Endotribelos semibruneus, Trivinho-Strixino, Susana & Pepinelli, Mateus, 2015

Trivinho-Strixino, Susana & Pepinelli, Mateus, 2015, A systematic study on Endotribelos Grodhaus (Diptera: Chironomidae) from Brazil including DNA barcoding to link males and females, Zootaxa 3936 (1), pp. 1-41 : 24-28

Endotribelos semibruneus sp. n.

( Figs 14–15 )

Type material. Holotype: Male with pupal and larval exuviae, slide mounted in Euparal, Brazil, Araraquara, SP, Córrego Chibarro, 9.vi.2008, S. Trivinho-Strixino (E2-20, LEIA-UFSCar). Paratypes: 1 male with pupal and larval exuviae as holotype except (E2-21, LEIA-UFSCar), 10.vi.2008; 1 male with pupal and larval exuviae, São Carlos, Córrego do Espraiado, 10.ix.2010 (E2-22, LEIA-UFSCar), barcode (MPSW-000116); 1 female with pupal and larval exuviae, Córrego do Espraiado, 3.v.2012 (E2-24, LEIA-UFSCar), barcode (BNB2-00740); 1 female with pupal and larval exuviae, Córrego do Espraiado, 6.v.2012 (E2-23, LEIA-UFSCar); 1 female with pupal exuviae, Córrego do Vintenove, São Carlos, 6.v.2012 (E2-25, LEIA-UFSCar); 1 4th instar larva, Córrego do Espraiado, 6.v.2012 (E2-26, LEIA-UFSCar); 1 4th instar larva, Córrego Espraiado, ix.2012 (E2-27-UFSCar).

Etymology. From Latin, semi and bruneus, referring to the partial brown color of the adult males.

Diagnostic characters. Endotribelos semibruneus sp. n. differs from all other species of the genus by the combination of the following characters. Adult male: thorax yellowish with large dark brown stripe down the middle of the scutum which slightly expands posteriorly; pleura with brown band; postnotum brown; anal point apex broader than base and shorter than inferior volsella. Pupa: abdominal posterolateral spur simple or double; intersegmental membrane III/IV and IV/V with two patches of shagreen. Larva: mentum with thirteen teeth; median tooth sutured and slightly shorter than first laterals; mandible with fourth inner teeth separated from other lateral teeth.

Male (n=3). Size.Total length 4.1–4.8 mm. Wing 1.8–2.1 mm long and 0.5–0.6 mm wide.

Coloration. Head yellowish; third and fourth palpomeres and antenna brown. Thorax scutum yellowish with large dark brown stripe down the middle line of scutum which exapands posteriorly; pleura with brownish band; postnotum brown ( Figs14 a, b). Abdomen brown as figure 14c. Fore legs brown, mid and hind legs pale brown.

Head. Temporal setae 15–19. Clypeus with 15–22 setae. Antenna 0.81–0.92 mm long; AR 1.68–1.74. Palpomere 2–5 lengths: 44–50, 156–162, 94–112, 131–150 µm.

Thorax. Ac 16–18; Dc 12–18; Pa 5–7; Scts 13–14 coarse, in a straight posterior row and with 8–9 finer setae on anterior face.

Wings. VR 1.13–1.20. Brachiolum with two setae. R with 28–38, R 1 30–40 and R4+5 45 –55 setae, remaining veins bare. Squama with 7–9 setae.

Legs. Scale on fore tibia 46–54 µm long, with a short spine at apex ( Fig. 14 c). Tibial combs of mid and hind legs partly fused; mid tibial spur on posterior comb 52–61 µm long; hind tibial spur anterior 29–30 µm, posterior 69–71 µm long. Lengths and proportions as in Table 9 .

Hypopygium ( Fig. 14 d). Anal point 83–89 µm long; apex broader than base. Tergite IX with 10–15 strong setae. Laterosternite IX with two setae. Transverse sternapodeme 87–92 µm long. Phallapodeme 100–110 µm long. Gonocoxite 94–134 µm long. Superior volsella 69–81 µm long, broad basally and strongly curved distally, with three long basal setae and one long distolateral, subapical seta ( Fig. 14 e). Gonostylus 192–222 µm long. HR 0.49–0.64. HV 1.85–2.49.

Female (n=3). Dimension and coloration. Length 3.6–3.8 mm. Wing length 2.2–2.4 mm. Coloration as male. Head. Temporal setae 12–14. Clypeus with 20–23 setae. Antenna 0.6–0.7 mm long; AR 0.28–0.33. Palpomere 2–5 lengths: 50–69, 137–175, 94–144, 160–181 µm.

