Nilothauma sooretamense, 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 : 33-35

Nilothauma sooretamense sp. n.

( Figs 55–57 )

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). Paratypes: 1 male, as holotype; 2 males, as holotype except for 18º58'03.1''S, 40º08'00.0''W, 22 m a.s.l., (Bosque 3); 1 male, as holotype except for 18º58'03.0''S, 40º08'03.6''W, 49 m a.s.l.; 1 male, as holotype except for 24–27.iii.2002, (Trilha 5) ( MZUSP, ZMBN, ZSM).

Diagnostic characters. The absence of dorsal lobe(s) on tergite IX and anal point combined with a superior volsella with ventral ridge, median volsella apparently fused with superior volsella, and hind ta2 shorter than hind ta3 will separate the male of N. sooretamense from all other Nilothauma species.

Etymology. Named after Reserva Biológica Sooretama.

Male (n = 5–6, except when otherwise stated). Total length 1.60–2.14, 1.91 mm. Wing length 0.838–1.033, 0.936 mm. Total length / wing length 1.91–2.30, 2.02. Wing length / length of profemur 2.07–2.21, 2.13.

Coloration. Thorax pale with darker notum; foretibia slightly darker apically, other leg segments and antenna yellowish brown.

Head. AR 0.18–0.24, 0.22. Thirteenth flagellomere 83–130, 109 µm long. Temporal setae 5–8, 6 in single row including 2–3, 2 inner verticals, 1–4, 3 outer verticals, and 0–3, 1 postorbitals. Frontal tubercles well developed. Clypeus with 13–19, 15 setae. Tentorium 54–75, 64 (4) µm long, 6–9, 8 (4) µm wide. Stipes 61–84, 72 (4) µm long. Palp segment lengths (in µm): 14–20, 17; 18–23, 20; 41–59, 50; 57–88, 77; 98–107, 101. Third palpomere with 2 sensilla clavata subapically, longest 14–23, 18 µm long. Fifth palpomere / third palpomere 1.69–2.39, 2.08.

Thorax. Dorsocentrals 5–6, 5 in single row; acrostichals 7–13, 9; prealars 2. Scutellum with 2 setae.

Wing. VR 1.40–1.44, 1.42. Brachiolum with 1 seta, R with 7–11, 9 setae; R1 with 5–9, 7 setae; R4+5 with 14–19, 17 setae; remaining veins bare.

Legs. Spur of foretibia 52–66, 60 µm long including 25–29, 27 µm long scale. Midtibia with 1 spur, 29–36, 33 µm long; hind tibia with 2 spurs, 34–43, 39 µm and 23–27, 24 µm long. Combs of midtibia 14–18, 16 µm long, of hind tibia 14–20, 17 µm long. Width at apex of foretibia 31–36, 34 µm, of midtibia 32–39, 35 µm, of hind tibia 36–44, 41 µm. Lengths and proportions of legs as in Table 11.

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

Hypopygium ( Figs 55–56 ). Tergite IX with subrectangular posterior margin, with 10–18, 13 setae. Anal point lacking. Laterosternite IX with 1 seta. Phalapodeme 36–47, 40 µm long; transverse sternapodeme 11–23, 19 µm long. Gonocoxite 50–66, 57 µm long. Inferior volsella 36–57, 45 µm long, 8–11, 10 µm wide at base, 7–14, 10 µm wide apically, weakly curved with broadly rounded apex, with microtrichia and 10–15, 12 simple, short setae subapically. Superior volsella ( Fig. 57 ), 34–45, 42 µm long, 29–44, 39 µm wide medially, with median ridge ventrally, tapering towards apex, with microtrichia. Median volsella apparently fused with superior volsella. Gonostylus 77–113, 98 µm long, weakly curved, nearly parallel-sided, all setae hair-like. HR 0.51–0.67, 0.59; HV 1.84–2.15, 1.96.

Female and immatures. Unknown.

Distribution. Known only from Espírito Santo, Brazil.

fe ti ta1 ta2 ta3 ta4

p1 410–482, 448 252–306, 284 432–533, 497 194–230, 221 151–191, 176 122–151, 138 p2 407–493, 447 263–310, 290 154–184, 173 54–72, 65 38–54, 47 22–29, 26 p3 450–533, 496 414–493, 449 182–252, 220 90–115, 104 101–126, 118 65–79, 71

ta5 LR BV SV BR

p1 54–68, 62 1.68–1.76, 1.72 2.04–2.10, 2.07 1.45–1.53, 1.49 4.1–5.5, 4.5 p 2 14–22, 18 0.51–0.61, 0.57 5.59–6.45, 5.91 4.18–4.37, 4.29 3.4–4.6, 3.9 p 3 29–43, 37 0.43–0.51, 0.49 3.39–3.65, 3.53 4.06–4.95, 4.32 3.9–5.4, 4.7

Figures

FIGURES 55 – 57. Nilothauma sooretamense sp. n., male. 55 — dorsal aspect of hypopygium. 56 — hypopygium with tergite IX and anal point removed, dorsal view left, ventral view right. 57 — superior volsella, dorsal view.