Simulium (Gomphostilbia) banluangense Takaoka, Srisuka & Fukuda, 2020

Takaoka, Hiroyuki, Srisuka, Wichai, Fukuda, Masako & Saeung, Atiporn, 2020, Twenty-one new species of the Simulium (Gomphostilbia) asakoae species group (Diptera, Simuliidae) in Thailand, with their genetic relationships, ZooKeys 950, pp. 51-152 : 51

Simulium (Gomphostilbia) banluangense Takaoka, Srisuka & Fukuda sp. nov. Fig. 17

Material examined.

Holotype: Male (with its associated pupal exuviae and cocoon) (in 80% ethanol) labeled as "Holotype: Simulium banluangense male, Thailand, 12-VI-2001, by W. Choochote & H. Takaoka", reared from a pupa collected from a stream (width 1.0 m, 25 °C, exposed to the sun, elevation 804 m, 18°32'33.3"N, 98°35'32.5"E), at Ban Luang, Chiang Mai Province, Thailand, 12-VI-2001, by W. Choochote and H. Takaoka.

Diagnosis.

Male: upper-eye (large) facets in 14 vertical columns and 14 or 15 horizontal rows on each side, and hind basitarsus (Fig. 17A ) spindle-shaped. Pupa: gill with a short common basal stalk and a short stalk of the ventral pair of filaments, which is thicker than the interspiracular trunk (Fig. 17E, F ), and terminal hooks triangular (Fig. 17G ).

Description.

Male (N = 1). Body length 2.4 mm.

Head. Slightly wider than thorax. Upper eye medium brown, consisting of 14 vertical columns and 14 or 15 horizontal rows of large facets on each side. Antenna: first flagellomere elongate, 1.9 times length of second. Maxillary palpus: proportional lengths of third, fourth, and fifth palpal segments 1.0:1.2:3.0; sensory vesicle 0.21-0.24 times length of third palpal segment.

Legs. Foreleg: tibia light brown except median large area of outer surface of basal three-fourths whitish and apical one-fourth dark brown; tarsus brownish black; basitarsus moderately dilated, 6.4 times as long as its greatest width. Midleg: tarsus dark brown except basal one-fourth to two-fifths of basitarsus dark yellow to light brown (border not well defined). Hind leg: tibia dark brown to brownish black except little less than basal half whitish yellow; tarsus (Fig. 17A ) brownish black except basal half of basitarsus and basal one-third of second tarsomere whitish yellow; basitarsus (Fig. 17A ) 3.8 times as long as wide, and 0.9 and 0.9 times as wide as greatest width of tibia and femur, respectively; calcipala (Fig. 17A ) slightly shorter than basal width, and 0.34 times as wide as greatest width of basitarsus.

Wing. Length 2.1 mm. Subcosta with seven hairs.

Genitalia. Coxite in ventral view (Fig. 17B ) nearly rectangular, 1.6 times as long as its greatest width. Style in ventrolateral view slightly tapered toward apex, with truncated apex, and 0.8 times as long as coxite. Ventral plate in ventral view (Fig. 17B ) with body transverse, 0.5 times as long as wide; ventral plate in caudal view (Fig. 17D ) rounded ventrally, with ventral margin slightly raised medially. Cercus small, rounded, with 15-17 hairs.

Pupa (N = 1). Body length 3.0 mm.

Thorax. Gill (Fig. 17E, F ) composed of eight slender thread-like filaments, arranged as [(2+1)+(1+2)]+2 or [3+(1+2)]+2 from dorsal to ventral; common basal stalk short, 0.5-0.6 times length of interspiracular trunk; dorsal and middle triplets sharing short stalk, stalk of ventral pair of filaments short, 0.8 times length of common basal stalk, and 0.4-0.5 times length of interspiracular trunk, and thicker than interspiracular trunk; primary stalk of dorsal triplet lying against that of lower pair at angle of 90° when viewed laterally; stalk of middle triplet directed inward; filaments of dorsal and middle triplets subequal in length (2.5-2.9 mm) and thickness to one another; two filaments of ventral pair subequal in length (3.2-3.5 mm) and thickness to each other and 1.6 times as thick as six other filaments of dorsal and middle triplets when compared basally.

Abdomen. Dorsally, segments 1 and 2 without minute tubercles; terminal hooks (Fig. 17G ) triangular, with outer margin slightly undulate, and little less than twice length of inner margin.

Cocoon (Fig. 17H ). Slipper-shaped, roughly to moderately woven, widely extended ventrolaterally; anterior margin thickly woven medially, with bulge; individual threads visible; 3.5 mm long by 3.0 mm wide.

Female and Larva. Unknown.

Etymology.

The species name, banluangense , refers to the name of the locality, Ban Luang, where this species was collected.

Distribution.

Thailand (Chiang Mai).

Discussion.

Simulium doisaketense described based on pupal and larval specimens from Thailand ( Jitklang et al. 2008), has the pupal gill with a short common basal stalk, like this new species, but the stalk of the ventral pair of filaments is medium-long, 1.3 times as long as the common basal stalk, and thinner than the interspiracular trunk, based on observations of the type specimen.

Figures

Figure 17. Male and pupa of S. banluangense sp. nov. A-D male E-H pupa. A hind basitarsus and second tarsomere (left side; lateral view) B coxites, styles and ventral plate (ventral view) C ventral plate and median sclerite (lateral view) D ventral plate (caudal view) E, F gill filaments (lateral view E right side F left side) G terminal hooks (caudal view) H cocoon (dorsal view). Scale bars: 1.0 mm (H); 0.1 mm (A, E, F); 0.02 mm (B-D); 0.01 mm (G).