Stilobezzia (Acanthohelea) spinellii, Huerta & Grogan, 2017

Huerta, Herón & Grogan, William L., 2017, New species and new records of predaceous midges in the genera, Schizonyxhelea Clastrier and Stilobezzia Kieffer from Mexico (Diptera: Ceratopogonidae), Zootaxa 4294 (4), pp. 401-418 : 408-411

Stilobezzia (Acanthohelea) spinellii new species

(Figs. 8–24)

Diagnosis. Males are the only extant New World species of S. ( Acanthohelea ) with sternite 9 having a deep V- or U-shaped posteromedian excavation; and parameres separate, subcylindrical, sub-parallel, extreme bases pointed, distal 1/3 tapered with elongate apicolateral concavities and blunt tips with a few tiny spicules. Females with dark brown legs except bases of femora and bases, apices of tibiae with pale rings; antennal flagellum with bases of flagellomeres pale; and wing with a darkly infuscated membrane.

Male. Head (Fig. 8). Dark brown. Antennal flagellum with flagellomeres 1–10 pale, 11–13 (Fig. 10) dark brown; plume pale, well developed; antennal ratio 1.07–1.33 (1.20, n=4). Palpus (Fig. 12) brown; segment 3 slender with small shallow subapical sensory pit; palpal ratio 2.50–2.60 (2.50, n= 4). Clypeus with 3–4 lateral, 2 subapical setae. Thorax (Fig. 14). Scutum dark brown, medial vittae, humeral pits and prescutellar depression paler; scutellum dark brown with 6 large setae; postscutellum, pleurae dark brown. Legs ( Figs. 15 a–c) dark brown; femora with narrow pale basal band, fore femur paler than mid, hind femora; hind femur more massive than fore, mid femora; tibiae with basal, apical pale bands which are more distinctive on hind tibia; hind tibia with dorsal row of long setae; fore, mid tarsi pale brown, hind tarsus darker brown. Wing ( Fig. 16 ) membrane, veins darkly infuscated; short anterior, longer posterior intercalary veins in distal portion of cell r3; 2nd radial cell 2.30 x longer than 1st; cubital fork at level of base of r-m crossvein; macrotrichia on costa, Rs, distal margins of M1, and cells r3 and m1; wing length 1.47–1.50 (1.48, n = 4) mm, width 0.47–0.49 (0.48, n= 4) mm; costal ratio 0.76–0.78 (0.77, n= 4). Haltere pale. Abdomen ( Fig. 20 ). Dark brown. Genitalia ( Figs. 20–21 ). Tergite 9 tapered on distal 1/3, posterior margin rounded, extending to apices of parameres; sternite 9 2.8 x broader than long, posteromedian excavation very deep, V- or U-shaped; sternite 10 narrow, not produced beyond bases of cerci. Gonocoxite stout, 1.60 x longer than greatest breadth, proximal ½ broad, inner margin with row of 5 long setae, distal half tapered, apex rounded. Gonostylus 0.80 length of gonocoxite; proximal 2/3 nearly straight; distal 1/3 curved, tapering to slightly pointed tip. Parameres ( Figs. 21, 23 ) separate, sub-cylindrical, sub-parallel; basal section ovoidal with extreme base pointed; proximal 2/3 broadening distally; distal 1/3 tapered with elongate apicolateral concavities and blunt tips with a few tiny spicules. Aedeagus ( Figs. 21–22 ) composed of 2 sinuous, stout, sclerites; basal arm moderately slender, heavily sclerotized with recurved apices; mid portion broad, wing-like, with heavily sclerotized apicomesal sections; distal portion slender, with convergent pointed tips that overlap.

