Nilothauma paucisetis, Dantas & Hamada, 2017

Dantas, Galileu P. S. & Hamada, Neusa, 2017, Three new species of Nilothauma Kieffer (Diptera: Chironomidae) from Brazil, Zootaxa 4282 (2), pp. 350-360 : 351-352

Nilothauma paucisetis sp. nov.

( Figs 1–7 )

Type material. Holotype: male, BRAZIL: Roraima: Serra da Mocidade, 01°42'22.5"N, 61°47'07.9"W, 29–30.i.2016, light-trap, J.M. Cavalcante ( INPA) . Paratype: 2 males, as holotype (INPA).

Diagnostic characters. Tergite IX without dorsal projections, with one dorsal seta; anal point distinct but small; inferior volsella straight, with 3–4 fine apical setae.

Etymology. From the Latin pauci (few) and setis (setae), referring to the presence of only few setae on TIX.

Male (n= 1–3). Total length 2.27–2.70 mm. Wing length 1.21–1.41 mm. Total length / wing length 1.88–1.91. Wing length/ length of profemur 2.38–2.40.

Coloration. Thorax, legs and abdomen uniformly brown.

Head ( Fig.1 ). Antenna as in Figure 3 . AR 0.35–0.40. Thirteenth flagellomere 198–230 µm long. Temporal setae 5–6 in a single row including 2 inner and 3–4 outer verticals. Frontal tubercles not distinct. Clypeus with 10–12 setae. Cibarial pump with anterior margin slightly concave, 130–150 µm long. Tentorium 60 µm long, maximum width 19 µm. Stipes 96–110 µm long. Palpomeres length (I–V, in µm): 20–28, 24–28, 79–88, 130–145, 154. Third palpomere with 3 sensilla clavata subapically, longest 12–13 µm long. Fifth palpomere / third palpomere 1.95. Eyes separated by 35–38 µm, dorsomedial extension 100–110 µm long, 50–53 µm wide.

Thorax ( Fig 2 ). Dorsocentrals 5–8 in single row; acrostichals 8–14, biserial, starting close to anterior margin of scutum; prealars 2–3. Scutellum with 2 setae.

Wing ( Fig 4 ). WW 0.29–0.30. VR 1.32–1.41. Brachiolum with 1 seta, R with 14 setae, R1 with 10–11 setae, R4+5 with 15–19 setae, remaining veins bare. Anal lobe reduced.

Legs. Spur of fore tibia 27–28 µm long, scale 18–21 µm long. Mid tibia with 1 spur, 13 µm long; hind tibia with 2 spurs, 13 and 16 µm long. Combs of mid tibia 14 µm long, of hind tibia 16 µm long. Width at apex of fore tibia 35–39 µm, of mid tibia 35–41 µm, of hind tibia 39–43 µm. Mid and hind legs with pseudopurs in ta1–ta4; all legs with slender and curved claws. Lengths (in µm) and proportions of leg segments presented in Table 1.

Abdomen. Tergites with few setae. Segment VIII 14 0–165 µm long, about 130 µm wide, weakly tapered anteriorly.

Hypopygium ( Figs 5–6 ). Tergite IX with wedge-shaped posterior margin; without dorsal projection, with one hair-like seta, posterior margin of tergite with 5–6 setae on each side. Anal point distinct but small, lanceolated, 21–25 µm long, 7–10 µm wide medially. Laterosternite IX with 2–3 setae. Phallapodeme slightly sinuous, 50–54 µm long; transverse sternapodeme straight, 26–27 µm long. Gonocoxite 92–97 µm long. Inferior volsella small, straight, 26–35 µm long, with microtrichia and 3–4 fine apical setae, of which at least 1 apically split. Superior volsella, 28–33 µm long, cylindrical, slender, straight to slightly sinuous ( Fig. 8 ), with microtrichia and 4–6 apical, small, fine setae. Median volsella ( Fig. 7 ) 18 µm long, cylindrical, straight, slightly curved apically, without microtrichia and basal setae, with 2 apical setae sitting on small tubercles. Gonostylus slender and curved, 97–92 µm long, with 2–4 dorsal setae near the base. HR 1.05–1.06. HV 2.50–3.10.

Female imago and immatures. Unknown.

Distribution. Known only from the type locality in the Serra da Mocidade National Park, Caracaraí, Roraima State, Brazil.

Figures

FIGURES 1 – 4. Nilothauma paucisetis sp. nov. (Diptera: Chironomidae). 1 — Head. 2 — Thorax. 3 — Antenna. 4 — Wing.

FIGURES 5 – 8. Nilothauma paucisetis sp. nov. 5 (Diptera: Chironomidae). Hypopygium in dorsal view. 6 — Hypopygium with tergite IX removed, left-ventral view, right—dorsal view. 7 — Median volsella. 8 — Variations of superior volsella.