Simulium (Gomphostilbia) peteri Anbalagan

Anbalagan, Sankarappan, Prasanna, Vimalanathan Arun, Dinakaran, Sundaram & Krishnan, Muthukalingan, 2014, Two new species of Simulium (Gomphostilbia) (Diptera: Simuliidae) from Peninsular India with keys to Peninsular Indian members of the genus Simulium, Zootaxa 3861 (5), pp. 451-465 : 452-458

Simulium (Gomphostilbia) peteri Anbalagan sp. nov.

(Figs. 1–3)

Type series. Holotype, ♂, INDIA: Kalthuruthy, Kollam district, Kerala state, 26-XI- 2013, 195 m (08º57′.54″ N, 77º06′.53″E), S. Anbalagan (Coll. S. Anbalagan, Bharathidasan University (BDU)). Paratypes, same data as holotype: 8 ♂♂, 10 ♀♀, 15 pupae, 121 larvae (Coll. S. Anbalagan, BDU). 4 ♂♂, 3 ♀♀ (Department of Environmental Biotechnology, BDU, Catalogue number: BL0014).

FIGURE 1. Female of Simulium (Gomphostilbia) peteri sp. nov. A, 3rd segment of right maxillary palp showing sensory vesicle (front view); B, left hind tibia (outer view); C, basitarsus and 2nd tarsomere of left hind leg showing calcipala and pedisulcus (outer view); D, tarsal claw; E, 8th sternite, ovipositor valves (ventral view); F, genital fork (ventral view); G, right paraproct and cerci (lateral view); H, spermatheca (lateral view). Scale bars. 0.01 mm for D; 0.02 mm for A and G–H; 0.1 mm for B, C and E.

Diagnosis. Female: Head narrower than width of thorax; antenna composed of scape, pedicel and 9 flagellomeres; scutum with 3 brownish-black longitudinal vittae; hind tibia light to dark brown with basal 1/4 white; tarsal claw with large basal tooth; sternite 8 covered with 7 or 9 long hairs and few short fine hairs on each side. Male: upper eye consisting of 12 vertical columns and 12 horizontal rows of large facets; subcosta with 3–5 dark brown hairs; segments 2–7 each with shiny dorsolateral or lateral patches; ventral plate with anterior margin straight or flat surface, and posterior margin convex medially. Pupa: gill composed of 8 slender thread-like filaments, arranged as [(1+2) or 3+(1+2) or 3]+2 filaments from dorsal to ventral, with short common basal stalk; cocoon wall pocket-shaped, thinly and moderately woven, widely extended ventrolaterally. Larva: labral fan with 32 main rays; hypostoma with row of 9 apical teeth and 5 hypostomal bristles per side lying parallel to lateral margin; posterior circlet with 80 rows of up to 16 hooklets per row.

