Cryptochironomus maculus Yan & Wang

Yan, Chuncai, Zhao, Guangjun, Liu, Ting, Guo, Qin, Hou, Ziyuan, Wang, Xinhua & Pan, Baoping, 2016, A new record and two new species of Cryptochironomus Kieffer, 1918 from China (Diptera, Chironomidae), Zootaxa 4208 (5), pp. 485-493 : 486-490

Cryptochironomus maculus Yan & Wang sp. n.

( Figs. 2 A–H)

Type material. Holotype: ♂ (BDN No. 24104), China, Jiangxi Province, Wuyishan National Nature Reserve , 26°54′10″N, 116°42′30″E, 13. vi. 2004, light trap, C. C. Yan . 9 Paratypes: 1 ♂ (BDN No. 23289), Hebei Province, Zunhua City, Hongshankou , 40°21′08″N, 118°05′40″E, 9. vii. 2001, light trap, Y. H. Guo ; 1 ♂ (BDN No. 08890), Guizhou Province, Maolan City, Sancha River , 27°31′11″N, 106°54′00″E, 29. vii. 1995, light trap, W. J. Bu ; 3 ♂♂ (BDN No. 0 9859, 0 9862, 09824), Yunnan Province, Eryuan County, Niujie Village, Meizi River , 25°46′72″N, 100°12′20″E, 23. v. 1996, sweeping net, B. X. Wang ; 1 ♂ (BDN No. 11021), Yunnan Province, Dali City, Zhonghelin , 26°10′22″N, 101°25′20″E, 22. v. 1996, X. H. Wang ; 2 ♂♂ (BDN No. 0 4279, 04189), Shaanxi Province, Liuba County, Miaotaizi , 33°41′20″N, 106°51′11″E, 3. viii. 1994, light trap, W. J. Bu. 1 gynandromorphic specimen (No. 09290), Sichuan Province, Yaan City, river close to Sichuan Agricultural University, 29°59′00″N, 102°59′11″E, 5. vi. 1996, light trap, X. H. Wang.

Diagnosis. Mid and hind legs with ta1 yellow-green with dark brown mark in basal part; anal point slender, parallel-sided; superior volsella semi-spherical shape; inferior volsella pillar-shaped, completely covered by superior volsella, and without microtrichia; anal tergite bands V-shaped; gonostylus fused with gonocoxite, point at apex bearing 1 strong seta.

Description. Male imago (n = 9, unless otherwise stated).

Total length 4.43–5.07, 4.75 mm; wing length 2.20–2.70, 2.46 mm; total length / wing length 1.83–2.07, 1.94; wing length /length of profemur 1.88–2.21, 2.02.

Coloration. Thorax yellow brown, with dark brown spots. Femora of front legs yellow brown, tibiae and tarsi dark brown; femora of mid and hind legs yellow green, mid and hind legs with ta1 yellow-green with dark brown mark in basal; ta2–5 of mid and hind legs yellow brown to dark brown gradually ( Fig. 2 A). Abdominal tergites I–IV yellow green, tergites V–VIII yellow brown, hypopygium dark brown.

Head. Antenna with 11 flagellomeres. AR: 1.58–2.78, 2.40. Ultimate flagellomere 570–1000, 907 (7) mm. Frontal tubercles ( Fig. 2 B) column, 11–30, 20 (7) mm high, 6–15, 10(7) mm wide at base, or conical, 17 (2) mm high. Temporal setae 13–23, 19 (8), including 4–7, 6 (8) inner verticals; 4–10, 7 (8) outer verticals; and 4–7, 6 (8) postorbitals. Clypeus with 12–17, 15 setae. Tentorium 113–155, 142 mm long, 40–52, 48 mm wide. Palpomere lengths (µm): 40–58, 48; 62–70, 65; 213–263, 231; 128–200, 186; 238–320; palp segment 5th / 3rd: 1.08–1.46, 1.20.

Thorax. Antepronotum with 3–6, 4 setae, acrostichals 9–13, 11, dorsocentrals 10–13, 11, prealars 4–7, 6. Scutellum with 10–24, 18 setae.

Wing ( Fig. 2 C). VR: 1.05–1.13, 1.10. R with 9–12, 10 setae. R1 with 20–29, 24 setae. R4+5 with 17–28, 22 setae. Brachiolum with 2–3, 2 setae. Squama with 9–12, 10 fringed setae. Anal lobe developed.

