Simulium (Simulium) grossifilum Takaoka & Davies, 1995

Takaoka, Hiroyuki, Sofian-Azirun, Mohd, Ya’Cob, Zubaidah, Chen, Chee Dhang, Lau, Koon Weng, Low, Van Lun, Pham, Xuan Da & Adler, Peter H., 2017, The black flies (Diptera: Simuliidae) of Vietnam, Zootaxa 4261 (1), pp. 1-165 : 90-95

Simulium (Simulium) grossifilum Takaoka & Davies, 1995

Simulium (Simulium) grossifilum Takaoka & Davies, 1995: 105 –115 (Female, male, pupa and larva); Takaoka et al., 2014b: 746.

Distribution. Peninsular Malaysia, Thailand and Vietnam (Vinh Phuc).

Remarks. This species was originally described from Peninsular Malaysia ( Takaoka and Davies 1995). The record from Vietnam was based on three females captured in Tam Dao National Park, Vinh Phuc Province, while flying around a human ( Takaoka et al. 2014b). The aquatic stages remain to be collected from Vietnam.

Simulium (Simulium) laocaiense Takaoka & Lau sp. nov.

Female. Body length 3.3 mm. Head. Slightly narrower than thorax. Frons black, shiny, with bluish reflection when illuminated at certain angles, with several dark stout hairs along lateral margins; frontal ratio 1.3:1.0:0.9; frons:head ratio 1.0:3.6. Fronto-ocular area well developed, short, directed laterally, and pointed apically. Clypeus brownish black, white pruinose when illuminated at certain angles, moderately covered with dark-brown mediumlong hairs (though mediolongitudinal portion of upper half widely bare). Labrum 0.7 times length of clypeus. Antenna composed of scape, pedicel and nine flagellomeres; first flagellomere 1.4 times length of second one; scape and pedicel whitish yellow, and basal two-thirds of first flagellomere yellow, rest dark brown to brownish black, when viewed dorsally (first flagellomere entirely yellow or ochreous when viewed ventrally); first to eighth flagellomeres each with pit-like depression with many sensilla on inner and outer sides. Maxillary palp with five segments, light to medium brown; proportional lengths of third, fourth, and fifth segments 1.0:1.4:2.8; third segment ( Fig. 38 A) with apex somewhat produced medially, with medium-sized ellipsoidal sensory vesicle (0.3 times length of third segment) having medium-sized opening. Maxillary lacinia with14 or 15 inner and 13 or 15 outer teeth. Mandible with 25 inner and 11 or 12 outer teeth. Cibarium ( Fig. 38 B) with 70 minute processes near posterodorsal margin. Thorax. Scutum black, slightly shiny and grayish pruinose on shoulders and lateral portions when illuminated at certain angles, moderately covered with whitish-yellow recumbent short hairs interspersed with several dark-brown long upright hairs on prescutellar area. Scutellum dark brown, covered with dark-brown upright long hairs and yellow short hairs. Postnotum brownish black, bare. Pleural membrane bare. Katepisternum brownish black, longer than deep, bare, and slightly shiny when illuminated at certain angles. Legs. Foreleg: coxa whitish yellow; trochanter and femur yellow; tibia whitish yellow except apical one-fifth brownish black; tarsus black, with moderate dorsal hair crest; basitarsus greatly dilated, 5.6 times as long as its greatest width. Midleg: coxa dark brown; trochanter, femur and tibia yellow except dorsal small portion of apical tip of tibia grayish; tarsus light to medium brown except basal half or little more of basitarsus yellow (though its border not well defined). Hind leg: coxa dark brown; trochanter yellow; femur yellow except dorsal portion of apical tip light brown; tibia yellow with apical cap medium brown; tarsus dark brown except basal two-thirds of basitarsus and basal half of second tarsomere yellowish white; basitarsus ( Fig. 38 C) nearly parallel-sided, 6.0 times as long as wide, and 0.9 and 0.7 times as wide as greatest widths of hind tibia and femur, respectively; calcipala ( Fig. 38 C) moderately developed, slightly shorter than its basal width, and 0.4 times as wide as greatest width of basitarsus; pedisulcus ( Fig. 38 C) well developed. Claw simple, without basal or subbasal tooth. Wing. Length 3.0 mm. Costa with dark spinules and hairs; subcosta almost fully haired; basal section of radius bare; R1 with dark-brown spinules and hairs; R2 with dark-brown hairs; hair tuft on base of radius dark brown; basal cell absent. Halter . White except base light brown. Abdomen. Basal scale dark brown to brownish black, with fringe of yellowish hairs. Dorsal surface of abdomen medium-brown to black; tergite 2 shiny and white pruinose when illuminated at certain angles and tergites 6–9 shiny. Ventral surface medium to dark brown except basal portion of segment 2 white; segment 7 with large median sternal plate. Terminalia . Sternite 8 ( Fig. 38 D) with 24–26 dark-brown medium-long to long stout hairs and six to nine yellow short hairs on each lateral surface. Ovipositor valve ( Fig. 38 D) wide, somewhat thick except area along inner margins and wide areas along posterior margin thin and transparent, somewhat rounded ventrally, densely covered with microsetae (except transparent portions along inner and posterior margins bare) interspersed with 19 or 20 yellow short hairs; inner margins somewhat concave, moderately separated from each other. Genital fork ( Fig. 38 E) of inverted-Y form, with narrow well sclerotized stem; arms of moderate width, each with heavily sclerotized lateral portion, with short projection directed anterodorsally. Paraproct in ventral view ( Fig. 38 F) nearly quadrate, 1.2 times as long as its width, with 33–35 short to medium-long hairs on lateral and ventral surfaces, and with anterior surface strongly sclerotized and pigmented with 8–14 short sensilla; paraproct in lateral view ( Fig. 38 G) 0.72 times as long as wide, and protruding ventrally beyond ventral margin of cercus. Cercus in lateral view ( Fig. 38 G) short, rectangular, 0.5 times as long as wide, with numerous short to mediumlong hairs. Spermatheca ( Fig. 38 H) nearly ovoid, 1.3 times as long as greatest width, well sclerotized except small portion of junction with duct unsclerotized, with faintly defined reticulate surface patterns; internal setae present; accessory ducts subequal in thickness to each other, and slightly thicker than major duct.

