Nilothauma complicatum, Mendes, Humberto Fonseca & Andersen, Trond, 2009

Mendes, Humberto Fonseca & Andersen, Trond, 2009, Neotropical Nilothauma Kieffer, 1921, with the description of thirteen new species (Diptera: Chironomidae), Zootaxa 2063, pp. 1-45 : 19-21

Nilothauma complicatum sp. n.

( Figs 20–23 )

Type material. Holotype male, BRAZIL: Espírito Santo: Linhares, Reserva Biológica Sooretama, 18º58'02.8''S, 40º07'53.6''W, 87 m a.s.l., 21–24.iii.2002, Malaise trap (Trilha 1), C. O. Azevedo et al. (BIOTA- FAPESP) ( MZUSP).

Diagnostic characters. The absence of dorsal lobe(s) on tergite IX and anal point combined with inferior volsella having an additional subapical branch will separate the male of N. complicatum from all other Nilothauma species.

Etymology. From Latin, complicatus, meaning folded together referring to the shape of the superior volsella.

Male (n = 1). Total length 2.26 mm. Wing length 1.28 mm. Total length / wing length 1.76. Wing length / length of profemur 2.20.

Coloration. Thorax and antenna uniformly brown, apex of foretibia, ta1 and ta2 dark brown, other legs uniformly brown.

Head. AR 0.47. Thirteenth flagellomere 259 µm long, stout subapical seta 36 µm long. Temporal setae 5 in single row including 2 inner verticals, 2 outer verticals, and 1 postorbital. Frontal tubercles minute. Clypeus with 20 setae. Tentorium 91 µm long, 14 µm wide. Stipes 95 µm long, 27 µm wide. Palp segment lengths (in µm): 16, 25, 73, 79, 116. Third palpomere with 2 sensilla clavata subapically, longest 14 µm long. Fifth palpomere / third palpomere 1.59.

fe ti ta1 ta2 ta3 ta4 ta5 LR BV SV BR p1 594 374 731 328 256 180 86 1.95 2.00 1.32 3.7 p2 569 367 234 88 54 27 18 0.64 6.25 4. 0 0 4.1 p3 662 601 – – – – – – – – – Thorax. Dorsocentrals 6 in single row, acrostichals 7, prealars 2. Scutellum with 2 setae.

Wing. VR 1.48. Brachiolum with 1 seta, R with 10 setae, R1 with 9 setae, R4+5 with 12 setae, remaining veins bare.

Legs. Spur of foretibia 70 µm long including 32 µm long scale. Midtibia with 1 spur, 34 µm long; hind tibia with 2 spurs, 39 µm and 27 µm long. Combs of midtibia 14 µm long, of hind tibia 18 µm long. Width at apex of foretibia 43 µm, of midtibia 40 µm, and of hind tibia 48 µm. Lengths and proportions of legs as in Table 4.

Abdomen. Tergites with few setae. Segment VIII long, weakly triangular, tapering anteriorly.

Hypopygium ( Figs 20–21 ). Tergite IX with subrectangular posterior margin, with 11 setae. Anal point absent. Laterosternite IX with 1 seta. Phalapodeme 41 µm long; transverse sternapodeme lacking. Gonocoxite 86 µm long. Inferior volsella ( Fig. 22 ) 75 µm long, 14 µm wide at base, 4 µm wide at apex, slightly sinuous, tapering apically, with two strong, curved setae apically, longest 27 µm long; with additional subapical branch, 18 µm long, 7 µm wide medially, 14 µm wide subapically, bearing 12 stout setae apically. Superior volsella ( Fig. 23 ), with triangular basal projection, with microtrichia; apical part 59 µm long, 14 µm wide at base, 7 µm wide at apex, strongly curved in basal 1/4, apical 3/4 tapering, with microtrichia and weak setae, with marginal row of flattened setae, with 2 long hair-like setae in basal 1/3. Median volsella apparently fused with superior volsella. Gonostylus 125 µm long, nearly straight, widest in basal 1/3, tapering towards apex; all setae hair-like. HR 0.69, HV 1.81.

Female and immatures. Unknown.

Distribution. Known only from the type locality in Espírito Santo, Brazil.

Figures

FIGURES 20 – 23. Nilothauma complicatum sp. n., male. 20 — dorsal aspect of hypopygium. 21 — hypopygium with tergite IX and anal point removed, dorsal view left, ventral view right. 22 — inferior volsella, dorsal view. 23 — superior volsella, dorsal view.