Simulium (Nevermannia) phami Takaoka, Sofian-Azirun

Takaoka, Hiroyuki, Sofian-Azirun, Mohd, Ya’Cob, Zubaidah, Chen, Chee Dhang, Lau, Koon Weng & Pham, Xuan Da, 2014, Three new species of Simulium (Nevermannia) (Diptera: Simuliidae) from Vietnam, Zootaxa 3866 (4), pp. 555-571 : 563-566

Simulium (Nevermannia) phami Takaoka, Sofian-Azirun & Ya’cob sp. nov.

( Fig. 5 )

Female. Body length 2.6 mm. Similar to female of S. (N.) langbiangense sp. nov. except following characters. Head. Frontal ratio 1.6:1.0:2.3. Frons:head ratio 1.0:5.0. Labrum as long as clypeus. Maxillary palp with proportional lengths of third, fourth, and fifth segments 1.0:0.9:1.4; sensory vesicle ( Fig. 5 A) elongate, 0.5–0.6 times length of third segment, with round medium-sized opening. Maxillary lacinia with 8 or 9 inner and 13 or 14 outer teeth. Mandible with 26 or 27 inner teeth and lacking outer teeth. Cibarium with 24 minute conical processes with pointed apices and numerous minute spinous processes near lower margin. Legs. Foreleg: trochanter yellow except anterior surface darkened; basitarsus slender, slightly dilated, 8.1 times as long as its greatest width. Hind leg: basitarsus ( Fig. 5 B) nearly parallel-sided, 6.8 times as long as its greatest width, and 0.7 and 0.6 times as wide as hind tibia and femur, respectively; calcipala well developed, 1.4 times as long as width in middle, and 0.6 times as wide as greatest width of basitarsus; pedisulcus well developed. Claw with large basal tooth 0.46 times length of claw. Wing. Length 2.6 mm. Subcosta with light-brown hairs except apical one-fourth bare. Abdomen. Tergites 2 and 6–8 somewhat shiny when illuminated at certain angles. Genitalia. Sternite 8 wide, bare medially but furnished with 25–28 long hairs and few short hairs on each side. Ovipositor valves triangular, thin, membranous except inner margin narrowly sclerotized, densely covered with microsetae interspersed with four to six short hairs. Genital fork ( Fig. 5 C) of inverted Y-form, with well sclerotized stem and relatively wide arms; each arm with lateral plate bearing round or triangular weakly-pigmented lobe-like projection directed posteromedially and short narrow stout projection directed anterodorsally. Paraproct in ventral view with six or seven sensilla on anteromedial surface; paraproct in lateral view with 30–36 medium to long hairs on ventral and lateral surfaces. Cercus in lateral view rounded posteriorly, 0.5 times as long as basal width. Spermatheca nearly ovoidal, 1.2 times as long as its greatest width.

Male. Body length 3.1–3.5 mm. Similar to male of S. (N.) langbiangense sp. nov. except following characters. Head. As wide as thorax. Upper eye consisting of large facets in 17 vertical columns and 18 horizontal rows. Clypeus brownish-black, not shiny, whitish pruinose, moderately covered with yellow hairs intermixed with darkbrown longer hairs. Antenna light brown except scape and pedicel medium brown, and base of first flagellomere yellowish-white; first flagellomere elongate, 2.3 times as long as second one. Maxillary palp grayish except segment 3 brownish-black; proportional lengths of third, fourth, and fifth segments 1.0:1.0:1.9; third segment of moderate size; sensory vesicle small, ellipsoidal, 0.2 times length of third segment, with small opening. Legs. Hind coxa light brown; hind basitarsus mostly grayish though more blackish near base and apex; basal half of hind second tarsomere grayish; fore basitarsus slender, 9.3–10.4 as long as greatest width; hind basitarsus enlarged, nearly parallel-sided ( Fig. 5 D) or spindle-shaped ( Fig. 5 E), 4.6–5.0 times as long as its greatest width, and 0.9 and 0.8–0.9 times as wide as greatest widths of hind tibia and femur, respectively; calcipala well developed, 1.3–1.4 times as long as width in middle, and 0.4 times as wide as greatest width of basitarsus; pedisulcus moderately developed. Wing. Subcosta with three hairs on each wing in one male and two and five hairs on each wing of one male; length 2.5–2.6 mm. Abdomen. Dorsal surface of abdominal segments dark brown to brownish-black except basal one-third of segment 2 whitish. Genitalia. Coxite in ventral view rectangular, 1.9 times as long as its greatest width. Style in ventral view short, 0.7 times length of coxite; style in lateral view slightly curved dorsally and nearly parallel-sided, with single stout apical spine (right style of one male with two additional smaller spines near apical spine, Fig. 5 F). Paramere ( Fig. 5 G) with six distinct hooks decreasing in length toward apex. Cercus small, rounded and encircled by 9–12 unbranched hairs.

