Polypedilum (Pentapedilum) chutteri Harrison

Oyewo, Emmanuel Adeoye & Saether, Ole A., 2008, Revision of Polypedilum (Pentapedilum) Kieffer and Ainuyusurika Sasa et Shirasaki (Diptera: Chironomidae), Zootaxa 1953, pp. 1-145 : 46-49

Polypedilum (Pentapedilum) chutteri Harrison

( Figs 13A–C)

Polypedilum (Pentapedilum) chutteri Harrison, 2001: 14 .

Material examined. SOUTH AFRICA: Free State, Vaal River near Lineques Drift , paratypes male, female, 24.iv.1958, F. M. Chutter ( AM) .

Diagnostic characters. The species is characterized by having about 100 setae in cell r 4+5, about 80 in cell m 1+2, foretibial scale with spur, and an antennal ratio of 0.7. It differs from the similar P. (Pe.) botiense by having base of superior volsella without microtrichia and with the projection less pointed, and by having a slightly spatulate anal point. The female is similar to most Pentapedilum species in having a spherical seminal capsule, broadly triangular postgenital plate, and nearly straight and brush-like ventrolateral lobe.

Male (n = 1)

Total length 3.55 mm long. Wing length 1.98 mm. Wing length / length of profemur 2.00. Thorax, abdominal segments, femur, tibia and tarsi dark brown.

Head. AR 0.70–0.73 according to Harrison (2001); flagellum incomplete in examined specimen. Temporal setae 10 including 4 inner verticals, 4 outer verticals, and 2 postorbitals. Clypeus with 20 setae. Tentorium 147 µm long. Palpomere lengths (in µm) 46, 60, 129, 117, 158. Fifth palpomere / third palpomere 1.22.

Thorax. Acrostichals 13, dorsocentrals 18 (26 in Harrison), prealars 7. Scutellum with 6 setae.

Wing. Anal lobe moderately developed. VR 1.18. Brachiolum with 2 setae, R with 18 (24 in Harrison), R 1 with 15, R 4+5 with 27 setae. Sc bare. RM with 3, M with 2, M 1+2 with 45, M 3+4 with 24, Cu bare; Cu 1 with 12, PCu with 29 and An with 28 setae. Cells r 4+5 with just over 100, m 1+2 with about 80, m 3+4, with 22, cell m basal of RM with 3, and an plus cu with 27 macrotrichia. Squama with 6 setae.

Legs. Scale on foretibia ( Fig.13A) including apical spur 44 µm long. Spurs on midtibia 55 µm long, on hind tibia 66 µm long. Comb on midtibia 23 µm long, comb on hind tibia 25 µm and 21 µm long. Width at apex of foretibia 41 µm, of midtibia 69 µm, of hind tibia 69 µm. Length and proportions of legs as in Table 10.

Hypopygium ( Figs 13A–C). Anal tergite bands fused basal to median setae. Tergite IX with 11 median setae, laterosternite IX with 4 setae. Anal point 64 µm long, 9 µm wide at base, nearly parallel-sided towards rounded, 9 µm wide apex. Transverse sternapodeme 32 µm long; phallapodeme 51 µm long. Gonocoxite 202 µm long. Superior volsella ( Fig.13C) 85 µm long, base bare with 4 inner setae, projection with 1 dorsolateral seta. Inferior volsella 145 µm long, parallel sided and with 1 prominent apical seta. Gonostylus very broad, 156 µm long. HR 1.29.

Female (n = 1)

Wing length 2.05 mm. Wing length / length of profemur 2.35. Coloration similar to male.

Head. Antennae lost (AR 0.5 in Harrison). Temporal setae 9 including 3 inner verticals, 3 outer verticals, and 1 postorbitals. Clypeus with 20 setae. Palpomere lengths (in µm): 60, 58, 99, 97, 120. Fifth palpomere / third palpomere 1.21.

Thorax. Dorsocentrals 26, prealars 8. Scutellum with 7 setae.

Wing. Anal lobe moderately reduced. VR 1.56. Brachiolum with 1 seta; R with 20, R 1 with 26, R 4+5 with 36, Sc bare, RM with 2, M with 9, M 1+2 with 65, M 3+4 with 28, Cu with 12, Cu 1 with 12, PCu with 31 setae and An bare. Cells r 4+5 and m 1+2 with more than 100 macrotrichia; cells m 3+4 with 13, cell m basal of RM with 3, cu plus an with 4 macrotrichia. Squama damaged.

Legs. Scale on foretibia 23 µm long, with pointed spur. Spurs on midtibia 54 µm long, on hind tibia 58 µm long. Comb on midtibia 25 µm long, combs on hind tibia 25 µm and 21 µm long. Width at apex of foretibia 54 µm, of midtibia 74 µm, of hind tibia 64 µm. Length and proportions of legs as in Table 11.

Genitalia. Gonocoxite IX with 4 setae, tergite IX with 8 setae, segment X with 4 setae on each side. Cercus 143 µm long. Seminal capsule almost spherical 69 µm long; 58 µm wide; neck sclerotized, 9 µm long.

Notum 175 µm long. Dorsomesal lobe 94 µm long, 49 µm wide, ventrolateral lobe and apodeme lobe not clear. Postgenital plate triangular.

Distribution. Known only from South Africa.