Synorthocladius bifidus, Liu, Yuedan & Wang, Xinhua, 2005

Liu, Yuedan & Wang, Xinhua, 2005, Synorthocladius Thienemann from China, with a review of the genus (Diptera: Chironomidae: Orthocladiinae), Zootaxa 1057, pp. 51-60 : 52-54

Synorthocladius bifidus sp. n. ( Figs. 1–4 )

Synorthocladius tamaparvulus Sasa sensu Wang 2000: 640 .

Holotype: Male, CHINA: Yunnan Province: Eryuan County: Niujie Township: Futianlin, Meicihe (26° 15 N, 100° 0 0 E), alt. 2262 m, 23.V.1996, light trap, B. Wang, slide no. 10086.

Paratypes: 2 males, same data as holotype; 5 males, Guangdong Province, Fengkai County, Heishiding Natural Conservation (23° 27 N, 111° 30 E), alt. 450 m, 20.IV.1988, light trap, X. Wang.

Male (n = 8, except when otherwise stated).

Total length 1.65–2.18, 1.90 mm. Wing length 1.15–1.45, 1.28 (7) mm. Total length/ wing length 1.35–1.58, 1.49 (7). Wing length/length of profemur 2.28–2.61, 2.39 (7).

Coloration [slide mounted material]: Head brown with dark brown frontal vertex. Thorax yellow with darker vittae, scutum, anterior anepisternum II, preepisternum, epimeron II, and postnotum. Abdominal segments yellow­brown. Legs yellow­brown. Wings light brown.

Head: Terminal flagellomere 200–280, 247 (7) µm long. AR 0.44–0.67, 0.57 (7). Temporal setae 3–6, 4, including 0–1, 1 inner verticals and 2­4, 3 postorbitals, without outer vertical. Clypeus with 4–6, 5 setae. Tentorium ( Fig. 1 ) 110–113, 120 µm long, narrow part sinuous and with well­developed medial tooth, appearing bifurcated. Stipes 98­114, 106 µm long. Palpomere lengths (in µm): 25–31, 29; 33–42, 35; 45–63, 56; 55–78, 66; 108–126, 117.

Thorax ( Fig. 2 ): Antepronotum with 1­4, 3 (6) lateral setae. Acrostichals 1­2, 1, dorsocentrals 1–4, 3, prealars 2–3, 3. Scutellum with 2–4, 3 setae.

Wing ( Fig. 3 ): Anal lobe normal. VR 1.12–1.22, 1.18 (7). R2+3 ends 1/3 distance between R1 and R4+5. Costal extension 60–84, 72 µm long. Brachiolum without setae; R with 1–4, 2 setae; remaining veins bare. Cu1 slightly curved and end of Cu1 slightly recurved. Squama with 6–10, 8 (6) setae.

Legs ( Table 1 ): Spur of front tibia 28–38, 33 µm (7) long, spurs of middle tibia 15–20, 17 µm and 15­20, 17 µm long, of hind tibia 33–45, 39 µm and 12­18, 14 µm long. Hind tibial comb with 8–11, 9 setae. Middle and hind tibial spurs with denticles. Pseudospurs absent.

ta3 ta4 ta5 LR

p1 160–200, 185(6) 110–140, 123(6) 70–80, 75(6) 0.58–0.64, 0.61(6) p2 90–120, 101 60–80, 74 50–70, 64 0.49–0.51, 0.50 p3 120–160, 144 80–100, 88 60–90, 74 0.51–0.60, 0.54 Hypopygium ( Fig. 4 ): Tergite IX with 12–15, 13 long setae. Anal point short and with pointed apex, 12–15, 14 µm long, 3–6, 5 µm wide at base. Anal point length/width 4.41– 5.68, 4.78, with 6­8, 7 long setae at base. Phallapodeme 67–87, 73 µm long; transverse sternapodeme 78–98, 88 µm long, with oral projection. Gonocoxite 118–165, 134 µm long. Gonostylus strongly arched, 56–78, 66 µm long, with small crista dorsalis near apex. Inferior volsella apically rounded, short and finger shaped, with 3 or 4, 3 setae. Megaseta 8–10, 9 long. HR 1.75–2.44, 2.05, HV 2.14–3.10, 2.71.

Female and immature stages: Unknown.

Etymology: The species name is from Latin, bifidus , split into two parts, referring to the bifurcated tentorium.

Distribution: The specimens were collected with a light trap in a subtropical mountain area in two South Chinese Provinces (Oriental China). They represent the first records of the genus in the Oriental Region.

Remark s: Among the recorded species of the genus, the present new species is close to S. semivirens (Kieffer) , but can be separated by having a short and finger­shaped inferior volsella, bifurcated tentorium, and darker scutal stripes. When we examined the specimen from Guangdong Province, we found that the species S. tamaparvulus listed in Wang (2000) was incorrectly identified. The material from Guangdong listed by Wang (2000) is actually the present new species.

Figures

FIGURES 1 – 4. Synorthocladius bifidus sp. n. (Holotype). 1, tentorium; 2, thorax; 3, wing; 4, hypopygium.

Tables

TABLE 1. Lengths (in µm) and proportion of leg segments of S. bifidus sp. n.

	fe	ti	ta1 ta2
p1	440–600, 545	450–560, 512	290–330, 315(7) 240–280, 262(6)
p2	420–550, 494	370–470, 425	190–230, 211 110–160, 134
p3	480–580, 540	420–580, 515	250–310, 279 150–210, 186