Demicryptochironomus (Irmakia) concavus, Yan, Chuncai, Tang, Hongqu & Wang, Xinhua, 2005

Yan, Chuncai, Tang, Hongqu & Wang, Xinhua, 2005, Demicryptochironomus Lenz from China (Diptera: Chironomidae), Zootaxa 910, pp. 1-31 : 16-20

Demicryptochironomus (Irmakia) concavus sp. n. ( Figs. 6 A–C)

Type material: Holotype male, CHINA: Gansu Province, Tianshui City, Dangchuan County, 1450 m. 5. VIII. 1993. Sweep net, B. Ji. (BDN no. 03383).

Etymology: From Latin concavus , concave, referring to the gonostylus, which is concave in the middle.

Diagnostic characters: This species is similar to D. spatulatus Zhang & Zheng, 1994 , in the characters of the tergite bands and superior volsella, but differs in having a lower antennal ratio (1.6 as opposed to 2.0), presence of frontal tubercles, no sensilla chaetica on the legs, stronger concavity of the gonostylus, and anal point conical with weaker ridges.

Male imago (n = 1)

Total length 3.23 mm. Wing length 1.80 mm. Total length/wing length 1.79. Wing length/length of profemur 2.14.

Coloration: Thorax dark yellowish brown, abdomen yellowish brown, tergite IX and hypopygium dark brown. Legs yellowish green.

Head: AR 1.63, Ultimate flagellomere 650 µm long. Frontal tubercles absent. Inner verticals lost, 4 outer verticals and 6 postorbitals. Clypeus with 12 setae. Tentorium 120 µm long, 38 µm wide. Palpomere lengths (in µm): 38, 40, 150, 163, 240.

Thorax: Antepronotals 4, dorsocentrals 8, acrostichals 8, prealars 3. Scutellum with 9 setae.

Wing ( Fig. 6 A): VR 1.23, R with 8 setae, R1 with 4 setae, R4+5 with 7 setae. Brachiolum with 4 setae. Squama lost. Anal lobe weakly developed.

Legs: Front tibia with 2 subapical setae, 105 µm and 118 µm long; spur of middle tibia 20 µm; 23 µm long, comb with 30 teeth, 11–12 µm long; spur of hind tibia 20 µm; 25 µm long, comb with 35 teeth, 11–12 µm long. Sensilla chaetica absent. Lengths (in µm) and proportions of legs:

Hypopygium ( Figs. 6 B, C): Ninth tergite with hyaline shelf at base of anal point, with posterior margins nearly straight and forming acute angle at base of anal point. Anal point 73 µm long, conical, 13 µm wide at base. Tergite IX with 10 setae. Laterosternite IX with 3 setae. Anal tergite bands Y­shaped. Phallapodeme 112 µm long. Transverse sternapodeme 32 µm long. Superior volsella slender, parallel sided, 63 µm long, rounded and slightly swollen at apex, with 2 long setae, without microtrichia. Gonocoxite 88 µm long and inner margins forming sharp angle in middle. Gonostylus 165 µm long, widest at base, constricted in middle, distal part nearly parallel sided, strongly curved medially, apically rounded, with strong longitudinal keel and 10 marginal setae. HR 0.53; HV 1.96.

Distribution: This species is known only from the type locality, Gansu Province (Palaearctic China).

Demicryptochironomus (Irmakia) constrictus sp. n. ( Figs. 7 A–C)

Type material: Holotype male, CHINA: Guizhou Province, Fanjing Mountain Natural Conservation, Huixiangping, 1. VI. 2002, B. Ji (BDN no. 15039).

Etymology: From Latin constrictus , constrict, referring to the constricted anal point.

Diagnostic characters: The species closely resembles D. (I.) neglectus Reiss in the shape of the superior volsella and the gonostylus. It can be distinguished by the strongly widened anal point, which is slender and conical in D. (I.) neglectus .

Male imago (n = 1)

Total length 3.98 mm. Wing length 1.98 mm. Total length/wing length 2.01. Wing length/length of profemur 1.94.

Coloration: Thorax brown, scutellum and upper scutum light yellow, abdomen yellowish brown, tergite IX and hypopygium dark brown. Femora of fore legs dark brown, remainder of fore legs and mid and hind legs yellowish green.

Head: AR 2.32, Ultimate flagellomere 790 µm long. Frontal tubercles cylindrical, 15 µm long, 5 µm wide. Temporal 13 setae, including 3 inner verticals, 7 outer verticals, and 3 postorbitals. Clypeus with 14 setae. Tentorium 150 µm long, 48 µm wide. Palpomere lengths (in µm): 42, 45, 200, 200, 282.

Thorax: Antepronotals 2, dorsocentrals 10, acrostichals 5, prealars 6. Scutellum with 16 setae.

Wing ( Fig. 7 A): VR 1.06, R with 16 setae, R1 with 14 setae, R4+5 with 16 setae. Brachiolum with 2 setae. Squama with 10 setae. Anal lobe well developed.

Legs: Front tibia with 2 subapical setae, 118 µm and 143 µm long; spur of middle tibia 25 µm; 28 µm long, comb with 36 teeth, 10–11 µm long; spur of hind tibia 25 µm; 38 µm long, comb with 46 teeth, 10–12 µm long. Sensilla chaetica absent. Lengths (in µm) and proportions of legs:

Hypopygium ( Figs. 7 B, C): Anal point 83 µm long, sharply widened medially, with ridges at base extending to tergite IX and with short lateral setae, apically rounded. Tergite IX with 33 setae. Laterosternite IX with 5 setae. Anal tergite bands Y­shaped. Phallapodeme 75 µm long. Transverse sternapodeme 35 µm long. Superior volsella digitiform, bearing 2 apical setae. Gonocoxite short, 95 µm long. Gonostylus 210 µm long, widest at base, constricted in middle, distal part of gonostylus nearly parallel sided, apically rounded, strongly curved in middle with weak longitudinal keel and 10 marginal setae, HR 0.45; HV 1.90.

Distribution: This species was collected with a light trap in a subtropical mountain area in Guizhou Province (Oriental Region).

Figures

FIGURE 6. Demicryptochironomus (Irmakia) concavus sp. n. A. Wing. B. Dorsal view of hypopygium. C. Ventral view of hypopygium.

FIGURE 7. Demicryptochironomus (Irmakia) constrictus sp. n. A. Wing. B. Dorsal view of hypopygium. C. Ventral view of hypopygium.