Simulium (Gomphostilbia) marosense Takaoka, Sofian-Azirun & Suana, 2019

Takaoka, Hiroyuki, Sofian-Azirun, Mohd, Chen, Chee Dhang, Halim, Muhammad Rasul Abdullah, Lau, Koon Weng, Low, Van Lun & Suana, I. Wayan, 2019, A new black fly species of Simulium (Gomphostilbia) (Diptera: Simuliidae) from Sulawesi, Indonesia, Zootaxa 4651 (2), pp. 392-400 : 392-399

publication ID	https://doi.org/ 10.11646/zootaxa.4651.2.12
publication LSID	lsid:zoobank.org:pub:27CFEEE9-8F24-4BAE-AA45-3F9533905196
persistent identifier	https://treatment.plazi.org/id/06A1B92E-89BF-40A9-B9A4-897BC66575D1
taxon LSID	lsid:zoobank.org:act:06A1B92E-89BF-40A9-B9A4-897BC66575D1
treatment provided by	Plazi
scientific name	Simulium (Gomphostilbia) marosense Takaoka, Sofian-Azirun & Suana
status	sp. nov.

Treatment

Simulium (Gomphostilbia) marosense Takaoka, Sofian-Azirun & Suana sp. nov.

urn:lsid:zoobank.org:act:06A1B92E-89BF-40A9-B9A4-897BC66575D1

Female. Body length 1.7–2.0 mm. Head. Nearly as wide as width of thorax. Frons brownish black, and densely covered with yellowish-white scale-like recumbent short hairs interspersed with few dark longer hairs near vertex; frontal ratio 1.57–1.62:1.00:3.21–3.52; frons:head ratio 1.00:6.25–6.32. Fronto-ocular area well developed, narrow, directed dorsolaterally. Clypeus brownish black, densely covered with yellowish-white scale-like hairs interspersed with several dark longer hairs on each side. Labrum 0.58–0.59 times length of clypeus. Antenna composed of scape, pedicel and nine flagellomeres, medium brown except scape, pedicel and flagellomeres 1, 2 and 3 yellow. Maxillary palp composed of five palpomeres, light to medium brown, proportional lengths of third, fourth, and fifth palpomeres 1.0:1.3:2.5–2.6; third palpomere ( Fig. 1A View FIGURE 1 ) somewhat widened apically; sensory vesicle ( Fig. 1A View FIGURE 1 ) medium sized, ellipsoidal (0.34–0.38 times length of third palpomere), with medium-sized opening. Maxillary lacinia with 10–12 inner and 11–13 outer teeth. Mandible with 19–21 inner teeth and eight or nine outer teeth. Cibarium ( Fig. 1B View FIGURE 1 ) medially forming small sclerotized plate folded forward from posterior margin, with mediolongitudinal ridge having dark narrow apical portion. Thorax. Scutum brownish black to black except anterolateral calli ochreous, thinly pruinose and shiny except three non-pruinose longitudinal vittae (one median, two submedian), when illuminated at certain angles, and densely covered with white to yellowish-white scale-like recumbent short hairs. Scutellum brownish black, covered with dark short hairs and dark-brown long upright hairs along posterior margin. Postnotum brownish black, slightly shiny when illuminated at certain angles, and bare. Pleural membrane bare. Katepisternum longer than deep, dark brown, shiny when illuminated at certain angles, moderately covered with fine short hairs. Legs. Foreleg: coxa whitish yellow; trochanter light brown except basal half whitish yellow; femur light brown with apical cap medium brown; tibia light brown except base whitish and apical one-third dark brown, with sheen on outer surface of basal three-fourths, when illuminated at certain angles; tarsus brownish black, with moderate dorsal hair crest; basitarsus moderately dilated, 5.9–6.0 times as long as its greatest width. Midleg: coxa dark brown except posterolateral surface brownish black; trochanter light brown except base whitish; femur light brown with apical cap medium