Nilothauma jaquei, 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 : 354-358

Nilothauma jaquei sp. nov.

( Figs 15–20 )

Diagnostic characters. Anal point well-developed; TIX without dorsal projections, with 42–45 dorsal setae; superior volsella slender, without microtrichia, with one apical seta and a lateral spine. Etymology. The name is in honor of Mr. Giacomo Pes (Jaque) for the support and warm welcome given during the field work in southern Brazil.

Male (n= 1–3). Total length 2.23–2.25 mm. Wing length 1.08–1.11 mm. Total length / wing length 2.02–2.06. Wing length / length of profemur 2.29–2.30.

Coloration. General coloration yellowish-green; antenna greenish-brow, palps pale; thorax with scutum, vittae, postnotum and inferior half of preepisternum light-brown, scutellum and haltere pale; wings unmarked. Fore femur with 1/3 basal and 1/3 apical brown, fore tibia with1/5 basal and 1/3 apical brown, apical half of ta1 and ta2–ta5 brown; mid femur greenish-yellow with brown apex, mid tibia and ta1 greenish-yellow, mid ta2–ta5 light brown; hind femur, tibia and ta1 greenish-yellow, ta2–ta5 light-brown.

Head ( Fig. 15 ). Antenna as in Figure 17 . AR 0.18. Thirteenth flagellomere 98–101 µm long. Temporal setae 5–6 in a single row including 2 inner and 3–4 outer verticals. Frontal tubercles not distinct. Clypeus with 17–18 setae. Cibarial pump with anterior margin concave, 135–153 µm long. Tentorium 70–87 µm long, maximum width 15–16 µm. Stipes 110–140 µm long. Palp segment lengths (I–V, in µm): 25–27, 23–25, 88–89, 104–106, 143–148. Third palpomere with 2 sensilla clavata subapically, longest 16 µm long. Fifth palpomere / third palpomere 1.61–1.66. Eyes separated by 30–37 µm, dorsomedial extension 103–108 µm long, 68–77 µm wide.

Thorax ( Fig. 16 ). Dorsocentrals 8–9 in single row; acrostichals 14–16, biserial, starting just before the anterior margin of scutum; prealars 2. Scutellum with 2 setae.

Wing ( Fig. 18 ). WW 0.36–0.38. VR 1.54–1.56. Brachiolum with 1 setae, R with 13–14 setae, R1 with 10–13 setae, R4+5 with 14–16 setae, remaining veins bare. Anal lobe reduced.

Legs. Spur of fore tibia 19–22 µm long, scale 24–25 µm long. Mid tibia with 1 spur, 14–15 µm long; hind tibia with 2 spurs, 17–18 and 20–21 µm long. Combs of mid tibia 16–18 µm long, of hind tibia 19–20 µm long. Width at apex of fore tibia 35–38 µm, of mid tibia 40–43 µm, of hind tibia 44–45 µm. Mid legs with pseudopurs in ta1–ta4; all legs with slender and curved claws. Lengths (in µm) and proportions of leg segments as in Table 3.

Abdomen. Tergites with few setae. Segment VIII 146–157 µm long, 160–179 µm wide medially, weakly tapered anteriorly.

Hypopygium ( Figs. 19–20 ). Tergite IX with square-shaped posterior margin; without dorsal lobe(s), with 42–45 strong dorsal setae in the median area and 8–9 weaker setae on each side close to base of anal point, distinct anal tergite bands present. Anal point well-developed, rounded at apex, 35–37 µm long, 15–18 µm wide medially. Laterosternite IX with 2 setae. Phallapodeme straight, 52–56 µm long; transverse sternapodeme straight, 18–20 µm long. Gonocoxite 78–80 µm long. Inferior volsella cylindrical, slender, with enlarged apex, 48–54 µm long, covered with microtrichia, with 4 curved bristle at apex, one of which is split. Superior volsella slender, slightly sinuous, 20–23 µm long, without microtrichia, with one apical seta and one lateral spine, 10–11 µm long. Median volsella strongly reduced, consisting of 3 tubercles, each with microtrichia and 1 apical seta. Gonostylus tapered at base, 96–102 µm long, with 3–4 dorsal setae near the base. HR 0.76–0.83. HV 2.19–2.34.

Female imago and immatures. Unknown.

Distribution. Known only from the type locality in Rio Grande do Sul State, Brazil.

Figures

FIGURES 15 – 18. Nilothauma jaquei sp. nov. (Diptera: Chironomidae). 15 — Head. 16 — Thorax. 17 — Antenna. 18 — Wing.

FIGURES 19 – 20. Nilothauma jaquei sp. nov. (Diptera: Chironomidae). 19 — Hypopygium in dorsal view. 20 — Hypopygium in dorsal view, with tergite IX removed.