Nilothauma hamadae sp. nov. Figures 4A, B, 16A

Type material.

Holotype male, slide-mounted: Brazil, Amazonas, Barcelos, Rio Aracá, Foz do Igarapé Cuieiras, 00°19'15"N, 63°16'15"W, 35 m a.s.l., 30.vii-01.viii.2009, light trap #11, N. Hamada et al. leg. (UFSC).

Etymology.

The specific epithet is a noun in the genitive case which honours Neusa Hamada for her great contribution to the knowledge of Amazonian Chironomidae .

Diagnostic characters.

The male can be distinguished from its congeners by the combination of: tergite IX with single, median setose dorsal lobe, consisting of a low, but wide protuberance with about 25 strong setae; anal point very broad (about half the width of tergite IX) and lanceolate; median volsella separated from superior volsella.

Description.

Male imago (n = 1). Total length 1.94 mm. Wing length 1.13 mm. Total length/wing length 1.71. Wing length/length of profemur 2.30.

Colouration. Head, thorax and abdomen medium brown. Legs light brown. Wing membrane hyaline.

Antenna. AR = 0.40. Thirteenth flagellomere 217 µm long.

Head. Temporal setae 7 in single row. Clypeus with 15 setae. Tentorium 75 µm long, maximum width 12 µm . Stipes 92 µm long. Palp segment lengths (in µm): 25, 25, 75, 127, 144. Third palpomere with 2 sensilla clavata subapically, longest 20 µm long. Fifth palpomere/third palpomere 1.93.

Thorax. Dorsocentrals 7 in single row, acrostichals 10, prealars 2. Scutellum with 4 setae.

Wing. VR = 1.37. Brachiolum with 1 seta, R with 13 setae, R1 with 7 setae, R4+5 with 14 setae, remaining veins bare.

Legs. Spur of fore tibia 34 µm long including 12 µm long scale. Mid-tibia with 1 spur, 15 µm long; hind tibia with 2 spurs, 20 and 25 µm long. Combs of mid-tibia 12 µm long, of hind tibia 15 µm long. Width at apex of fore tibia 34 µm, of mid-tibia 34 µm, of hind tibia 39 µm . Lengths and proportions of legs as in Table 3.

Hypopygium (Fig. 4A, B). Tergite IX narrow, tapering to apex, with central rounded lobe bearing 25 simple, strong setae; with 9 simple setae along posterior margin underneath the anal point. Anal point lanceolate, 42 µm long, 27 µm wide. Tergite bands lacking. Laterosternite IX with 1 seta. Phallapodeme 40 µm long; transverse sternapodeme 15 µm long. Gonocoxite 75 µm long. Inferior volsella strongly curved, 37 µm long, 7 µm wide medially, with microtrichia in basal half, with 4 simple setae apically and 1 simple seta subapically. Superior volsella 30 µm long, 4 µm wide at base, covered with microtrichia and fringed at apex. Median volsella 7 µm long, with 2 simple setae, longest 10 µm . Gonostylus 112 µm long, with basal half strongly curved and distal half straight. HR = 0.67. HV = 1.73.

Female adult and immatures.

Unknown.

Distribution

(Fig. 16A). Known from Barcelos (Amazonas State), in the Brazilian Amazon.