Dasyhelea cyrtostyla, Grogan & Díaz & Spinelli & Ronderos, 2019

Grogan, William L., Díaz, Florentina, Spinelli, Gustavo R. & Ronderos, Maria M., 2019, The Biting Midges of the Caribbean island Curaçao (Diptera: Ceratopogonidae) I. Species in the genus Dasyhelea Kieffer, Zootaxa 4700 (3), pp. 301-325 : 314-315

Dasyhelea cyrtostyla n. sp.

( Figs. 22–30 , 61–63 )

Diagnosis. The only Neotropical species of the mutabilis group with the following combination of characters. Males with apical portion of gonostylus very slender, recurved with a sharply pointed tip; gonocoxal apodemes broadly fused with paramere; paramere with apical section abruptly recurved and adpressed to ventral surface of paramere; and aedeagus with straight basal arch, posterolateral arms with mesal short, slender, subapical toothlike process. Females with moderately short antennal flagellum, flagellomeres 2–8 vasiform, slightly longer than broad, 9–12 slightly longer than 2–8, 13 longest with abruptly tapered apex; subgenital plate with semi-circular anterior portion with broad, ovoid lumen, posterior portion with 2 small posterior sub-basal triangular points; spermatheca large (57.5 x 32.5 µm), ovoid, very heavily sclerotized, neck short, moderately stout, curved.

Male. Head ( Fig. 22 ). Dark brown. Eyes contiguous for a distance equal to the width of 3 ommatidia. Antennal flagellum moderately long; flagellomeres 2–4 very short, 5–9 rhomboid, 10–13 elongate, 10 longest, 13 broadest; antennal ratio 0.77–0.84 (0.80, n=2); flagellum length 0.43–0.47 (n=2) mm. Frontal sclerite elliptical, with elongate posterior extension. Clypeus with 4 pairs of setae. Palpus ( Fig. 23 ) light brown; segment 3 as long as 4+5 combined with scattered capitate sensillae on mesal surface; palpal ratio 2.75–3.14 (2.94, n=2). Thorax. Dark brown; scutellum yellowish, with 6 large, 4 smaller setae. Wing ( Fig. 24 ) moderately slender; membrane hyaline with moderately dense macrotrichiae; veins brown; radial cells without lumen; apices of costa, radius at perpendicular angle with wing margin; fork of CuA 1 just beyond level of apex of costa; without a well-defined anal lobe; wing length 0.62– 0.70 (0.66, n=2) mm, width 0.22–0.27 (0.25, n=2) mm; costal ratio 0.40–0.46 (0.43, n=2). Abdomen. Dark brown. Genitalia ( Figs. 25 , 61–63 ). Tergite 9 broad basally, tapering progressively distally to rounded apex that extends to apices of gonocoxites; apicolateral process slender, with stout subapical seta; cercus conspicuous, located at base of apicolateral process with 4 thin setae. Sternite 9 ( Figs. 25 , 61 ) moderately short, 0.40 length of greatest width; posteromedian portion convex, extending to basal arch of aedeagus. Gonocoxite moderately slender, 1.9 x longer than broad; gonostylus as long as gonocoxite, broadest basally, tapering gradually distally, apical 1/5 very slender, recurved with a sharply pointed tip. Paramere and gonocoxal apodemes ( Figs. 25 , 62 ) heavily sclerotized, nearly symmetrical; gonocoxal apodemes stout, curved, nearly symmetrical, broadly fused with paramere; paramere stout on proximal 2/3, progressively tapering distally, distal 1/3 slender abruptly bent ventrally and adpressed to ventral surface of paramere, tip pointed. Aedeagus ( Figs. 25 , 63 ) massive, heavily sclerotized; 0.45 length of greatest width; basal arch very shallow, straight; basal arms short, rounded; posterolateral arms stout, heavily sclerotized, convergent with mesal short, slender, subapical toothlike process; a hyaline, semicircular structure lies between distal margin of basal arch and posterolateral arms.