brown; tibia light brown except base white and apical cap dark brown, with sheen on posterior surface of basal three-fourths when illuminated at certain angles; tarsus brownish black except basal half of basitarsus white. Hind leg: coxa light to medium brown; trochanter whitish yellow; femur medium brown with extreme base whitish yellow and apical cap dark brown; tibia ( Fig. 1C View FIGURE 1 ) light brown except more than basal one-fourth yellowish white (though yellowish white on posterior surface of basal half), subbasal triangular spot medium brown and apical one-third brownish black, and covered with whitish fine hairs on outer and posterior surfaces of basal three-fourths and sheeny when illuminated at certain angles; tarsus brownish black except basal seven-tenths (though base light brown) and little less than basal half of second tarsomere whitish; basitarsus ( Fig. 1D View FIGURE 1 ) narrow, nearly parallel-sided though slightly narrowed apically, 5.8–6.2 times as long as wide, and 0.6–0.7 and 0.6 times as wide as greatest widths of tibia and femur, respectively; calcipala ( Fig. 1D View FIGURE 1 ) slightly longer than width at base, and 0.42 times as wide as greatest width of basitarsus; pedisulcus ( Fig. 1D View FIGURE 1 ) well developed; claw ( Fig. 1E View FIGURE 1 ) with large basal tooth 0.53 times length of claw. Wing. Length 1.7 mm. Costa with dark spinules and hairs except basal patch of hairs yellow. Subcosta with one to five hairs except in one female, subcosta with no hair. Hair tuft on base of radius dark brown. Basal portion of radius fully haired; R 1 with dark spinules and hairs; R 2 with hairs only. Basal cell absent. Halter . White except basal portion darkened. Abdomen. Basal scale light brown, with fringe of whitish hairs. Dorsal surface of abdomen brownish black to black except basal three-fifths or four-fifths whitish to light gray, moderately covered with dark short to long hairs; tergites of segments 2 and 6–9 shiny when illuminated at certain angles. Ventral surface of segment 2 white, those of other segments medium to dark brown; sternal plate on segment 7 undeveloped. Terminalia . Sternite 8 ( Fig. 1F View FIGURE 1 ) bare medially, with 11–13 medium-long to long hairs together with few slender short hairs on each side. Ovipositor valves ( Fig. 1F View FIGURE 1 ) triangular (though posteromedial corners rounded), thin, membranous, moderately covered with microsetae interspersed with two or three short hairs; inner margins sinuous or nearly straight, somewhat sclerotized, and moderately separated from each other. Genital fork ( Fig. 1G View FIGURE 1 ) of usual inverted-Y form, with slender stem; arms of moderate width, moderately folded dorsally. Paraproct in ventral view ( Fig. 1H View FIGURE 1 ) triangular, pointed medially, with four or five sensilla on anteromedial surface; paraproct in lateral view ( Fig. 1I View FIGURE 1 ) slightly produced ventrally beyond ventral tip of cercus, 0.8 times as long as wide, with 16–19 medium-long to long hairs on ventral and lateral surfaces. Cercus in lateral view ( Fig. 1I View FIGURE 1 ) short, rounded posteriorly, 0.5 times as long as wide. Spermatheca ( Fig. 1J View FIGURE 1 ) ellipsoidal, 1.6 times as long as its greatest width, well sclerotized except duct and small area near juncture with duct unsclerotized, and with many fissures on outer surface; internal setae absent; both accessory ducts subequal in diameter to each other and to major one.

