Brachylinga divaricata 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 : 77-79

Brachylinga divaricata Webb spec. nov.

( Figs. 12, 35, 58, 81, 104, 127, 150, 173, 194, 216)

Etymology

Divaricatus (Latin) = spread apart. This name refers to the divergence of the male sternite 8 and is used as an adjective.

Diagnosis

Brachylinga divaricata is taxonomically associated with B. bicolor 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; the halter knob yellow; and in having the hypoproct ( Fig. 12) quadrate, posterior margin emarginate. Brachylinga divaricata differs from B. bicolor in having the gonocoxite ( Fig. 35) with short, dark reddish brown macrosetae apicomedially and numerous elongate, dark reddish brown macrosetae anteromedially; and the distiphallus in dorsal view ( Fig. 127) elongate, tapered apically with a dorsal carina. Females of B. bicolor , B. concava , B. divaricata , and B. ornata are indistinguishable based on external characters. Internally, B. bicolor , B. concava and B. ornata have the spermathecal ducts directed anteriorly ( Figs. 188, 192, 199) while in B. divaricata the spermathecal ducts are directed laterally before bending at a right angle and continuing anteriorly ( Fig. 194).

Description of holotype male (INBIO 744842)

Body length 7.0 mm.

Head. Length 0.84 mm. Ommatidia smaller ventrally and laterally. Frons pruinescence whitish gray ventrally with small black pruinescent band dorsolateral to antennal base (appearance variable when specimen rotated), dorsal half of frons black; setae black. Antenna/head length 0.86; scape black, pruinescence gray, pedicel and flagellum dark brown; scape length 0.28 mm, width 0.12 mm, length/width 2.3, scape/ pedicel length 3.5, scape/flagellum width 0.92, setae black, elongate; pedicel length 0.08 mm, length/width 0.8; flagellum length 0.34 mm, width 0.13 mm, length/width 2.6, flagellum/scape length 1.2. Parafacial pruinescence black, white dorsally and narrowly along margin of eye. Maxillary palpus dark reddish brown, pruinescence gray; length 0.50 mm, length/width 8.3; setae pale reddish brown. Genal setae white. Occipital setae white (occasionally pale gold) becoming lanceolate, dorsally along margin of eye. Postocular macrosetae dark reddish brown.

Thorax. Macrosetae dark reddish brown, 3 np, 2 sa, 1 pa, 2 dc, 2 sc. Mesonotum black, pruinescence brownish gray; setae black, elongate intermixed with white to pale gold, lanceolate, appressed setae. Pleuron pruinescence gray; setae white to pale yellow on propleuron, anepisternum, laterotergite, metanepisternum, and scutellum, absent on katepisternum. Wing. Membrane pale gray; veins brown; length 5.2 mm, length/width 2.9; pterostigma faint pale brown, very narrow; cell m 3 closed, petiolate. Halter stalk dark brown, knob pale. Legs. Coxa setae white, present on posterior surface of midcoxa; macrosetae dark reddish brown. Femora dark reddish brown, pruinescence white; ventral setae black on fore­ and midfemora; av 0:0:4, pv 0:0:5. Tibiae dark yellow, apical fourth dark reddish brown. Tarsomere 1 dark yellow; 2–5 dark reddish brown.

