Simulium (Simulium) tulshii Takaoka & Shrestha, 2010

Takaoka, Hiroyuki & Shrestha, Suchitra, 2010, New species of black flies (Diptera: Simuliidae) from Nepal 2731, Zootaxa 2731, pp. 1-62 : 49-56

Simulium (Simulium) tulshii Takaoka & Shrestha sp. nov.

Description. Female. Body length 2.8–3.5 mm. Head. Narrower than thorax. Frons brownish-black, whitishgray pruinose, very slightly shiny when illuminated at certain angle of light, and covered with several whitishyellow and dark brown hairs along each lateral margin and with several whitish-yellow hairs above antennal base; frontal ratio 1.22–1.24:1.00:1.07–1.24; frons-head ratio 1.00:4.14–4.59. Fronto-ocular area ( Fig. 26A) well developed, short, directed laterally. Clypeus brownish-black, whitish-gray pruinose, moderately covered with whitish-yellow hairs though small area along dorsal margin bare. Labrum 0.71–0.72 times as long as clypeus. Antenna composed of scape, pedicel and 9 flagellomeres, medium brown except scape, pedicel and base of 1st flagellomere yellow. Maxillary palp ( Fig. 26B) composed of 5 segments, dark brown to brownishblack, proportional lengths of 3rd, 4th and 5th segments 1.00:1.04–1.05:2.45–2.62 (left palp showing abnormality that 5th segment is connected with middle portion of 4th segment as shown in Fig. 26C); 3rd segment ( Fig. 26D) somewhat widened apically; sensory vesicle ( Fig. 26D) oblong, 0.38–0.43 times as long as 3rd segment, with medium-sized opening. Lacinia with 12–14 inner and 15 or 16 outer teeth. Mandible with 32 inner and 16 outer teeth. Cibarium ( Fig. 26E) with small median projection directed posterodorsally, and with numerous sharply pointed processes along posterodorsal margin and even on median projection; similar processes scattered on transparent membrane near posterodorsal margin. Thorax. Scutum black, shiny, with whitish-gray pruinose patterns (variable depending of direction of illumination), densely covered with whitish-yellow fine hairs interspersed with dark brown upright hairs on prescutellar area. Scutellum dark brown, with whitish-yellow hairs and dark brown upright hairs. Postnotum dark brown, shiny, whitish-gray pruinose, bare. Pleural membrane bare. Katepisternum longer than deep, blackish, whitish-gray pruinose, shiny when illuminated at certain angle of light, bare. Legs. Foreleg: coxa and trochanter whitish-yellow; femur whitish-yellow except apical cap dark yellow to light brown and posterior surface dark yellow; tibia yellowish-white except apical 1/4 dark brown, and with white large sheen on outer surface; tarsus brownishblack, with moderate dorsal hair crest; basitarsus greatly dilated, 6.67 times as long as its greatest width. Midleg: coxa brownish-black; trochanter whitish-yellow with posterior surface partially dark yellow; femur yellow except apical cap dark yellow to light brown; tibia yellowish-white to yellow except apical cap medium brown and mediolongitudial portion of apical 1/2 to 3/4 of outer surface dark yellow; tibia with white large sheen on posterior surface; tarsus medium brown except little less than basal 1/2 of basitarsus and base of 2nd tarsomere whitish-yellow. Hind leg: coxa dark brown to brownish-black; trochanter yellowish-white; femur medium to dark yellow except base yellowish-white and apical cap medium to dark brown; tibia yellowish-white to yellow except apical cap dark brown and most of outer surface from middle to base of apical cap dark yellow to light brown; tibia with white large sheen on posterior surface; tarsus medium to dark brown except basal 2/3 of basitarsus and little less than basal 1/2 of 2nd tarsomere yellowish-white ( Fig. 26F); basitarsus ( Fig. 26F) nearly parallel-sided, 6.18 times as long as wide, and 0.68 and 0.57 times as wide as greatest width of hind tibia and femur, respectively; calcipala ( Fig. 26F) developed, small, 0.67 times as long as its basal width, and 0.35 times as wide as greatest width of basitarsus; pedisulcus ( Fig. 26F) well developed at basal 1/3 of 2nd tarsal segment. Claw with small subbasal tooth ( Fig. 26G). Wing. Length 2.7–2.9 mm. Costa with dark spinules and light brown hairs except basal patch of hairs yellow; subcosta with hairs except apical 1/3 to 1/2 bare; basal section of radial vein bare; R 1 with dark spinules and hairs; R 2 with hairs; hair tuft on stem vein yellow; basal cell absent. Abdomen. Basal scale medium to dark brown, with fringe of pale hairs. Dorsal surface of abdomen dark brown to brownish-black except basal 1/2 to 3/5 of 2nd segment dark yellow, moderately covered with yellow fine short hairs intermixed with short to medium-long dark brown hairs; tergite 2 shiny, white iridescent when illuminated, and tergites 6–8 shiny. Ventral surface of segment 7 with pair of round weakly sclerotized sternal plates. Genitalia. Sternite 8 ( Fig. 26H) with 18–27 whitishyellow medium-long to long stout hairs on each lateral surface. Ovipositor valves ( Fig. 26H) large, produced posteromedially, with rounded apices, membranous, covered with numerous microsetae and 14–22 whitishyellow medium-long hairs per side, except apical 1/3 or more bare; inner margins widely concave; narrow portion along inner margin moderately sclerotized and central portion of apical bare portion weakly sclerotized. Genital fork ( Fig. 26I) of inverted-Y form, with narrow well-sclerotized stem; arms of moderate width, each with distinct projection directed anterodorsally. Paraproct in ventral view ( Fig. 26J) with shallow groove medially on ventral surface nearly along anteromedial margin, with moderately sclerotized anteromedial surface bearing 9 or 10 sensilla, with numerous short to medium-long hairs on lateral and ventral surfaces; paraproct in lateral view ( Fig. 26K) nearly triangular, moderately protruding ventrally beyond cecus, with shallow groove along ventral margin, and with numerous short to medium-long hairs on posterior 1/2. Cercus in lateral view ( Fig. 26K) rounded posteriorly, 0.60 times as long as wide, with numerous short and medium-long hairs. Spermatheca ( Fig. 26L) nearly ovoid, well sclerotized except portion at junction with duct unsclerotized, without distinct reticulate pattern on its surface, and with internal setae; accessory ducts subequal in thickness to each other, and subequal to, or slightly thicker than, major duct.