Male. Unknown.

Pupa. Body length (excluding gill filaments) 3.5–4.0 mm. Head. Integument dark brown except ventral surface ochreous, and moderately covered with round tubercles except lateral and ventral surfaces and antennal sheaths bare: frons with two medium-long trichomes (one unbranched and one bifid, or two bifid, or two trifid, or quadrifid and quinquefid) ( Fig. 39 A); one female pupa with additional short hair on right side and one minute seta on left side ( Fig. 39 B), and one male pupa with additional short trichome on left side ( Fig. 39 C); face with one medium-long trichome on each side (one unbranched and one bifid, or two bifid, or trifid and quadrifid) ( Fig. 39 D) on each side. Thorax. Integument dark brown except wing sheaths ochreous, moderately covered with round tubercles; thorax with three anterodorsal trichomes (one unbranched or bifid, one trifid, one quadrifid or quinquefid) ( Fig. 39 E), two anterolateral trichomes (one bifid, one trifid or quadrifid) ( Fig. 39 F), one bifid mediolateral trichome ( Fig. 39 G), and three ventrolateral trichomes (all bifid, or one unbranched and two bifid) ( Fig. 39 H) on each side; all trichomes medium-long. Gill ( Fig. 39 I) with six slender thread-like filaments in pairs; common basal stalk short, with basal fenestra ventrally; dorsal and ventral pairs short stalked and middle pair almost sessile; outer filament of dorsal pair longest (1.5 mm long), followed by outer filament of middle pair (1.3 mm long), inner filament of dorsal pair and outer filament of ventral pair (1.1 mm long), inner filament of middle pair (1.0 mm long) and inner filament of ventral pair (0.9 mm long); relative thickness of six filaments from dorsal to ventral 1.0:0.8:1.0:0.6:0.9:0.5; all filaments dark brown, gradually tapered toward apex; outer filament of dorsal pair and inner filament of ventral pair divergent basally at angle of 60 degrees; cuticular surface with well-defined annular ridges and furrows throughout their length except apical portions less distinct, covered with minute tubercles. Abdomen. Dorsally, entire surface of segment 1 and anterior one-third of segment 2 light brown, other segments unpigmented; segment 1 smooth (without tubercles), with one unbranched slender medium-long seta ( Fig. 39 J) on each side; segment 2 smooth, with one unbranched slender short seta, five unbranched short setae, of which four are stout ( Fig. 39 K), on each side; segments 3 and 4 each with four unbranched hooked spines and one unbranched short seta on each side; segment 8 with spine-combs in transverse row on each side; segments 5–9 each with comb-like groups of minute spines; segment 9 without terminal hooks. Ventrally, all segments unpigmented; segment 4 with one unbranched hook and few short setae on each side; segment 5 with pair of unbranched or bifid hooks submedially and few unbranched short seta on each side; segments 6 and 7 each with pair of unbranched or bifid inner and unbranched outer hooks widely spaced and few unbranched short seta on each side; segments 4–8 each with comb-like groups of minute spines. Grapnel-like hooklets absent. Cocoon ( Fig. 39 L, M). Wall-pocketshaped, thickly woven, with short round anterodorsal projection, ochreous, not extended ventrolaterally; individual threads invisible; 3.1 mm long by 1.6 mm wide.

