Dasyhelea thomasi, 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 : 231-233

Dasyhelea thomasi new species

( Figs. 17–18 )

Diagnosis. The only Neotropical species of the leptobranchia group with males having the posteromedian projection of sternite 9 with a truncate apex, an elongate slender paramere with a more slender, greatly recurved distal portion with a sharply pointed tip, and slender, elongate posterolateral arms of the aedeagus, the apices of which are slightly convergent with narrow angled blunt tips. Female unknown.

Male. Head ( Fig. 17 A). Brown. Eyes contiguous for a distance equal to the width of 2–3 ommatidia. Frontal sclerite ( Fig. 17 B) pale, elliptical with lower marginal ear-like lobes. Antennal flagellum with flagellomeres 2–9 rhomboid, 10–12 elongate, 13 slightly broader, 11 longest; flagellomeres 2–10 with whorl of long sensilla chaetica comprising the dense plume that extends just beyond apex of flagellomere 12; antennal ratio 0.84–1.00 (0.92, n=2). Clypeus ( Fig. 17 C) with 7 pairs of setae. Palpus ( Fig. 17 C) light brown, very short; segment 3 short, shorter or equal to length of segments 4+5 combined with 2–3 capitate sensilla on mesal surface; palpal ratio 2.25–3.85 (3.05, n=2). Thorax. Brown. Scutellum with 6 large, 2 smaller setae. Legs including tarsi brown; hind tibial comb with 7 spines; prothoracic tarsal ratio 2.35–2.43 (2.39, n=2), mesothoracic tarsal ratio 2.25–2.35 (2.30, n=2), metathoracic tarsal ratio 2.10–2.20 (2.15, n=2). Wing ( Fig. 17 D) moderately slender; membrane slightly infuscated, covered with sparse macrotrichia; 2nd radial cell reduced to long suture; apex of costa, radius truncate, perpendicular to wing margin; fork of CuA1 at level of mid-portion of 2nd radial cell; anal lobe absent; wing length 0.82 (n=2) mm, width 0.26–0.28 (0.27, n=2) mm; costal ratio 0.41–0.49 (0.45, n=2). Halter pale brown. Abdomen. Brown. Genitalia ( Figs. 17 E, 18A).Tergite 9 moderately short, gradually tapered distally, apex rounded; apicolateral process slender, cylindrical with large apical seta; cercus well developed, moderately long, flattened with 4 apical setae, the distal most seta longest. Sternite 9 ( Figs. 17 E, 18B) 0.50 length of greatest width; anterior margin straight; posterolateral margins curved, heavily sclerotized on extreme apical portion, gradually tapering to truncate apex. Gonocoxite straight, stout, 1.5 x longer than broad, broadest on proximal 1/3, slightly tapered distally; gonostylus 0.80 length of gonocoxite, nearly straight, proximal half broadest distally, distal half gradually tapered, slightly curved, with narrowed apex and bluntly pointed tip. Gonocoxal apodemes and paramere ( Figs. 17 E, 18C) forming an asymmetrical structure; basal portion of gonocoxal apodemes stout, deeply recurved; distal portion of left apodeme slender, with pointed tip that narrowly connects to base of paramere; distal portion of right apodeme broad, broadly connected to paramere; paramere with proximal portion nearly straight, slightly tapered distally, distal portion slender, recurved 180º, tapered distally to slender pointed tip. Aedeagus ( Figs. 17 E, 18D) 0.90 length of greatest width; proximal portion massive, heavily sclerotized; basal arch shallow, extending 0.20 of total length; basal arm broadest apically, anterolaterally directed; posterolateral arms heavily sclerotized, elongate, slender, of unequal lengths, tapering slightly distally, apices slightly convergent with narrow angled, pointed tips.

Female. Unknown.

Type material. Holotype male labeled “ Guadeloupe, Basse Terre , Corrosol, 8-IX-2011, MC Thomas & RH Turnbow, Backlight trap ” (deposited in FSCA) . One paratype male with same data as holotype ( MLPA) .

Derivation of specific epithet. We are pleased to name this unusual new species for one of the collectors, Michael Thomas, in recognition of his important contributions to the systematics of Coleoptera in the Caribbean region.

Discussion. Dasyhelea thomasi is somewhat similar to D. juanae n. sp. in that the apex of tergite 9 is rounded and the aedeagal posterolateral arms are slender and elongate. However, males of D. juanae differ from males of D. thomasi by their narrowly separated, greatly divergent apicolateral processes, sternite 9 with a convex posterior margin, more massive paramere with a much broader slightly recurved apex and more slender, longer, equal-size aedeagal posterolateral arms with sharply pointed tips.

Figures

FIGURE 17. Dasyhelea thomasi n. sp. Holotype male. A. head. B. frontal sclerite. C. palpus. D. wing. E. genitalia.

FIGURE 18. Dasyhelea thomasi n. sp. Holotype male. A. genitalia. B. sternite 9. C. gonocoxal apodemes and paramere. D. aedeagus. Scale bar: 0.05 mm.