Description. Female. Body length 1.8mm. Head. Narrower than width of thorax. Frons nearly black, shiny when illuminated at certain angles, thinly yellowish pruinose with several stout dark hairs along lateral and lower margins; frontal ratio 1.62:1.00:2.13; frons-head ratio 1.00:4.54. Fronto-ocular area well developed, narrow, directed dorso-laterally. Antenna composed of scape, pedicel and 9 flagellomeres, brown except scape, pedicel and basal 1/2 of 1st flagellomere yellow. Clypeus grayish white, shiny, thinly whitish pruinose with dark stout hairs. Labrum 0.48 times as long as clypeus. Maxillary palp composed of 5 segments; proportional lengths of 3rd, 4th and 5th segments 1.00:1.35:2.94; 3rd segment (Fig. 1A) moderately enlarged; sensory vesicle (Fig. 1A) mediumsized (0.32 times as long as 3rd segment), with medium-sized round opening. Maxillary lacinia with 8 inner and 14 outer teeth. Mandible with 21 inner and 9 outer teeth. Cibarium bare. Thorax. Scutum dark brown except anterolateral calli dark ochreous, with 3 brownish-black longitudinal vittae (1 narrow median and 2 lateral), median vitta united anteriorly to anterior calli, lateral vittae united posteriorly to brownish-black prescutellar area; scutum shiny when illuminated at certain angles, densely covered with yellow scale-like recumbent short hairs interspersed with dark brown long upright hairs on prescutellar area. Scutellum shiny, with dark brown long upright hairs. Postnotum shiny and bare. Pleural membrane bare. Katepisternum medium to dark brown, longer than deep, shiny when illuminated at certain angles, densely covered with fine short hairs. Legs. Foreleg: coxa yellow; trochanter yellow except apical portion somewhat darkened; femur light brown except apical 1/2 of brownish black; tibia brown; tarsus brownish black with moderate dorsal hair crest; basitarsus slightly dilated, 6.3 times as long as its greatest width. Midleg: coxa yellowish brown except posterior surface dark brown; trochanter yellow; femur and tibia brown; tarsus brownish-black except basal 1/2 of basitarsus dark yellow. Hind leg: coxa yellowish brown; trochanter yellow; femur medium brown with base yellow and apical cap dark brown; tibia (Fig. 1B) light to dark brown with basal 1/4 white, covered with brownish fine hairs on outer and posterior surfaces; tarsus brownishblack except basal 2/3 of basitarsus (though base light brown); basitarsus (Fig. 1C) narrow, nearly parallel-sided, 6.14 times as long as wide, and 0.64 and 0.58 times as wide as greatest width of tibia and femur, respectively; calcipala (Fig. 1C) slightly shorter than width at base, and 0.58 times as wide as greatest width of basitarsus. Pedisulcus (Fig. 1C) well defined. Claw (Fig. 1D) with large basal tooth 0.57 times as long as claw. Wing. Length 1.6 mm. Costa with dark spinules and hairs except hairs on basal portion yellow. Subcosta with dark hairs except near apex bare. Hair tuft on stem vein dark brown. Basal section of vein R fully haired; R1 with dark spinules and hairs; R2 with hairs only. Basal cell absent. Haltere. Light brown except apical white. Abdomen. Base of each segment dark brown, basal scale dark brown, with fringe of dark brown hairs, dorsal surface of abdomen brown to brownish black except basal 1/2 of segment 2 yellow, moderately covered with brown short to long hairs; tergites of segment 2 and 6–8 shiny when illuminated at certain angles. Ventral surface of segments 2 and 3 whitish-yellow except lateral side brownish yellow, and those of other segments light to dark brown; sternal plate on segment 7 undeveloped. Genitalia. Sternite 8 (Fig. 1E) well sclerotized and bare medially, covered with 7–9 long hairs and few short fine hairs on each side. Ovipositor valves tongue-like, thin, membranous, moderately covered with microsetae interspersed with two short hairs; inner margins slightly concave, somewhat sclerotized, and slightly separated from each other. Genital fork (Fig. 1F) of usual inverted-Y forms; stem slender and well sclerotized; arms of moderate width, lateral plate of each arm with thin lobe directed medioposteriorly and small stout projection directed anterodorsally. Paraproct concave, with 2 or 3 sensilla on anteromedial surface; paraproct in lateral view (Fig. 1G) somewhat produced ventrally, 0.63 times as long as wide, with about 15 medium-long to long hairs on lateral and ventral surfaces. Cercus in lateral view (Fig. 1G) short, rounded posteriorly, 0.39 times as long as its greatest width. Spermatheca (Fig. 1H) ellipsoidal, 1.73 times as long as its greatest width, well sclerotized except duct and small area near juncture with duct unsclerotized, and with many fissures on surface; internal setae absent; both accessory ducts slender, subequal diameter to major one.

