Polypedilum (Pentapedilum) uncinatum (Goetghebuer)

Oyewo, Emmanuel Adeoye & Saether, Ole A., 2008, Revision of Polypedilum (Pentapedilum) Kieffer and Ainuyusurika Sasa et Shirasaki (Diptera: Chironomidae), Zootaxa 1953, pp. 1-145 : 119-125

Polypedilum (Pentapedilum) uncinatum (Goetghebuer)

( Figs 39–41)

Tanytarsus uncinatus Goetghebuer, 1921: 110 .

Polypedilum (Pentapedilum) uncinatum (Goetghebuer) ; Edwards (1929: 376), Pinder (1978: 134).

Polypedilum (Pentapedilum) tritum auct ., not Walker (856: 162, 342).

Material examined. BELGIUM: Vinderhaute , holotype male, 17.vi.1920, M. Goetghebuer ( IRSN No. 18.073); Vinderhaute, 3 males, 1 female, 17.vi.1920, M. Goetghebuer ( IRSN No. 611); Melle, 3 males, 30.iv.1931, 1 female, 04.v.1931, M. Goetghebuer ( IRSN No. 18.073); Meirelbeke, 1 male, 1 female, 30.iv.1931, M. Goetghebuer ( IRSN No. 18.073) . SWEDEN: Ängerån , 3 males, 10–20.vii.1981, K. Müller ( ZSM No. 20) . GERMANY: Oberbayern , Dietramzell , Zellar Wald, 1 male, 27.vii.1997, sweep net, W. Schacht ( ZSM); Oberbayern Ldkr. FFB, Eichenau Municipal, Starzelbach, Höhe Kirch, 2 pupae, 4.vii.1998, F. Reiss ( ZSM); Munich, Isar River, km 53, drift, 2 pupae, 16.v.1984, F. Reiss ( ZSM); Oberbayern, Murnauer Moos, 1 male, 3 pupae, 06.viii.1979, 21.v.1989, F. Reiss ( ZSM No. 3); Ostholstein, Plön, 1 male, 17.v.1973, F. Reiss ( ZSM No. 906) . THE NETHERLANDS: Goirle , 1 male with larva and pupa, 25.iv.1980, mass rearing, Müller-Pillot ( ZSM No. 20121) . GREECE: locality and date not stated, 2 pupae, M. Baehr ( ZSM No. 28) .

Diagnostic characters. Among species with numerous setae on the wing membrane, uniformly colored abdomen, foretibial scale without spur, base of superior volsella with microtrichia, tergite IX with less than 15 median setae, and cell m basal of RM with more than 10 setae, the species is characterized by having a parallel-sided anal point, cell m basal of RM with 13–61 setae, squama with 5–9 setae, and projection of superior volsella normally with a lateral seta. The species is close to P. (Pe.) nubens , which, however, has a shorter, spatulate anal point and normally lacks a lateral seta on the projection of the superior volsella. The females may be distinguished by the shape of the lobes of gonapophysis VIII, especially as the ventrolateral lobe of P. (Pe.) uncinatum is broad and brush-like while that of P. (Pe.) tritum is slightly curved and slender. The pupa has median shagreen on tergite II and some shagreen on tergite VII, conjunctive III / IV with spinules, and relatively well developed pedes spurii B. The larva has a mandible with dorsal tooth, median teeth of mentum slightly longer than or subequal to second lateral teeth, third antennal segment subequal to or slightly shorter than fourth, and combined length of third and fourth antennal segment longer than second segment.

Male (n = 10–12, unless otherwise stated)

Total length 2.63–3.90, 3.13 (4) mm. Wing length 1.68–2.47, 2.08 mm. Total length / wing length 1.49– 2.23, 1.73 (4). Wing length / length of profemur 2.11–2.62, 2.34 (9). Thorax pale brown to dark brown; abdominal segments brown to dark brown; femur, tibia and tarsi brown to dark brown.

Head. AR 1.40–1.62, 1.53 (9). Ultimate flagellomere 562–758, 679 µm long. Temporal setae 9–13, 11 including 2–5, 4 inner verticals, 3–6, 4 outer verticals, and 2–4, 3 postorbitals. Clypeus with 17–23, 19 setae. Tentorium 114–137, 125 µm long, 2–7, 5 (9) µm wide at posterior tentorial pit. Stipes 115–177, 136 µm long. Palpomere lengths (in µm): 26–49, 40; 40–63, 53; 136–179, 159 (9); 117–167, 136 (8); 199–265, 228 (5). Fifth palpomere / third palpomere 1.22–1.60, 1.43 (5). Third palpomere with 2–3 sensilla clavata.

