Research Article |
Corresponding author: Atiporn Saeung ( atisaeung.noi@gmail.com ) Academic editor: Art Borkent
© 2022 Wichai Srisuka, Kittipat Aupalee, Yasushi Otsuka, Masako Fukuda, Hiroyuki Takaoka, Atiporn Saeung.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Srisuka W, Aupalee K, Otsuka Y, Fukuda M, Takaoka H, Saeung A (2022) A new species of Simulium (Gomphostilbia) (Diptera, Simuliidae) from Thailand, with a key to identify females of 14 species of the Simulium varicorne species-group. ZooKeys 1083: 1-12. https://doi.org/10.3897/zookeys.1083.77428
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Simulium (Gomphostilbia) khelangense sp. nov. is described on the basis of females, collected by a sweeping net in Lampang, Phitsanulok and Chiang Mai Provinces, Thailand. This new species is placed in the S. chumpornense subgroup of the S. varicorne species-group in the subgenus Gomphostilbia Enderlein by having the antenna with eight flagellomeres, pleural membrane bare, and female subcosta lacking hairs. It is similar to S. kuvangkadilokae Pramual & Tangkawanit from Thailand in the same subgroup but is barely distinguished from the latter species by the head width relative to the greatest width of the frons and length of the labrum relative to the clypeus. A genetic analysis using the COI gene sequences similarly shows that S. khelangense sp. nov. is most closely related to S. kuvangkadilokae, with a genetic distance of 1.23–2.81%. A revised key to identify females of 14 species of the S. varicorne species-group is provided.
Aquatic insects, biodiversity, blackflies, sweeping net, taxonomy
The Simulium varicorne species-group, one of the 15 species-groups of the subgenus Gomphostilbia Enderlein of the genus Simulium Latreille, redefined by
Biting habits and other biological aspects of these species remain unknown, although females of S. burtoni and S. chumpornense were captured using human attractants at low and medium elevations in Doi Inthanon National Park in Chiang Mai (
Recently, we found a female of an unnamed species of the S. varicorne species-group, for which hereafter we call “Simulium sp.” as used by
In this study, we aimed to evaluate the status of S. sp. by morphologically and molecularly examining additional adult females collected by a sweeping net while they were flying around a human attractant, and to provide a revised key to identify females of 14 species of the S. varicorne species-group.
Nine females of adult black flies (with eight antennal flagellomeres and without hairs ventrally on their subcosta) preserved in 80% ethanol after collection at three localities were used in this study. All were morphologically examined for color of legs, and heads and abdomens of three females (from each site) were treated with KOH solution overnight and observed in detail. The methods of collection, description and illustration, as well as terms for morphological features, followed those of
All but two were separated into three parts, head, thorax, and abdomen, and the thoraces were used for DNA analysis. The localities, number of females, designated numbers for DNA analysis are as follows:
The procedures for DNA extraction, PCR amplification, and sequencing followed those of
After DNA sequencing, sequence assembly and alignment were conducted using Geneious Prime 2021.1.1 (
This paper and the nomenclatural acts have been registered in ZooBank (www.zoobank.org), the official register of the International Commission on Zoological Nomenclature. The Life Science Identifier (LSID) numbers are noted under the new species of black flies.
All females seem to be indistinguishable from one another in many features except the mandible, which had three or four distinct outer teeth in six females (CPPH-1, CPPT-1, CPPT-2, CPPT-3, CPRK-2 and CPRK3), but had a few weak outer teeth in one female (CPRK-1).
All females of S. sp. have the subcosta lacking hairs ventrally indicating that these females are placed in the S. chumpornense subgroup in the S. varicorne species-group. Among six known species of the S. chumpornense subgroup, S. kuvangkadilokae and S. piroonae, both from Thailand, are similar to S. sp. in having the hind tibia darkened on the apical half. However, S. sp. is distinguished from S. kuvangkadilokae by the width of the head relative to the greatest width (4.21–4.66 versus 3.78–4.05), length of the labrum relative to the clypeus (0.65–0.69 versus 0.57–0.59), and length of the fore basitarsus relative to its greatest width (6.29–6.38 versus 5.56); from S. piroonae by the length of the sensory vesicle relative to the third segment (0.33–0.39 versus 0.25–0.30), and length of the fore basitarsus relative to its greatest width (6.29–6.38 versus 5.54–5.68) (
A genetic analysis using the COI gene sequences shows two clear clades, one consisting of S. kuvangkadilokae and S. sp. including the sample previously reported (MT262583), and the other consisting of S. chumpornense and S. piroonae (Fig.