Male. Body length 2.2 mm. Head. 0.93 times wider than thorax. Upper eye medium brown, consisting of 12 vertical columns and 12 horizontal rows of large facets. Face brownish black, grayish-white pruinose. Clypeus black, whitish pruinose, densely covered with golden-yellow scale-like medium-long hairs (directed upward and lateral) interspersed with several dark brown simple longer hairs. Antenna composed of scape, pedicel and 9 flagellomeres, yellow to brown; 1st flagellomere elongate, 1.75 times as long as 2nd one. Maxillary palp light to medium brown, with 5 segments, proportional lengths of 3rd, 4th, and 5th segments 1.00:1.10:2.63; 3rd segment (Fig. 2A) widened apically; sensory vesicle (Fig. 2A) globular, small (0.18 times as long as 3rd segment), and with small opening. Thorax. Scutum slightly darker than female and short hairs on scutum golden yellow. Legs. Foreleg: coxa yellow; trochanter yellow with some portions light brown; femur light brown; tibia brown with median 2/3 light brown and covered with dark brown hairs; tarsus brown to dark brown; basitarsus moderately dilated, 6.91– 6.98 times as long as its greatest width. Midleg: coxa yellowish brown; trochanter yellow to brown; femur yellow except apical 1/4 brown; tibia medium brown to dark brown; tarsus dark brown to brownish-black except anterior surface of little less than basal 1/2 of basitarsus dark yellow to light brown. Hind leg: coxa dark yellow to light brown; trochanter yellow; femur light brown except apical 1/2 dark brown; tibia (Fig. 2B) brown except basal and apical dark brown; tarsus medium to dark brown except basal 1/2 (or little less) of basitarsus whitish-yellow and little less than basal 1/3 of 2nd tarsomere white; basitarsus (Fig. 2C) slender, parallel-sided, 6.4–6.6 times as long as wide, and 0.51–0.53 and 0.47–0.49 times as wide as greatest width of tibia and femur, respectively; calcipala (Fig. 2C) nearly as long as wide, and 0.42 times as wide as greatest width of basitarsus. Pedisulcus (Fig. 2C) well defined. Wing. Length 1.4mm. Costa with dark brown spinules as well as dark brown hairs except basal portion with patch of yellowish hairs. Subcosta with 3–5 dark brown hairs. Hair tuft on stem vein dark brown. Basal portion of radius fully haired; R1 with dark spinules and hairs and R2 with hairs only. Basal cell absent. Haltere. Yellowish brown except outer surface ochreous, basal stem darkened and apical white. Abdomen. Basal scale dark brown, with fringe of light to medium brown hairs. Dorsal surface of abdomen dark brown except segment 2 yellow (though posterior 1/4 of dorsal surface medium brown), covered with dark brown short to long hairs; segments 2–7 each with shiny dorsolateral or lateral patches; ventral surface of segment 2 yellow, those of segments 3 and 4 yellow except sternites medium brown, and those of other segments medium to dark brown. Genitalia. Coxite in ventral view (Fig. 2D) nearly rectangular, 1.42 times as long as its greatest width. Style in ventral view (Fig. 2D) bent inward, slightly tapered from base toward middle, then slightly widened, tapered to round apex and with apical spine; style in medial view 0.86 times as long as coxite, gently bent inward, nearly parallel-sided from base to apical 3/4, then tapered to apex, and with apical spine; style in ventrolateral view (Fig. 2E) very slightly tapered toward apical 3/4, with rounded apex. Ventral plate in ventral view (Fig. 2F) with body transverse, 0.52 times as long as wide, nearly parallel-sided, with anterior margin produced straight or flat surface, and posterior margin convex medially, densely covered with microsetae on ventral surface; basal arms of moderate length, directed forward, then slightly convergent apically; ventral plate in end view (Fig. 2G) concave ventrally, densely covered with microsetae on posterior surface. Median sclerite thin, plate-like, wide. Paramere of moderate size, with 4 distinct long and stout hooks and several smaller ones. Aedeagal membrane moderately setose, slightly sclerotized at base but dorsal plate not well defined. Ventral surface of abdominal segment 10 with distinct hairs near posterior margin. Cercus in lateral view (Fig. 2H) small, rounded, with 7 or 9 hairs.