Thorax. Acrostichals 8–18, 14; dorsocentrals 15–28, 19, 20; prealars 4–7, 5. Scutellum with 8–18, 10 (8) setae.

Wing. Anal lobe moderately developed. VR 1.03–1.15, 1.11. Brachiolum with 1–3, 2 setae; R with 30–73, 49; R 1 with 24–39, 32; R 4+5 with 66–100, 80; Sc with 16–37, 25; RM with 2–3, 2; M with 9–18, 12; M 1+2 with 37–79, 60; M 3+4 with 34–67, 46; Cu with 27–55, 34; Cu 1 with 16–32, 21; PCu with 31–70, 52; An with 24–39, 34 setae. Cells r 4+5, m 1+2, m 3+4, cu plus an each with more than 100 macrotrichia, cell m basal of RM with 13– 61, 30 (9) macrotrichia. Squama with 5–9, 6 setae.

Legs. Scale on foretibia ( Figs 39A–B) 30–58, 50 µm long, rounded or tapering, without subapical spur. Spurs on midtibia 42–62, 53 µm long; on hind tibia 55–71, 64 µm long. Comb on midtibia 17–30, 23 µm long; combs on hind tibia 20–35, 25 µm and 17–33, 21 µm long. Width at apex of foretibia 40–58, 50 µm; of midtibia 43–70, 54 µm; of hind tibia 41–70, 58 µm. Length and proportions of legs as in Table 53.

Hypopygium ( Fig. 39C). Tergite IX with 7–13, 10 median setae, laterosternite IX with 1–2, 2 setae. Anal point ( Fig. 39D) 50–62, 59 (9) µm long, 8–21, 12 (9) µm wide at base, nearly parallel-sided towards 4–9, 6 (9) µm wide apex. Transverse sternapodeme 39–70, 56 µm long; phallapodeme 66–114, 88 µm long. Gonocoxite 112–214, 162 µm long. Superior volsella ( Figs 39E–G) 45–76, 62 µm long; base with sparse microtrichia and 3–5, 4 inner setae; projection with 1 lateral seta close to base. Inferior volsella 81–140, 113 µm long, parallelsided, with prominent apical seta. Gonostylus ( Fig. 39H) 105–171, 146 µm long. HR 0.97–1.26, 1.11; HV 1.85–2.87, 214 (4).

Female (n = 2–3)

Total length not measurable. Wing length 1.97–2.35 mm. Coloration as in male.

Head. AR 0.35–0.39. Length of flagellomeres (in µm): 136–149, 94–99, 90–102, 57–60, 138–155. Tentorium 121–171 µm long, 5–7 µm wide at sieve pore. Temporal setae 8–12 including 4–5 inner verticals, 4 outer verticals, and 2–3 postorbitals. Clypeus with 20–23 setae. Palpomere lengths (in µm): 43–48, 43–48, 145– 176, 162, fifth palpomere lost.

Thorax. Acrostichals 13–22, dorsocentrals 30–38, prealars 6–8. Scutellum with 9–11 setae.

Wing. Anal lobe moderately developed. VR 1.06–1.10. Brachiolum with 2–3 setae, R with 42–55, R 1 with 53, RM with 3–4, M with 11–16, M 3+4 with 52–79, PCu with 40–103, Cu with 38, Cu 1 with 17–38, and An with 30–59 setae. Cells r, m 1+2, m 3+4, cell m basal of RM; and cu plus an densely covered with macrotrichia. Squama with 8–9 setae.

4+5

Legs. Scale on foretibia 39–52 µm long, rounded or tapering, without subapical spur. Spurs on midtibia 57–60 µm long, on hind tibia 59–67 µm long. Comb on midtibia 24–29 µm long, combs on hind tibia 23–33 µm and 22–26 µm long. Width at apex of foretibia 50–60 µm, of midtibia 52–60 µm, of hind tibia 51–67 µm. Length and proportions of legs as in Table 54.