Female. Similar to male with the following notable sexual differences. Head (Fig. 9). Eyes larger, more broadly contiguous. Antennal flagellomeres (Figs. 11a–b) greatly elongate, dark brown, bases paler; antennal ratio 1.06–1.07 (1.06, n=2). Palpus (Fig. 13) brown; segment 3 longer, slenderer with slightly deeper pit; palpal ratio 3.50–3.70 (3.60 n =2). Mandible with 6 teeth. Thorax. Scutellum with 6 large setae. Legs ( Figs. 18 a–c) similar to male; hind tibial comb with 8 large spines; prothoracic tarsal ratio 2.20 (n=2); mesothoracic tarsal ratio 2.60–2.80 (2.70, n=2); metathoracic tarsal ratio 2.20 (n=2); claws shorter than their respective tarsomeres 5, talon of fore leg twice as long as basal tooth, talon of mid leg 4 x longer than basal tooth, talon of hind leg 3 x longer than basal tooth. Wing ( Fig. 17 ) darkly infuscated; 2nd radial cell 3 x longer than 1st; macrotrichia sparse on costa, R1, R2, R3, M1, M2, abundant on distal portions of cells r3, m1; wing length 1.75–1.77 (1.76, n=2) mm, width 0.62–0.65 (0.63, n=2) mm; costal ratio 0.78–0.79 (0.78, n=2). Abdomen ( Fig. 19 ). Brown. Sternite 9 dark brown; anterior margin straight, posteromedian excavation broad, V-shaped, extending 1/3 of total sternite length. Sternite 10 short with 4 pairs of large setae; cercus rounded. Two elongate ovoid, heavily sclerotized spermathecae with hyaline punctuations, measuring 0.075 by 0.32 mm, 0.055 by 0.042 mm with short necks, and a 3rd rudimentary spermatheca.

FIGURES 8–14. Stilobezzia (Acanthohelea) spinellii n. sp. Male: 8, 10, 12, 14. Female: 9, 11a–b, 13. 8–9. Head, frontal view. 10–11b. Flagellomeres XI–XIII, lateral view. 11a. Flagellomeres I–X, lateral view. 12–13. Palpus, lateral view. 14. Thorax, lateral view. Scales: 8, 9, 14 = 0.1 mm; 10, 11a–b = 0.064 mm; 12, 13 = 0.04 mm.

Distribution. Mexico (Oaxaca) ( Fig. 24 ).

Etymology. We are pleased to name this new species after our good friend and colleague Gustavo R. Spinelli, Museo de La Plata, Argentina, in recognition of his numerous important contributions to our knowledge of New World Ceratopogonidae .

Type material. Holotype male, allotype female, MEXICO, Oaxaca, Santo Domingo Petapa , Localidad La Esperanza, 23–29-jul-2009, cerca a la localidad, trampa CDC, B. Salceda-Sánchez, A. Rodríguez-Atanacio & J. Ordoñez-Álvarez ( CAIM) . Paratypes, 5 males, 1 female, same data as holotype ( CAIM; 2 males deposited in FSCA) .

Discussion. The aedeagus and parameres of males of this new species are similar to those of males of S. (Acanthohelea) atrichopogon Lane & Forattini , S. (A.) tibialis Lane & Forattini , and S. (A.) thomasi Grogan et al.

(2013). However, the most notable differences between these 3 species are the shapes and orientations of the distalmost portions of their parameres. For example, in S. (A.) atrichopogon they are bifurcate, with greatly divergent apices; in S. (A.) tibialis they are rounded; in S. (A.) thomasi they are rounded with a hyaline pointed process that is adpressed to the ventral surface; whereas in this new Mexican species, they are blunt, with tiny apical spines.

Females of this new species are very similar to females of S. (A.) atrichopogon , but in that species, the legs are yellow with slightly darker femorotibial joints. The legs of this new species are also similar to those of females of S. (A.) tibialis . However, the wing of S. (A.) tibialis has an irregular spot at the level of the r-m crossvein, whereas in females of this new Mexican species, the entire wing is darkly infuscated.

Figures

FIGURE 24. Distribution of Schizonyxhelea zoologica n. sp. (solid rectangles), and Stilobezzia (Acanthohelea) spinellii n. sp. (solid circles) in Mexico.

FIGURES 15 – 19. Stilobezzia (Acanthohelea) spinellii n. sp. Male: 15 a – c – 16. Female: 17 – 19. 15, 18. Legs, lateral view. a. Fore leg. b. Mid leg. c. Hind leg. 16 – 17. Wings. 19. Abdominal segments 8 – 10 and spermathecae, ventral view. Scales: 0.1 mm. Abbreviations: A = anal vein; c = costal vein; CuA 1 and CuA 2 = cubital veins, anterior branches; CuP = cubital vein, posterior branch; M 1 and M 2 = medial veins; r-m = radial-medial crossvein; R 1 = radial vein, first longitudinal vein; R 3 = radial vein, second longitudinal vein. Scales: 0.1 mm.

FIGURES 20 – 23. Stilobezzia (Acanthohelea) spinellii n. sp. Male. 20. Abdomen and genitalia, ventral view. 21. Genitalia, ventral view. 22. Aedeagus, ventral view. 23. Parameres, ventral view. Scales: 20 = 0.1 mm; 21 = 0.064 mm; 22, 23 = 0.04 mm.