Simulium (Gomphostilbia) chaowaense Takaoka, Srisuka & Saeung, 2020
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publication ID |
https://dx.doi.org/10.3897/zookeys.950.51298 |
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publication LSID |
lsid:zoobank.org:pub:3E805885-D335-4FB3-AE8D-FA443FAD82AE |
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persistent identifier |
https://treatment.plazi.org/id/20CF4BE9-8A76-48F6-A1A8-C37CA48336D7 |
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taxon LSID |
lsid:zoobank.org:act:20CF4BE9-8A76-48F6-A1A8-C37CA48336D7 |
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scientific name |
Simulium (Gomphostilbia) chaowaense Takaoka, Srisuka & Saeung |
| status |
sp. nov. |
Simulium (Gomphostilbia) chaowaense Takaoka, Srisuka & Saeung sp. nov. Figs 15 View Figure 15 , 25G View Figure 25
Material examined.
Holotype: Male (with its associated pupal exuviae and cocoon) (in 80% ethanol) labeled as "Holotype: Simulium chaowaense male, QSBG col. no. 164, Thailand, 16-III-2017, by W. Srisuka", collected from a small stream (width 40 cm, depth 3.5 cm, bed sandy, moderate flow, pH 7.3, 21.9 °C, partially, elevation 582 m, 18°45'30.2"N, 100°20'11.4"E), Chao Wa Waterfall, Song District, Phrae Province, Thailand, 16-III-2017, by W. Srisuka (Coll. No. 164).
Paratypes: Three males (thorax of one male for DNA analysis) (with their associated pupal exuviae and cocoons), and six mature larvae (one mature larva for DNA analysis) (in 80% ethanol), same data as in the holotype
Diagnosis.
Male: number of upper-eye facets in 14 or 15 vertical columns and 14 or 15 horizontal rows, and moderately widened hind basitarsus (Fig. 15A View Figure 15 ) 0.9 times as wide as hind femur. Larva: medium-long postgenal cleft (Fig. 15H View Figure 15 ) 1.2-1.3 times as long as the postgenal bridge and all abdominal segments greyish (Fig. 25G View Figure 25 ).
Description.
Male (N = 4). Body length 2.0-2.3 mm.
Head. Distinctly wider than thorax. Upper eye dark brown, consisting of large facets in 14 or 15 vertical columns and 14 or 15 horizontal rows on each side. Antenna light to medium brown except scape, pedicel, and base of first flagellomere yellow; first flagellomere elongate, 1.8 times length of second. Maxillary palpus: proportional lengths of third, fourth, and fifth palpal segments 1.0:1.0-1.2:2.5-2.8; sensory vesicle globular or ellipsoidal, 0.16-0.17 times length of third palpal segment.
Thorax. Scutum with faint longitudinal vittae (one median and two submedian).
Legs. Foreleg: tibia whitish yellow except basal one-fourth light brown and apical one-third dark brown; basitarsus moderately dilated, 7.3-7.4 times as long as its greatest width. Hind leg: coxa light brown; femur light to medium brown with base yellow and apical cap dark brown (though apical tip yellow); tibia dark brown except little less than basal half yellow; tarsus (Fig. 15A View Figure 15 ) brownish black except little less than basal half of basitarsus and little less than basal half of second tarsomere whitish yellow; basitarsus (Fig. 15A View Figure 15 ) 3.8-4.0 times as long as wide, and 0.8-0.9 and 0.9 times as wide as greatest width of tibia and femur, respectively; calcipala (Fig. 15A View Figure 15 ) slightly shorter than basal width, and 0.36 times as wide as greatest width of basitarsus.
Wing. Length 1.6-1.7 mm. Subcosta with 2-8 hairs.
Genitalia. Coxite in ventral view (Fig. 15B View Figure 15 ) nearly rectangular, 1.8 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. 15B View Figure 15 ) with body transverse, 0.7 times as long as wide, posteroventral margin somewhat concave medially (though slightly convex medially on posterodorsal margin), and lateral margin emarginated medially; basal arms of moderate length, slightly divergent, then convergent apically; ventral plate in caudal view (Fig. 15D View Figure 15 ) rounded ventrally. Cercus with 15 or 16 hairs.
Pupa (N = 4). Body length 2.3-2.5 mm.
Head. Integument yellow.
