Stilpon congoensis, Grootaert, Patrick & Shamshev, Igor, 2013

Grootaert, Patrick & Shamshev, Igor, 2013, The flies of the family Hybotidae (Diptera, Empidoidea) collected during the Boyekoli Ebale Congo 2010 Expedition in Democratic Republic of Congo, Zootaxa 3603 (1), pp. 1-61 : 56-57

Stilpon congoensis sp. nov.

( Figs. 76–78 )

Material examined. HOLOTYPE, 3 labelled: D.R. CONGO, Kona , 13 May 2010, primary swamp forest (reg. 30038, MS reference as St. 2, leg. P. Grootaert); Holotype / Stilpon congoensis / Grootaert et Shamshev sp. nov. ( RBINS). PARATYPES: 1 Ƥ, same provenance as holotype; 1 Ƥ, Kona , 26 May 2010. Malaise trap 4 in secondary forest; 2 Ƥ, Yaekela , 2–7 May 2010, secondary forest, Malaise trap 1 (reg. 30025, leg. P. Grootaert); 1 3, Likombo forest, 2 km SW Bomane, 1.28349, 23.72358, 20–22 May 2010, Malaise traps, lowland evergreen primary forest (disturbed), (leg. A.H. Kirk-Spriggs; BECE 00558).

Diagnosis. Recognised by brown palpi, hind femur brown on about apical two-thirds. Male: gland-like structures between tergites 1–2 and 2–3.

Description. Length: body 1.7 mm, wing 1.1 mm. Male. Head black in ground-colour. Occiput greyish pollinose. Vertical bristles short, black. Frons sublinear with slightly divergent sides above, broad, entirely tomentose. Anterior ocellar bristles minute. Antenna with scape and pedicel dark brown, postpedicel and stylus slightly paler. Palpus brown, with long, black, subapical seta (as long as palpus).

Thorax black in ground-colour. Scutum entirely tomentose; katepisternum shining, otherwise mesopleuron tomentose. Postpronotal bristle long, inclinate. Acrostichal and dorsocentral setae undifferentiated, complete posteriorly.

Legs largely yellow, hind femur brown on about apical two-thirds. Fore femur markedly thickened, with row of very short anteroventral and row of moderately long posteroventral setae. Fore tibia spindle-like, with ordinary setation. Mid femur slender, with 2 black, moderately long, spine-like, ventral bristles on about middle, 2 longer, thinner, yellow bristles near base and 1 long black anterior subapical bristle. Mid tibia with row of black, anteroventral spinules. Hind trochanter lacking spinules. Hind femur (viewed laterally) evenly thickened toward middle, with 1 row of short anteroventral bristles. Hind tibia with unmodified posterior apical comb, clothed with ordinary setulae. Hind basitarsus somewhat thickened.

Wing normally developed, covered with uniform microtrichia; rather deeply, uniformly infuscate. Costal vein with moderately long setulae along anterior margin; costal bristle brown, short. Vein R2+3 straight, about 2.0 times as long as Rs. Distance between apices of veins R2+3 and R4+5 nearly 1.5 times longer than distance between apices of veins R l and R2+3. Veins R4+5 and M1+2 divergent and arcuate in apical part. Halter with black knob and yellow stem.

Abdomen largely brownish yellow, with weakly sclerotised sclerites; segments 7 and 8 brown; tergite 7 deeply concave anteriorly; tergites bearing black unmodified posteromarginal setulae; sternites 4–6 divided medially, sternites 7 and 8 deeply concave anteriorly, sternite 8 with long posteromarginal setae. Gland-like structures between tergites 1–2 and 2–3, plate-like. Terminalia ( Fig. 76–78 ) rather large, brown. Cerci narrowly fused; left cercus unbranched ( Fig. 76 ), lacking spines, with several unmodified setae of different lengths; right cercus unbranched, short, rather subrectangular, lacking spines, with several marginal unmodified setae of different lengths. Epandrium ( Fig. 76 ) completely divided. Right surstylus ( Fig. 77 ) bearing several long unmodified setae of different lengths, lacking spines. Left epandrial lamella small, fused to hypandrium, with 3 moderately long setae in apical part. Left surstylus ( Fig. 78 ) represented by 3 digitiform sclerites, with upper lobe undivided; upper lobe with 1 very long apical seta, no surstylar comb; middle lobe attenuated and pointed apically, with some short unmodified setae; lower lobe with 1 long and 1 short apical unmodified setae. Phallus short.

Female. Mid femur with somewhat thinner and longer, yellowish setae at about middle. