Simulium (Gomphostilbia) tamdaoense Takaoka, Sofian-Azirun

Takaoka, Hiroyuki, Sofian-Azirun, Mohd, Ya’Cob, Zubaidah, Chen, Chee Dhang, Lau, Koon Weng & Pham, Hong Thai, 2014, New species and records of black flies (Diptera: Simuliidae) from Vinh Phuc Province, Vietnam, Zootaxa 3838 (3), pp. 347-366 : 351-353

2. Simulium (Gomphostilbia) tamdaoense Takaoka, Sofian-Azirun & Ya’cob sp. nov.

Male. Body length 2.2 mm. Head. Somewhat wider than thorax. Upper eye medium brown, consisting of 14 vertical columns and 14 horizontal rows of large facets. Face brownish-black, white pruinose. Clypeus brownish-black, whitish pruinose, densely covered with golden-yellow scale-like medium-long hairs (mostly directed upward) interspersed with several dark brown simple longer hairs. Antenna composed of scape, pedicel and 9 flagellomeres, light to medium brown except scape, pedicel and base of first flagellomere whitish-yellow; first flagellomere elongate, 1.6 times length of second one. Maxillary palp light to medium brown, with 5 segments, proportional lengths of third, fourth, and fifth segments 1.0:1.2:3.1; third segment ( Fig. 2A ) slender; sensory vesicle ( Fig. 2A ) globular or ellipsoidal, small (0.2 times length of third segment), and with opening of medium size. Thorax. Scutum dark brown to brownish-black, without longitudinal vittae, shiny and thinly gray pruinose on shoulders, on wide area along each lateral margin and on prescutellar area when illuminated at certain angles, and densely covered with golden-yellow scale-like recumbent hairs. Scutellum ochreous, covered with yellow short hairs and dark-brown long upright hairs along posterior margin. Postnotum dark-brown to brownish-black, 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. Foreleg: coxa whitish-yellow; trochanter yellow though outer surface somewhat darkened; femur light brown with apical cap medium brown (though apical tip yellowish); tibia white to grayish except base light brown and little more than apical 1/3 brownishblack, and covered with white hairs on basal 2/3 of outer surface and white sheen on basal 2/3 of outer surface when illuminated at certain angles; tarsus brownish-black; basitarsus moderately dilated, 6.8 times as long as its greatest width. Midleg: coxa medium brown except posterior surface brownish-black; trochanter yellowish; femur light brown with base somewhat yellowish and apical cap medium brown (though apical tip yellow); tibia medium brown except basal 1/4 yellowish; tarsus dark-brown to brownish-black except basal 1/3 or more of basitarsus dark yellow to light brown (border not well defined). Hind leg: coxa light brown though apical portion whitish-yellow; trochanter whitishyellow; femur light to medium brown with base narrowly whitish-yellow and apical cap dark brown (though apical tip whitish-yellow); tibia ( Fig. 2B ) dark-brown to brownish-black except basal 1/2 whitish-yellow, covered with yellow hairs on basal 2/3 of outer surface; tarsus ( Fig. 2C ) medium to dark brown except basal 1/2 of basitarsus and basal 1/3 of second tarsomere whitish-yellow; basitarsus ( Fig. 2C ) enlarged, spindle-shaped, 4.2 times as long as wide, and 0.9 and 0.9 times as wide as greatest width of tibia and femur, respectively; calcipala ( Fig. 2C ) slightly shorter than basal width, and 0.4 times as wide as greatest width of basitarsus. Pedisulcus ( Fig. 2C ) well defined. Wing. Length 1.7 mm. Other characters as in S. (G.) hongthaii sp. nov. Halter . Grayish except basal stem darkened and apical half grayish ochreous. Abdomen. Basal scale dark brown, with fringe of light to medium-brown hairs. Dorsal surface of abdomen dark-brown to black except anterior 1/3 of segment 2 yellowish, covered with dark-brown short to long hairs; segments 2 and 5–8 each with pair of shiny dorsolateral or lateral patches. Genitalia. Coxite in ventral view ( Fig. 2D ) nearly rectangular, 1.8 times as long as its greatest width. Style in ventral view ( Fig. 2D ) bent inward, bluntly rounded apically and with apical spine; style in medial view ( Fig. 2E ) shorter than coxite (0.8 times length of coxite), gently bent inward, nearly parallel-sided to apex; style in ventrolateral view ( Fig. 2F ) slightly tapered toward apex, with truncated apex. Ventral plate in ventral view ( Fig. 2D ) with body transverse, 0.5 times as long as wide, with anterior margin produced anteromedially, and posterior margin somewhat concave medially (though posterior margin slightly convex medially when ventral plate is slightly inclined), lateral margins somewhat emarginated medially, and densely covered with microsetae on ventral surface; basal arms of moderate length, directed forward, then convergent apically; ventral plate in lateral view ( Fig. 2G ) moderately produced ventrally; ventral plate in end view ( Fig. 2H ) trapezoidal, ventral margin nearly straight, densely covered with microsetae on posterior surface except portion near each lateral tip narrowly bare. Median sclerite thin, plate-like, wide. Parameres ( Fig. 2I ) of moderate size, each with 3 distinct long stout hooks and with 6–8 minute setae on outer surface of basal arm. Aedeagal membrane sparsely setose, not sclerotized at base; dorsal plate not defined. Ventral surface of abdominal segment 10 ( Fig. 2J, K ) without distinct hairs near posterior margin. Cercus in lateral view ( Fig. 2J ) small, rounded, with 12 or 13 hairs.