FIGURE 2. Male of Simulium (Gomphostilbia) peteri sp. nov. A, 3rd segment of left maxillary palp showing small sensory vesicle (frontal view); B, left hind tibia (outer view); C, basitarsus and 2nd tarsomere of left hind leg showing calcipala and pedisulcus (outer view); D, coxites, styles, ventral plate and median sclerite (ventral view); E, right style with coxite (ventrolateral view); F & G, ventral plate (F, ventral view and G, end view); H, 10th abdominal segment and cercus (right side and lateral view). Scale bars. 0.05 mm for D; H for 0.01 mm; 0.02 mm for A and E–G; 0.1 mm for B and C.

Pupa. Body length 2.5–2.8 mm. Head. Integument dark yellow, moderately covered with small round tubercles; antennal sheath without any protuberances; face with pair of simple very long trichomes with uncoiled apices, and frons with 2 pairs of simple very long trichomes with coiled or uncoiled apices; 3 frontal trichomes on each side arising close together, subequal in length to one another and slightly longer than facial one. Thorax. Integument yellow, moderately covered with round tubercles, with 4 simple very long dorsomedial trichomes with coiled or uncoiled apices, 1 simple very long anterolateral trichome with uncoiled apex, 1 simple small mediolateral trichome with uncoiled apex, and 1 simple ventrolateral trichomes with uncoiled apex. Gill ( Fig. 3 A) composed of 8 slender thread-like filaments, arranged in [(1+2) or 3+(1+2) or 3]+2 filaments from dorsal to ventral, with short common basal stalk having somewhat swollen transparent organ ventrally at base; common basal stalk 0.34–0.36 times length of interspiracular trunk; dorsal and middle triplets sharing short stalk; dorsal and middle triplets each composed of 1 individual and 2 paired filaments with short primary stalk and very short to short secondary stalk or 3 filaments arising at same level from short to medium-long primary stalk; ventral paired filaments with medium-long stalk which is 1.20–1.25 times as long as common basal stalk and 0.37–0.41 times as long as interspiracular trunk; stalk of ventral pair 1.08–1.12 times as thick as primary stalk of middle triplet, 1.17–1.19 times as thick as primary stalk of dorsal triplet, and 0.68–0.74 times as thick as common stalk of middle and dorsal triplets; primary stalk of dorsal triplet lying against stalk of lower pair at angle of 60–90 degrees when viewed laterally; all filaments yellowish brown, gradually tapered toward apex; 6 filaments of dorsal and middle triplets subequal in length (2.0– 2.3 mm long including their own stalks and basal common stalk) and thickness to one another; 2 filaments of ventral pair subequal in length (2.7–3.0 mm long including their own stalk and common basal stalk) and thickness to each other, and 1.10–1.25 times as thick as those of 6 other filaments when compared basally; cuticle of all filaments with well-defined annular ridges and furrows though becoming less marked apically, densely covered with minute tubercles. Abdomen. Dorsally, segments 1 and 2 pigmented with tubercles; segment 1 with 1 simple slender medium-long hair-like seta on each side; segment 2 and 3 with 1 simple slender medium-long hair-like seta; segments 3 and 4 with 4 hooked spines and 1 short hair like seta on each side; segment 5 lacking spine–combs; segments 6–9 each with spine-combs in transverse row (though those on segment 9 slightly smaller than those on segment 8) and comb-like groups of minute spines on each side; segment 9 with pair of triangular flat terminal hooks of which outer margin is 3.0–3.5 times as long as inner margin and crenulated ( Fig. 3 B). Ventrally, segments 4 and 5 with 1 simple hook and few simple slender very short setae on each side; segments 6 and 8 with pair of bifid inner and simple outer hooks somewhat spaced from each other and few very short simple slender setae on each side; segments 4–8 with comb-like groups of minute spines. Each side of segment 9 with 3 grapnel-shaped hooklets. Cocoon. Wall pocket-shaped, thinly and moderately woven, widely extended ventrolaterally; anterior margin somewhat thickly woven, with dorsal portion not or slightly produced anteriorly when viewed dorsally; posterior 1/2 with floor roughly or moderately woven; individual threads visible; 3.5–4.0 mm long by 2.4–2.6 mm wide.

