Simulium (Gomphostilbia) adleri Jitklang & Kuvangkadilok, 2008

Takaoka, Hiroyuki, Ya’Cob, Zubaidah & Sofian-Azirun, Mohd, 2018, Classification, annotated list and keys for the black flies (Diptera: Simuliidae) of Peninsular Malaysia, Zootaxa 4498 (1), pp. 1-65 : 27-31

26. Simulium (Gomphostilbia) adleri Jitklang & Kuvangkadilok, 2008 [ 2007]

Simulium (Gomphostilbia) adleri Jitklang & Kuvangkadilok, 2008 [ 2007]: 556–560 (Male, pupa and larva).

This species was originally described from males, pupae and larvae collected from Thailand ( Jitklang and Kuvangkadilok, 2007). It was recorded from Peninsular Malaysia by Ya’cob et al. (2016a, b). It is characterized in the pupa by the frons and thorax without tubercles, stalks of two triplets and that of the ventral paired filaments not lying in the same plane, and conical terminal hooks, and in the larva by the short postgenal cleft, which is shorter than the postgenal bridge, and dark gray transverse bands on the abdomen except segment 6 unpigmented ( Jitklang and Kuvangkadilok, 2007).

The female of this species is described based on a pharate female, and the pupa is redescribed and illustrated.

Female. Body length 2.0 mm. Head. Slightly narrower than thorax. Frons brownish black, densely covered with yellow scale-like recumbent short hairs; frontal ratio 1.9:1.0:2.3; frons:head ratio 1.0:4.1. Fronto-ocular area well developed, narrow, directed dorsolaterally. Clypeus brownish black, slightly shiny when illuminated at certain angles, and densely covered with yellowish-white recumbent hairs interspersed with several dark longer hairs on each side. Labrum 0.64 times as long as clypeus. Antenna composed of scape, pedicel and nine flagellomeres, light to medium brown except scape, pedicel and basal half of first flagellomere yellow. Maxillary palp composed of five segments, proportional lengths of third, fourth, and fifth segments 1.0:0.8:1.7; third segment ( Fig. 6A ) enlarged; sensory vesicle ( Fig. 6A ) long, 0.65 times length of third segment and with medium-sized opening. Maxillary lacinia with 10 or 11 inner and 13 outer teeth. Mandible with 18 inner teeth and 6 minute outer teeth. Cibarium ( Fig. 6B ) with dorsal margin having short plate produced forward and downward, and with weakly sclerotized mediolongitudinal stripe bearing V-shaped ridge apically. Thorax. Scutum brownish black, gray pruinose, somewhat shiny when illuminated at certain angles, densely covered with yellow scale-like recumbent hairs (except on median and two submedian narrow longitudinal vittae). Scutellum brownish black, gray pruinose, covered with yellow short hairs and dark brown long upright hairs. Postnotum brownish black, gray pruinose, somewhat shiny 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 pale and dark short hairs.

Legs. Foreleg: coxa whitish yellow; trochanter dark yellow; femur dark yellow with apical cap light brown (though extreme tip yellow); tibia medium brown except base yellowish; tarsus dark brown, with moderate dorsal hair crest; basitarsus somewhat dilated, 5.2 times as long as its greatest width. Midleg: coxa medium brown; trochanter yellow; femur yellow on basal half and dark yellow on rest except apical cap light brown (though extreme tip yellow); tibia light to medium brown except basal one-third yellow; tarsus light to medium brown except basal half of basitarsus yellow. Hind leg: coxa light brown; trochanter yellow; femur dark yellow with base yellow and apical cap light brown (though extreme tip yellow); tibia ( Fig. 6C ) yellow on basal two-thirds with faint dark triangular subbasal spot, and medium to dark brown on apical one-third; tarsus ( Fig. 6D ) light brown except little more than basal half of basitarsus (though base light brown) and little more than basal half of second tarsomere yellow; basitarsus ( Fig. 6D ) narrow, nearly parallel-sided; calcipala ( Fig. 6D ) well developed, 1.4 times as long as wide; pedisulcus ( Fig. 6D ) well developed; claw ( Fig. 6E ) with large basal tooth 0.52 times length of claw. Wing. Length not measurable. Costa with dark brown spinules and light-brown hairs except basal patch of yellow hairs. Subcosta haired except near apex bare. Hair tuft on base of radial vein yellow. Basal portion of radius fully haired. Basal cell absent. Abdomen. Basal scale with fringe of yellowish-white hairs. Dorsal surface of abdomen dark brown, moderately covered with dark short to long hairs; tergites of segments 2 and 6–8 shiny when illuminated at certain angles. Terminalia . Sternite 8 ( Fig. 6F ) bare medially, with 17–19 medium-long to long hairs together with five to nine slender short hairs on each side. Ovipositor valves ( Fig. 6F ) triangular (though medioposterior corners appearing to be truncated), thin, membranous, moderately covered with microsetae, without short hairs; inner margins nearly straight, moderately sclerotized. Genital fork ( Fig. 6G ) of usual inverted-Y form, with slender stem; arms of moderate width, and moderately folded dorsally. Paraproct in ventral view ( Fig. 6H ) triangular, with anteromedial surface slightly sclerotized having four sensilla; paraproct in lateral view ( Fig. 6I ) much produced ventrally, with 18 or 19 medium-long to long hairs on ventral and lateral surfaces. Cercus in lateral view ( Fig. 6I ) short, rounded posteriorly, 0.44 times as long as wide. Spermatheca ( Fig. 6J ) ellipsoidal, 1.7 times as long as greatest width, well sclerotized except duct and small area near juncture with duct unsclerotized; internal setae absent; both accessory ducts slender, subequal in diameter to each other and slightly wider than major one.

