Brachypogon biradialis, Spinelli, Gustavo R., Borkent, Art & Ronderos, María M., 2013

Spinelli, Gustavo R., Borkent, Art & Ronderos, María M., 2013, Two new peculiar species of Neotropical Brachypogon Kieffer (Diptera: Ceratopogonidae), Zootaxa 3702 (1) : -

Brachypogon biradialis n. sp.

( Figs. 1–7 , 16)

Diagnosis. Female: only species of Brachypogon with the wing exhibiting two elongate radial cells with narrow lumen and cell r3 with a forked intercalary vein. Male: unknown.

Description. Female. Head ( Fig. 1 ) dark brown. Eyes with interfacetal spicules, broadly separated medially. Clypeus with 4–5 pairs of lateral setae. Antenna moniliform; scape with two setae; flagellum entirely dark brown, with 13 flagellomeres; flagellomeres 1–3 slightly broader than long, 4–8 as long as broad, 9–13 slightly longer than broad, AR 0.74–0.80 (0.77, n=4); flagellomere 1 with 1–3 apical sensilla coeloconica. Palpus paler than flagellum; segment 3 short, swollen, with subapical, deep sensory pit; fourth segment with 2 setae; PR 0.92–1.21 (1.10, n=4). Mandible with 5 apical teeth, preceded by 2–3 minute denticles.

Thorax ( Fig. 2 ). Uniformly dark brown. Scutellum with six setae; katepisternum with one slender seta ( Fig. 3 ). Legs entirely dark brown; hind tibial comb with 9 spines; foreleg TR 2.96–3.23 (3.06, n=4), midleg TR 2.30–3.00 (2.72, n=4), hind leg TR 2.14–2.33 (2.26, n=4); tarsomeres 4 subcylindrical; tarsal claws with short internal basal teeth, unequal and longer in foreleg ( Fig. 4 ), small and equal in mid-, hind legs. Wing ( Fig. 5 ) length 0.79–0.89 (0.83, n=4) mm, width 0.37–0.40 (0.38, n=4) mm, CR 0.58 (n=4); two elongate radial cells with narrow lumen, first one slightly longer than second; radial veins thick; costa, R1, R3 with black, stout setae; r3 with forked intercalary vein; distal portion of M2 visible; membrane infuscated, with marginal macrotrichia in r3, m1, m 2 in holotype, more abundant and also few in cua 1 in paratypes. Halter whitish.

Abdomen ( Fig. 6 ). Dark brown. Sternite 8 entire, with broadly V-shaped posteromedian excavation; sternite 9 divided medially, each portion deeply excavated caudomedially; sternite 10 with 2 pairs of setae, anterior pair minute, posterior pair elongate, slender. Two ovoid spermatheca ( Fig. 7 ), both with short, broad neck; unequal in length, measuring 50–56 (53, n=4) by 42–47 (44, n=4) µm, and 45–52 (48, n=4) by 33–45 (40, n=4) µm; rudimentary third spermatheca present.

Male. Unknown.

Distribution. Subantarctic Chile (approximately 38 ºS), Argentina (Somuncurá plateau, in Río Negro province) ( Fig. 16). The paratype from 34 km S. Collipulli was collected near a stream in a woodland setting and that from Conguillo National Park was collected from an Araucaria / Nothofagus forest.

Taxonomic discussion. The wing of this species resembles those of species of Borkenthelea Spinelli & Grogan , except for the presence of a forked intercalary vein in cell r3. However, Borkenthelea spp. differs by having eyes contiguous medially, flagellomeres elongated and the katepisternum devoid of setae.

Type material. Holotype female, labeled “ Argentina, Río Negro, Chipauquil (puesto policial), 40º57’41.1’’S, 66º38’20.8’’W, 481m, 4-XII-2006, G. Spinelli, aerial net” (MLP). Paratypes, 3 females from Chile, as follows: 34 km S Collipulli, 23-XII-1984, J.A. Downes, JAD 1678/1/18 (CNCI); nr. Nahuelbuta, 24-XII-1984, J.A. Downes, JAD 1680/1/5 (CNCI); Conguillo National Park, 1150 m, 4/ 5-II-1988, L. Masner, Malaise trap, CD 896 (CNCI).

Derivation of specific epithet. The name biradialis (two radials) refers to the two distinctive narrow radial cells of this species.

Figures

FIGURES 1 – 7. Brachypogon biradialis n. sp., female. 1 — head, in anterior view; 2 — thorax, in lateral view; 3 — katepisternum, in lateral view; 4 — foretarsus, in anterior view; 5 — wing; 6 — abdominal segments 6 – 10, in ventral view; 7 — spermathecae, in ventral view.