Female. Head ( Fig. 26 ). Brown. Eyes contiguous for a distance equal to the width of 3 ommatidia. Antennal flagellum with flagellomeres 2–8 vasiform, slightly longer than broad, 9–12 subequal, slightly longer than 2–8, 13 longest with tapered apex; antennal ratio 0.82 (n=2); flagellum length 0.35–0.36 (n=2) mm. Frontal sclerite elliptical, with elongate ventral extension. Clypeus ( Fig. 27 ) with 5 pairs of setae. Palpus ( Fig. 28 ) light brown; segment 3 about as long as 4+5 combined with 3–4 capitate sensillae on mesal surface; palpal ratio 2.57–2.62 (2.59, n=2). Thorax. Brown; scutellum with 7 large, 3 smaller setae. Legs uniformly brown; tarsi pale, tarsomeres 5 infuscated; hind tibial comb with 7 spines; prothoracic tarsal ratio 1.83–2-08 (1.95, n=2), mesothoracic tarsal ratio 2.07–2.15 (2.11, n=2), metathoracic tarsal ratio 2.20-2.31 (2.25, n=2). Wing ( Fig. 29 ) moderately broad; membrane hyaline with dense macrotrichiae; radial cells without lumen; apices of costa, radius at perpendicular angle with wing margin; fork of CuA 1 at level anterior to base of 2 nd radial cell; wing length 0.62 mm, width 0.30 mm; costal ratio 0.44. Halter pale. Abdomen brown. Subgenital plate ( Fig. 30 ) sub-circular with ovoid central lumen; posteromedian margin rounded; posterolateral arms stout, heavily sclerotized, nearly straight, posterior margin with 2 small posterior sub-basal triangular points. Spermatheca ( Fig. 30 ) large (57.5 x 32.5 µm), ovoid, very heavily sclerotized; neck short, moderately stout, curved, length 7.5 µm.

Distribution. Curaçao.

Type material. Holotype male, allotype female, labeled “ Curaçao, Christoffel Nat. Pk., N car route, Thorn scrub area, 13-XI-2014, M. C. Thomas, Backlight trap (deposited in FSCA) . Paratypes, 1 male, 1 female: 1 female with same data as holotype ; 1 male with same data except Weg Narr, Playa Kanao, 12°9ʹ7.82ʹʹ N, 68°52ʹ9.13ʹʹ W, 10-XI-2014 .

Derivation of specific epithet. The specific epithet is a combination of two Greek terms, cyrto (curved) and styl (a pointed instrument), in reference to the slender, recurved apical section of the male gonostylus.

Discussion. Males of D. curacaoensis n. sp. have a somewhat similar aedeagus to that of D. cyrtostyla n. sp., but in that species the basal arch is convex, moderately deep and the posterolateral arms are shorter with tapered sharply pointed apices. Males of D. curacaoensis n. sp. also differ from D. cyrtostyla n. sp. in having a paramere that has a J-shaped apical section, and much shorter gonostyli with broader, rounded apices. Females of D. curacaoensis n. sp. readily differ from those of D. cyrtostyla n. sp. in having a very short antennal flagellum with moniliform flagellomeres 2–12 and only 13 longer than broad, a broader frontal sclerite, a subgenital plate with a narrow slit-like lumen, and a much smaller (35 x 28 µm vs. 57.5 x 32.5 µm in D. curacaoensis ) ovoid spermatheca with a broader neck.

Males of Dasyhelea guadeloupensis Delécolle & Rieb (1994) also have a wing with a poorly developed anal lobe and an aedeagus that is somewhat similar to D. cyrtostyla n. sp., but in D. guadeloupensis the posterolateral arms are slender with sharply pointed tips and the basal arch is convex and very deep. Males of D. guadeloupensis also differ from D. cyrtostyla n. sp. in having an elongate sternite 9 that overlies most of the aedeagus with a trifurcate apex, a much shorter paramere with a broadly rounded apex, more elongate gonocoxites with a broad elongate, mesal subapical lobe, and gonostyli that are narrower basally, curved distally with broader, rounded apices. Females of Dasyhelea guadeloupensis also have more elongate flagellomeres 9–13 than in females of D. cyrtostyla n. sp., but females of that Guadeloupe species also have a much broader, apically rounded clypeus, a wing with a more poorly developed anal lobe, a longer more distally rounded subgenital plate without 2 small sub-basal triangular points, with a narrower lumen, and a smaller (44 x 37 µm vs. 57.5 x 32.5 µm in D. curacaoensis ) globular spermatheca with a longer, retort-like neck.

Figures

FIGURES 22–30. Dasyhelea cyrtostyla n. sp. Holotype male, 22–25, allotype female, 26–30. 22, 26 head. 23, 28 palpus. 24, 29 wing. 25 genitalia. 27 clypeus. 30 apex of abdomen and spermatheca. Scale bars = 0.05 mm.

FIGURES 52–69. Male Dasyhelea genitalia structures: sternites 9 (left column), gonocoxal apodemes and parameres (middle column), and aedeagi (right column). 52–54 D. aliciae n. sp., 55–57 D. recurva n. sp., 58–60 D. latiala n. sp., 61–63 D. cyrtostyla n. sp., 64–66 D. curacaoensis n. sp., 67–69 D. rhopaloparamera n. sp. Scale bars = 0.05 mm.