Stilobezzia (Acanthohelea) monopicta, Cazorla, Carla G. & Spinelli, Gustavo R., 2010

Cazorla, Carla G. & Spinelli, Gustavo R., 2010, Four new Neotropical species of Stilobezzia (Acanthohelea) Kieffer (Diptera: Ceratopogonidae), Zootaxa 2669, pp. 45-56 : 48

Stilobezzia (Acanthohelea) monopicta n. sp.

( Figs. 10–17 , 36 , 39 )

Diagnosis. The only species of Neotropical Stilobezzia (Acanthohelea) with a single, small and diffuse dark spot on anterior portion of r-m crossvein.

Male. Head. Dark brown. Antenna with flagellomeres as in Fig. 10 ; plume dark brown, moderately developed; antennal ratio 0. 88–1.10 (0.98, n= 2). Maxillary palpus brown; third segment stout with apical sensory pit; palpal ratio 3.00–4.00 (3.76, n= 4).

Thorax. Scutum dark brown, humeral pits pale yellowish, two faint longitudinal yellowish bands down to prescutellar depression; scutellum pale yellowish with 6 strong setae, 4 thiner ones; postscutellum dark brown. Legs dark brown, fore coxa pale brown, fore femur, basal 2/3 of mid femur, basal 1/4 of hind femur pale; hind tibial comb with 5–6 spines; prothoracic TR 1.71–1.85 (1.78, n= 5), mesothoracic TR 2.21–2.50 (2.43, n= 5), metathoracic TR 1.73–1.93 (1.82, n= 5). Wing ( Fig. 11 ) length 1.63–1.80 (1.73, n= 6) mm; width 0.57–0.58 (0.57, n= 6) mm; membrane slightly infuscated, especially on anterior cells; veins dark brown; small diffuse dark spot on anterior portion of r-m crossvein cubital fork proximal to level of beginning of r-m crossvein; macrotrichia on costa, R1, R3, M1, distributed in V-shaped way distally on r3, scarce on m1; first radial cell narrow, second 3.15 times longer than first. Halter pale.

Abdomen. Dark brown. Genitalia ( Figs. 12–13 , 36 ). Tergite 9 not reaching level of end of gonocoxite, progressively narrowing distad, posterior margin rounded; sternite 9 folded in the available specimens, with deep posteromedian excavation; sternite 10 produced beyond base of cercus; cercus rounded, short, divergent. Gonocoxite stout, 1.61 times longer than greatest breadth, inner margin with mesal stout protuberance. Gonostylus as long as gonocoxite, straight with blunt tip. Parameres separate, subparallel, each with basal portion straight, articulated to stout apodeme; posteromedian process slightly sclerotized, slightly curved, divergent distally in some specimens, tip bulbous. Aedeagus composed of two sinuose, stout, convergent sclerites, each with pointed tip.

Female. Similar to male, with usual sexual differences.

Head. Dark brown. Antenna with flagellomeres as in Fig. 14 ; antennal ratio 1.27–1.33 (1.29, n= 4). Maxillary palpus ( Fig. 15 ) dark brown; palpal ratio 3.10–3.50 (3.26, n= 6). Mandible with 7 teeth.

Thorax. Scutellum with 7–8 strong setae, 5–6 thiner ones; hind tibial comb with 8 spines; prothoracic TR 1.92–2.00 (1.94, n=5), mesothoracic TR 2.46–2.50 (2.48, n= 6), metathoracic TR 1.87–2.00 (1.92, n= 6). Wing ( Fig. 16 ) lenght 1.86–2.00 (1.95, n= 6) mm; width 0.72–0.76 (0.74, n= 6) mm; cubital fork at same level of beginning of r-m crossvein; macrotrichia on costa, R1, R2, R3, M1, M2,Cua1 abundant on distal portion of r3, m1, scarce on m2; second radial cell 2.76 times longer than first.

Abdomen. Dark brown. Genitalia as in Fig. 17 ; anterior margin of sternite 8 convex, posteromedian excavation V-shaped; sternite 10 with five pairs of setae; cercus short, rounded; two ovoid spermathecae with very short necks, measuring 9.1 x 5.8 µm, 8.3 x 5.1 µm, rudimentary third present.

Distribution. Argentina (Catamarca, La Rioja and San Luis provinces) ( Fig. 39 ).

Types. Holotype male, ARGENTINA, San Luis Prov., Merlo, 14/ 15-XI-2007, G. Spinelli, CDC light trap; allotype female, same dat as holotype except 15-XI-2007, at light. Paratypes 9 males, 10 females as follows: same data as holotype, 2 females; same data as allotype, 2 males, 1 female; Catamarca prov., Departamento Londres, El Shincal, XII-2004, S. Bogan, 4 males, 4 females, at light. La Rioja Prov., río Miranda, 18-XI-07, G. Spinelli, 3 males, 3 female, at light.

Discussion. Stilobezzia (Acanthohelea) monopicta resambles the Patagonian species S. (A.) patagonica Ingram & Macfie , especially by the similar shape of the aedeagal sclerites and parameres, but the latter species lacks the dark spot on the wing membrane and their spermathecae are very conspicuous and elongated.

Stilobezzia (A.) guianae (Macfie) from Guyana is the other Neotropical species with spotted wings, exhibiting one dark spot on r-m crossvein and another at apex of R3. However, the female of S. guianae differs from this new species by the presence of two strong setae on the tarsomere 5 of all legs. The male genitalia is also very different, with globose gonocoxite, straight posteromedian processes of parameres and aedeagal sclerites more slender and nearly straight.

Figures

FIGURE 39. Distribution of Stilobezzia (Acanthohelea) guarani, S. (Acanthohelea) monopicta, S. (Acanthohelea) paranaense and S. (Acanthohelea) xerophila.

FIGURE 10 – 17. Stilobezzia (Acanthohelea) monopicta sp. n., 10 – 13 male; 14 – 17 female; 10 — antenna, 11 — wing, 12 — genitalia (ventral view), 13 — parameres removed, 14 — antenna, 15 — maxillary palpus, 16 — wing, 17 — genitalia (dorsal view). Scale bars: 0, 0 5 mm.

FIGURE 34 – 38. Stilobezzia (Acanthohelea) guarani sp. n., 34 — scutum, 35 — male genitalia; Stilobezzia (Acanthohelea) monopicta sp. n., 36 — male genitalia; Stilobezzia (Acanthohelea) paranaense sp. n., 37 — male genitalia; Stilobezzia (Acanthohelea) xerophila sp. n., 38 — male genitalia. Scale bars: 0, 0 5 mm.