Endotribelos bicolor, 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 : 3-11

Endotribelos bicolor sp. n.

( Figs 1–4 )

Type material. Holotype: Male with pupal and larval exuviae, Brazil, São Carlos, SP, Represa do Fazzari, 20.iv.2014, S. Trivinho-Strixino, (E3-07, LEIA-UFSCar). Paratypes: 1 male with pupal exuvia, in two slides mounted in Euparal, Brazil, Luiz Antônio, SP, Lagoa do Óleo, 25.vii.2003, (E3-08, E3-09, LEIA-UFSCar); 1 pupa with pharate female, Luiz Antônio, SP, Represa do Beija-Flor, xi.2011 (E3-10, LEIA-UFSCar); 1 female with pupal and larval exuviae, same locality; 04.x.2001 (E3-11, LEIA-UFSCar).

Etymology. From Latin, bicolor , referring to the brown and yellow coloration of adult male.

TABLE 1. List of specimens of Endotribelos with mtDNA COI sequences (DNA Barcoding) known.

Endotribelos semibruneus sp. n. BRAZIL, São Carlos, Córrego do Espraiado, 3 may 2012 BNB2-00740 -21,8972; -47,8736 830 m. a.s.l. KP237047 female

Endotribelos fulvidus sp. n. female BRAZIL, São Carlos, Córrego do 29, 1 may 2012 BNB2-00741 -21,9367; -47,9042 685 m. a.s.l. KP237046 Endotribelos fulvidus sp. n. female BRAZIL, São Carlos, Córrego do 29, 1 may 2012 BNB2-00744 -21,9367; -47,9042 685 m. a.s.l. KP237040 TABLE 2. Estimates of evolutionary divergence between sequences of Endotribelos species. The number of base substitutions per site from between sequences are shown. Analyses were conducted the Kimura 2-parameter model and conducted in MEGA6 software.

Diagnostic characters. Endotribelos bicolor sp. n. differs from all other species of the genus by the combination of the following characters. Adult male: thorax yellowish with brown mesonotal stripes and short brown triangular spot before the scutellum; scutellum pale; postnotum brown; abdomen with uniform brown coloration; anal point with apex larger than base and shorter than inferior volsella. Pupa: abdominal posterolateral spur with one or two large teeth; intersegmental membrane III/IV and IV/V with two patches of coarse shagreen. Larva: mentum with sixteen teeth; median teeth ½ times shorter than first laterals; mandible with four inner teeth.

Description. Male (n=2). Size. Total length 4.7–5.0 mm. Wing 2.0– 2.4 mm long and 0.6–0.7 mm wide.

Coloration. Head yellowish; fourth and fifth palpomere and antenna brown. Thorax scutum yellowish brown with brown mesonotal stripes and short brown triangular spot before the scutellum; postnotum brown ( Figs 1 a, b). Abdomen brown as shown in figure 1c. Legs pale brown.

Head. Temporal setae 20. Clypeus with 22–24 setae. Antenna 1.06–1.20 mm long; AR 1.4–2.0. Palpomere 2–5 lengths: 31–44, 175–219, 100–125, 118–150 µm.

Thorax. Ac 21; Dc 14–19; Pa 5; Scts 13–16 coarse and 7–13 finer setae on anterior face..

Wings. VR 1.06. Brachiolum with two setae. Setae present on veins R with 28, R1 with 28 and R4+5 with 32 setae, remaining veins bare. Squama with 10 setae.

Legs. Scale on fore tibia 38–46 µm long. Tibial combs of mid and hind legs partly fused; mid tibial spur anterior short 30 µm, posterior 69 µm long; hind tibial spur anterior 46–50 µm, posterior 81–84 µm long ( Fig. 1 e). Lengths and proportions as in Table 3 .

Hypopygium ( Fig. 1 e). Anal point 75–84 µm long; 9 µm wide medially; 12–15 µm near apex. Tergite IX with 15–21 strong setae. Laterosternite IX with two setae. Phallapodeme 112–133µm long. Gonocoxite 146–169 µm long. Superior volsella 123 µm long, broad basally and strongly curved distally, with 3–4 long basal setae and one 65–77 µm long sub-apical seta near 27 µm distal from extremity ( Fig. 1 f). Gonostylus 209–250 µm long. HR 0.67–0.69. HV 2.05–2.18.

Female (n=1). Dimension and coloration. Wing length 2.2 mm. Coloration as male except the brown markings of the posterolateral corner of scutum.