Male. Body length 1.9–2.0 mm. Head. Somewhat wider than thorax. Upper eye medium brown, consisting of large facets in 12 vertical columns and 13 horizontal rows (13 vertical columns and 14 horizontal rows in one male). Clypeus brownish black, whitish pruinose, moderately covered with golden-yellow medium-long hairs interspersed with several dark-brown longer hairs along each lateral margin. Antenna composed of scape, pedicel and nine flagellomeres, medium brown except scape, pedicel, flagellomeres 1 and 2, and entire surface or only anterior surface of flagellomere 3 yellow; first flagellomere elongate, 1.6–1.7 times length of second one. Maxillary palp light to medium brown, with five palpomeres, proportional lengths of third, fourth, and fifth palpomeres 1.0:1.2–1.3:2.9–3.1; third palpomere ( Fig. 2A View FIGURE 2 ) widened apically; sensory vesicle ( Fig. 2A View FIGURE 2 ) small, globular or ellipsoidal (0.14–0.22 times length of third segment), and with small opening. Thorax. Scutum brownish black to black, shiny and white pruinose on shoulders, lateral area along each lateral margin and prescutellar area, when illuminated at certain angles, and densely covered with yellow scale-like recumbent short hairs. Scutellum dark brown, covered with dark short hairs and dark long upright hairs along posterior margin. Postnotum dark brown, slightly shiny and white pruinose when illuminated at certain angles, and bare. Pleural membrane bare. Katepisternum dark brown, longer than deep, shiny when illuminated at certain angles, moderately covered with fine short hairs. Legs. Color almost same as that of female. Fore basitarsus moderately dilated, 6.6–6.8 times as long as its greatest width. Hind basitarsus ( Fig. 2B View FIGURE 2 ) nearly parallel-sided, 5.9–6.1 times as long as wide, and 0.5–0.6 and 0.6 times as wide as greatest widths of tibia and femur, respectively; calcipala ( Fig. 2B View FIGURE 2 ) as wide as or slightly shorter than basal width, and 0.5 times as wide as greatest width of basitarsus. Pedisulcus ( Fig. 2B View FIGURE 2 ) well developed. Wing. Length 1.5–1.7 mm.

Other characters as in female except subcosta bare. Halter . Ochreous except basal stem darkened. Abdomen. Basal scale dark brown, with fringe of light-brown hairs. Dorsal surface of abdomen brownish black to black except anterior half of segment 2 ochreous and covered with dark-brown short to long hairs; segments 2 and 5–8 each with pair of shiny dorsolateral or lateral patches; ventral surface of segment 2 whitish, those of segments light to medium brown. Genitalia. Coxite in ventral view ( Fig. 2C View FIGURE 2 ) nearly rectangular, 1.6 times as long as its greatest width. Style in ventral view ( Fig. 2C View FIGURE 2 ) bent inward, with blunt apex having single spine; style in ventrolateral view ( Fig. 2D View FIGURE 2 ) 0.8 times length of coxite, with basal portion 0.4 times as wide as length, moderately tapered toward middle, then slightly toward apex, with rounded apex. Ventral plate in ventral view ( Fig. 2C View FIGURE 2 ) with body transverse, 0.6 times as long as wide, with anterior margin slightly produced anteromedially, posterior margin somewhat concave medially, and lateral margins slightly narrowed posteriorly, and densely covered with microsetae on ventral surface; basal arms of moderate length, nearly parallel-sided; ventral plate in lateral view ( Fig. 2E View FIGURE 2 ) slightly produced ventrally; ventral plate in caudal view ( Fig. 2F View FIGURE 2 ) rounded ventrally, densely covered with microsetae on posterior surface. Median sclerite ( Fig. 2G View FIGURE 2 ) weakly sclerotized, plate-like and wide. Parameres ( Fig. 2H View FIGURE 2 ) of moderate size, each with four distinct long and medium-long stout hooks, and without minute setae on outer surface of basal arm. Aedeagal membrane ( Fig. 2H View FIGURE 2 ) sparsely setose; dorsal plate not defined. Ventral surface of abdominal segment 10 ( Fig. 2I, J View FIGURE 2 ) somewhat sclerotized along anterior margin, with four or five distinct hairs near base of cercus. Cercus ( Fig. 2I, J View FIGURE 2 ) small, rounded, with 11 or 12 hairs.