Neighbor-joining tree of the four Thai species in the S. chumpornense subgroup of the S. varicorne species-group based on 658 bp COI gene sequences. Bootstrap and posterior probability values (NJ/BI) are shown above each branch. The scale bar represents 0.01 substitutions per nucleotide position. Sequences in bold type are generated in this study.
Holotype : Female (whole body) captured by a sweeping net, at Ban Lek, Fang District, Chiang Mai Province, 20°04'36.3"N, 99°10'53.0"E, 1571 m in elevation, 29 III 2018, by Wichai Srisuka (Site 2). Paratypes: One female and one female (except thorax), same data and date as for the holotype, three females (except thorax), collected at Pratoo Pha, Mueang, Lampang Province (Site 1); three females (except thorax) collected at Ban Romklao Botanic Garden, Chat Trakan, Phitsanulok Province (Site 3).
Female adult: the only species of the S. chumpornense subgroup with antenna with eight flagellomeres, pleural membrane bare, subcosta bare, and hind tibia darkened on apical half, with dark subbasal marking and relatively slender fore basitarsus (6.29–6.38 times as long as its greatest width).
Female (N = 9). Body length 2.3–2.5 mm.
Head. Slightly narrower than thorax. Frons brownish black, dull, densely covered with yellowish-white scale-like recumbent short hairs; frontal ratio 1.35–1.44:1.00:1.71–2.09; frons:head ratio 1.00:4.21–4.66. Fronto-ocular area well developed, directed laterally and slightly upward. Clypeus brownish black, densely covered with yellowish-white scale-like short hairs interspersed with several dark unbranched longer hairs along lateral margin on each side. Labrum 0.65–0.69 times as long as clypeus. Antenna (Fig.
Female of Simulium khelangense sp. nov. A antenna (left side; dorsal view) B third palpal segment with sensory vesicle (right side; front view) C cibarium D mid tibia (left side; outer view) E hind tibia (left side; outer view) F hind basitarsus and second tarsomere (left side; outer view) G claw of hind tarsus (lateral view) H eighth sternite and ovipositor valves (ventral view) I genital fork (ventral view) J, K paraprocts and cerci (right side; J ventral view K lateral view) L spermatheca. Scale bars: 0.1 mm (D–F); 0.05 mm (A); 0.02 mm (B, C, H–L); 0.01 mm (G).
Thorax. Scutum brownish black (except anterolateral calli ochreous), shiny, gray-pruinose with three longitudinal nonpruinose vittae (one medial and two submedial), densely covered with yellowish-white scale-like recumbent short hairs intermixed with brownish similar hairs. Scutellum dark brown, covered with yellowish-white short hairs and dark brown upright long hairs. Postnotum dark brown, bare, slightly shiny and gray-pruinose when illuminated at certain angle. Pleural membrane bare. Katepisternum dark brown, longer than deep, moderately covered with yellowish fine hairs interspersed with dark brown hairs.
Legs. Foreleg: coxa and trochanter yellowish white; femur medium brown though apical tip yellow; tibia medium brown, except base yellow, and median large portion on outer surface and apex light brown; tarsus brownish black, with moderate dorsal hair crest; basitarsus somewhat dilated, 6.29–6.38 times as long as its greatest width. Midleg: coxa dark brown; trochanter light brown; femur medium to dark brown though apical tip yellow; tibia (Fig.
Wing. Length 2.0 mm. Costa with dark brown spinules and dark brown hairs except basal portion with patch of white hairs. Subcosta bare. Hair tuft on base of radial vein white. Basal portion of radius fully haired. Basal cell absent.
Halter. White with base of stem darkened.
