Nilothauma zitoi, 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 : 37-38

Nilothauma zitoi sp. n.

( Figs 64–74 )

Type material. Holotype male, BRAZIL: São Paulo: São Simão, Ponte Tio Zito, 19.i.2003, at light, H. F. Mendes & T. Andersen ( MZUSP).

Diagnostic characters. The two dorsal, setose wart-like lobes on tergite IX combined with a small anal point, inferior volsella with apically split setae, and gonostylus widest in apical 1/3 will separate the male of N. zitoi from all other Nilothauma species.

Etymology. Named after the late João Ribeiro da Fonseca (Tio Zito), the owner of the land where the species was collected.

Male (n = 1). Total length 2.92 mm. Wing length 1.42 mm. Total length / wing length 2.05. Wing length / length of profemur 2.35.

Coloration. Pale with vittae, anterior part of preepisternum, and posterior part of postnotum brown; antenna and legs yellowish brown.

Head ( Fig. 64 ). AR 0.32. Thirteenth flagellomere 203 µm long. Temporal setae 5 in single row including 1 inner vertical and 4 postorbitals. Frontal tubercles minute. Clypeus with 9 setae. Cibarial pump, tentorium and stipes as in Figure 65 . Tentorium 71 µm long, 18 µm wide. Stipes 80 µm long, 8 µm wide. Palp segment lengths (in µm): 17, 29, 63, 84, 121. Third palpomere with 2 sensilla clavata subapically, longest 19 µm long. Fifth palpomere / third palpomere 1.98.

Thorax ( Fig. 66 ). Dorsocentrals 5 in single row, acrostichals 3, prealars 2. Scutellum with 2 setae.

Wing ( Fig. 70 ). VR 1.53. Brachiolum with 1 seta, R with 7 setae, R1 with 3 setae, R4+5 with 2 setae apically, remaining veins bare.

Legs ( Figs 67–69 ). Spur of foretibia 57 µm long including 24 µm long scale. Midtibia with 1 spur, 29 µm long; hind tibia with 2 spurs, 43 µm and 28 µm long. Combs of midtibia 12 µm long, of hind tibia 15 µm long. Width at apex of foretibia 39 µm, of midtibia 41 µm, of hind tibia 43 µm. Lengths and proportions of legs as in Table 13.

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

Hypopygium ( Figs 71–72 ). Tergite IX with broadly triangular posterior margin; with 3 submarginal to marginal setae to each side of base of anal point; with pair of dorsal, wart-like lobes medially, each with about 10 long setae. Anal point small, digitate with rounded apex, 13 µm long, with microtrichia in basal 1/2. Laterosternite IX without setae. Phalapodeme 65 µm long; transverse sternapodeme lacking. Gonocoxite 94 µm long. Inferior volsella 68 µm long, 17 µm wide subapically, curved with broadly rounded apex, with microtrichia and 10 setae of which 4 are split apically. Superior volsella ( Fig. 73 ) 35 µm long, 12 µm wide medially, weakly curved with broadly rounded apex, with microtrichia. Median volsella ( Fig. 74 ) 25 µm long, curved, tapering, with microtrichia and 2 basal and 3 apical to subapical setae. Gonostylus 110 µm long, widest in apical 3/4, all setae hair-like. HR 0.85, HV 2.65.

Female and immatures. Unknown.

Distribution. Known only from the type locality in São Paulo, Brazil.

fe ti ta1 ta2 ta3 ta4 ta5 LR BV SV BR p1 605 433 621 376 253 221 98 1.43 1.75 1.67 2.6 p2 539 392 245 114 90 57 41 0.63 3.89 3.80 3.1 p3 629 645 392 196 180 123 65 0.61 2.96 3.25 5.2

Figures

FIGURES 64 – 70. Nilothauma zitoi sp. n., male. 64 — head. 65 — cibarial pump, tentorium and stipes. 66 — thorax. 67 — apex of foretibia. 68 — apex of midtibia. 69 — apex of hind tibia. 70 — wing.

FIGURES 71 – 74. Nilothauma zitoi sp. n., male. 71 — dorsal aspect of hypopygium. 72 — hypopygium with tergite IX and anal point removed, dorsal view left, ventral view right. 73 — superior volsella, dorsal view. 74 — median volsella, dorsal view.