Male. Body length 2.7–3.6 mm. Head. Wider than thorax. Upper eye consisting of large facets in 21 vertical columns and in 23 horizontal rows. Clypeus black, thickly white pruinose, covered with whitishyellow hairs along and near lateral margins (most of central portion bare). Antenna composed of scape, pedicel and 9 flagellomeres, medium brown except scape and pedicel dark yellow and base of 1st flagellomere whitish-yellow; 1st flagellomere elongate, 1.9 times as long as 2nd one. Maxillary palp dark brown, composed of 5 segments with proportional lengths of 3rd, 4th, and 5th segments 1.00:1.17:2.73; 3rd segment ( Fig. 27A) of normal size; sensory vesicle ( Fig. 27A) small, ellipsoidal, 0.24 times as long as 3rd segment, and with small opening. Thorax. Scutum black, with whitish-gray pruinose pattern, i.e., anterior pair of large spots on shoulders extending posteriorly along lateral margins and connected to large transverse spot entirely covering prescutellar area; either anterior or posterior 1/2 of large pruinose spot on each shoulder disappearing depending on angle of light; some pruinose areas shiny when illuminated at certain angle of light; scutum uniformly and moderately covered with whitish-yellow recumbent short hairs interspersed with dark brown long upright hairs on prescutellar area. Scutellum medium brown, with several dark long upright hairs as well as whitish-yellow short hairs. Postnotum, pleural membrane and katepisternum as in female.