Pupa. Body length 2.3–2.5 mm. Head. Integument light brown, moderately covered with small round tubercles except antennal sheaths and ventral surface almost bare; frons with three unbranched long trichomes with straight apices, arising close together on each side; face with one unbranched long trichome with straight apex on each side, which is as long as or slightly shorter than frontal ones. Thorax. Integument light brown, moderately covered with round tubercles, and with three long dorsomedial trichomes with coiled apices, two long anterolateral trichomes with straight apices, one medium-long mediolateral trichome with straight apex, and three ventrolateral trichomes (one medium-long, two short) with straight apices on each side; all trichomes unbranched. Gill ( Fig. 3A View FIGURE 3 ) composed of eight slender thread-like filaments, arranged as 3+3+2 filaments, of which two triplets arising close together from dorsal surface of common basal stalk, and directed upwards, with short common basal stalk having somewhat swollen transparent basal fenestra at base; two triplets not sharing stalk, and composed of one individual and two paired filaments with extremely short stalk, or of three individual filaments arising at same level, with extremely short stalk; stalk of ventral pair of filaments 0.56–0.86 times as long as interspiracular trunk; filaments of triplets subequal in length (1.0– 1.8 mm) and thickness to one another; two filaments of ventral pair subequal in length (3.0– 3.6 mm) (though inner filaments always slightly longer than outer one), and thickness to each other, and 1.9–3.0 times as long as six filaments of dorsal and middle triplets; all filaments light to medium brown, gradually tapered toward apex; cuticle of all filaments with annular ridges and furrows though becoming less marked apically, densely covered with minute tubercles. Abdomen. Dorsally, segments 1 and 2 almost entirely dark gray to light brown, segments 3 and 4 dark gray to light brown narrowly along anterior margin, and segment 9 yellow, and other segments unpigmented; segments 1 and 2 bare or sparsely covered with microtubercles; segment 1with one unbranched slender short hairlike seta on each side; segment 2 with one minute seta submedially near anterior margin, and one unbranched slen- der short hair-like seta and five minute setae near posterior margin, on each side; segments 3 and 4 each with one minute seta submedially near anterior margin, four hooked spines and one minute seta near posterior margin, on each side; segment 5 without spine-combs and comb-like groups of minute spines on each side; segments 6–9 each with spine-combs in transverse row (though spine-combs on segment 9 somewhat smaller than those on other segments) and comb-like groups of minute spines on each side; segment 5 with four minute setae near posterior margin on each side; segments 6 and 7 each with two minute setae near posterior margin on each side; segment 8 with one minute seta near posterior margin on each side; segment 9 with pair of conical terminal hooks ( Fig. 3B View FIGURE 3 ). Ventrally, segment 4 with one unbranched hook (subequal in size to those on segments 5–7) and few minute setae on each side; segment 5 with pair of bifid hooks submedially and few minute setae on each side; segments 6 and 7 each with pair of bifid inner and unbranched outer hooks somewhat spaced from each other and few minute setae on each side; segments 4–8 each with comb-like groups of minute spines. Each side of segment 9 with three grapnel-shaped hooklets. Cocoon ( Fig. 3C View FIGURE 3 ). Wall-pocket-shaped, almost transparent or light yellow, thinly woven, moderately extended ventrolaterally; anterior margin somewhat thickly woven medially, without anterodorsal projection; posterior threefifths with floor roughly woven; individual threads visible; 3.0– 3.3 mm long by 2.0– 2.5 mm wide.