Abdomen. Dark reddish brown, pruinescence white, dense; dorsal setae white, appressed; lateral setae white, erect. Terminalia (INBIO 993911) dark yellowish brown. Tergite 8 ( Fig. 12), narrow medially (0.02 mm); setae pale yellow, absent medially on posterior margin. Sternite 8 ( Fig. 35), sides diverging apically, posterior margin moderately emarginate. Epandrium ( Fig. 12), sides tapered apically; setae dark reddish brown. Cercus ( Fig. 12) ending basal to apex of hypoproct. Hypoproct ( Fig. 12), apical margin emarginate, ending distal to apex of cercus. Gonocoxite ventral view ( Fig. 35), basal half broad, rounded laterally, median margin rounded, tapered apically to short attenuate apex; setae dark yellow, moderately thick intermixed with black elongate, moderately thick macrosetae basomedially with short coarse macrosetae along apicomedial margin; dorsal view ( Fig. 58), posteromedial lobe short, gonocoxal bridge absent; lateral view ( Fig. 81) broad basally, tapered apically in broad curve; ventral lobe ( Fig. 35) lacking spines. Gonostylus ( Fig. 104), basodorsal lobe large with several coarse spines; ventral margin straight, setae dark yellow, extending apically in distinct tuft; fine, short spines absent laterally. Aedeagus with dorsal apodeme ( Fig. 127) broad, rectangular, posterolateral margin rounded; ventral apodeme ( Fig. 150) broad, slightly expanded anteriorly, not extending to anterior margin of dorsal apodeme; distiphallus dorsal view ( Fig. 127) elongate, tapered apically with dorsal carina, lateral view ( Fig. 173) thick basally, tapered apically in broad curve with several apicolateral spines; ejaculatory apodeme ( Fig. 127), anterior margin slightly emarginate.

Variation (n=10). Body length 6.2–7.0, 6.7 mm.

Thorax. Macrosetae 3 np, 2 sa, 1 pa, 1 dc, 2 sc. Legs. Anteroventral macrosetae 0:0:2–4; pv 0:0:3–11.

Female

Similar to male except for following.

Variation (n=8). Body length 5.9–7.3 mm.

Head. Frons pruinescence yellowish brown, whitish silver dorsolateral to antennal base with dark brown moderate sized circle dorsolateral to antennal base; setae dark brown. Antenna dark brown. Parafacial pruinescence dark reddish brown medially, silver laterally and dorsal.

Thorax. Macrosetae dark reddish brown, 3–4 np, 2 sa, 1 pa, 2 dc, 2 sc. Legs. Anteroventral macrosetae 0:0:2–4, pv 0:0:2–6. Tibiae dark yellow, apical fourth dark reddish brown. Tarsomere 1 dark yellow; 2–5 dark reddish brown.

Abdomen. Dark reddish brown, lightly pruinose, tergites 2–3 orange brown posterolaterally, tergites 4–7 orange brown across posterior margin; dorsal setae dark brown, appressed, whitish yellow, erect laterally on tergite 1, whitish yellow, appressed across posterior margin of tergites 2–4; lateral setae whitish yellow on tergites 1–4, dark reddish brown on tergites 5–8. Terminalia (INBIO 535685). Furca ( Fig. 194) oval; length 0.44 mm, width 0.32 mm; anterolateral projection short, narrow. Common duct ( Fig. 194) shorter than furca. Spermathecal duct ( Fig. 194) expanded posteriorly, diverging laterally then anteriorly before becoming thread­like.

Distribution Brachylinga divaricata is known from Costa Rica ( Fig. 216).

Habitats and phenology

Brachylinga divaricata has been collected in Malaise traps from 9 February to 11 March.

Specimens examined

Type specimen. The holotype male of Brachylinga divaricata Webb (INBIO 744842) is labeled "Est. Maritza, 600m, lado O Vol. Orosi, Prov. Guanacaste, Costa Rica, G. Rodrigues, 27 feb–10 mar. 1992, L­N326900, 373000" and is deposited in the INBC. PARATYPES: COSTA RICA. GUANACASTE. Southwest side of Volcan Cacao, Estación Cacao [10.93, ­85.47], 305–427 m, II– III–1989, 2♂ INB 384005 ( INHS) , 384011 (MEIC); Parque Nacional Volcán Rincón de la Vieja, Estación Las Pailas [10.78, ­85.35], 800 m, 9–27.II.1993, K. Taylor, 5♂ INB 993908 ( USNM) , 993911, 993913, 993920, 993925, 6♀ 993903 ( INHS) , 993910 (MEIC), 993924 (USNM), 993926, 993928, 999931 (INBC); Lado O Vol. Orosi, Estancia Maritza [9.8, ­83.55], 600 m, 27.II–11.III.1992, D. Brenes, 1♂ INB 482420, 2♀ 436791, 535685 ( INBC) ; Liberia , 6 km NE Quebrada Grande, Rio Gongora [10.895, ­85.37], 700 m, –. II.1992, 1♂ INB 803070 ( INBC) .