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 : 18-19

Onconeura sp. “ buriti”

( Figs 8 A–C)

Material examined. Male, with pupal and larval exuviae, BRAZIL, Mato Grosso State, Nova Mutum, Fazenda Buriti, 150 – 250 m a.s.l., 09.i.1999, H. F. Mendes. Hypopygium and larva not in good condition.

Diagnostic characters. The pupae are separable from other species by having 4 L-setae on segments III– VII, anal lobe fringe longer than twice as long as anal lobe length. Median area of TII, TIII and SII without shagreen, posterior field of shagreen on SII with spinules strongly needle like.

Pupa (n=1). Total length 2.0 mm.

Cephalothorax. FS longer than 130 µm. Po 55 µm; MAps 68 µm and 53 µm. LAps 13 µm. Precorneal setae Pc1 22 µm long, Pc2 70 µm long, Pc3 50 µm long. One sensillum near precorneal setae. Dc1 43 µm long; Dc2 35 µm long; Dc3 15 µm long; Dc4 128 µm long. Distance between Dc1 and Dc2 15 µm; Dc2 and Dc3 111 µm; Dc3 and Dc4 13 µm. Wing sheath with at least four rows of pearls.

Abdomen ( Figs 8 A–B). Tergite I and sternite I without shagreen. Tergite II–VIII with posterior row of spines anteriorly with smaller spines. TII with very sparse oral fine shagreen points, shagreen on posterior tergites getting stronger, more abundant and posterior distributed on tergites. Sternite with field of elongate spinules posterior region. Sternite III with sparse shagreen. Sternites IV–VIII with shagreen getting stronger and abundant on posterior sternites, caudal row of spines present, but with very small spinules on sternite VIII. Parasternites II–VIII with shagreen, shagreen restricted to oral region on paraternites VII and VIII. Conjunctive TII/III with 3 hooklets; TIII/IV with 5 hooklets; TIV/V with 6 hooklets; TV/VI with 5 hooklets; TVI/VII with 4 hooklets.

O-setae present ventral and dorsal in all segments. Segment I with 4 D-setae, 1 L-setae, without V-setae. Segment II –VII with 5 D, 4V-setae. Segment VIII with 2 D, 1 V-seta. Segments II and VIII with 3 L-setae. Segment III–VII with 4 L-setae. Segment IV with D1-seta 55 µm long, D5-seta 68 µm long, L1-seta 27 µm long, L2-seta 68 µm long, L3-seta 30 µm long, L4 -seta 13 µm long. Segment VIII with D4-seta 48 µm long, D5- seta 63 µm long, L1-seta 15 µm long, L2-seta 55 µm long, L3-seta 30 µm long.

Anal lobe 175 µm long. Anal lobe fringe with lateral 3 stout and median 20 taeniate setae; taeniate setae about 400 µm long, two median spurs ( Fig. 8 C). Anal macrosetae 50 µm long; median setae 225 µm long.

Remarks. Although the associated material is not in condition to be described as a formal species we could observe that the abdominal setae of the larvae are mostly bifid. The male antenna is composed of 12 flagellomeres and the wing has a well defined anal lobe. This specimen was sampled among submerged vegetation in moderately fast flowing stream in northern Mato Grosso State.

Figures

FIGURE 8. Onconeura sp. “ buriti ”, pupa. A — abdomen, dorsal view. B — abdomen, ventral view. C — detail of median corner on anal lobus.