Stilobezzia (Acanthohelea) medialuna, Da Silva & Ferreira-Keppler & Cazorla, 2023

Da Silva, Irene M., Ferreira-Keppler, Ruth L. & Cazorla, Carla G., 2023, Stilobezzia Kieffer (Diptera: Ceratopogonidae) from the Brazilian Amazon: three new species, redescription of S. (Stilobezzia) maculata Lane and new records, Zootaxa 5249 (4), pp. 485-499 : 486-488

Stilobezzia (Acanthohelea) medialuna n. sp.

( Figs. 1–12 , 50 )

Type material: Holotype male ( INPA ) labeled: “Holotype Stilobezzia (Acanthohelea) medialuna Silva & Cazorla ”. BRAZIL, Amazonas, Manaus, ZF-2, Km 14, Base LBA, 02º35′21″S – 60º06′55″W, Malaise trap over stream, 1– 15.xii.2017, J.A. Rafael and F.F. Xavier: Allotype female, same data as holotype.

Paratypes: 3 males, 2 females, same data as holotype. Campina Biological Reserve , Campinarana, 02º58′94″ S – 60º03′07″ W, suspensa trap over stream, 18.ix–04.x.2018, I.M. Da Silva and R.L. Ferreira-Keppler: 1 female; 04–23.x.2018: 3 males ( INPA ); 23.x–09.xi.2018: 1 female ( INPA ) .

Diagnosis. Only extant species of Stilobezzia (Acanthohelea) in the Neotropical Region with males that have elongated genitalia with stout crescent-shaped gonocoxites, and gonostylus curved 90° at mid-length with toothed apex and a lung-shaped hyaline membrane between the parameres and aedeagus. Females with tarsomere 5 of fore and mid legs with 3 pairs of batonnets and hind leg with 1 pair; abdomen dark brown except segment 10 and cerci paler, and sternite 8 with a large V-shaped posteromedian excavation and 2 ovoid spermathecae.

Description. Male. Head ( Fig. 1 .) dark brown.Antenna with yellowish brown pedicel; light brown flagellomeres with pale brown basal ring; segments 11–12 with stout bristles at base; brown with dense plume; AR 0.90–1.02 (0.97; n=3). Palpus dark brown; segment 5 as long as 3; segment 3 with round deep sensory pit; PR 1.81–2.50 (2.07; n=3). Thorax ( Figs. 1–2 ) dark brown with stout setae, humeral pits slightly lighter; scutellum with 4 stout setae. Legs dark brown; basal 2/3 of fore and mid femora, paler; hind leg darkest, apex of tibia yellowish; tibial comb with 7–8 spines; tarsomeres pale brown; prothoracic TR 1.93–2.1 (1.99; n=4); mesothoracic TR 2.17–2.41 (2.24; n=4); metathoracic TR 1.77–1.93 (1.86; n=4). Wing ( Fig. 5 ) hyaline with dark radial cells; second radial cell 2X longer than first; cubital fork at level of base of r-m cross vein; wing length 1.30–1.36 (1.32; n=4) mm; width 0.40–0.42 (0.41; n=4) mm; costal ratio 0.75–0.76 (0.75; n=4). Halter stem pale brown, knob whitish. Abdomen ( Fig. 1–2 ) dark brown; tergites 1–8 with brown lateral spots; pleural segments 7–8 yellowish brown. Genitalia ( Figs. 8–9 ). Dark brown: tergite 9 triangular distal portion slightly sclerotized, bilobed with apical seta; sternite 9 3X wider than long; cerci conspicuous, divergent. Gonocoxite greatly elongate, crescent-shaped 5.70X longer than wide. Gonostylus 1.80X shorter than gonocoxite, curved about 90º at mid-length; apical portion with toothed apex. Parameres ( Fig. 9–10 ) subparallel, slender, stem slightly wider at base, apical portions abruptly curved, apically directed. Aedeagus ( Fig. 11 ) composed of two convergent sclerites, each slender, slightly curved, with widened, blunt apices. Lungshaped hyaline membranes ( Fig. 9 ) between parameres and aedeagus, apparently basally connected.

Female. Similar to male, with the following notable sexual differences: Head ( Fig. 3–4 ). AR 1.17–1.18 (1.17; n=2); PR 2.44–3.00 (2.71; n=3). Mandible with 6–7 teeth. Thorax ( Figs. 3 ): claws 1.42X shorter than tarsomere 5; fore and mid tarsomeres with 3 pairs of batonnets, hind tarsomere with 1 pair; basal tooth smaller; prothoracic TR 2.03–2.17 (2.12; n=3); mesothoracic TR 2.21–2.52 (2.36; n=3); metathoracic TR 2.15–2.29 (2.22; n=3). Wing ( Fig. 7 ) with macrotrichiae on C, R 1, R 3, and end of M 1; wing length 1.14–1.46 (1.33; n=3) mm; width 0.42–0.54 (0.47; n=3) mm; costal ratio 0.77–0.79 (0.78; n=3). Abdomen ( Fig. 12 ). Sternite 8 with large V-shaped posteromedian excavation and 4 pairs of setae; sternite 9 with sinuous, sclerotized margins; sternite 10 with 2 pairs of setae; cerci triangular, short, paler. Two ovoid, sclerotized spermathecae, without necks, measuring 90–80 µm and 70–70 µm (n=3), plus, an ovoid rudimentary third spermatheca.

Distribution. Brazil (Amazonas: Manaus).

Etymology. The specific name medialuna refers to the shape of the gonocoxite, which resembles a crescent moon.

Remarks. This species resembles the Patagonian species Stilobezzia (Acanthohelea) curvistyla Cazorla & Spinelli, 2007 by the shape of the aedeagus and the 90º curved gonostylus, however S. curvistyla can be distinguished by the pointed apex of the gonostylus, the sclerotized protuberance on the proximal inner margin of the gonocoxite and the conspicuous posterior pointed projection of tergite 9. Females of S. curvistyla have much more elongated spermathecae and the posteromedian excavation of sternite 8 is U-shaped. The male genitalia of this new species also resemble S. (A.) guarani Cazorla & Spinelli, 2010, from northeastern Argentina and Paraguay, by the shape of the aedeagus and the elongated parameres with curved apical portion, but differing in the shape of the gonocoxite, elongate with inner protuberance bearing two small sclerotized teeth.

Figures

FIGURE 50. Distribution of the new species of Stilobezzia Kieffer from Manaus, Amazonas, Brazil.

FIGURES 1–12. Stilobezzia (Acanthohelea) medialuna n. sp., male 1–2, 6, 8–11; female 3, 6–7, 12; 1. Habitus, lateral view; 2 Habitus, dorsal view; 3. Habitus, lateral view. 4. Head, dorsal view; 5. Wing; 6–7. Wing; 8–9. Genitalia, ventral view; 10. Parameres, ventral view; 11. Aedeagus, ventral view. 12. Genitalia, ventral view.