Nilothauma spiesi, 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 : 35-36

Nilothauma spiesi sp. n.

( Figs 58–60 )

Type material. Holotype male, CHILE: IX Region: Cautin, Queule, Rio Pirén, 4 km from Rio Queule, 3.ii.1986, drift net, M. Spies ( ZSM).

Diagnostic characters. The two dorsal, setose lobes on tergite IX and the presence of a lateral thorn on laterosternite IX combined with a parallel-sided anal point, inferior volsella with apically split setae, and median volsella apparently fused with superior volsella will separate the male of N. spiesi from all other fe ti ta1 ta2 ta3 ta4 ta5 LR BV SV BR p1 608 433 – – – – – – – – – p2 663 470 295 129 101 74 46 0.63 4.08 3.84 – p3 682 672 424 221 193 120 64 0.63 2.97 3.19 –

Etymology. Named after Martin Spies, who collected the specimen.

Male (n = 1). Total length 3.08 mm.

Coloration. Thorax pale yellow with median anepisternum II brown; legs and antenna pale yellow.

Head. AR 0.18. Thirteenth flagellomere 126 µm long; stout subapical seta 58 µm long. Temporal setae 7 in single row including 3 inner verticals, 2 outer verticals, and 2 postorbitals. Frontal tubercles apparently absent. Clypeus with about 10 setae. Tentorium and stipes not measurable. Palp segment lengths (in µm): 16, 29, 77, 116, fifth lost. Third palpomere with 2 sensilla clavata subapically, longest 15 µm long.

Thorax. Dorsocentrals 8 in single row, acrostichals 11, prealars 2. Scutellum with 2 setae.

Wing. Not measurable. Brachiolum with 1 seta, R with 13 setae, R1 with 12 setae, R4+5 with 15 setae, remaining veins bare.

Legs. Spur of foretibia 52 µm long including 23 µm long scale. Midtibia with 1 spur, 32 µm long; hind tibia with 2 spurs, 34 µm and 37 µm long. Combs of midtibia 18 µm long, of hind tibia 16 µm long. Width at apex of foretibia 43 µm, of midtibia 45 µm, of hind tibia 52 µm. Lengths and proportions of legs as in Table 12.

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

Hypopygium ( Figs 58–59 ). Posterior margin of tergite IX with shoulders, with 3–4 submarginal to marginal setae to each side of base of anal point; with pair of dorsal, wart-like projections submedially, each with 4–5 strong setae. Anal point parallel-sided, 27 µm long, 7 µm wide, with rounded apex. Laterosternite IX without seta, with lateral thorn. Phalapodeme 57 µm long; transverse sternapodeme lacking. Gonocoxite 102 µm long. Inferior volsella curved with rounded apex, 52 µm long, 9 µm wide basally, 7 µm wide subapically, with microtrichia and 6 subapical setae of which 5 are split apically. Superior volsella ( Fig. 60 ) subrectangular with broadly rounded apex, 32 µm long, 23 µm wide, with microtrichia and few setae. Median volsella fused with superior volsella, apparently represented by 2 setae on small tubercles. Gonostylus parallel-sided, weakly curved, 113 µm long, all setae hair-like. HR 0.90, HV 2.72.

Female and immatures. Unknown.

Distribution. Known only from IX Region, Chile.

Figures

FIGURES 58 – 60. Nilothauma spiesi sp. n., male. 58 — dorsal aspect of hypopygium. 59 — hypopygium with tergite IX and anal point removed, dorsal view left, ventral view right. 60 — superior volsella, dorsal view.