Mature larva. Body length 4.3–4.9 mm. Body creamy to dark ochreous except proleg grayish, ventral surface of thoracic segments 2 and 3 grayish or ochreous, and abdominal segments 1–4 almost entirely light grayish; body with grayish black markings, i.e., thoracic segment 1 encircled with broad transverse band (though disconnected ventrally), abdominal segments 5 and 6 each with W-shaped broad transverse band on dorsolateral surfaces of posterior 1/2 of each segment, abdominal segments 7 and 8 each with broad transverse band almost entirely covering dorsal and dorsolateral surfaces, and dorsolateral spots on abdominal segment 7 and 8 with transverse band on ventral surface. Cephalic apotome yellowish brown, and moderately covered with simple minute setae; head spots indistinct or very faintly positive. Lateral surface of head capsule yellowish brown except eye-spot region whitish, and very sparsely covered with simple minute setae; spots indistinct. Ventral surface of head capsule yellowish brown except somewhat darkened area near posterior margin on each side of postgenal cleft, and very sparsely covered with simple minute setae. Antenna composed of 3 segments and apical sensillum, somewhat longer than stem of labral fan; proportional lengths of 1st, 2nd, and 3rd segments 1.00:0.58:0.89. Labral fan with 32 main rays. Mandible ( Fig. 3 C) with 3 comb-teeth decreasing in length from 1st to 3rd; mandibular serration composed of 2 teeth (1 medium-sized and 1 small); major tooth at acute angle against mandible on apical side; supernumerary serrations absent. Hypostoma ( Fig. 3 D) with row of 9 apical teeth; median and each corner tooth prominent (though median tooth slightly longer than corner teeth) and much longer than 3 intermediate teeth on each side; lateral margin smooth; 5 hypostomal bristles per side lying parallel to lateral margin. Postgenal cleft ( Fig. 3 E) lanceolate, 2.6 times as long as postgenal bridge. Cervical sclerite composed of 2 very pale small pieces, not fused to occiput, widely separated medially from each other. Thoracic cuticle bare. Abdominal cuticle almost bare except few posterior segments sparsely to moderately covered with simple minute setae dorsally and dorsolaterally and last segment densely covered with colorless simple setae on each side of anal sclerite. Rectal scales absent. Rectal papilla compound, each of 3 lobes with 5 finger-like secondary lobules. Anal sclerite of usual X-form, with anterior arms as long as or little longer than posterior ones, broadly sclerotized at base; accessory sclerite absent. Last abdominal segment expanded ventrolaterally forming double bulges on each side, visible as large conical ventral papilla when viewed from side. Posterior circlet with 80 rows of up to 16 hooklets per row.

Etymology. The species name peteri is in honor of Professor Peter H. Adler, Department of Entomology, Clemson University, USA, who greatly contributed many works on black flies.

Habitat. S. (G.) peteri sp.n. larvae and pupae are mainly found on leaf litter. Teloganodes ( Ephemeroptera : Teloganodidae ) and Hydropsyche ( Trichoptera : Hydropsychidae ) are associated with this species.

Affinities. S. (G.) peteri is assigned to the subgenus Gomphostilbia by having a bare pleural membrane and haired katepisternum in the female and male and is placed in the batoense species group by having a dark hair tuft on the stem vein, dark brown male and female tibiae, slender and parallel-sided male hind basitarsus. The characters of the antenna, scutum, hind basitarsus, tarsal claw, genital fork, respiratory filaments and hypostoma of S. (G.) pattoni and S. (G.) bucolicum are similar to those of the new species. It is distinguished from S. (G.) pattoni and S. (G.) bucolicum by the large basal tooth in the female and smaller number of upper eye large facets in the male, respectively.

Figures

FIGURE 3. Pupa and larva of Simulium (Gomphostilbia) peteri sp. nov. A & B, pupa; C – E, larva. A, right gill filaments (outer view); B, terminal hooks (end view); C, right mandible (lateral view); D, hypostoma (ventral view); E, head capsule showing postgenal cleft and hypostoma (ventral view). Scale bars. 0.01 for B – D; 0.1 mm for E; 0.2 mm for A.