Endotribelos jiboia, 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

Endotribelos jiboia sp. n.

( Figs 11–13 )

Type material. Holotype: Male with pupal and larval exuviae, slide mounted in Euparal, Brazil, Bahia, Serra da Jibóia , 19.ix.2009, D.P. Cordeiro (E3-25, LEIA-UFSCar).

Etymology. The name jiboia refers to the locality where the species were collected: Serra da Jibóia , Bahia state, Brazil.

Diagnostic characters. Endotribelos jiboia sp. n. differs from all other species of the genus by the combination of the following characters. Adult male: uniform brown coloration of the abdomen; anal point thin, as broad at base as apex and as longer than inferior volsella. Pupa: abdominal posterolateral spur simple; intersegmental membrane III/IV and IV/V with two patches of coarse shagreen. Larva: mentum with fourteen teeth; median teeth slightly lighter than laterals; mandible with fourth inner tooth separated from others inner teeth by a little gap.

Male. Size. Total length near 3.8 mm.

Coloration. Head pale brown; antenna and palp brown. Mesothorax pale brown, posnotum dark brown. Legs pale brown.

Head. Temporal setae 17. Clypeus with 12 setae. Antenna 0.92 mm long; AR 1.38. Palpomere not measurable.

Thorax. Ac 12 biserial, beginning near antepronotum; Dc 13; Pa 2; Scts not discernible. Wings and legs not measurable (inserted into the pupal exuviae).

Legs. Scale on fore tibia 31 µm long, with a short spine at apex ( Fig. 11 c). Tibial combs of mid and hind legs partly fused; mid tibial spur anterior short, 15 µm, posterior 34 µm long ( Fig. 11 d); hind tibial spur anterior 22 µm, posterior 40 µm long ( Fig. 11 e).

Hypopygium ( Fig. 11 a). Anal point 58 µm long; 5 µm wide medially. Tergite IX with 13 strong setae. Laterosternite IX with two setae. Transverse sternapodeme 37 µm long. Phallapodeme 60 µm long. Gonocoxite 92 µm long. Superior volsella 74 µm long, broad basally and strongly curved distally, with three long basal setae and one 38 µm long sub-apical seta ( Fig. 11 b). Gonostylus 131 µm long. HR 0.70. HV 2.7.

Pupa. Abdomen 2.8 mm long. Wing sheath 0.9 mm long. Exuviae coloration pale brown.

Cephalothorax. Cephalic tubercles 61 µm long, conical, apically with several pointed spinules; frontal setae 151 µm long ( Fig. 12 a). Antepronotal seta 1, precorneal setae 2, dorsocentral setae 4. Distance between Dc1 and Dc2 38 µm, between Dc2 and Dc3 134 µm, between Dc 3 and Dc 4 21 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. 12 b). Hook row continuous with near 30 curved spines occupying near ½ width of segment II ( Fig. 12 c). Pedes spurii A and B present. Spur on segment VIII simple ( Fig. 12 d). 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 24 taeniate fringe setae on each side.

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

Head. Dorsal head length 425 µm; width 312 µm; IC 0.73. Antennal segments 1-5: 37, 14, 9, 5, 3 µm. AR 1.14; antennal blade 40 µm long, surpassing antennal segment 5 ( Fig. 13 a). Dorsal sclerites of head as in figure 13b, clypeus 28 µm long. Pecten epipharyngis formed by three toothed plates ( Fig. 13 c). Premandible with two major and one minor teeth; brush well developed. Mandible 126 µm long, with small dorsal tooth, apical and four inner teeth dark brown; fourth inner tooth separated from others inner teeth by a little gap; seta subdentalis slender, 38 µm long ( Fig. 13 d). Mentum 91 µm wide, strongly arched with fourteen dark brown teeth; median teeth slightly lighter and shorter than first laterals; 2nd lateral teeth smaller than the 3rd lateral teeth ( Fig. 13 e). Ventromental plate as long as mentum, with very distinct striations; distance between ventromental plates 29 µm.

Figures

FIGURE 11. Endotribelos jiboia sp. n. Male. a. Hypopygium, left dorsal view, right dorsal view, tergite IX removed and with detail of left superior volsella. b. Superior volsella. c. Fore tibia end. d. Mid tibia end. e. Hind tibia end.

FIGURE 12. Endotribelos jiboia sp. n. Pupa. a. cephalic tubercle. b. Abdominal tergites I-IV. c. Hook spines. d. Posterolateral spur of segment VIII.

FIGURE 13. Endotribelos jiboia sp. n. Larva. a. Antenna. b. Dorsal sclerites of head c. Pecten epipharyngis. d. mandible. e. Mentum and ventromental plate.