Sigmoitendipes oliveirai new species

http://zoobank.org/ 24D6FE7B-6AE9-43A1-952C-FB9EC05739A3

Type material: Holotype: BRAZIL, Mato Grosso, Ribeirão Cascalheira, Fazenda Campina Grande, Rio Suiamissu, 12°48’35”S 52°06’56”W, 10.x.2007, light trap, LC Pinho et al., 1 male (MZUSP).

Etymology: Named after the late Dr. Sebastião José de Oliveira for his pioneering studies on the taxonomy of Brazilian chironomids.

Diagnostic characters: See key.

Description

Male (n = 1). Total length 4.53 mm. Wing length 1.97 mm. Total length / wing length 2.30. Wing length / length of profemur 1.43.

Coloration. Thorax brown; head, legs and abdomen paler brown. Wing translucent.

Antenna. AR 2.19. Ultimate flagellomere 946 µm long.

Head. Temporal setae 24 including 2 inner verticals, 11 outer verticals and 11 postorbitals. Clypeus with 14 setae. Frontal tubercle indicated as paler area. Tentorium 144 µm long, 35 µm wide. Stipes 169 µm long, 12 µm wide. Palp segment lengths (in µm): 45, 47, 72, 100, 167. Third palpomere with 3 sensilla, longest 17 µm long.

Thorax. Antepronotum without setae. Dorsocentrals 7, acrostichals apparently absent, prealars 2. Scutellum with 8 setae in single row.

Wing (Fig. 12A). VR 1.10. Brachiolum with 1 seta, R with 27, R 1 with 23, R 4+5 with 25 setae, other veins and cells bare. Squama with 5 setae.

Legs. Scale of fore tibia 55 µm long; spur of mid tibia 52 µm long including 20 µm long comb; spurs of hind tibia 50 µm and 45 µm long including 22 µm long comb. Width at apex of fore tibia 60 µm; of mid tibia 57 µm; of hind tibia 62 µm. Lengths and proportions of legs as in Table 5.

Hypopygium (Figs 12B, C). Tergite IX covered with microtrichia; laterosternite IX with 1 seta. Anal point spatulate, 65 µm long, 20 µm wide at base, 17 µm wide subapically, with 4 setae to each side of the base of which 1 on the ventral side. Transverse sternapodeme 47 µm long, straight. Phallapodeme 87 µm long. Gonocoxite 147 µm long. Superior volsella (Fig. 12D) 62 µm long, with somewhat rounded, 45 µm long, 40 µm wide, setose lobe with 3 apical setae; with 62 µm long dorsal lobe with 4 outer and 1 inner setae, slightly hooked at apex. Inferior volsella 144 µm long; 25 µm wide at base; 10 µm wide at its narrowest; with 10 µm long, dorsal, rounded projection, starting 85 µm from base; apically subtriangular, 20 µm wide; with 16 simple setae, longest apical seta 57 µm long. Gonostylus 199 µm long. HR 0.74. HV 2.27.

Female and immatures. Unknown.

Distribution and ecology

Only known from Mato Grosso, where it was collected in a light trap at a fast flowing river with mostly rocky bottom sediments.