Stilobezzia (Acanthohelea) guarani, 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 : 46

Stilobezzia (Acanthohelea) guarani n. sp.

( Figs.1–9 , 39 )

Diagnosis. The only species of Neotropical Stilobezzia (Acanthohel e a) distinguished by the basal 2/3 of hind femora and apex of tibia dark brown and blackish knees, and the gonocoxite elongate with inner protuberance bearing two small sclerotized teeth.

Male. Head. Dark brown. Antenna (lost in the holotype) with flagellomeres as in Fig. 1 ; plume dark brown; antennal ratio 0.65. Maxillary palpus brown; third segment stout with apical sensory pit; palpal ratio 2.20–2.5 (2.35, n=2).

Thorax. Dark brown. Scutum, with anteromesal pale yellowish spots, as in Fig. 34 . Legs brown, basal 2/3 of hind femora, apex of hind tibia dark brown, knees blackish; hind tibial comb with 4–5 spines; prothoracic TR 2.22–2.29 (2.25, n=2); mesothoracic TR 2.50–2.70 (2.60, n=2); metathoracic TR 2.14–2.44 (2.29, n=2). Wing ( Fig. 2 ) length 0.92–1.13 (1.25, n=2) mm; width 0.33–0.39 (0.36 n =2) mm; membrane hyaline; anterior veins pale; cubital fork distal to level of beginning of r-m crossvein; macrotrichia on costa, scarce on distal margin of r3, m1; first radial cell narrow; second 3.23 times longer than first. Halter pale brown.

Abdomen. Pale. Genitalia ( Figs. 3–5 , 35 ): dark brown; tergite 9 reaching level of end of gonocoxites, posterior margin rounded; cercus not in position to be described; sternite 9 with broad, shallow posteromedian excavation. Gonocoxite elongate, 2.28 times longer than greatest breadth, inner margin with mesal stout, blunt protuberance bearing two small sclerotized teeth (evident in paratype, Fig. 4 ). Gonostylus pale, stout, nearly straight, 0.6 times longer than gonocoxite, blunt apex. Parameres separate, each with basal portion slender, articulated to strongly sclerotized, trilobed apodeme; posteromedian process broad on mid portion, gradually tapering to pointed apex, later curved ventrad. Aedeagus represented by two slender, convergent, slightly sinuose sclerites, each with slightly bulbous tip.

Female. Similar to male, with usual sexual differences.

Head. Dark brown. Antenna as in Fig. 6 , flagellomeres 1–8 pale, apices darker, 9–13 dark brown; antennal ratio 0.85–0.87 (0.86, n= 2). Maxillary palpus ( Fig. 7 ) very dark brown; palpal ratio 2.20 (n= 2). Mandible with 7 teeth.

Thorax. Scutum pale yellowish, humeral areas, anterolateral margins, prescutellar depression dark brown; scutellum yellowish brown with 4 strong setae, 2 thiner ones; postscutellum dark brown. Legs pale brown; coxae dark brown except basal 1/2 of hind coxa pale; basal 2/3 of hind femora, apex of hind tibia dark brown, knees blackish; hind tibial comb with 7 spines; prothoracic TR 2.29–2.50 (2.43, n= 3), mesothoracic TR 2.70– 3.16 (2.85, n= 3), metathoracic TR 2.29–2.66 (2.46, n= 3); claws as long fifth tarsomere, those of hind leg shorter. Wing ( Fig. 8 ) length 1.12–1.27 (1.17, n= 3); width 0.48–0.55 (0.50, n= 3) mm; membrane hyaline; anterior veins pale, CuP dark brown; cubital fork slightly distal to level of beginning of r-m crossvein; macrotrichia on costa, R1, R2, M1, M2, abundant on distal margin of r3, m1, scarce on distal margin of m2, cua1; second radial cell 2.92 times longer than first.

Abdomen: pale brown, segments 8–9 dark brown. Genitalia as in Fig. 9 ; anterior margin of sternite 8 convex, posteromedian excavation V-shaped; sternite 10 short, setae no distinguishable in studied specimens; cercus short, rounded. Two ovoid, strongly sclerotized spermathecae with hyaline punctations, with short necks, measuring 5.2 x 3.8 µm, 4.6 x 3.3 µm; rudimentary third present.

Distribution. Argentina (Misiones province) and Paraguay (Itapúa department) ( Fig. 39 ).

Types. Holotype male, Misiones prov., National route 14, km 813, arroyo Anyico, 18-V-2008, G. Spinelli, 1 male, sweep net; allotype female Argentina, Misiones prov., Corpus, 17-IX-1999, G. Spinelli. Paratypes 1 male, 2 females as follows: same data as allotype except 18-V-2004, A. Jiménez, 1male, female, CDC light trap; Paraguay, Itapúa, Encarnación, arroyo Santa María, III-1996, G. Spinelli, 1 female, sweep net.

Discussion. Stilobezzia (A.) guarani is similar to Stilobezzia (A.) xerophila (described below) but the female abdomen of the latter species is pale brown except segments 8–10 dark brown, and the male gonocoxite lacks the conspicuous inner protuberance with two teeth.

Figures

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

FIGURE 1 – 9. Stilobezzia (Acanthohelea) guarani sp. n., 1 – 5 male; 6 – 9 female; 1 — antenna, 2 — wing, 3 — genitalia (ventral view), 4 — gonocoxite of paratype, 5 — parameres removed, 6 — antenna, 7 — maxillary palpus, 8 — wing, 9 — 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.