Genitalia ( Fig. 39I). Gonocoxite IX with 5–7 setae, tergite IX with 16–33 setae, segment X with 3–6 setae. Cercus 82–86 µm long, 5–8 µm wide at tip. Seminal capsule almost spherical, 52–69 µm long, 40–57 µm wide, with sclerotized, 7–17 µm long neck. Notum 178–214 µm long. Dorsomesal lobe ( Fig.39K) 74–105 µm long, 33–48 µm wide. Ventrolateral lobe as in Figure 39L. Apodeme lobe as in Figure 39J. Postgenital plate small, triangular.

Pupa (n = 10, unless otherwise stated)

Total length 3.45–5.19, 4.63 (8) mm. Exuviae with cephalothorax, margins of segments and caudolateral spur brown.

Cephalothorax ( Figs 41A, 40A). Frontal apotome as in Figure 40A, cephalic tubercules absent. Frontal seta 26–71, 43 (7) µm long. Prealar tubercle apparently absent. Wing sheath 1.01–1.58, 1.33 (7) mm long.

Abdomen ( Figs 41B–G). Tergite I bare; tergites II – VI each with strong, prominent anterior row of spines. Tergite II – III with weak spinules in sparse median shagreen; tergite IV with extensive anterior to posterior shagreen; tergites V – VI with extensive shagreen in two median patches and two distinct posterior patches of shagreen; tergite VII with paired anterolateral spots of fine spinules; tergite VIII bare or with very weak anterolateral spinules. Tergites VII – VIII without shagreen. Conjunctives III / IV and IV / V each with bi- to multiserial band of anteriorly directed spinules or spinules pointed in both directions. Tergite II with single row of 33–86, 54 strong caudal hooks. Pedes spurii A present on segment IV. Pedes spurii B weakly developed on segment II. Caudolateral spur ( Figs 41H–I) 74–169, 112 µm long, with strong apical tooth or bifid tooth, 1–3, 2 lateral teeth and several accessory points. Segments I– IV without L taeniae; V – VI each with 3 taeniae; VII with 4; VIII with 4–5, 4 taeniae. Anal lobe fringe with 20–46, 30 taeniae. Length of genital sac overreach 186–450, 284 µm.

Larva (n = 1)

Total length not measurable. Head segments brown with postoccipital margin, teeth of mentum and mandible brownish black. Frontoclypeal apotome anteriorly broadened, anterior margin straight ( Fig. 41B).

Head. AR 1.11. Antennal segment ( Figs 41C–D) lengths (in µm): 71, 27, 14, 20, 6. Base of antennal segment 17 µm wide, ring organ 13 µm from base. Blade at apex of 1st segment 53 µm long, shorter than segments 2–5. Apical style of second segment 10 µm long. Lauterborn organs minute. Pecten epipharyngis ( Fig. 41E) consisting of 3 platelets, each with 4 unequal teeth. Premandible ( Fig. 41G) 90 µm long, bifid with prominent premandibular brush. Mandible ( Fig. 41F) 144 µm long, with 1 apical, 1 dorsal, and 3 inner teeth; seta subdentalis slender and well developed, distally straight; seta interna prominent. Mentum ( Fig. 41H) 101 µm wide, with 8 pairs of teeth. Pair of median teeth 21 µm wide, second lateral tooth as large as median, first lateral tooth smaller, third to sixth lateral teeth decrease progressively to a minute seventh tooth. Ventromental plate 106 µm wide, distance between plates 50 µm; median apices of plates pointing anteriorly. Ratio of ventromental plate / mentum 1.04.

Remarks. The type material of P. (Pe.) uncinatum and P. (Pe.) tritum from the Belgium Museum confirms the differences observed in the shapes of the superior volsella of the male and the lobes of gonapophysis VIII of the female. However, the lateral seta is inserted about halfway on the projection of the superior volsella in both species. Also, the shape of the anal point varies within the species and these characters could not be used to separate the species as shown in Goetghebuer (1921; 1937–1954). However, most P. (Pe.) tritum have a slightly and smoothly curved gonostylus, while in P. (Pe.) uncinatum basal 2/3 of the gonostylus is very broad before sharply narrowing towards apex. Most important, P. (Pe.) tritum has a conspicuous subapical spur on foretibia, while P. (Pe.) uncinatum lacks spur.

Distribution. Widespread in the Holarctic region.