Brachylinga tridentata Webb, 2006

Webb, Donald W. & Metz, Mark A., 2006, A Revision of the New World Genera Brachylinga Irwin and Lyneborg and Lysilinga Irwin and Lyneborg (Diptera: Therevidae: Therevinae) with the Description of a New Genus, Elcaribe Webb, Zootaxa 1288 (1288), pp. 1-241 : 140-142

Brachylinga tridentata Webb spec. nov.

( Figs. 23, 46, 69, 92, 115, 138, 161, 184, 205, 213)

Etymology

Tres = three (Greek), dentis = tooth (Latin). The named is proposed for the tridentate appearance of the apex of the distiphallus in dorsal view ( Fig. 138) and is used as an adjective.

Diagnosis Brachylinga tridentata is taxonomically associated B. mimica in lacking setae on the katepisternum; in having the postocular, mesonotal, and coxal macrosetae dark reddish brown; in having the male parafacial black ventrally and silver dorsally; in having the halter knob dark reddish brown; and in lacking an anterodorsal patch of short black setae on the gena. Brachylinga tridentata differs from B. mimica in having the distiphallus in dorsal view ( Fig. 138) with a dorsoapical carina and an apicolateral projection, and the apical half of the gonostylus ( Fig. 184) short and thick.

Description of male holotype (INBIO 205328)

Body length 7.3 mm.

Head. Length 0.90 mm. Ommatidia smaller ventrally and laterally. Frons pruinescence silver, black dorsally; setae black. Antenna/head length 0.68; dark brown, pruinescence gray on scape and pedicel; scape length 0.20 mm, width 0.12 mm, length/ width 1.7, scape/pedicel length 3.3, scape/flagellum width 0.86, setae pale brown, elongate; pedicel length 0.06 mm, length/width 0.5; flagellum length 0.35 mm, width 0.14 mm, length/width 2.5, flagellum/scape length 1.8. Parafacial pruinescence silver, black ventrally. Maxillary palpus dark brown, pruinescence gray; length 0.42 mm, length/width 7.0; setae pale yellow. Genal setae white. Occipital setae white becoming pale gold, lanceolate along margin of eye dorsally. Postocular macrosetae dark reddish brown.

Thorax. Macrosetae dark reddish brown, 3 np, 2 sa, 1 pa, 2 dc, 2 sc. Mesonotum dark brown, pruinescence brownish gray; setae black, elongate intermixed with dark yellow appressed setae. Pleuron pruinescence gray; setae white on propleuron, anepisternum, laterotergite, metanepisternum, and scutellum, absent on katepisternum. Wing. Membrane pale gray; veins brown; pterostigma faint pale brown, narrow; cell m 3 closed, petiolate (occasionally opened slightly). Halter stalk dark brown, knob pale brown. Legs. Coxa setae white, present on posterior surface of midcoxa; macrosetae dark reddish brown. Femora dark reddish brown, pruinescence white; ventral setae black, elongate on fore­ and midfemora; av 1:0:3, pv 0:0:3. Tibiae dark yellow, apical fourth dark reddish brown particularly on hindtibia. Tarsomere 1 dark yellow, dark reddish brown apically; 2–5 dark reddish brown.

Abdomen. Brown, pruinescence white; dorsal setae white, appressed; lateral setae white erect. Terminalia . Tergite 8 ( Fig. 23), narrow medially (0.02 mm); setae pale yellow, absent medially on posterior margin. Sternite 8 ( Fig. 46) rectangular, sides rounded, posterior margin emarginate. Epandrium ( Fig. 23), sides tapered apically, setae dark yellow intermixed with dark reddish brown setae. Cercus ( Fig. 23), ending basal to apex of hypoproct. Hypoproct ( Fig. 23), posterior margin emarginate, ending distal to apex of cercus. Gonocoxite ventral view ( Fig. 46), basal half quadrate rounded laterally, median margin rounded, tapering towards attenuate point, setae dark yellow intermixed with black macrosetae; dorsal view ( Fig. 69) posteromedial lobe short, rounded, gonocoxal bridge absent; lateral view ( Fig. 92) rectangular, tapering apically to thick point; ventral lobe ( Fig. 46) with ventral spines. Gonostylus ( Fig. 115), basodorsal lobe moderately large; ventral margin curved, setae dark yellow with ventral setae elongate, extending apically in distinct tuft; fine short spines absent laterally. Aedeagus with dorsal apodeme ( Fig. 138) rectangular, posterolateral margin rounded; ventral apodeme ( Fig. 161) short, thick, tapered anteriorly, not extending to anterior margin of dorsal apodeme; distiphallus dorsal view ( Fig. 138) tapering to point apically with dorsoapical carina and apicolateral projection, ventral view ( Fig. 161) apicolateral projection with short thick spines, lateral view ( Fig. 184) tapered apically with short ventrally curved apex; ejaculatory apodeme ( Fig. 138), anterior margin truncate.

Female

Similar to male except as follows.

Variation (n=8).

Body length 5.3–7.3, 6.0 mm.

Head. Frons dull yellowish brown, ventral third white with large, distinct, brown circle dorsolaterally; setae dark brown, short on dorsal half. Parafacial dark reddish brown, silver dorsally and laterally.

Thorax. Macrosetae 3 np, 2 sa, 1 pa, 2 dc, 2 sc. Wing. Halter brown. Legs. Anteroventral macrosetae 0–2:0:3–4, pv 0:0:3–6.

Abdomen. Dark reddish brown, glossy with anteromedial area orangish brown on tergite 1, posterolaterally on tergites 2–4, as narrow band across medial area of tergites 5–6, and covering posterior half of tergite 7, pruinescence gray posterolaterally on tergites 2–4 and across posterior half of tergites 5–6; dorsal and lateral setae dark reddish brown, short with white, elongate, appressed setae across posterior margin of tergites 1–3. Terminalia (MEI 138881). Furca ( Fig. 205) oval, posterior and lateral margins rounded, anterior margin truncate; length 0.46 mm, width 0.38 mm; anterolateral projection absent. Common duct ( Fig. 205) shorter than furca. Spermathecal duct ( Fig. 205) directed anteriorly.

Distribution Brachylinga tridentata is known from Costa Rica ( Fig. 213).

Habitats and phenology

Brachylinga tridentata has been collected in Malaise traps in a tree fall gap open to the sun or in shaded tropical forest from 21 February to 4 April.

Specimens examined

Type specimen. The holotype male of B. tridentata Webb (INBIO CR1002 205328) is labeled "Estacion Santa Rosa, Prov. guana., COSTA RICA, 300m, 24–27 FEB 1995, A. Azofeifa, L_N_313000_359800, #5284" and is deposited in INBC. PARATYPES. COSTA RICA. GUANACASTE. Santa Rosa National Park, 300 m, 21.II–14.III.1987, D. Janzen, I. Gauld, 2♀ MEI 138822, 138924 ( LACM), Malaise trap in treefall gap open to sun, 4♀ MEI 138881–2, 138898, 138921 ( LACM), Malaise trap in shaded area, 1♀ MEI 138989 ( LACM), Malaise trap ; 14.III–4.IV.1987, 1♂ MEI 139010, 1♀ 139017 ( INHS), Malaise trap in treefall gap open to sun .