Thorax. Ac 16–23; Dc 19–25; Pa 5–6; Scts 12–13 coarse and 7 finer setae on anterior face. Wings. VR 1.19–1.23. Brachiolum with two setae. R with 29–351, R1 48–50, R4+5 85–97, M 6 setae, remaining veins bare. Squama with 11–13 setae.

Legs. Scale on front tibia 38–41 µm long, with a short spine at apex. Tibial combs of mid and hind legs partly fused; mid tibial spur anterior 54–69 µm long; hind tibial spur anterior 34–44 µm, posterior 61–69 µm long. Lengths and proportions as in Table 10 .

Genitalia. Setal patches on sternite VIII with 26−32 setae. GC IX with 2 setae. Segment X with 13–14 setae. Seminal capsule 109–119 µm long. Notum 94−125 µm long, rami 31–45 µm. Gonocoxapodeme semicurved 112–125 µm long. Cercus 88 µm long.

Pupa (n=6, 3 males, 3 females). Abdomen 3.7–4.8 mm long. Wing sheath 1.1–1.3 mm long. Exuviae coloration greyish; intersegment dark gray.

Cephalothorax. Cephalic tubercles conical, apically with several pointed spinules; frontal setae 147–191 µm long ( Fig. 15 a). Antepronotal seta 1, precorneal setae 2, dorsocentral setae 4. Distance between Dc1 and Dc 2 25–31 µm, between Dc2 and Dc3 203–250 µm, between Dc3 and Dc 4 19–22 µm.

Abdomen. Tergite I bare, II with fine shagreen, III–VI covered with shagreen, spines near central part of anterior margin stronger, VII and VIII bare. Paratergites V and VI with spines posteriorly. Conjuntives III/IV and IV/V with two large patches of anteriorly directed short spines. Hook row continuous with near 66–77curved spines occupying near 1/2 width of segment II. Pedes spurii A and B present. Spur on segment VIII simple or double ( Fig. 15 b). Abdominal lateral setation: segment II–IV with three L setae, V–VI with three taeniate setae, VII–VIII with four taeniate setae. Anal lobes with 35−40 taeniate fringe setae on each side.

4th instar larva (n=6, 4 larval skins and 2 larvae). Head capsule yellowish, tips of mandibles, mentum and occipital ring blackish. Larvae bright red when alive. Total length near 10 mm.

Head. Dorsal head length 488–650 µm; ventral 231−244 µm; width 350−440 µm; IC 1.48–1.62. Antenna 77–88 µm long; basal segment 41–48 µm. AR 1.13–1.20; antennal blade slightly longer than antennal flagellum ( Fig. 15 d). Clypeus 28–32 µm long ( Fig. 15 c). Pecten epipharyngis formed by three toothed plates. Premandible 80–89 µm long with two major and one minor teeth; brush well developed ( Fig. 15 e). Mandible 134–152 µm long, with small dorsal tooth, apical and four inner teeth dark; fourth inner tooth separated from others inner teeth by a gap; seta subdentalis slender, 27–33 µm long ( Fig. 15 f). Mentum 92–125 µm wide, with thirteen teeth; median tooth sutured and slightly shorter than first laterals; 2nd lateral teeth smaller than 3rd lateral, 4rd lateral teeth flatters and separated from the other lateral teeth ( Fig. 15 g). Ventromental plate 115– 134 µm width, with very distinct striations; distance between ventromental plates 25–43 µm.

Abdomen. Procercus short as long as wide, with 7 anal setae. Anal tubules large, 425–444 µm, with median constriction. Posterior parapods with brownish claws.

Figures

FIGURE 14. Endotribelos semibruneus sp. n. Male. a. Thorax, dorsal view. b. Thorax, lateral view. c. Fore tibial spine. d. Hypopygium, left dorsal view, right dorsal view, tergite IX removed and with detail of left superior volsella. e. Superior volsella.

FIGURE 15. Endotribelos semibruneus sp. n. Pupa a. Cephalic tubercles. b. Spur. Larva. c. Dorsal sclerites of head. d. Antenna. e. Premandible. f. Mandible. g. Mentum and ventromental plate.

Tables

TABLE 9. Lengths (in Μm) and proportions of legs of Endotribelos semibruneus sp. n. male.

	fe	ti	ta1	ta2	ta3
p1	1138–1261	923–1107	1046–1092	785–892	553–646
p2	1092–1261	923–1015	523–692	308–338	231–277
p3	1185–1707	985–1154	754–892	446–523	369–431

TABLE 10. Lengths (in Μm) and proportions of legs of Endotribelos semibruneus sp. n. female.

	fe	ti	ta1	ta2	ta3
p1	1169–1277	1000–1108	1200–1538	861–1077	600–723
p2	1123–1169	1015–1308	568–723	307–369	200–261
p3	1185–1323	1061–1261	738–938	461–569	338–431