Head. Temporal setae 8, uniserial. Clypeus with 28 setae. Antenna 0.68 mm long; AR 0.36. Palpomere 2–5 lengths: 37, 188, 112, 144 µm

Thorax. Ac 20; Dc 25; Pa 6; Scts 24.

Wings. VR 1.13. Brachiolum with two setae. Setae present on veins R, R1, R4+5 and M, remaining veins bare. Squama with 10 setae.

Legs. Scale on front tibia 47 µm long. Tibial combs of mid and hind legs partly fused; mid tibial spur 31 µm long; hind tibial spur anterior 53 µm, posterior 67 µm long. Lengths and proportions as in Table 4 .

Genitalia ( Fig. 2 ): Setal patches on sternite VIII with 17–18 setae. GC IX with two setae. Segment X with 8 setae. Seminal capsule 91 µm long. Notum 128 µm long, rami 66 µm. Coxosternapodeme IX 168 mm long. Cercus 106 µm long.

Pupa (n=4, 2 males and 2 females). Abdomen 4.2–5.1 mm long. Wing sheath 1.4–1.6 mm long. Exuviae coloration pale brown.

Cephalothorax. Cephalic tubercles 109 µm long, conical, apically with several pointed spinules; frontal setae 144 µm long ( Fig. 3 a). Antepronotal seta 1, precorneal setae 2, dorsocentral setae 4. Distance between Dc1 and Dc2 44–75 µm, between Dc2 and Dc3 198–316 µm, between Dc 3 and Dc 4 22–34 µm.

Abdomen. Tergite I bare, II–VI covered with shagreen, spines near central part of anterior margin stronger, VII and VIII bare. Paratergites V and VI with posterior patches of fine spines. Conjuntives III/IV and IV/V with two large patches of anteriorly directed large spines ( Fig. 3 b). Hook row continuous with near 32 large curved spines occupying near 1/3 width of segment II. Pedes spurii A and B present. Spur on S VIII with one large apical tooth and 0–1 lateral tooth ( Fig. 3 c). 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 32–40 taeniate fringe setae on each side.

4th instar larva. Head capsule yellowish with mandibular tips, mentum and occipital ring blackish.

Head. Dorsal head length 625 µm; width 562 µm; IC=0.89. Antennal basal segment 77 µm long. AR 1.02; antennal blade 61 µm long, shorter than antennal flagellum ( Fig. 4 c). Dorsal sclerites of head as in figure 4a, clypeus 62 µm long. Pecten epipharyngis formed by three toothed plates ( Fig. 4 b). Premandible with two major and one minor teeth; brush well developed. Mandible 320 µm long, with small dorsal tooth, apical and four inner teeth dark brown; seta subdentalis slender, 61 µm long ( Fig. 4 d). Mentum 215 µm wide, with sixteen dark teeth; median teeth 1/2 shorter than first laterals; 2nd lateral teeth smaller than the 3rd lateral teeth ( Fig. 4 e). Ventral plate 143 µm long, with very distinct striations, distance between ventramental plates 69 µm.

Figures

FIGURE 1. Endotribelos bicolor sp. n. Male. a. Thorax, dorsal view. b. Thorax, lateral view. c. Abdomen dorsal view. d. Front, mid and hind tibial spurs. e. Hypopygium, left dorsal view, right dorsal view tergite IX removed and with details of left upper volsella. f. Superior volsella.

FIGURE 2. Endotribelos bicolor sp. n. Female. Genitalia ventral.

FIGURE 3. Endotribelos bicolor sp. n. Pupa. a. cephalic tubercle. b, c. Abdominal tergites I-IV and detail of hook spines. d. Posterolateral spur of segment VIII.

FIGURE 4. Endotribelos bicolor sp. n. Larva. a. Dorsal sclerites of head. b. Pecten epipharyngis. c. Antenna. d. Mandible. e. Mentum and ventromental plate.

Tables

TABLE 3. Lengths (in Μm) and proportions of legs of Endotribelos bicolor sp. n. male.

	fe	ti	ta1	ta2	ta3
p1	1230–1277	1015–1077	1200–1292	760–954	569–769
p2	1107–1246	969–1108	584–692	323–400	230–292
p3	1230–1369	1046–1261	876–969	507–569	415–461

TABLE 4. Lengths (in Μm) and proportions of legs of Endotribelos bicolor sp. n. female.

	fe	ti	ta1	ta2	ta3
p1	1338	1061	1492	953	707
p2	1292	1138	-	-	-
p3	1307	1261	984	584	446