Dasyhelea

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 : 235-238

Dasyhelea sp. nr. thomsenae Wirth

( Figs. 19–20 )

Diagnosis. The only Neotropical species of the mutabilis group in which the male has the following combination of characters: a wing that lacks a well defined anal lobe, apicolateral processes with sub-bifid apices, paramere with J-shaped distal portion, an aedeagus with divergent posterolateral arms with broad apices and slender posteromedian projection with rounded tip. Female unknown.

Male. Head ( Fig. 19 A). Brown. Eyes contiguous for a distance equal to the width of 4–5 ommatidia. Antennal flagellum dark brown; flagellomeres 2–9 rhomboidal, 10–13 elongate, 10–12 slender, 13 shorter, broader than 10– 12; flagellomeres 2–10 with single whorl of long sensilla chaetica that comprise the sparse plume that extends to base of flagellomere13; antennal ratio 0.85. Clypeus ( Fig. 19 B) with 4 pairs of setae. Palpus ( Fig. 19 B) pale; segment 3 moderately slender, shorter than 4+5 combined, with 1–2 capitate sensilla on proximal half of mesal surface; palpal ratio 3.60. Thorax. Dark brown; scutellum paler, with 5 large setae. Femora, tibiae brown; tarsomeres 1–4 pale, tarsomeres 5 infuscated; apex of hind tibial comb with 6 spines, 1st longest; prothoracic tarsal ratio 1.93, mesothoracic tarsal ratio 2.12, metathoracic tarsal ratio 2.08. Wing ( Fig. 19 C) moderately broad; membrane hyaline with moderately dense macrotrichia; a 2nd small, narrow radial cell present; fork of CuA1 distad of level of apex of 2nd radial cell; without a well defined anal lobe; wing length 0.66 mm, width 0.28 mm; costal ratio 0.43. Halter brown. Abdomen. Brown. Genitalia ( Figs. 19 D, 20A). Tergite 9 tapering slightly distally, posterior margin truncate, extending to apices of gonocoxites; apicolateral process elongate, cylindrical, with small, slender subapical seta, apex sub-bifid, outer prong much longer than inner prong; cercus not discernible. Sternite 9 ( Figs. 19 D, 20B) 0.42 length of greatest width; proximal portion with straight base and tapered apicolateral margins; distal portion elongate, triangular, gradually tapered, apex truncate, extending to level of posterior margin of basal arch of aedeagus. Gonocoxite stout, 1.80 x longer than greatest width with small, pointed mesal process; gonostylus 0.85 length of gonocoxite, proximal portion broad at base with pointed basodorsal “elbow”, tapering progressively at proximal 1/4, distal portion slender, slightly curved, extreme apex tapered, tip pointed. Gonocoxal apodemes and paramere forming an asymmetrical structure ( Figs. 19 D, 20C); right apodeme broad, recurved at base, middle 1/3 swollen, distal 1/3 slender, tapered distally, narrowly connected to extreme base of paramere; left apodeme shorter, broader than right, extreme base recurved, broadly connected to paramere; paramere tapering progressively distally, distal portion curved, J-shaped, tip sharply pointed. Aedeagus ( Figs. 19 D, 20D) 0.70 length of greatest width; basal arch stout, heavily sclerotized, extending 0.25 of total length; basal arm heavily sclerotized, stout, apex recurved; posterolateral arms simple, moderately stout, distal half laterally curved, apices divergent, tips slightly recurved; posteromedian projection slender, tip roundly pointed, extending just below apices of posterolateral arms.

Female. Unknown.

Distribution. Guadeloupe.

Material examined. Guadeloupe, Basse Terre, NE Pigeon (16.14404º N, 61.74977º W), 23-V-2012, RH Turnbow, BL trap, 1 male ( FSCA).

Discussion. The male genitalia of this species are very similar to those of two previously described species: D. thomsenae Wirth 1952 , from California and New Mexico, USA ( Wirth 1952), from Maryland and Virginia (Borkent & Grogan 2009), and more recently collected specimens from Florida, Kentucky and Mississippi (WLG; personal observations); and, D. auli Remm (1962) , which was originally described from Estonia, but is also known from Poland and Romania ( Dominiak 2012). WLG borrowed two California males of D. thomsenae from the USNM that are virtually identical to three males mentioned above from Florida, Kentucky and Mississippi. He also compared these five USA males with color photographs of male D. auli sent to us by Patrycja Dominiak of the holotype from Estonia, and 2 other males from Poland and Romania . We consider males of both species to be identical, and therefore, it is likely that D. auli is a junior synonym of D. thomsenae , a possibility that will be addressed by a study in progress by Grogan & Dominiak. Most males of D. thomsenae and D. auli differ from this Guadeloupe male by their shorter gonostylus with a bulbous distal portion, a wing with a shorter costa (costal ratio 0.38–0.40) and a better developed anal lobe. However, one male of D. thomsenae from California has a long slender gonostylus with a slender apex. Because we have not examined the holotype male of D. thomsenae , we can't be certain that the gonostylus of this Guadeloupe male is actually different than in that species. Therefore, we prefer to not propose a name for this Guadeloupe male .

The male of this Guadeloupe specimen is also somewhat similar to males of the Patagonian D. monticola Ingram & Macfie (1931) and the Neotropical D. suarezi Spinelli & Ronderos (1987) , which also have J-shaped parameres and a fork of CuA1 located distad to the level of the second radial cell. However, the aedeagus of D. monticola differs from this new species by its posterolateral arms that bear an outer triangular process and a shorter, more slender triangular posteromedian projection ( Díaz et al. 2014). Males of D. suarezi differ from this new species by their much broader, deeply bifid apicolateral processes and their aedeagus with a longer posteromedian projection with a spatula-shaped apex ( Spinelli & Ronderos 1987).

Figures

FIGURE 19. Dasyhelea sp. nr. thomsenae Wirth. Male. A. head. B. palpus. C. wing. D. genitalia.

FIGURE 20. Dasyhelea sp. nr. thomsenae Wirth. Male. A. genitalia. B. sternite 9. C. gonocoxal apodemes and paramere. D. aedeagus. Scale bar: 0.05 mm.