Mature larva. Body length 4.0– 4.5 mm. Body creamy white, thoracic segments 1–3 and abdominal segments 1–8 each with light gray annular band (though that of abdominal segments 7 and 8 widely disconnected ventrally and ventrolaterally), markedly overlaid with reddish-brown or ochreous annular band (though those on thoracic segments 1–3 and abdominal segments 1–4 often disconnected dorsomedially and those of abdominal segments 6–8 widely disconnected ventrally and ventrolaterally). Cephalic apotome of head capsule whitish yellow (though little more than basal half partially grayish to light brown near head spots, or completely light to medium brown except areas on both lateral margins whitish yellow); head capsule moderately covered with unpigmented minute setae dorsally (though sparsely laterally and ventrally); head spots distinctly positive; lateral surface of head capsule whitish yellow or light brown except eye-spot region white, with faint to distinct small round spot below eye-spot region, and one or two small and two relatively larger spots near posterior margin; eyebrow faintly defined; ventral surface of head capsule yellow except areas surrounding postgenal cleft darkened to varying extent, or entirely light brown; spots on each side of postgenal cleft positive. Antenna composed of three segments and apical sensillum, longer than stem of labral fan; proportional lengths of first, second, and third segments 1.0:0.8:0.9. Labral fan with 34–36 primary rays. Mandible ( Fig. 3D View FIGURE 3 ) with three comb-teeth decreasing in length from first tooth to third; mandibular serration composed of two teeth (one medium-sized, one small); major tooth at acute angle against mandible on apical side; supernumerary serrations absent. Hypostoma ( Fig. 3E View FIGURE 3 ) with row of nine apical teeth, of which median tooth slightly longer than each corner tooth; three intermediate teeth on each side shorter than corner tooth; lateral margin smooth; four hypostomal bristles per side, lying nearly parallel to lateral margin. Postgenal cleft ( Fig. 3F View FIGURE 3 ) arrow-head-shaped, long, 2.9–3.1 times length of postgenal bridge. Cervical sclerites composed of pair of small medium brown rod-like pieces. Thoracic and abdominal segments 1–8 almost bare except few posterior abdominal segments sparsely covered with dark unbranched minute setae dorsally, and abdominal segment 9 moderately covered with unbranched colorless minute setae on dorsolateral and lateral surfaces of each side of anal sclerite and on each lateral surface to base of ventral papilla. Rectal scales minute and colorless. Rectal organ compound, each of three lobes with five to eight finger-like secondary lobules. Anal sclerite of usual X-form, with anterior arms nearly as long as or slightly shorter than posterior ones, broadly sclerotized at base; accessory sclerite absent. Last abdominal segment with pair of large conical ventral papillae. Posterior circlet with 67–70 rows of hooklets with up to 13 or 14 hooklets per row.

Type material. HOLOTYPE: Female (with associated pupal exuviae) (preserved in ethanol), reared from a pupa, collected from a moderately-flowing stream (width 3–5 m, depth 15–20 cm, bottom rocky and sandy, temperature 30.0˚C, partially shaded, elevation 54 m, S 4° 58’ 44.886” E 119° 40’ 25.898”), Leang Leang , Bantimurung, Maros, southern Sulawesi, Indonesia, 4-IV-2019, by M. Sofian-Azirun, C.D. Chen, M.R.A, Halim, K.W. Lau & I.W. Suana GoogleMaps ; five females, 10 males, three pupae and four mature larvae, same data as in the holotype. GoogleMaps

Biological notes. The pupae and larvae of this new species were collected from fallen leaves and trailing grass in the water.

Distribution. Sulawesi.

Etymology. The species name marosense refers to the place name, Maros, where this new species was collected.

Remarks. This new species is assigned to the Simulium batoense species-group of the subgenus Gomphostilbia , redefined by Takaoka (2012), by having the antenna with nine flagellomeres, bare pleural membrane, dark hair tuft on the base of the radius, dark tibiae of the female ( Fig. 1C View FIGURE 1 ) and male, and slender male hind basitarsus ( Fig. 2B View FIGURE 2 ). It is further placed in the S. duolongum subgroup within the S. batoense species-group, defined by Takaoka (2012), by having the pupal gill with eight thread-like filaments, of which two filaments of the ventral pair are 1.9–3.0 times as long as the six other filaments ( Fig. 3A View FIGURE 3 ).

The female of this new species is similar to that of S. (G.) torautense Takaoka & Roberts , one of eight species of the S. duolongum subgroup known in Sulawesi ( Takaoka, 2003), in many characters including a narrow frons (frons:head ratio 1.0: 6.3 in this new species and 1.0: 6.1–6.9 in S. (G.) torautense ), but it is barely distinguished from the latter species by the hind tibia whitish on the basal half of the posterior surface (yellowish white on the basal one-sixth in S. (G.) torautense ), and the relative length of the hind basitarsus against its greatest width (5.8–6.2 in this new species versus 6.6 in in S. (G.) torautense ). The females of six other species have a relatively wider frons (frons:head ratio 1.0: 4.1–5.8) ( Takaoka, 2003).

