Polypedilum (Cerobregma) paucisetum, Zhang, Ruilei, Wang, Xinhua & Saether, Ole A., 2006

Zhang, Ruilei, Wang, Xinhua & Saether, Ole A., 2006, Two unusual species of Polypedilum Kieffer (Diptera: Chironomidae) from Oriental China, Zootaxa 1282, pp. 39-48 : 40-43

Polypedilum (Cerobregma) paucisetum sp. n.

( Figs. 1–7 )

Type material

Holotype male, CHINA: Guangdong Province, Fengkai County, Heishiding Natural Reserve, 20.iv.1988, light trap, X. Wang (BDN No.: 05921). Paratypes: 9 males as holotype; 2 males, Guizhou Province, Fanjing Mountain Natural Reserve, Huoguo Temple, 3.viii.2001, light trap, R. Zhang; 3 males, Guizhou Province, Jiangkou County, 27.vii.2001, light trap, R. Zhang; 1 male, Guizhou Province, Luodian County, 420 m a.s.l., 7.viii.1995, light trap, W. Bu; 1 male, Yunnan Province, Mengla County, Menglun Township, 12.iv.1987, H. Zou.

Diagnostic characters

The species has an Uresipedilum ­like superior volsella, which is unique in the subgenus Cerobregma . The low number of anal tergite setae and the setae along inner margin of the gonostylus being not­split, will separate the species from other members of the subgenus.

Description

Male (n = 10 except when otherwise stated). Total length 2.59–3.38, 2.99 mm. Wing length 1.62–2.13, 1.93 mm. Total length / wing length 1.43–1.67, 1.55. Wing length / length of profemur 1.95–2.21, 2.11.

Coloration. Head brown. Thorax brown with darker vittae, postnotum and preepisternum. Abdominal segments entirely brown or tergites II–V brown with pale posterior margins. Legs and wings uniformly brown.

Head. AR 0.54–0.91, 0.72. Ultimate flagellomere 368–525, 441 m long. Temporal setae 11–18, 16; including 3–10, 7 inner verticals; 4–9, 7 outer verticals and 1–3, 2 postorbitals. Clypeus with 16–30, 22 setae. Tentorium 107–143, 117 m long, 36–52, 43 m wide. Palpomere lengths (in m): 31–47, 39; 49–57, 52; 104–146, 121; 109–151, 130; 177–252, 211.

Wing ( Fig. 1 ). VR 1.14–1.32, 1.23. Brachiolum with 1 seta; R with 18–29, 23; R1 with 20–35, 29; R4+5 with 34–67, 50; RM with 0–3; M with 0–2 setae. Squama with 11–19, 16(8) setae.

Thorax. Antepronotals and scutal tubercle absent. Dorsocentrals 12–23, 18; acrostichals 9–19, 14; prealars 5–11, 8. Scutellum with 11–19, 15 setae.

Legs. Terminal scale ( Fig. 2 ) of front tibia triangular, 44–70, 57 m long with small spine; spur on median tibiae 52–68, 62 m long including 23–34, 30 m long comb, unspurred comb 18–34, 25 m long; spur on posterior tibia 57–78, 67 m long including 29–52, 37 m long comb, un­spurred comb 23–36, 29 m long. Width at apex of front tibia 49–65, 56 m; of mid tibia 52–68, 58 m; of hind tibia 55–73, 65 m. Lengths (in m) and proportions of legs as in Table 1 .

Hypopygium ( Figs. 3–7 ). Anal tergite bands strongly developed, fused basally and apically, completely surrounding 1–5, 3 strong median anal tergite setae. Laterosternite with 2–3, 3 setae. Anal point 62–100, 79 m long, tapering. Phallapodeme 81–108, 97 m long; transverse sternapodeme 26–55, 37 m long. Gonocoxite 130–168, 152 m long with bulb­like apicolateral extension. Superior volsella ( Figs. 3–5 ) not projecting posteriorly, base with 2–4 inner and 2–4 apical setae, with microtrichiae; apicomedial projection long, slender, with sharply pointed apex. Inferior volsella apically split in 3 lobes with 20–27 not­split subapical setae and an apical seta. Gonostylus 120–165, 139

m long, with long, not­split setae along inner margin. HR 0.98–1.20, 1.09. HV 1.88–2.29, 2.14.

Remarks

In this new species, the basal portion of the superior volsella is low and broad, the apical processes arise from the inner margin of its base and are directed inwards, which are typical in the subgenus Uresipedilum Oyewo and Saether. The superior volsella is somewhat similar to the volsellae of P. (C.) bulbocaudatum Saether and Sundal , P. (C.) subulatum Saether and Sundal ( Saether & Sundal 1999: Figs. 43–44) and P. (C.) okigrandis Sasa ( Sasa 1993: Fig. 10.5). However, in these three species the apical process of the superior volsella arise from the outer margin of its base. In the new species neither the setae along the inner margin of the gonostylus nor any setae of the inferior volsella are split, which separate it from most other members of the subgenus Cerobregma . However, according to the descriptions both P. (C.) kamotertium Sasa (Sasa 1989: 64) and P. (C.) okigrandis lack split setae. Saether and Sundal (1999), however, assumed that the branching of the setae had been overlooked. Kobayashi et al. (2003) showed that this is indeed the case at least in P. (C.) kamotertium .

Figures

FIGURES 1 – 7. Polypedilum (Cerobregma) paucisetum sp. n., male. 1. Wing. 2. Fore tibial scale. 3 – 5. Superior volsella. 6. Hypopygium, dorsal view. 7. Hypopygium, ventral view. Scales = 50 m.

Tables

TABLE 1. Lengths (in m) and proportions of legs of Polypedilum (Cerobregma) paucisetum sp. n., male (n = 8 – 14).

	fe	ti	ta1	ta2	ta3	ta4	ta5	LR
p1	830–1040, 917	546–630, 592	956–1215, 1097	641–783, 712	441–525, 483	368–473, 423	179–221, 196	1.75–1.93, 1.85
p2	977–1242, 1096	777–972, 875	399–515, 451	242–326, 284	189–242, 220	133–186, 155	80–106, 94	0.48–0.56, 0.51
p3	987–1323, 1159	830–1053, 942	578–756, 644	336–441, 391	315–410, 354	221–273, 219	95–137, 113	0.64–0.72, 0.69