Pupa. Body length 3.0– 3.5 mm. Similar to pupa of S. (N.) langbiangense sp. nov. except following characters. Head. Integument moderately or sparsely covered with tubercles; frons with two short unbranched setae ( Fig. 5 H) near lateral margin on each side. Thorax. Integument moderately (though sparsely on certain portions) covered with round tubercles. Gill ( Fig. 5 I) with five long thread-like slender filaments, arranged as four dorsal or lateral filaments and one ventral filament; four dorsal or lateral filaments arranged from outside to inside as 2+2 filaments with very short stalk ( Fig. 5 J) in five gills, or 1+2+1 filaments ( Fig. 5 K) in four gills, or 3+1 filaments ( Fig. 5 L) in five gills; common basal stalk of moderate length, 0.8–1.1 times length of interspiracular trunk ( Fig. 5 I); all filaments blackish brown, tapered toward tip, subequal in length (4.2–5.0 mm) and thickness to one another; cuticular surface with well-defined annular ridges and furrows, and densely covered with minute tubercles, of which relatively larger ones are on ridges forming distinct reticulate patterns and smaller ones on interridges. Cocoon ( Fig. 5 M). Wall-pocket shaped, compactly woven without open spaces in web, thin, with anterior margin somewhat thickly woven, and extending ventrolaterally; anterodorsal projection short; individual threads visible; 4.0– 4.3 mm long by 3.2 mm wide.

Mature larva. Body length 6.5–6.8 mm. Similar to mature larva of S. (N.) langbiangense sp. nov. except following characters. Body color: abdominal segment 2 lacking purplish-brown markings; abdominal segments 3 and 4, each with one large dorsal and one lateral purplish-brown spots on each side, though lateral spot on segment 4 much smaller or completely absent in three larvae, and those on abdominal segments 5–8, which are less distinctive. Cephalic apotome with narrow area along posterior margin not darkened in five of six larvae. Antenna: proportional lengths of first, second, and third segments 1.0:1.1:0.8. Labral fan with 38–42 main rays. Hypostoma with four to seven hypostomal bristles per side. Postgenal cleft small, quadrate or rounded, 0.5 times as long as postgenal bridge. Histoblast of pupal gill with five filaments. Anal sclerite with anterior arms 0.9–1.0 times length of posterior ones. Rectal organ compound, each lobe with 16–18 long finger-like secondary lobules. Posterior circlet with 74–76 rows of up to 14 or 15 hooklets per row.

Type specimens. HOLOTYPE: Female (with associated pupal exuviae and cocoon) (preserved in 80% ethanol), reared from pupa, collected from a small stream (width 1–2 m, depth 10–20 cm, water temperature 15.0˚C, partially shaded, altitude 1,539 m, 12˚01’24.991” N/108˚25’30.704” E), moderately flowing in Resort Park, Longbiang, Lac Duong District, Lam Dong Province, Vietnam, 25-IV-2014, by H. Takaoka, M. Sofian- Azirun and Z. Ya’cob. PARATYPES: Two males (with associated pupal exuviae and cocoon), all reared from pupae, one pupa, four pupal exuviae and two mature larvae (all preserved in 80% ethanol), same data as those of holotype; four mature larvae (preserved in 80% ethanol), same data as the holotype of S. (N.) langbiangense sp. nov.

Biological notes. The pupae and larvae of this new species were collected from slender pine tree leaves and round grass leaves in the water. Associated species were S. (N.) langbiangense sp. nov., S. (G.) sp. ( S. asakoae species-group), and Simulium (Simulium) tani . The habit of biting of the females remains unknown.

Etymology. The species name phami is in honor of Dr. Xuan Da Pham, Director, National Institute of Food Control, Ministry of Health, Hani, Vietnam, for his great support of our joint surveys on black flies in Vietnam.

Remarks. Simulium (N.) phami sp. nov. is readily assigned to the S. feuerborni species-group based on the combination of the following characteristics: male genitalia with a lamellate ventral plate, a short inwardly-twisted style ( Fig. 5 F), a simple narrow median sclerite and several parameral hooks ( Fig. 5 G); and the larval head capsule with a small short postgenal cleft.

This new species is most striking in having the pupal gill with five filaments ( Fig. 5 I), a character never reported among the members of the S. feuerborni species-group. All the known species of this group, of which the pupae are known, have the gill with six filaments, except S. (N.) borneoense Takaoka from Sabah, Malaysia, which has four gill filaments ( Takaoka 2001).

Apart from the difference in the number of the pupal gill filaments, the female, male and mature larva of this new species are morphologically similar to those of S. (N.) langbiangense sp. nov., though there are differences in several features including the size of the opening of the female sensory vesicle ( Fig. 5 A), the number of minute processes on the female cibarium, the presence or absence of the anterodorsal projection on the cocoon ( Fig. 5 M) and the size of the larval postgenal cleft.

Figures

FIGURE 5. Female, male and pupa of Simulium (Nevermannia) phami sp. nov. A – C, female; D – G, male; H – M, pupa. A, third segment of maxillary palpal segment with sensory vesicle (right side; front view); B, basitarsus and second tarsomere of left hind leg (outer view); C, genital fork (ventral view); D & E, basitarsi and second tarsomeres of left hind legs (outer view; D, basitarsus parallel-sided; E, basitarsus spindle-shaped); F, style (right side; dorsolateral view); G, paramere (left side; caudal view); H, two short setae on frons (left side; front view); I, basal portion of five gill filaments and anterior portion of thorax with interspiracular trunk shown in broken line (right side; lateral view); J – L, basal portions of five gill filaments with different arrangements (dorsal view; J & K, left side; L, right side); M, cocoon (dorsal view). Scale bars. 1.0 mm for M; 0.1 mm for B, D, E & I – L; 0.02 mm for A, C, F & G; 0.01 mm for H.