Nigranitida margaretae Webb

Webb, Donald W. & Metz, Mark A., 2004, The South American genus Nigranitida Metz (Diptera: Therevidae: Therevinae) with the description of three new species, Zootaxa 757, pp. 1-16 : 13-15

Nigranitida margaretae Webb spec. nov.

Etymology: This species is named in honor of the senior author’s granddaughter, Margaret Kelly McClain.

Diagnosis. Nigranitida margaretae is unique within the genus Nigranitida , as it is the only species to possess setae on the katepisternum and the male gonostylus to have a basodorsal lobe and a thin lateral flange.

Description of holotype male (MEI 121138).

Morphological variation (n=2).

Body length 5.3 mm (5.3–6.2, 5.8 mm).

Head. Length 0.64 mm (0.64–0.90, 0.77 mm). Frons pruinescence gray, with small median dark area dorsally. Antenna, dark brown, pruinescence gray, Ant./HL 0.84 (0.73– 0.84, 0.79); scape length 0.16 mm (0.16–0.20, 0.18 mm), length/width 1.6 (1.6–1.8, 1.7 mm), scape/pedicel length 2.0, scape/flagellum width 0.7 (0.7–0.9, 0.8), setae dark brown with a few white, elongate setae ventrally; pedicel length 0.08 mm (0.08–0.10, 0.09 mm), length/width 0.7, (0.7–1.0, 0.8); first flagellomere oval, tapered apically, flagellum length 0.30 mm (0.30–0.36, 0.33 mm), length/width 2.1 (2.1–3.0, 2.6), flagellum/scape length 1.9 (1.8–1.9, 1.8). Parafacial pruinescence silver gray. Maxillary palpus pale reddish brown, apex yellow; length 0.30 mm (0.30–0.38, 0.34 mm), length/width 6.0 (4.8–6.0, 5.4); setae white. Genal setae white. Occipital setae white ventrally becoming appressed dorsolaterally; macrosetae dark reddish brown, extending ventrally in single row from lateral end of postocular macrosetae.

Thorax. Macrosetae 3 np, 1 (1–2) sa, 1 pa, 0 dc, 2 sc. Mesonotum with vittae dark brown, pruinescence light gray, separated by broad band of gray pruinescence; setae white, erect intermixed with pale brown, appressed setae. Pleuron dark reddish brown, pruinescence silver, dense; setae white on propleuron, anepisternum, katepisternum, laterotergite, metanepisternum, and scutellum. Wing. Length 4.0 mm (4.0–5.0, 4.5 mm), length/width 2.4 (2.4–2.8, 2.6); membrane opaque; veins brown; pterostigma dark brown. Halter dark brown. Legs. Femora dark brown, pruinescence white; setae white ventrally on fore­ and midfemora; av 3:1:4, pv 0:0:3. Tibiae dark yellowish brown, apex brown. Tarsi dark reddish brown.

Nigranitida margaretae spec. nov. 28. Tergite 8, epandrium, cerci, hypoproct, dorsal view (MEI 106756). 29. Sternite 8, hypandrium, gonocoxite, ventral view. 30. Gonocoxite, hypandrium, dorsal view. 31. Gonocoxite, left lateral view. 32. Gonostylus, left lateral view. 33. Aedeagus, dorsal view (inset ejaculatory apodeme cross­section). 34. Aedeagus, ventral view. 35. Aedeagus, left lateral view. Scale= 0.1 mm.

Abdomen. Cuticle dark reddish brown, pruinescence white, dense, less dense on anterolateral corners of tergites 2–3 and 5–8; dorsal setae white, appressed, lateral setae white, erect. Terminalia . Epandrium (Fig. 28) quadrate, anterior margin deeply emarginate, posterolateral margin broad, slightly scalloped, setae dark yellow; hypoproct (Fig. 28), posterior margin emarginate, ending at apex of cercus. Gonocoxite ventral view (Fig. 29), sides broadly rounded, ending in short blunt point, setae dark yellow; dorsal view (Fig. 30), gonocoxal bridge large; lateral view (Fig. 31) quadrate, tapering to broad dorsoposterior point. Gonostylus (Fig. 32) lacking basodorsal lobe; ventral margin rounded, setae dark yellow. Aedeagus with dorsal apodeme (Fig. 33) oval, sides rounded, anterior margin truncate; ventral apodeme (Fig. 34), anterior margin deeply emarginate, tapered laterally to thick point, ventral surface lacking pair of short, ventromedial projections; distiphallus (Fig. 33) broad basally, tapered posteriorly, lateral view (Fig. 35), sinuate; ejaculatory apodeme (Fig. 33) bulbous posteriorly, anterior half moderately expanded laterally, sides emarginate, anterior margin truncate, not extending beyond anterior margin of dorsal apodeme.

Female. Unknown.

Biology. Nigranitida margaretae has been collected in Malaise traps in September and October.

Specimens Examined. The holotype male of Nigranitida margaretae Webb (MEI 18051) was collected in Argentina, Mendoza Prov., Parque Provincial Telleca, dunes, 9/ 17­IX­1999; malaise, M.E. Irwin, F.D. Parker, 32.3622°S, 66.0456° W. and is deposited in the CAS (Type No. 18025). PARATYPE: Argentina, Tucumán Prov., Fuete Quemado [­ 26.617, ­66.05], 18.X.1997, Irwin, M. E., Parker, F. D., Roig, S., 1 male MEI 106756 (INHS).