Polypedilum (Pentapedilum) hamoni Freeman

Oyewo, Emmanuel Adeoye & Saether, Ole A., 2008, Revision of Polypedilum (Pentapedilum) Kieffer and Ainuyusurika Sasa et Shirasaki (Diptera: Chironomidae), Zootaxa 1953, pp. 1-145 : 62-66

Polypedilum (Pentapedilum) hamoni Freeman

( Figs 19, 20A–D)

Polypedilum (Pentapedilum) hamoni Freeman, 1958: 302 ; Freeman and Cranston (1980: 195).

Material examined. DEMOCRATIC REPUBLIC OF CONGO: Bukavu, River Mufuli , 2400 m a.s.l., paratypes male, female, 12.v.1957, J. Hamon ( BMNH) . TANZANIA: Tanga Region, West Usambara Mts., Mazumbai, Kaputu stream, 3 males, 6.xi.1990, sweep net and Malaise trap, ZMBN Tanzania expedition ( ZMBN).

Diagnostic characters. The species belongs to a group of species having less than 100 setae in cell m 1+2, but sometimes more than 100 setae in cell r 4+5. The foretibial scale lacks a spur, the base of the superior volsella lacks microtrichia and has 2–3 inner basal setae as in P. (Pe.) calvescens , but the abdominal segments are not banded as in P. (Pe.) calvescens and the anal point not spatulate. The female genitalia are similar to P. (Pe.) wittei but can be distinguished by having a long seminal capsule neck. The postgenital plate of P. (Pe.) wittei is steep sided and almost pointed apically, as compared to the more gently sloped plate of P. (Pe.) hamoni .

Male (n = 4, unless otherwise stated)

Total length. 2.86–3.30 (2) Wing length 1.91–2.31, 2.01 mm. Total length / wing length 1.57–1.72 (2). Wing length / length of profemur 1.96–2.24, 2.07. Thorax with brown markings, postnotum blackish; abdominal segments clear green without dark markings; femur, tibia and tarsi brown.

Head ( Fig. 19A). AR 1.91–2.15, 2.01. Ultimate flagellomere 754–923, 813 µm long. Temporal setae 11 including 3–4, 4 inner verticals, 3–5, 3 outer verticals, and 2–3, 2 postorbitals. Clypeus with 15–21, 17 setae. Tentorium 117–141, 132 µm long; 5–7, 6 µm wide at posterior tentorial pit. Stipes 114–140, 125 µm long. Palpomere lengths (in µm): 31–38, 36; 48–54, 52; 140–152, 144; 138–264 (3); 186–264 (3). Fifth palpomere / third palpomere 1.33–1.73 (3). Third palpomere with 2 sensilla clavata.

Thorax ( Fig. 19B). Acrostichals 8–11, 10; dorsocentrals 12–15, 14; prealars 4. Scutellum with 5–9, 7 setae.

Wing ( Fig. 19F). Anal lobe developed. VR 1.15–1.20, 1.18. Brachiolum with 1 seta; R with 22–24, 23; R 1 with 14–26, 20; R 4+5 with 36–49, 43; M 1+2 with 26–38, 31; M 3+4 with 2–10, 6 setae. All other veins bare. Cell r 4+5 with 79–103, 90; m 1+2 with 38–69, 57; m 3+4 with 12–26, 22 macrotrichia; cell m basal of RM, and an plus cu bare. Squama with 9–12 (3) setae.

Legs. Scale on foretibia ( Fig. 19C) 32–50, 39 µm long, rounded, without apical spur. Spurs on midtibia ( Fig. 19D) 57–70, 61 µm long, on hind tibia ( Fig. 19E) 65–71, 69 µm long. Comb on midtibia 21–24, 23 µm long; combs on hind tibia 21–28, 23 µm and 23–29, 26 µm long. Width at apex of foretibia 52–55 µm; of midtibia 47–60, 53 µm; of hind tibia 54–61, 58. Length and proportions of legs as in Table 20.

Hypopygium ( Fig. 19G). Tergite IX with 10–15, 13 median setae; laterosternite IX with 2 setae. Anal point 52–74, 62 µm long, 11–17, 13 µm wide at base, gradually tapering to nearly parallel-sided towards 5–6, 5 µm wide apex. Transverse sternapodeme 42–54, 46 µm long; phallapodeme 70–96, 84 µm long. Gonocoxite 149–165, 164 µm long. Superior volsella ( Fig. 19J, K) 75–93, 82 µm long, base bare with 3 inner setae, projection with 1 dorsolateral seta. Inferior volsella ( Fig. 19H, I) 117–138, 125 µm long, parallel sided, with prominent apical seta. Gonostylus 137–159, 146 µm long. HR 1.10–1.23, 1.11; HV 2.01–2.41 (2).

Female (n = 1)

Total length not measurable. Wing torn, length not measurable. Thorax coloration similar to male; abdominal segments brown without bands; femur, tibia and tarsi brown.

Head. Antennae lost. Temporal setae 9, including 4 inner verticals, 3 outer verticals, and 2 postorbitals. Clypeus with 20 setae. Tentorium 167 µm long, 10 µm at posterior tentorial pit. Stipes 167 µm long. Palpomere length (in µm): 38, 43, 157, 113, 309. Fifth palpomere / third palpomere 1.73. Third palpomere with 2 sensilla clavata.

Thorax. Acrostichals 11, dorsocentrals 20, prealars 6. Scutellum with 11 setae.

Wing. Anal lobe moderately developed. VR 1.17. Brachiolum with 1 seta, R with 30, R 1 with 35, R 4+5 with 65, Sc with 7, RM with 2, M with 8, M 1+2 with 67, M 3+4 with 42, Cu with 23, Cu 1 with 19, PCu with 50, and An with 20 setae. Cell m basal of RM bare. Cells r 4+5 and m 1+2 with more than 100 macrotrichia, m 3+4 with about 99 macrotrichia. Squama with 7 setae.

Legs. Foreleg lost. Spur on midtibia 71 µm long, on hind tibia 71 µm long. Comb on midtibia 21 µm long, combs on hind tibia 29 µm and 24 µm long. Width at apex of midtibia 62 µm, of hind tibia 71 µm. Length and proportions of legs as in Table 21.

Genitalia ( Fig. 20A). Gonocoxite IX with 4 seta; tergite IX with 20 seta; segment X with 6 seta. Cercus 102 µm long, 7 µm wide at apex, with 1 apical seta. Seminal capsule ovoid, 76 µm long, 45 µm wide; neck sclerotized, 15 µm long. Notum 162 µm long. Dorsomesal lobe ( Fig. 20B) 93 µm long, caudally broad; ventrolateral lobe ( Fig. 20C) nearly straight; apodeme lobe ( Fig. 20D) curved, nearly L-shaped. Postgenital plate triangular.

Distribution. Known from the Democratic Republic of Congo, Ghana, Nigeria, Zimbabwe, South Africa, Sudan and Burkina Faso.