Smittia brevipennis (Boheman)

Saether, Ole A., 2004, The chironomids (Diptera, Chironomidae) described by Lundström (1915) from arctic Siberia, with a redescription of Derotanypus sibiricus (Kruglova & Chernovskii), Zootaxa 595, pp. 1-35 : 22-23

Smittia brevipennis (Boheman)

( Fig. 22 )

Chironomus brevipennis Boheman, 1856: 575 .

Smittia brevipennis Bohem. ) sensu Lundström (1915: 20).? Smittia subaptera Goetghebuer, 1934: 133

Material examined. RUSSIA: West Taimyr, Taimyr Gulf, 1 Ψ, 11(28) vi 1901, A. A. Birula; New Siberian Islands, Cap Wosnessenje, 2 Ψ, 13 (26) –14 (27) vi 1902, M. I Brussnew.

FEMALE IMAGO (n = 1–3)

Total length 2.26–2.87 mm. Wing length 0.66–0.79 mm, i.e. reduced. Total length/ wing length 3.41–3.53. Wing length/length of profemur 1.37–1.50. Coloration blackish brown.

Head. AR 0.41. Lengths of flagellomeres (in m) as: 68–75, 41–53, 49, 30–45, 84. Temporal setae 6–9, consisting of 1–4 inner verticals, 1–2 outer verticals, and 2–4 postorbitals. Clypeus with 4–13 setae. Tentorium 116–131 m long, 15–21 m wide. Palpomere lengths (in m): 26–30, 34–44, 49, 49, 86.

Thorax. Antepronotum with 2 lateral setae. Acrostichals 2–11 (starting near antepronotum; see Remarks below); dorsocentrals 6–19 (see Remarks below); prealars 5– 6. Scutellum with 4–6 setae.

Wing. VR 1.21–1.24. Costal extension 53–71 m long. Brachiolum with 1 seta, R with 7–11, R1 with 4, R4+5 with 9–12, costal extension with 1–4 non­marginal setae.

Legs. Spur of front tibia 34–36 m long, spurs of mid tibia 30 m and 19–26 m long, spurs of hind tibia 41–53 m and 19–26 m long. Width at apex of front to hind tibiae (in m) as: 32–38, 38–45–60, 56. Comb of 12 setae; shortest seta 24–30 m long. longest seta 38–41 m long. Lengths (in m) and proportions of legs:

Abdomen. Tergite VIII with about 40–55 setae. Sternite VIII with 28–33 median setae and 3–4 setae to each side.

Genitalia ( Fig. 22 ). Tergite IX undivided but with caudal concavity, with about 45–65 setae. Gonocoxite with 9–14 setae. Cercus 75–109 m long. Seminal capsule elongate ovoid, 79–131 m long, 45–71 m wide.

Spermathecal ducts with long loops. Gonapophysis VIII divided, with large ventrolateral lobe and relatively narrow dorsomesal lobe. Notum 116–173 m long.

Remarks

The genitalia agree with the diagnosis in Saether (1977: 103) and confirm placement of the specimens within Smittia Holmgren. The variation in the numbers of acrostichals and dorsocentrals is much larger than expected within one species. The specimen from Taimyr has 11 weak acrostichals and 13 dorsocentrals. One of the specimens from the New Siberian Islands has 4 acrostichals and 6 dorsocentrals, while the other has 19 dorsocentrals and apparently only 2 acrostichals, which are longer than in the other specimens. Normally this would be sufficient to suspect that three species are involved. However, parthenogenetic species with or without reduced wings often show abnormal and aberrant variation, and the present specimens agree in all other major features.

Figures

FIGURES 22 – 23. Female genitalia, ventral view, 22: Smittia brevipennis (Boheman), specimen from Taimyr, 23: Diamesa chorea sensu Lundström, (?) not Lundbeck.