Abdomen. Basal scale light brown, with fringe of yellowish-white fine hairs. Dorsal surface of abdomen medium brown to brownish black except little less than basal one-half lighter, moderately covered with yellowish-white short hairs interspersed with dark brown long hairs; tergites of segments 2 and 6–8 shiny; sternal plate on segment 7 undeveloped.
Genitalia. Sternite 8 (Fig.
Male, pupa and larva. Unknown.
The species name khelangense refers to Khelang, an old name of Lampang Province, where this new species was collected.
Thailand (Lampang, Phitsanulok and Chiang Mai).
Females of this new species were captured while attracted to a human, though they have a large claw tooth, a characteristic suggesting that this species is ornithophilic (
Simulium khelangense sp. nov. is placed in the varicorne species-group in the subgenus Gomphostilbia by having the antenna with eight flagellomeres (Fig.
The female of this new species is distinguished from those of S. kuvangkadilokae and S. piroonae of the S. chumpornense subgroup, as noted above. This species is also distinguished from the four other members of the same subgroup: S. chumpornense from Thailand, S. sumbaense Takaoka & Suana from Sumba, Indonesia, S. tomae Takaoka from Sulawesi, Indonesia, and S. varicorne Edwards from Sumatra and Java, Indonesia, and Peninsular Malaysia, by the hind tibia darkened on the apical half (darkened on the apical one-third in the latter four species) (
The female of S. breviflagellum Takaoka & Sofian-Azirun from Vietnam is not included because its female is unknown.
1 | Antenna with seven flagellomeres | 2 |
– | Antenna with eight flagellomeres | 3 |
2 | Sensory vesicle 0.29–0.31 times length of third palpal segment | S. charlesi Takaoka |
– | Sensory vesicle 0.21–0.25 times length of third palpal segment | S. novemarticulatum Takaoka & Davies |
3 | Pleural membrane haired | S. trirugosum Davies & Györkös |
– | Pleural membrane bare | 4 |
4 | Subcosta haired ventrally | 5 |
– | Subcosta bare | 8 |
5 | Abdominal segments 5–8 shiny dorsally | 6 |
– | Abdominal segments 6–8 shiny dorsally | 7 |
6 | Flagellomeres darkened except basal one-third of first flagellomere yellow | S. huangi Takaoka |
– | Flagellomeres 3 and 5–8 darkened and others yellow | S. burtoni Takaoka & Davies |
7 | Hind femur entirely darkened | S. shogakii Rubtsov |
– | Hind femur darkened on apical one-third | S. synanceium Chen & Cao |
8 | Hind tibia darkened on apical half | 9 |
– | Hind tibia darkened on apical one-third | 11 |
9 | Fore basitarsus 6.29–6.38 times as long as its greatest width | S. khelangense sp. nov. |
– | Fore basitarsus 5.54–5.68 times as long as its greatest width | 10 |
10 | Head 3.78–4.05 times as wide as greatest width of frons | S. kuvangkadilokae Pramual & Tangkawanit |
– | Head 4.30–4.54 times as wide as greatest width of frons | S. piroonae Takaoka & Srisuka |
11 | Head 6.7 times as wide as greatest width of frons | S. tomae Takaoka |
– | Head 3.7–5.2 as wide as greatest width of frons | 12 |
12 | Head 4.7–5.2 times as wide as greatest width of frons | S. varicorne Edwards |
– | Head 3.9–4.0 as wide as greatest width of frons | 13 |
13 | Height of frons 1.7 times as long as narrowest width | S. chumpornense Takaoka & Kuvangkadilok |
– | Height of frons 1.3–1.4 times as long as narrowest width | S. sumbaense Takaoka & Suana |
Considering the morphological and genetic evidence, we conclude that S. sp. sensu
We are grateful to Dr Peter H. Adler (Professor Emeritus, Clemson University, Clemson, SC, USA) for reading the current manuscript and providing valuable comments. We acknowledge funding from the Ministry of Education, Malaysia, under the Higher Institution of Centre of Excellence (HICoE) niche area vector and vector-borne diseases (Project no. MO002–2019). This research was funded by the Office of Research Administration, Chiang Mai University, Thailand (A. Saeung).