Legs ( Fig. 2 A). Front tibia with 3 subapical setae, 130–163, 142 (7) mm, 138–168, 153 (6) mm and 160–180, 168 (5) mm long. Mid legs with 2 tibial spurs, 25–35, 30 mm and 30–47, 40 mm, ta1 with 1–5, 2 sensilla chaetica, comb with 34–54, 43 teeth, 10–13, 12 mm long. Hind legs with 2 tibial spurs of hind tibia 30–38, 33 mm and 35– 55, 46 mm long, ta1 1–2, 2 sensilla chaeticae, comb with 56–66, 61 teeth, 10–13, 12 mm long. Lengths (in µm) and proportions of thoracic legs as in Table 1 .

Hypopygium ( Fig. 2 D–E). Tergite IX bearing 22–30, 26 setae. Laterosternite IX with 2–7, 4 setae. Anal point 70–87, 77 (8) mm long, slender, and parallel-sided. The basal ridge of anal point stretched towards the middle of tergite IX. Superior volsella semi-spherical shaped, with 4 long setae apically. Inferior volsella pillar-shaped, completely covered by superior volsella, with 3 long setae, without microtrichia. Anal tergite bands V-shaped. Phallapodeme 95–113, 106 mm long. Transverse sternapodeme 55–88, 72 mm long. Gonocoxite 113–150, 131 mm long, bearing 5–8, 7 strong setae along inner margin. Gonostylus 160–188,169 mm long, with 6–10, 8 short setae along inner margin, fused with gonocoxite, point at apex bearing 1 strong seta. HR: 0.60–0.92, 0.78; HV: 2.63– 3.07, 2.82.

Gynandromorphic imago (n = 1).

Head. Antenna with 5 flagellomeres ( Fig. 2 F). AR: 0.60. Ultimate flagellomere 210 mm. Frontal tubercles ( Fig. 2 G) conical, 12 mm high, 7 mm wide at basal.

Wing ( Fig. 2 H). VR: 1.16. R with 24 setae. R1 with 22 setae. R4+5 with 45 setae. Brachiolum with 2 setae. Squama with 14 fringed setae. Anal lobe slightly reduced.

Etymology. The specific name is from Latin macula, means ‘mark’, referring to mid and hind legs ta1 yellowgreen with dark brown spot in basal part.

Remarks. The new species is easily recognized by mid and hind legs ta1 yellow-green yellow green with dark brown spot in basal part. This species has marked sexual dimorphism, and one gynandromorphs, as an abnormal creature of unusual juxtaposition of male and female structures, was collected from Southwest of China.

C. maculus Yan & Wang sp. n. is very close to C. rostratus Kieffer, 1921 in the characters of hypopygium: anal point slender, parallel-sided; superior volsella semi-spherical shaped; gonostylus fused with gonocoxite, pointed at the apex bearing 1 strong seta. But the new species can be separated from the latter on the basis of following characters: (1) the inferior volsella pillar-shaped, whereas C. rostratus with much small and tubercle-like inferior volsella; (2) tarsi 1 of mid and hind legs yellow green with dark brown spot in basal; whereas the mid and hind legs C. rostratus yellow brown to dark brown gradually.

Female and immature stages unknown.

Figures

FIGURE 2. Cryptochironomus maculus Yan & Wang sp. n., male. A—legs; B—frontal tubercles; C—wing; D—hypopygium (dorsal view); E—hypopygium (ventral view); F—antenna; G—frontal tubercles; H—wing; (F – G, gynandromorphic imago).

Tables

TABLE 1. Lengths (in µm) and proportions of adult male legs in C. maculus Yan & Wang sp. n. (n = 9).

	P1	P2	P3
fe	1150–1270, 1089	970–1100, 1039	1050–1300, 1057
ti	830–1000, 912	830–1025, 926	1025–1350, 1206
ta1	1460–1590, 1532 (5)	580–690, 641	810–930, 860
ta2	590–770, 692 (5)	210–320, 274	380–420, 398 (8)
ta3	540–610, 572 (5)	170–230, 201	300–340, 323 (8)
ta4	500–550, 530 (5)	100–140, 122	180–200, 193 (8)
ta5	220–240, 226 (5)	80–110, 92	100–120, 108 (8)
LR	1.62–1.82, 1.70 (5)	0.65–0.72, 0.69	0.68–0.75, 0.72