Mature larva. Body length 8.0 mm. Body ochreous to reddish brown, mottled to varying extent with grayish black to black pigment except ventral surface of abdominal segments 2–9 unpigmented; intersegmental spaces from thoracic segment 3 to abdominal segment 4 paler. Head. Cephalic apotome ( Fig. 40 A) whitish yellow except large area of triangular shape on posterior half light to medium brown and narrow area along posterior margin dark brown; head spots moderately positive though posterolateral spots indistinct; lateral surface of head capsule whitish yellow, with distinct eyebrow, with eye-spot region whitish and two large spots in front of posterior margin and three isolated spots below eye-spot region positive; ventral surface of head capsule ( Fig. 40 D) yellow except areas along posterior margin widely darkened, with dark brown elongate spot on each side of cleft. Antenna composed of three articles and apical sensillum, slightly longer than stem of labral fan; length ratio of articles (from base to tip) 1.0:1.2:0.5. Labral fan with 52 primary rays. Mandible ( Fig. 40 B) with mandibular serration composed of two teeth (one medium-sized and one small); major tooth at obtuse angle apically against mandible; comb-teeth decreasing in length from first to third; supernumerary serrations absent. Hypostoma ( Fig. 40 C) with nine anterior teeth, of which median tooth slightly longer than each corner tooth; lateral margins weakly serrate apically; nine hypostomal bristles divergent posteriorly from lateral border on each side. Postgenal cleft ( Fig. 40 D) medium-long, triangular; sheath of subesophageal ganglion well pigmented, wine-glass-shaped. Cervical sclerites on each side composed of one light-brown elliptical piece, not fused to occiput. Thorax and Abdomen. Thoracic and abdominal cuticle bare except last segment of abdomen moderately covered with short colorless setae on each side of anal sclerite. Rectal scales present. Rectal organ unobservable. Anal sclerite X-shaped, with broadened anterior arms 0.7 times length of posterior ones; five sensilla on base of anal sclerite and seven sensilla posterior to posterior arms. Last abdominal segment bulged laterally but lacking ventral papillae. Posterior circlet with 164 rows of hooklets with up to 22 hooklets per row.