Pupa. Body length 2.4 mm. Nearly as in pupa of S. (G.) hongthaii sp. nov. except following characters.

Thorax. Integument yellow, moderately covered with round tubercles except mediodorsal and mediolateral surface sparsely covered with round tubercles. Gill ( Fig. 2L ) composed of 8 slender thread-like filaments, arranged as [(2+1)+ (1+2)]+2 filaments from dorsal to ventral, with medium-long common basal stalk having somewhat swollen transparent basal fenestra at base; common basal stalk 0.8 times length of interspiracular trunk; dorsal and middle triplets share short stalk; dorsal triplet composed of 1 individual and 2 paired filaments with medium-long primary and short secondary stalks, and middle triplet composed of 1 individual and 2 paired filaments and bearing medium-long primary and secondary stalks; stalk of ventral pair of filaments medium-long, 1.2 times length of common basal stalk, 1.1 and 1.2 times as thick as primary stalks of middle and dorsal triplets, respectively, and 0.9 times as thick as common stalk of middle and dorsal triplets; primary stalk of dorsal triplet lying against that of lower pair at angle of about 80 degrees when viewed laterally; 6 filaments of dorsal and middle triplets subequal in thickness to one another; 2 filaments of ventral pair subequal in thickness to each other, and much thicker than 6 other filaments when compared basally; all filaments light brown, gradually tapered toward apex, and with apical portions of various lengths lost, thus their exact lengths not known; cuticle of all filaments with well-defined annular ridges and furrows though becoming less marked apically, densely covered with minute tubercles.

Abdomen. Dorsally, segment 5 lacking spine-combs but with comb-like groups of minute spines on each side; segments 6–9 each with spine-combs in transverse row (those on segment 9 well developed as those on segments 6–8) and comb-like groups of minute spines on each side; segment 9 with pair of triangular flat terminal hooks of which apices are curved anterodorsally (when viewed laterally) and outer margin is 1.8–1.9 times length of inner margin and crenulated when viewed caudally ( Fig. 2M ). Ventrally, segment 4 with 1 or 2 unbranched hooks (somewhat shorter and thinner than those on segments 5–7). Cocoon. Wall-pocket-shaped, thinly and moderately woven, widely extended ventrolaterally; anterior margin somewhat thickly woven, with anterodorsal portion somewhat broken medially, though having short bulge when viewed dorsally; 3.0 mm long by 2.4 mm wide.

Female and mature larva. Unknown.

Type specimen. Holotype. Male (reared from a pupa and preserved with its associated pupal exuviae and cocoon in a vial with 80% ethanol), collected from a roadside ditch (width 0.5–1.0 m, bed sandy, water temperature 23˚C, exposed to sun, altitude 173 m, N21˚25’687’’/E105˚36’928’’), flowing slowly along the road to Tam Dao Town, Vinh Phuc Province, Vietnam, 10-XI-2013, by H. Takaoka.

Biology. The pupa of this new species was collected from a trailing grass. The associated species was S. (G.) sp. ( Simulium ceylonicum species-group).

Etymology. The species name tamdaoense refers to the name of the locality, Tam Dao, where this new species was collected.

Remarks. As in the preceding species, this new species is assigned to the asakoae species-group by having the yellow hair tuft of the stem vein, enlarged male hind basitarsus and ventral plate with lateral margins emarginated medially ( Fig. 2D ).The male of S. (G.) tamdaoense sp. nov. appears to be related to S. (G.) chiangdaoens e Takaoka & Srisuka described from Thailand and S. (G.) tanahrataense Takaoka, Sofian-Azirun & Ya’cob described from Peninsular Malaysia by having a similar number of upper-eye enlarged facets (in 13 or 14 vertical columns and 15 or 16 horizontal rows in S. (G.) chiangdaoense and in 13 vertical columns and 14 horizontal rows in S. (G.) tanahrataense ) and a similar relative width of the hind basitarsus against the hind tibia (1.0 in S. chiangdaoense and 0.9 in S. (G.) tanahrataense ) ( Takaoka & Srisuka 2009; Takaoka et al. 2014a). However, the male of S. (G.) tamdaoense sp. nov. is distinguished from these two species by the absence of hairs on the subcosta. The pupa of S. (G.) tamdaoense sp. nov. is distinguished from S. (G.) chiangdaoense by the simple wall-pocket-shaped cocoon (cf., with a long anterodorsal projection in S. (G.) chiangdaoense ), and from S. (G.) tanahrataense by the narrower terminal hooks ( Fig. 2M ) (i.e., ratio of the outer margin against the inner margin is 1.8–1.9 in this new species and 2.7–2.8 in S. (G.) tanahrataense ).

Figures

FIGURE 2. Male and pupa of S. (G.) tamdaoense sp. nov. A–K, male; L& M, pupa. A, third segment of right maxillary palp with sensory vesicle (front view); B, tibia of left hind leg (outer view); C, basitarsus with calcipala and second tarsomere with pedisulcus of left hind leg (outer view); D, coxites, styles and ventral plate (ventral view); E & F, right styles (E, medial view; F, ventrolateral view); G, ventral plate and median sclerite (lateral view); H, ventral plate (caudal view); I, left paramere (posterolateral view); J & K, right cerci (J, lateral view; K, caudal view); L, anterior portion of thorax and gill filaments (right side, outer view); M, terminal hooks (caudal view). Scale bars = 0.1 mm for B, C & L, and 0.02 mm for A, D–K & M.