Legs. Color nearly as in female except hind basitarsus whitish-yellow on little more than basal 1/2 ( Fig. 27B); fore basitarsus moderately dilated, 7.62 times as long as its greatest width; hind basitarsus ( Fig. 27B) slightly enlarged, nearly parallel-sided (though apical 1/4 somewhat tapered apically), 5.16 times as long as its greatest width, and 0.73 and 0.76 times as wide as greatest widths of hind tibia and femur, respectively; calcipala ( Fig. 27B) small, 0.67 times as long as its basal width and 0.32 times as wide as greatest width of basitarsus; pedisulcus ( Fig. 27B) well marked. Wing. Length 2.6 mm; other characteristics as in female except subcosta bare. Abdomen. Basal scale brownish-black, with fringe of whitish-yellow long hairs. Dorsal surface of abdomen dark brown to brownish-black, moderately covered with whitish-yellow fine short hairs intermixed with dark brown short to medium-long hairs; segments 2 and 4–7 each with pair of whitish-gray pruinose spots dorsolaterally, those on segment 2 connected broadly to each other in middle; ventral surface of abdomen medium to dark brown. Genitalia. Coxite in ventral view ( Fig. 27C) nearly quadrate, 1.20 times as long as wide; coxite in lateral view ( Fig. 27D) 0.79 times as long as wide. Style in ventral view ( Fig. 27C) elongate, slightly sinuous, nearly parallel-sided, 1.83 times as long as coxite, with subapical spine; style in lateral view ( Fig. 27D) spatulate dorsoventrally, tapered from apical 1/4 to apex; style in ventrolateral view ( Fig. 27E) widest little beyond middle, 0.36 times as wide as long; style in medial view ( Fig. 27F) with short subbasal bulge directed dorsally, bearing no spinule on its surface. Ventral plate in ventral view ( Fig. 27G) Yshaped, covered with setae densely on anterior surface and moderately on posterior surface of ventrally produced process which bearing 2 vertical rows of spines on posterior surface; arms diverged basally from each other at angle of 60 to 90 degrees, then directed forward; ventral plate in lateral view ( Fig. 27H) with distinct serrated posterior margin and densely covered with minute setae on ventrally produced process; ventral plate in end view ( Fig. 27I) having 2 vertical rows of 7–9 teeth on posterior surface, and moderately covered with minute setae on ventrally produced elliptical process. Median sclerite ( Fig. 27J) well sclerotized, plate-like, wide except near base narrow, with several fissures near apex forming sharply pointed apical tips. Paramere ( Fig. 27K) wide basally, with several short to long hooks. Aedeagal membrane very densely covered with minute setae; dorsal plate ( Fig. 27L) small, well sclerotized except medial portion incompletely sclerotized. Abdominal segment 10 ( Fig. 27M,N) with 0 or 1 distinct hair on ventral surface. Cercus ( Fig. 27M,N) small, rounded, with 9–11 distinct hairs.

