Boreoheptagyia brevitarsis (Tokunaga), 1981

Makarchenko, Eugenyi A., Endo, Kazuo, Wu, Jingyang & Wang, Xinhua, 2008, A review of Boreoheptagyia Brundin, 1966 (Chironomidae: Diamesinae) from East Asia and bordering territories, with the description of five new species, Zootaxa 1817 (1), pp. 1-17 : 6-8

Boreoheptagyia brevitarsis (Tokunaga)

( Figs 14–20 )

Prodiamesa (Monodiamesa) brevitarsis Tokunaga, 1936: 528 .

Heptagyia brevitarsis (Tokunaga) ; Tokunaga (1939: 302); Sasa and Kikuchi (1995: 207).

Boreoheptagyia brevitarsis (Tokunaga) ; Serra-Tosio (1989: 140); Makarchenko (1981: 89, 1985: 38, 2006: 259) misidentifications; Endo (2002: 12).

Boreoheptagyia kurobeia Sasa et Okazawa, 1992 ; Endo (2002: 12).

Material examined. JAPAN: Honshu , Kyoto Prefecture, Kibune , 2 males, 16.x.1934, M. Tokunaga ( KPU) ; Gifu Prefecture, Kamioka, Futatsuya, Takahara River , 1 male, 28.v.2001, K. Endo ; Niigata Prefecture, Yuzawa, Tsuchitaru, Kedo-sawa , 1 male, 26.vi. 2001, K. Endo ; Hokkaido, Shintoku, Yutomuraushi River , 700 m a.s.l., Malaise trap, 2 males, 11–21.vi. 1999, K. Endo; Kiushu , Fukuoka Prefecture, Hoshino, Kumado River , 1 male, 26.iii.2002, K. Endo .

Male (n = 3)

Total length 2.27–2.50 mm. Wing length 1.7–2.16 mm. Total length / wing length 1.16–1.27.

Coloration. Body dark brown. Legs brown, tibiae of all legs white medially.

Head. Frontal tubercles 24–28 µm long, with 2–3 setae basally. Temporal setae includes 7–10 frontals, 7– 9 inner verticals, 8–18 outer verticals, and 4–7 postorbitals. Clypeus with 10–14 setae. Antenna with 13 flagellomeres. AR 0.11–0.16. Lengths (in µm) of palpomeres 1–5: 28–32, 36–46, 72–86, 96–100,148–160. Head width / palp length 1.16–1.20.

Thorax. Antepronotum with 7 lateral setae. Acrostichals 30–37, dorsocentrals 17–23 in anterior and posterior groups, prealars 17–28, supraalars 1–2. Scutellum with 61–70 setae.

Wing. Costal extension 65–73.8 µm long. Anal lobe well developed, fully fringed. Alula without setae. Squama with 27–48 setae. R and R 1 with 8–11 setae, R 4+5 with 2–4 setae, R 2+3 reduced and visible only in basal part. RM/MCu 2.5–2.6.

Legs. Spur of foretibia 32–36 µm long, spurs of midtibia 28–36 µm and 32–36 µm long, of hind tibia 32– 38 µm and 48–56 µm long. Hind tibial comb with 11–12 setae. Lengths and proportions of legs as in Table 3.

Hypopygium ( Figs 15–20 ). Tergite IX with concave posterior margin and 29–36 setae. Laterosternite IX with 3–4 setae. Transverse sternapodeme 60–64 µm wide. Aedeagal lobe sharply triangular, phallapodeme not clearly discernable, sometimes visible as narrow appendage ( Figs 19–20 ). Gonocoxite 180 µm long; basal lobe widely triangular with rounded apex and 1–2 setae. Gonostylus 88 µm long, wrinkled, slightly curved, ending in short megaseta.

Remarks. We redescribe the male of B. brevitarsis as K. Endo compared specimens from the Kolyma River Basin of the Magadan Region in Russia and from Hokkaido of Japan with the type material of B. brevitarsis deposited in Kyushu University, Japan and concluded that all males from Kolyma River and some males from Hokkaido clearly differs from the type material in several features of the thorax and hypopygium. We therefore describe these specimens as a separate species, B. sasai sp. n., below.

Distribution. The species is now for certain only known from Japan. All other records based on larvae from China and the Russian Far East should be revised.

Figures

FIGURES 14–20. Boreoheptagyia brevitarsis (Tokunaga, 1936) males from Hokkaido (14, 16, 19), Honshu (15, 20) and Kyushu (17, 18). 14. Scutum, dorsal view. 15–17. Tergite IX. 18. Transverse sternapodeme. 19–20. Hypopygium with tergite IX removed, dorsal view. Scale bars: Fig. 14 = 200 µm, Figs 15–20 = 50 µm.