Dasyhelea hamula, Grogan, Willliam L., Díaz, Florentina, Spinelli, Gustavo R. & Ronderos, Maria M., 2016

Grogan, Willliam L., Díaz, Florentina, Spinelli, Gustavo R. & Ronderos, Maria M., 2016, The biting and predaceous midges of Guadeloupe (Diptera: Ceratopogonidae). II. Species of the subfamily Dasyheleinae, Zootaxa 4184 (2), pp. 201-254 : 211

Dasyhelea hamula new species

( Figs. 3–4 )

Diagnosis. The only Neotropical species of the grisea group in which the male aedeagal posterolateral arms are serrate at proximal-most inner margin and the apices are abruptly recurved anteroventrally with slender pointed tips; and paramere with a sharply pointed subapical tubercle, apical portion heavily sclerotized, narrow with broader, short, recurved tip. Female with a poorly developed arrowhead-shaped subgenital plate and a heavily sclerotized ovoid spermatheca with conical, oblique neck.

Male. Head ( Fig. 3 A) light brown. Antennal flagellum with flagellomeres 2–9 short, rhomboidal, 10–13 elongate, cylindrical, 13 longest; antennal ratio 0.87. Palpus ( Fig. 3 B) pale; segment 3 as long as 4+5 combined, with scattered capitate sensilla; palpal ratio 2.60. Thorax brown. Scutellum with 9 large, 2 smaller setae. Prothoracic tarsal ratio 2.27, mesothoracic tarsal ratio 2.78, metathoracic tarsal ratio 2.40. Wing ( Fig. 3 C) moderately slender, membrane hyaline with moderately dense macrotrichia; anterior veins darker than posterior veins; apex of costa, radius at slight oblique angle; 2nd radial cell poorly developed, narrow; fork of CuA1 at level of base of 2nd radial cell; anal lobe moderately well developed; wing length 0.96 mm, width 0.34 mm; costal ratio 0.52. Halter dark brown. Abdomen. Light brown. Genitalia ( Figs. 3 D, 4A). Tergite 9 tapering distally, apex truncate, extending considerably beyond gonocoxites; apicolateral process moderately short, conical with single apical seta; cercus very small with 3–4 minute setae. Sternite 9 ( Figs. 3 D, 4B) 0.40 length of greatest width, with an extended, convex posteromedian margin that overlies the basal arch of aedeagus. Gonocoxite stout, straight, 1.70 x longer than broad, broadest mesally with short, blunt tubercle; gonostylus as long as gonocoxite, nearly straight, broadest on basal portion, tapering slightly distally, apex curved with pointed tip. Gonocoxal apodemes and paramere ( Figs. 3 D, 4C) forming an asymmetrical structure; right gonocoxal apodeme stout, curved, considerably shorter than left, in broad contact with basal portion of paramere; left apodeme not contacting paramere; paramere slender proximally, broader on mid-section with a sharply pointed subapical tubercle, apical portion heavily sclerotized, narrow with broader, short, recurved tip. Aedeagus ( Figs. 3 D, 4D) 0.60 length of greatest width; basal arch very shallow, 0.12 of total length; basal arm stout, ventral portion heavily sclerotized, apex recurved, tip rounded; posterolateral arms heavily sclerotized, slightly converging distally, proximal most inner margin serrate, apex abruptly recurved anteroventrally with slender pointed tip.

Female. Head ( Fig. 3 E). Dark brown. Eyes contiguous for a distance equal to the width of 5 ommatidia. Frontal sclerite ( Fig. 3 F) broad, elliptical, slightly bilobate with long, slender ventral projection. Antennal flagellum with flagellomeres 2–8 vasiform, 9–13 elongate, 13 considerably longer than 9–12; antennal ratio 1.06. Clypeus with 4 pairs of setae. Palpus ( Fig. 3 G) pale; segment 3 as long as 4+5 combined with numerous capitate sensillae on entire surface; palpal ratio 2.14. Thorax. Scutum dark brown; scutellum pale brown with 6 large, 2 smaller setae. Femora, tibiae pale brown, hind femur with mesodorsal dark spots; femorotibial joints darker; tarsi with tarsomeres 1–4 pale, 5 infuscated; hind tibial comb with 5 spines; prothoracic tarsal ratio 2.60, mesothoracic tarsal ratio 2.77, metathoracic tarsal ratio 2.51. Wing ( Fig. 3 H) moderately broad, membrane hyaline with moderately dense macrotrichia; anterior veins darker than posterior veins; apex of costa, radius at oblique angle; 2nd radial cell reduced to a suture; fork of CuA1 at level just anterior to base of 2nd radial cell; wing length 0.90 mm, width 0.36 mm; costal ratio 0.53. Halter dark brown. Abdomen ( Fig. 3 I). Dark brown. Subgenital plate lightly sclerotized, distal section poorly developed, arrowhead-shaped, nearly disjunct from basal portion; posterolateral arms moderately broad, apices slightly recurved. Spermatheca heavily sclerotized, slightly ovoid with hyaline punctations, diameter 48 µm, neck conical, slightly oblique, length 12 µm.

Distribution. Guadeloupe.

Type material. Holotype male, allotype female labeled “ Guadeloupe, Basse Terre Pigeon , 03°04'6.97'' S ; 59°59'23.58'' W, 9-IX-2011, MC Thomas & RH Turnbow, Blacklight trap ” (deposited in FSCA).

Derivation of specific epithet. The specific epithet, hamula , is Latin for “a little hook”, a reference to the slender hooked apex of the male paramere of this species.

Discussion. This new species is very similar to D. spatula n. sp., which also has a broad, elliptical, bilobate frontal sclerite, a dark brown scutum and similarly colored legs. However, the holotype male of D. spatula n. sp., differs from the holotype male of this new species by its much shorter, divergent apicolateral processes and the much broader, triangular, spatulate distal portion of the paramere. The allotype female of D. spatula n. sp. differs from the allotype female of this new species by its more deeply bilobate frontal sclerite, pale halter, spermatheca with a longer recurved neck and by the subgenital plate with a broader, elongate anterior portion, the posteromedian base of which is U-shaped and a longer, slender distal portion.

Figures

FIGURE 3. Dasyhelea hamula n. sp. Holotype male, A – D, Allotype female, E – I. A, E. head. B, G. palpus. C, H. wing. D. genitalia. F. frontal sclerite. I. subgenital plate and spermatheca.

FIGURE 4. Dasyhelea hamula n. sp. Holotype male. A. genitalia. B. sternite 9. C. gonocoxal apodemes and paramere. D. aedeagus. Scale bar: 0.05 mm.