Pupa. Body length 3.0– 3.5 mm. Head. Integument including antennal sheaths yellow to dark yellow, densely and elaborately covered with small round tubercles except most tubercles on frons with pointed apices ( Fig. 28A); frons with 2 pairs of simple or bifid long stout trichomes somewhat separated from each other in some pupae; face with pair of bifid, trifid or quadrifid long stout trichomes ( Fig. 28B). Thorax. Integument yellow to dark yellow, densely and elaborately covered with small round or cone-shaped tubercles except most tubercles on dorsal and dorolateral surfaces bearing pointed apices similar to those on frons; thorax on each side with 2 simple, bifid or trifid, long stout trichomes anterodorsally, 2 simple, bifid or trifid stout trichomes (1 long, 1 medium-long) anterolaterally, 1 simple long stout trichome mediolaterally, and 3 simple or bifid stout trichomes (1 short or medium-long, 2 long) ventrolaterally. Gill ( Fig. 28C,D) with 6 short inflated filaments arranged as 2+1+1+2 from dorsal to ventral; dorsal and ventral pairs each with short stalk; 2 filaments of dorsal pair directed upward, abruptly turned outward and downward, then directed posteriorly (extending up to abdominal segment 2 in 1 pupa) or inwardly or laterally, and tapered toward apex after curving downward; outer filament of 2 individual filaments directed forward and gradually tapered toward apex, inner filament directed downward and forward, and tapered from basal 1/3 toward apex; dorsal filament of ventral pair directed forward, and gradually tapered toward apex, ventral filament of ventral pair directed downward, inward and forward, and first widened to varying extent from base, then tapered from middle or apical 2/3 to apex (length of apical slender portion variable among individual pupae); all filaments variable in length (1.6–2.4 mm), nearly transparent to light ocherous, moderately covered with minute slender spinous processes on inflated portion and parts of slender portion (though spinous processes becoming shorter and fewer on slender portions) ( Fig. 28E), and densely covered with minute tubercles on entire surface. Abdomen. Dorsally, segment 1 weakly sclerotized, light ocherous, moderately covered with minute spines, with 1 simple or bifid medium-long seta on each side; segment 2 transparent or somewhat light ocherous, moderately covered with minute spines, with 1 simple medium-long seta and 5 simple short stout spines on each side; segments 3 and 4 transparent, each with 4 distinct simple hooks and 1 short simple seta on each side; segments 5 and 6 transparent, lacking spine-combs (though segment 6 with spine-combs in 1 pupa); segments 7–9 each with distinct spine-combs in transverse row (though those on segment 9 much smaller in 1 pupa), and also comb-like groups of minute spines on each side; segment 9 with pair of terminal hooks of irregular form ( Fig. 28F). Ventrally, segments 3–8 transparent, each with comb-like groups of minute spines; segment 4 with few short to medium-long somewhat stout setae on each side; segment 5 with pair of simple and/or bifid stout hooks submedially and few simple short setae on each side; segments 6 and 7 each with pair of bifid inner and simple outer stout hooks somewhat separated from each other and few simple short setae on each side. Grapnel-shaped hooklets absent on each side of segment 9. Cocoon ( Fig. 28G). Shoe-shaped, with very low to low anterior collar, soft, roughly woven, with many small open spaces anteriorly, and not extending ventrolaterally; individual threads visible; light yellow; 4.2–6.8 mm long by 1.6–2.0 mm wide.

