Stenochironomus okialbus Sasa, 1990

Song, Chao, Zhu, Bin-Qing, Moubayed-Breil, Joel, Lei, Teng & Qi, Xin, 2022, Taxonomic study on the genus Stenochironomus Kieffer from the Baishanzu Nature Reserve, China (Diptera, Chironomidae), ZooKeys 1104, pp. 93-113 : 93

publication ID

https://dx.doi.org/10.3897/zookeys.1104.81403

publication LSID

lsid:zoobank.org:pub:E19A9296-55A8-4640-8DC0-0F9E34357F1E

persistent identifier

https://treatment.plazi.org/id/E660BFC4-1161-56C1-9A67-A44404417C81

treatment provided by

ZooKeys by Pensoft

scientific name

Stenochironomus okialbus Sasa, 1990
status

 

Stenochironomus okialbus Sasa, 1990 View in CoL

Figs 9 View Figure 9 , 10 View Figure 10

Stenochironomus okialbus Sasa, 1990: 122, fig. 10.

Material examined.

3 male adults, collected by light trap in Zhejiang Province, Lishui City, Qingyuan County, Baishanzu National Nature Reserve , 27.76°N, 119.31°E, 11-12.VIII.2020, leg. Song C. GoogleMaps

Diagnostic characters.

Stenochironomus okialbus differs from other related species by a combination of characters: wing with dark markings in the middle and apex; superior volsella short and small, spatulate, with four or five long setae; inferior volsella elongate, with 2-4 long setae and a slender terminal spine; posterior margin of tergite IX with 8-10 setae and eight spines.

Description.

Male imago (N = 3). Total length 2.94-3.98, 3.62 mm. Wing length 1.80-1.85 mm. Total length / wing length 1.85-2.20, Wing length / length of pro-femur 178-1.88.

Coloration (Fig. 8 View Figure 8 ). Body almost pale yellowish or white, except postnotum with spot area and tergite IV-VII brown; wing with dark pigmentation on median and apical parts; all legs pale yellow with dark knees and apex of tibia.

Head. AR 1.10-1.25, 1.12, ultimate flagellomere 430-660, 580 µm long. Temporal with 12-16, 14 setae, including 7-8, 7 inner verticals, 4-7, 6 outer verticals and 1-2, 2 postorbitals. Clypeus with 12-20, 17 setae. Tentorium 155-220, 190 μm long, 30-53, 44 μm wide. Palpomere lengths (μm): 33-48, 37; 40-65, 55; 123-195, 170; 85-125, 116; 130-218, 194. Palpomere ratio (5th /3rd) 1.05-1.21, 1.13.

Thorax. Dorsocentrals 14-21, 18; acrostichals 9-12, 11; prealars 5-6, 6; Scutellum with 7-12 setae in two rows.

Wings. VR 1.06-1.10, 1.08. Brachiolum with 1-2, 2 setae. Distribution of setae on veins: R, 20-29, 25; R1, 21-39, 31; R4+5, 49-53, 51. Squama with 10-18, 14 setae. Anal lobe normally developed.

Legs. Fore leg: width at apex of tibia 53-63, 58 μm, tibia with blunt scale 35-50, 44 µm long. Mid leg: width at apex of tibia 53-70, 61 μm, tibia with two apical spurs 43-53, 48 and 45-58, 52 µm long. Hind leg: width at apex of tibia 58-73, 64 μm, tibia with two apical spurs 45-55, 51 and 45-56, 52 µm long. Lengths (in μm) and proportions of legs as in Table 6 View Table 6 .

Hypopygium (Fig. 10 View Figure 10 ). Anal point 110-125, 118 μm long, 43-60; wide, 52 µm width at base, 18-20, 18 µm at apex; slightly swollen and rounded apically. Tergite IX with 19-25, 22 long setae on median part; posterior margin of tergite IX with 6 strong setae and 3 spines. Laterosternite IX with 3-4, 4 setae. Transverse sternapodeme 35-48, 41 μm long; phallapodeme 85-95, 89 μm long. Gonocoxite 138-175, 159 μm long. Gonostylus 185-200, 196 μm long. Superior volsella short, 25-30, 28 μm long, 23-25, 24 μm wide, with 4-5 long setae. Inferior volsella linearly elongate, 183-220, 208 μm long, with 2-3 long setae and 1 stout terminal spine. HR 0.74-0.86, 0.81; HV 1.58-1.97, 1.84.

Remarks.

The morphological characters of the Chinese specimens fit well with the original description and illustrations provided by Sasa (1990): wing with two spotted areas; narrow dark rings on knee points; anal point slightly swollen and rounded. However, some relevant differentiating characters were observed within the examined specimens: the inferior volsella have only two or three long setae, while it bears four in the Japanese specimens; average values of the AR 1.10-1.25 are lower than 1.37-1.41 in the Japanese species.

According to the molecular data, specimen (LC462365) of Stenochironomus okialbus , shows a large genetic distance to other specimens (up to 14%); as the specimen is not accessible it should be rechecked. The K2P distance between Japanese and Chinese specimens is 1.7%, which well supports them as the same species.

Distribution.

Oriental China (Zhejiang) and Japan.

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Diptera

Family

Chironomidae

Genus

Stenochironomus

Loc

Stenochironomus okialbus Sasa, 1990

Song, Chao, Zhu, Bin-Qing, Moubayed-Breil, Joel, Lei, Teng & Qi, Xin 2022
2022
Loc

Stenochironomus okialbus

Sasa 1990
1990