly, 0.5 times as long as its greatest width, and covered with medium-long and short hairs. Spermatheca ovoidal, 1.19–1.22 times as long as wide.

Male. Body length 2.3 mm. Nearly as in male of S. (S.) sapaense sp. nov. except following characters. Head. Slightly wider than thorax. Upper eye medium brown, with large facets in 18 vertical columns and in 18 horizontal rows. Antenna medium brown to brownish black except scape, pedicel dark yellow, base of first flagellomere whitish yellow; first flagellomere elongate, 1.9 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 1.0:1.2:2.4; third segment of moderate size; sensory vesicle small, ellipsoidal (0.2 times as long as third segment), and with small opening.

Legs. Foreleg: trochanter yellow partially darkened on apical half; femur medium brown except basal portion dark yellow to light brown and apical cap dark brown; basitarsus greatly dilated, 4.5 times as long as its greatest width. Midleg: coxa brownish black; trochanter medium brown except base yellow; femur medium brown with apical cap dark brown though basal extreme somewhat paler; tarsus light brown except basal tips of basitarsus, second and third tarsomeres whitish yellow, and fifth tarsomere dark brown. Hind leg: trochanter yellow; femur dark brown except apical cap brownish black and extreme base whitish yellow; tibia dark brown except apical cap brownish black and basal tip whitish yellow; tarsus ( Fig. 65 B) medium brown except little more than basal half of basitarsus whitish yellow (though extreme base darkened) and basal half of second tarsomere whitish yellow; basitarsus ( Fig. 65 B) much enlarged, gradually widened from base to apical one-third, then slightly narrowed to apex, 3.7 times as long as its greatest width, and 0.9 and 1.0 times as wide as greatest widths of hind tibia and femur, respectively. Wing. Length 1.8 mm. Genitalia. Style in ventrolateral view ( Fig. 65 C) elongate, 3.1 times as long as its greatest width at base, gradually tapered toward apex. Ventral plate in ventral view ( Fig. 65 E) with arms directed forward. Abdominal segment 10 with three or four hairs on ventral surface and three or four hairs on lateral surface on each side. Cercus with seven distinct hairs.

Pupa. Body length 2.3–2.5 mm. Nearly as in S. (S.) sapaense sp. nov. except following characters. Thorax. Integument: surrounding area of pit-like organ near base of each gill bare ( Fig. 65 G). Gill ( Fig. 65 H) with six slender thread-like filaments directed forward and downward, decreasing in length from dorsal to ventral, with dorsal filament of dorsal pair longest (1.4 mm) and ventral filament of ventral pair shortest (0.8 mm); relative thickness of six filaments from dorsal to ventral when compared basally 1.0:0.7:0.6:0.6:0.6:0.6.

Type material. HOLOTYPE: Male (with its associated pupal exuviae and cocoon) in 80% ethanol, labeled in a vial as [ UMSRP: Vietnam 0 44, Holotype, Simulium (S.) lowi , Male, coll. Vietnam, 8-XI-2013, Takaoka et al.], reared from a pupa collected from a small stream (width 0.5 m, bottom rocky, water temperature 17˚C, shaded, elevation 975 m, 21˚27’501’’N/105˚38’941’’E), slow-flowing in bushes along the road near the Tam Dao National Park , Vinh Phuc Province, northern Vietnam , 8-XI-2013, by H. Takaoka, M. Sofian-Azirun & Z. Ya’cob. PARATYPES: Two males (with their associated pupal exuviae and cocoons) in 80% ethanol, same data as those of the holotype, labeled in each vial as [ UMSRP: Vietnam 0 44, Paratype, Simulium (S.) lowi , Male, coll. Vietnam, 8- XI-2013, Takaoka et al.].

Biological notes. The pupae of this new species were collected from dead tree leaves in the current. Associated species were S. (G.) hongthaii , S. (G.) sanchayense sp. nov., S. (G.) vinhphucense sp. nov. and S. (N.) sp. ( S. feuerborni species-group).

Distribution. Vietnam (Vinh Phuc).

Etymology. The species name lowi is in honor of Dr. V.L. Low, senior lecturer, Tropical Infectious Diseases Research and Education Centre, University of Malaya, who greatly contributed to phylogenetic studies of black flies.

Remarks. This new species is morphologically distinguished from S. (S.) brevipar in the male by the arms of the ventral plate not divergent when viewed ventrally ( Fig. 65 E) (moderately divergent in S. (S.) brevipar , as shown in Fig. 65 D), and style with its greatest width basally when viewed ventrolaterally ( Fig. 65 C) (at the basal one-third in S. (S.) brevipar , as shown in Fig. 65 F), and in the pupa by the dorsal filament of the dorsal pair gradually tapered toward the apex ( Fig. 65 I) (abruptly tapered basally, then gradually tapered in S. (S.) brevipar , as shown in Fig. 65 J).

Figures

FIGURE 62. Female of Simulium (Simulium) sapaense sp. nov. A, Third segment of maxillary palp with sensory vesicle (right side; front view); B, Cibarium (front view); C, Hind basitarsus and second tarsomere (left side; outer view). D, Sternite 8 and ovipositor valve (right side only; ventral view); E, Genital fork (ventral view); F & G, Paraprocts and cerci (F, ventral view; G, lateral view). H, Spermatheca. Scale bars. 0.1 mm for C; 0.02 mm for A, B and D – H.

FIGURE 63. Male of Simulium (Simulium) sapaense sp. nov. A, Third segment of maxillary palp with sensory vesicle (left side; front view); B, Hind basitarsus and second tarsomere (left side; outer view); C, Coxites, styles and ventral plate (ventral view); D, Coxite (right side; ventrolateral view); E & F, Styles (right side; E, ventrolateral view; F, medial view); G, Ventral plate and median sclerite (lateral view); H, Ventral plate (caudal view); I, Median sclerite (caudal view); J, Paramere (left side; caudal view); K, Dorsal plate (caudal view); L & M, Abdominal segment 10 and cerci (right side; L, lateral view; M, caudal view). Scale bars. 0.1 mm for B; 0.02 mm for A and C – M.

FIGURE 64. Pupa of Simulium (Simulium) sapaense sp. nov. A, Tubercles with minute secondary projections on frons; B, Frontal trichomes; C, Facial trichome; D, Anterior portion of thorax near base of gill showing pit-like organ surrounded by tubercles (dorsal view); E – H, Thoracic trichomes (E, anterodorsal; F, anterolateral; G, mediolateral; H ventrolateral); I, Anterior part of thorax and gill filaments (right side; outer view); J, Hair-like seta on dorsal surface of abdominal segment 1; K, Hair-like seta, minute seta and stout seta on dorsal surface of abdominal segment 2. Scale bars. 0.1 mm for I; 0.05 mm for D; 0.02 mm for B – H; 0.01 mm for A, J and K.

FIGURE 65. Female, male and pupa of Simulium (Simulium) lowi sp. nov. (except D, F and J are characters of S. brevipar from Peninsular Malaysia). A, Female; B – F, Male; G – J, Pupa. A, Hind basitarsus and second tarsomere (left side; outer view); B, Hind basitarsus and second tarsomere (left side; outer view); C & D, Styles (right side; ventrolateral view); E & F, Ventral plates (ventral view); G, Anterior portion of thorax near base of gill showing bare area surrounding pit-like organ (dorsal view); H, Anterior part of thorax and gill filaments (right side; outer view); I & J, Basal portions of gill filaments (right side; outer view). Scale bars. 0.1 mm for A, B and H; 0.05 mm for G, I and J; 0.02 mm for C – F.