The male of this new species is most similar to that of S. (G.) manadoense Takaoka and S. (G.) singgihi Takaoka among eight species of the S. duolongum subgroup in Sulawesi, in sharing many characters including the number of upper-eye large facets, color of the antenna, relative length of the first antennal flagellomere against the second, scutal color pattern, relative lengths of the fore and hind basitarsi against their greatest width ( Takaoka, 2003). However, the male of this new species is barely distinguished from the two species by the hind tibia whitish on the basal half of the posterior surface (whitish on the basal one-sixth in the latter two species).

The males of six other species are also similar to the male of this new species but are barely distinguished by the following characters: S. (G.) abadii Takaoka, S. (G.) torautense and S. (G.) syafruddini Takaoka by the higher number of upper-eye large facets in 15–17 horizontal rows; S. (G.) tumidum Takaoka by the lower number of upper-eye large facets in 11 vertical columns and 12 horizontal rows and scutal color pattern composed of a dark nonpruinose median vitta and white pruinose areas on the rest of the scutum; S. (G.) kolakaense Takaoka by the relative length of the first antennal flagellomere against the second one (1.4); and S. (G.) hadiae Takaoka by the scutal color pattern composed of a dark non-pruinose median longitudinal vitta, two dark non-pruinose round spots on each side, and white pruinose areas on the rest of the scutum ( Takaoka, 2003).

The pupa of this new species is characterized by the arrangement and relative length of the pupal gill filaments ( Fig. 3A View FIGURE 3 ), by which it is distinguished from all eight species of the S. duolongum subgroup in Sulawesi, except S. (G.) kolakaense , which has a similar arrangement and relative length of the pupal gill filaments. However it is distinguished from S. (G.) kolakaense by the relative length of the stalk of the ventral pair of filaments against the interspiracular trunk (0.56–0.86 in this new species versus 1.1–2.3 in S. (G.) kolakaense ) and dorsum of abdominal segments 1–4 darkened (not darkened in S. (G.) kolakaense ).

In the larva, this new species is distinguished from S. (G.) hadiae , S. (G.) syafruddini , S. (G.) singgihi and S. (G.) tumidum by the number of rows of the posterior circlet (67–70 in this new species versus 79–84 in the latter three species), from S. (G.) kolakaense by the number of primary rays of the labral fan (34–36 in this new species versus about 44 in the latter species), and from S. (G.) torautense by the body length (4.0– 4.5 mm in this new species versus 4.7–5.4 mm in the latter species). The larvae of two other known species, S. (G.) abadii and S. (G.) manadoense , are unknown.

This new species is distinguished from 18 other species of the S. duolongum subgroup outside Sulawesi except S. (G.) friederichsi Edwards from Java and Sumatra, which is known only from the male ( Edwards, 1934), by a combination of the narrow female frons relative to the width of the head, smaller number of male upper-eye large facets, relative length of two long filaments of the ventral pair of the pupal gill against six other filaments ( Fig. 3A View FIGURE 3 ), darkened dorsum of the pupal abdominal segments 1–4, and lack of dark stout spinous setae on the dorsal surface of the larval abdomen.

The male of S. (G.) marosense sp. nov. is distinguished from that of S. (G.) friederichsi by the difference in the scutal color pattern, which is composed of dark non-pruinose areas in the form of an inverted T in the middle, white pruinose areas on each shoulder, a narrow area along each lateral margin and a wide prescutellar area in S. (G.) marosense sp. nov., but is composed of a dark non-pruinose median longitudinal vitta, two dark non-pruinose oblong spots on each side, and white pruinose areas on the rest of the scutum in S. (G.) friederichsi ( Takaoka, 1991) .