Mature larva. Body length 9.0 mm. Body grayish. Abdomen gradually widened from segment 1 to segment 7, then narrowed to segment 9. Cephalic apotome ( Fig. 29A) yellow except anterior area and narrow areas along lateral and posterior magins, in particular, near mediolateral head spots, light to medium brown; head spots moderately positive though anterior spot of mediolongitudinal spots indistinct; lateral surface of head capsule dark brown except eyes-pot region yellowish, area below eye-spot region to varying extent light brown, and eyebrow area somewhat lighter; ventral surface of head capsule ( Fig. 29B) dark brown except most area of hypostoma and parts of postgenal bridge yellow to light brown. Antenna ( Fig. 29C) composed of 3 segments and apical sensillum, slightly longer than stem of labral fan; length ratio of 3 segments (from base to tip) 1.0:1.4:0.7; antenna dark brown except base and ventral surface of segment 1, 4 areas (including apex) of segment 2 and apical sensillum unpigmented. Labral fan with 38 main rays. Mandible ( Fig. 29D) with mandibular serrations composed of 2 teeth (1 large and 1 medium-sized) (though another small tooth at base of main tooth in right mandible— Fig. 29E); main tooth at obtuse angle against mandible on apical side; supernumerary serrations absent; comb-teeth composed of 4 or 5 teeth, of which 1st tooth longest and others subequal in length to one another (though comb-teeth decreasing in length from 1st to 3rd in right mandible— Fig. 29E). Hypostoma ( Fig. 29F) with 9 anterior teeth, of which median tooth longest of all; inner tooth of 3 intermediate teeth on each side longer than 2 others though little shorter than each corner tooth; lateral margins weakly serrate apically; 9 hypostomal bristles divergent posteriorly from lateral border on each side. Postgenal cleft ( Fig. 29B), of medium-size, 1.21 times as long as postgenal bridge; subesophageal ganglion well pigmented, wine-glass shaped. Histoblast of pharate pupal gill with 6 inflated filaments. Thoracic and abdominal cuticle bare except abdominal segments 8 and 9 moderately to densely covered with short colorless setae on dorsal and lateral surfaces. Rectal scales present. Rectal organ of 3 simple large lobes, without secondary lobules. Anal sclerite X-shaped, with short broad anterior arms 0.73 times as long as posterior ones and with forked apices. Last abdominal segment not bulged laterally and lacking ventral papillae. Posterior circlet with 94 rows of hooklets with up to 22 hooklets per row.

Type specimens. Holotype female (with associated pupal exuviae and cocoon) (preserved in 80% ethanol), reared from pupa collected from a small moderately-flowing water canal (water temperature 15.5˚C, exposed to the sun, altitude 2,745 m, 28˚78’67.3” N, 83˚73’38.7” E) Jomsom , Mustang, Nepal, 23.IX.2009 . Paratypes: 3 females, 2 males, all with associated pupal exuviae and cocoons, same data as those of holotype ; 2 pupae collected from a moderately-flowing very small stream (water temperature 15.0˚C, exposed to the sun, altitude 3,448 m, 28˚81’80.3” N, 83˚84’34.1” E), Jharkot , Mustang, Nepal, 21.IX.2009 ; 3 mature larvae collected from a rapidly-flowing small stream (water temperature 8.0˚C, exposed to the sun, altitude 3,743 m, 28˚81’69.7” N, 83˚87’14.0” E), Muktinath , Mustang, Nepal, 21.IX.2009 .

Biological notes. The pupae and larvae of this new species were collected from grass leaves trailing in the water. No other species was collected.

Etymology. The specific name tulshii is in honor of Mr. Tulshi Krishna Shrestha, father of the junior author, who kindly accompanied and assisted in field surveys.

Remarks. Simulium (S.) tulshii sp. nov. is assigned to the variegatum species-group of the subgenus Simulium (Simulium) redefined by Takaoka (2003) in that it has a combination of the following characteristics: claw with a small subbasal tooth ( Fig. 26G), ovipositor valves rounded, with inner margins widely concave ( Fig. 26H) in the female, ventral plate with toothed posterolateral margins ( Fig. 27I), style elongate, without a basal protuberance ( Fig. 27F) in the male, and six gill filaments ( Fig. 28C,D) in the pupa.

This new species is characterized by the female cibarium with numerous spinous processes on and near the posterodorsal margin ( Fig. 26E), and the six inflated pupal gill filaments ( Fig. 28C,D).

Interestingly, the similar arrangement of six inflated gill filaments has been reported for S. (S.) flavum Takaoka, S. (S.) lorense Takaoka and S. (S.) malinoense Takaoka , all described from Sulawesi, Indonesia, although two filaments directed upward are not curved downward apically in the latter three known species ( Takaoka 2003). Apart from the pupal gill filaments, all these three known species are different from S. (S.) tulshii sp. nov. by many characteristics including the cibarium with few to several minute processes, short ovipositor valves in the female, narrow ventral plate in the male, wall-pocket shaped cocoon, and rectal organ compound, each lobe with several secondary lobules.