Polypedilum (Pentapedilum) intuber, Oyewo & Saether, 2008

Oyewo, Emmanuel Adeoye & Saether, Ole A., 2008, Revision of Polypedilum (Pentapedilum) Kieffer and Ainuyusurika Sasa et Shirasaki (Diptera: Chironomidae), Zootaxa 1953, pp. 1-145 : 67-68

Polypedilum (Pentapedilum) intuber sp. n.

( Figs 21A–B)

Type material. Holotype male, CANADA: Manitoba, Lake Winnipeg, 5 km off Selkirk (Horse) Island, 29.vi.1969, light trap, S. S. Chang ( CNC); Manitoba, Lake Winnipeg , Hecla Island , 2 paratype males, 27.vi.1971, light trap, M. P. McLean ( ZMBN).

Other material. USA: Alabama, Elmore Co., Wallahatchee Creek, 3.2 miles west of Tallassee at Hwy 8, 1 male, 21.iii.1989, W.E. Garrett (Coll. J. Epler) .

Diagnostic characters. The species has numerous setae on the wing membrane, uniformly colored abdomen, foretibial scale with spur, base of superior volsella without microtrichia and projection almost straight as in P. (Pe.) muscicola and P. (Pe.) botasaneanui, but P. (Pe.) muscicola lacks seta on the projection and P. (Pe.) botasaneanui has a spatulate anal point. The male hypopygium is similar to P. (Pe.) tritum , which, however, has microtrichia on the base of the superior volsella and usually a more curved projection.

Etymology. From Latin tuber, swelling, and the prefix in-, not, without, referring to the narrow projection of the superior volsella and the parallel-sided anal point.

Male (n = 3, except when otherwise stated)

Total length 3.11–3.72 mm. Wing length 1.83–2.15 mm. Total length / wing length 1.70–1.73. Wing length / profemur 2.27–2.40. Coloration pale brown with darker vittae, posterior anepisternum II, preepisternum and postnotum. Haltere knob blackish brown. Abdomen brown. Legs brownish stramineous.

Head. AR 1.56–1.63. Temporals 11–14. Clypeus with 20–27 setae. Tentorium 122–133 µm long. Stipes 133–143 µm long. Palpomere lengths (in µm): 30–43, 57–70, 140–173, 137–143, 190–226 (2).

Thorax. Antepronotum bare. Dorsocentrals 16–21, uniserial; acrostichals 17 (2); prealars 5–6. Scutellum with 10–14 setae in single row.

Wing. Anal lobe moderately developed. VR 1.12–1.14. Brachiolum with 1 seta, Sc with 16 (1), R with 47–65, R 1 with 25–39, R 4+5 with 80–114, RM with 2 (1), M with 11 (1), M 1+2 with about 65 (1), M 3+4 with about 45, Cu 1 with about 20, PCu with about 50 setae. Cell m basal of RM with about 50, r 4+5, m 1+2, m 3+4, an plus cu each with more than 100 macrotrichia. Squama with 6–8 setae.

Legs. Scale on foretibia including apical spur 56 (1) µm long. Spurs on midtibia 48 µm long, on hind tibia 64 µm long. Width at apex of foretibia 48 µm, of midtibia 48 µm, of hind tibia 50 µm. Length and proportions of legs as in Table 23.

Hypopygium ( Fig. 21A). Tergite IX with 11–14 oromedian setae and 20–23 setae at base of anal point, laterosternites IX with 3 setae. Phallapodeme 75–93 µm long. Transverse sternapodeme 43–63 µm long. Anal point 79–91 µm long. Gonocoxite 147–160 µm long. Inferior volsella with 14–16 setae, with 1 prominent apical seta. Superior volsella ( Fig. 21B) 59–70 µm long, 6–8 µm wide at base, 3–4 µm wide at apex. Gonostylus 167–183 µm long. HR 0.84–0.88, HV 1.86–2.03.

Remarks. This species is very close to Polypedilum (Pentapedilum) tritum . In P. intuber the anal point is clearly longer than the superior volsella and at most twice as wide at base as at apex. Townes (1945: 62) mentions that the gonostylus of P. tritum often is somewhat broader and the superior volsella narrower than fig-

ured by him, and he possibly had some specimens of P. intuber mixed into his series.

Distribution. Known only from Canada.