Onconeura

Wiedenbrug, Sofia, Mendes, Humberto F., Pepinelli, Mateus & Trivinho-Strixino, Susana, 2009, Review of the genus Onconeura Andersen et Saether (Diptera: Chironomidae), with the description of four new species from Brazil, Zootaxa 2265, pp. 1-26 : 20

Onconeura sp. “hat ”

( Figs 9 A, B)

Thienemanniella semifimbriata -Gruppe spec. 5: Wiedenbrug 2000: 97.

Material examined. 1 pupal exuviae. BRAZIL, Rio de Grande do Sul State, São Francisco de Paula, Arroio dos Carros 800–900 m a.s.l., drift, 23.xi.1994, Fittkau and Wiedenbrug.

Diagnostic characters. The pupae are separable from other species by the fringe with few short nontaeniate setae, the short L2 -seta and the characteristic keel shape of the frontal apotome ( Fig. 9 A).

Pupa (n=1). Total length 1.7 mm.

Cephalothorax ( Fig. 9 A). Frontal apotome protuberant keel shaped. FS lost. Po 20 and 8 µm; MAps 33 µm and lost. One lateral antepronotal. 3 Precorneal setae Pc2 53 µm long. One sensillum near precorneal setae. Dc1 30 µm long; Dc4 55 µm long. Distance between Dc1 and Dc2 15 µm; Dc2 and Dc3 133 µm; Dc3 and Dc4 3 µm. Wing sheath with at least three rows of pearls.

Abdomen ( Fig.9 B). Tergite I and sternite I without shagreen. Tergite II–VIII with shagreen and posteriorly row of spines followed anteriorly by smaller spinules. Sternites II–VIII with fine shagreen, shagreen extending to parasternites. Sternites VI–VII with 1 row of small spinules. Sternite VIII with shagreen only and low broad posterior projection. Conjunctive TII/III – TV/VI with 6 hooklets; TVI/VII with 5 hooklets.

O-setae present ventral and dorsal in all segments (not drawn). Segment II with 4 D, 4V and 3L-setae. Segments III–VII with 5 D, 4V and 4 L-setae. Segment VIII with 2 D, 1 V and 3 L-setae. Segment IV with D1- seta 26 µm long, D5-seta 35 µm long, L1-seta 15 µm long, L2-seta 40 µm long and thick, L3-seta 10 µm long. L4-seta 17 µm long. Segment VIII with D4-seta 28 µm long, D5-seta 45 µm long, L1-seta 10 µm long, L2-seta 28 µm long, L3-seta 18 µm long.

Anal lobe 120 µm long. Anal lobe fringe with lateral 3 stout and shorter setae and 5 longer non-taeniate setae 70 µm long, one median spur long, triangular. One anal macroseta; median setae 35 µm long.

Remarks. This pupal exuviae was collected with drift net in a low order stream flowing through a meadow, about 4 m wide, maximum depth about 50 cm, with stony bottom in northeastern Rio Grande do Sul State.

Figures

FIGURE 9. Onconeura sp. “ hat ” A – B pupa and Onconeura sp. “ taquara ” C – F pupa. A - cephalothorax. C — frontal apotome. D — thorax. B, E — abdomen, dorsal view. F — detail of posterior row of spines on tergite IV.