Type material. HOLOTYPE: Female (with its associated pupal exuviae and cocoon) in 80% ethanol, labeled in a vial as [ UMSRP: Vietnam 0 35, Holotype, Simulium (S.) laocaiense , Female, coll. Vietnam, 20-XII-2014, Takaoka et al.], reared from a pupa collected from a stream (width 0.5–2.0 m, depth 3 cm, bottom rocky, water temperature 11.0˚C, exposed to the sun, elevation 1,853 m, 22˚21’18.609”N/103˚46’27.550”E) moderately flowing from a forest, Sapa , Lao Cai Province, northern Vietnam, 20-XII-2014, by H. Takaoka, M. Sofian-Azirun, Z. Ya’cob, C.D. Chen & K.W. Lau . PARATYPES: One pupa and three pupal exuviae in 80% ethanol, labeled in each vial as [ UMSRP: Vietnam 0 35, Paratype, Simulium (S.) laocaiense , coll. Vietnam, 20-XII-2014, Takaoka et al.], collected from a small stream (width 0.5 m, depth 10 cm, bottom rocky, water temperature 11.0˚C, exposed to the sun, elevation 1,750 m, 22˚21’43.110”N/103˚47’19.221”E) slowly flowing from a secondary forest, Sapa , Lao Cai Province, northern Vietnam , 20-XII-2014, by H. Takaoka, M. Sofian-Azirun, Z. Ya’cob, C.D. Chen & K.W. Lau; one mature larva in 80% ethanol, labeled in a vial as [ UMSRP: Vietnam 0 35, Paratype, Simulium (S.) laocaiense , Larva , coll. Vietnam, 20-XII-2014, Takaoka et al.], collected from a stream (width 0.5–1.0 m, bottom rocky, water temperature 9.0˚C, partially shaded, elevation 1,680 m, 22˚22’05.320”N/103˚47’34.403”E) slowly flowing from a secondary forest, Oguy Ho, Sapa , Lao Cai Province, northern Vietnam, 20-XII-2014, by H. Takaoka, M. Sofian- Azirun, Z. Ya’cob, C.D. Chen & K. W. Lau.

Biological notes. The pupae of this new species were collected from trailing grasses. Associated species were S. (N.) laichauense sp. nov., S. (S.) sapaense sp. nov., S. (S.) sp. ( S. multistriatum species-group) and S. (S.) turgidum sp. nov.

Distribution. Vietnam (Lao Cai).

Etymology. The species name laocaiense refers to the name of the province, Lao Cai, where this new species was collected.

Remarks. Simulium (S.) laocaiense sp. nov., though its male is unknown, is placed in the S. griseifrons species-group, defined by Takaoka and Davies (1996), based on the similarity of the female enlarged ovipositor valve ( Fig. 38 D) to that of S. (S.) rudnicki Takaoka & Davies described from Peninsular Malaysia, which is a member of this species-group ( Takaoka and Davies 1995; Takaoka and Choochote 2004c).

This new species is characterized by the simple cocoon with a somewhat produced anterodorsal portion ( Fig. 39 L, M), by which this new species is distinguished from most species of the S. griseifrons species-group, the cocoons of which are usually fenestrated or rarely shoe-shaped or simple wall-pocket-shaped.

This new species is similar in the female terminalia to S. (S.) vietnamense Takaoka, Sofian-Azirun and Chen described from females collected from Vietnam ( Takaoka et al. 2014b), but is distinguished from the latter by lacking hairs on the basal portion of the female radial vein.

Figures

FIGURE 38. Female of Simulium (Simulium) laocaiense sp. nov. A, Third segment of maxillary palp with sensory vesicle (left side; front view); B, Cibarium (front view); C, Hind basitarsus and second tarsomere (left side; outer view). D, Sternite 8 and ovipositor valve (right side only; ventral view); E, Genital fork (ventral view); F & G, Paraprocts and cerci (F, ventral view; G, lateral view). H, Spermatheca. Scale bars. 0.1 mm for C; 0.02 mm for A, B and D – H.

FIGURE 39. Pupa of Simulium (Simulium) laocaiense sp. nov. A – C, Frontal trichomes of different sizes and types; D, Facial trichome; E – H, Thoracic trichomes (E, anterodorsal; F, anterolateral; G, mediolateral; H, ventrolateral); I, Anterior part of thorax and gill filaments (right side; outer view); J, Hair-like seta and minute seta on dorsal surface of abdominal segment 1; K, Hair-like seta, minute seta and stout seta on dorsal surface of abdominal segment 2; L & M, Cocoons (L, dorsal view; M, lateral view). Scale bars. 1.0 mm for L and M; 0.1 mm for I; 0.02 mm for A – H, J and K.

FIGURE 40. Larva of Simulium (Simulium) laocaiense sp. nov. A, Head capsule (dorsal view); B, Mandible; C, Hypostoma; D, Head capsule (ventral view). Scale bars. 0.1 mm for A and D; 0.05 mm for C; 0.02 mm for B.