Thorax. Integument yellow, moderately covered with round tubercles except posterior half sparsely covered with small tubercles on dorsolateral and lateral surfaces. Gill (Fig. 15E View Figure 15 ) composed of eight slender thread-like filaments, arranged asr [(2+1)+3]+2 from dorsal to ventral; common basal stalk 0.7-0.8 times length of interspiracular trunk; dorsal and middle triplets sharing short stalk, and dorsal and middle triplets mostly composed of one individual and two paired filaments with extremely short secondary stalk; stalk of ventral pair of filaments 1.0-1.2 times length of common basal stalk, and 0.7-0.9 times length of interspiracular trunk; primary stalk of dorsal triplet lying against that of lower pair at angle of 70-80° when viewed laterally; filaments of dorsal and middle triplets subequal in length (2.5-2.6 mm) and thickness to one another; two filaments of ventral pair subequal in length (3.0 mm) and thickness to each other (though inner filaments slightly thicker than inner one) and 1.5 times as thick as six other filaments of dorsal and middle triplets when compared basally.
Abdomen. Dorsally, all segments light yellowish; segments 1 and 2 without minute tubercles; segment 9 with pair of wide flat terminal hooks (Fig. 15F View Figure 15 ), of which outer margin is 1.7-2.4 times length of inner margin and crenulated when viewed caudally.
Cocoon (Fig. 15G View Figure 15 ). Slipper-shaped, moderately woven, moderately extended ventrolaterally; anterior margin without bulge or projection; individual threads visible; 3.2-3.6 mm long by 2.0-2.4 mm wide.
Mature larva (N = 5). Body length 4.1-4.5 mm. Body with following color markings: thoracic segment 1 encircled with greyish band (though disconnected ventromedially), ventral surface of thoracic segment 2 grey and that of thoracic segment 3 ochreous; abdominal segments 1-4 encircled with grey transverse band, and abdominal segments 5-8 greyish dorsally and dorsolaterally; abdominal segments 5 and 6 each overlaid with light reddish brown transverse band, appearing W-shaped, on dorsal and dorsolateral surfaces (though often faded out to varying extent, leaving small round medial spot and dorsolateral spots, or only small medial spot), and also overlaid with pair of round spots on ventral surface; abdominal segments 7 and 8 each overlaid with light reddish brown pigments to varying extent on dorsal and dorsolateral surfaces (completely faded out in one larva) (Fig. 25G View Figure 25 ); abdominal segment 7 with light reddish brown transverse band on ventral surface (often faded out, leaving pair of round spots).
Head. Head capsule yellow to dark yellow except eye-spot region whitish, sparsely covered with minute setae (though moderately on dorsal surface); head spots faintly to moderately positive. Antenna: proportional lengths of first, second, and third articles 1.00:0.65-0.75:0.81-0.95. Labral fan with 34-38 primary rays. Hypostoma with row of nine apical teeth, of which median tooth little longer than each corner tooth; lateral margin smooth; four hypostomal bristles per side lying nearly parallel to lateral margin. Postgenal cleft (Fig. 15H View Figure 15 ) rounded, 1.2-1.3 times length of postgenal bridge.
Thorax and Abdomen. Thoracic and abdominal cuticle very sparsely covered with unpigmented minute setae (though few posterior abdominal segments sparsely to moderately covered with dark minute unbranched or bifid setae (rarely trifid setae) on dorsal and dorsolateral surfaces; last abdominal segment densely covered with unbranched colorless minute setae on dorsolateral and lateral surfaces of each side of anal sclerite and on each lateral surface even down to base of ventral papilla. Rectal scales minute, unpigmented. Rectal organ compound, each of three lobes with seven to nine finger-like secondary lobules. Anal sclerite of usual X-form, with anterior arms 1.1 times as long as posterior ones. Posterior circlet with 73-78 rows of hooklets with up to 13 or 14 hooklets per row.
Female. Unknown.
Etymology.
The species name, chaowaense , refers to the name of the waterfall, Chao Wa, where this species was collected.
Distribution.
Thailand (Phrae).
Discussion.
This new species is similar to S. tanahrataense described from males and their associated pupal exuviae collected from Peninsular Malaysia ( Takaoka et al. 2014b) in many characters including the number of male upper-eye facets. However, it is barely distinguished in the male from the latter species by the first flagellomere of the antenna 1.8 times as long as the second (2.1 times in S. tanahrataense ), male hind basitarsus 0.9 times as wide as the hind femur (1.0 time in S. tanahrataense ), and ventral plate with the ventral margin rounded (Fig. 15D View Figure 15 ) when viewed posteriorly (straight or slightly concave in S. tanahrataense ). The pupa of this new species is almost indistinguishable from that of S. tanahrataense , although there is a slight difference in the length of filaments of the dorsal and middle triplets including their stalks and the common basal stalk (2.5-2.6 mm in this new species versus 1.6-2.2 mm in S. tanahrataense ).
This new species is similar to S. confertum from Vietnam ( Takaoka et al. 2017a) in having the similar number of male upper-eye large facets but is distinguished from the latter species by the ventral plate with the ventral margin rounded when viewed posteriorly (nearly straight in S. confertum ).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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