Pupa. Body length 2.0 mm. Head. Integument yellow, bare; antennal sheath without any protuberances; frons with three pairs of long trichomes with coiled apices ( Fig. 7A ) arising close together, subequal in length to one another; face with pair of medium-long trichomes with straight apices ( Fig. 7B ). Thorax. Integument yellow, bare except dorsal surface near posterior margin sparsely covered with small tubercles, with three long anterodorsal trichomes (decreasing in length from anterior to posterior) with coiled apices ( Fig. 7C ), two anterolateral trichomes (anterior one medium-long, with straight apex, posterior one with coiled apex) ( Fig. 7D ), one short mediolateral trichome with straight apex ( Fig. 7E ), and three short ventrolateral trichomes with straight apices (one much shorter than two others) ( Fig. 7F ), on each side; all trichomes unbranched. Gill ( Fig. 7G, H ) composed of eight slender thread-like filaments, arranged as (1+2)+(1+2) +2 from dorsal to ventral; middle triplet closely lying inward against dorsal triplet and ventral pair; common basal stalk short, having somewhat swollen basal fenestra ventrally at base; common basal stalk 0.7 times length of interspiracular trunk; dorsal and middle triplets not sharing stalk, each composed of one individual and two paired filaments with extremely short first and secondary stalk; ventral paired filaments with short stalk 0.7 times length of common basal stalk; secondary stalk of dorsal triplet lying against that of ventral pair at angle of 25 degrees when viewed laterally; all filaments light brown, outer filament of ventral pair gradually tapered toward apex and well-defined annular ridges and furrows, seven other filaments slightly tapered toward apex and weakly defined furrows; all filaments densely covered with minute tubercles; six filaments of dorsal and middle triplets subequal in length (0.7–0.8 mm long including their own stalks and common basal stalk) and thickness to one another; inner filament of ventral pair 1.0 mm long; outer filament of ventral pair 1.5 mm long, and 1.6 times as thick as six other filaments when compared basally. Abdomen. Dorsally, all segments unpigmented and without tubercles; segment 1 with one unbranched slender short hair-like seta ( Fig. 7I ) on each side; segment 2 with one extremely short minute seta ( Fig. 7J ) submedially near anterior margin on each side, one slender short hair-like seta and five short setae ( Fig. 7K ) submedially on each side; segments 3 and 4 each with four hooked spines and one short seta on each side; segment 5 lacking spine-combs; segments 6–8 each with spinecombs in transverse row and comb-like groups of minute spines on each side; segment 9 with comb-like groups of minute spines near anterior margin on each side and pair of flat triangular terminal hooks ( Fig. 7L ). Ventrally, segment 4 with few simple slender short setae on each side; segment 5 with pair of bifid hooks submedially and few short simple slender 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 short simple slender 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. Wallpocket-shaped, thinly woven; anterior margin relatively thickly woven, without bulge or projection; posterior half with floor roughly woven; individual threads invisible; 2.1 mm long by 1.9 mm wide.

Specimen examined. Pharate female (with associated pupal exuviae and cocoon) (preserved in 80% ethanol) dissected out of a pupa, collected from a moderately flowing stream (width 0.9 m, water temperature 23.3˚C, partially shaded, elevation 423 m, 04°23'429" N, 101°36'265" E), Jalan Sungai Koyan , Raub, Pahang, Malaysia, 26-VIII-2 0 13, by Z. Ya’cob.

Remarks.The female of this species is characterized by the elongate sensory vesicle ( Fig. 6A ), and the pupa is characterized by the bare frons.

Figures

FIGURE 6. Female of Simulium (Gomphostilbia) adleri. (A) Third maxillary palpal segment with sensory vesicle (right side; front view). (B) Cibarium (front view). (C) Tibia of hind leg (left side; outer view). (D) Basitarsus and second tarsomere of hind leg (left side; outer view). (E) Tarsal claw. (F) Sternite 8 and ovipositor valves (ventral view). (G) Genital fork (ventral view). (H) and (I) Paraprocts and cerci (right side; H, ventral view; I, lateral view). (J) Spermatheca. Scales. 0.05 mm for C and D; 0.02 mm for A, B and F–J; 0.01 mm for E.

FIGURE 7. Pupa of Simulium (Gomphostilbia) adleri. (A) Frontal trichome. (B) Facial trichome. (C)–(F) Thoracic trichomes (C, anterodorsal; D, anterolateral; E, mediolateral; F, ventrolateral). (G) Anterior part of thorax and gill filaments (left side; outer view). (H) Basal part of gill (left side; dorsal view). (I) Hair-like seta on dorsal surface of abdominal segment 1. (J) Microseta on dorsal surface of abdominal segment 2. (K) Hair-like seta and minute seta on dorsal surface of abdominal segment 2. (L) Terminal hooks (caudal view). Scales. 0.1 mm for G; 0.05 mm for H; 0.02 mm for A–F, I, K and L; 0.01 mm for J.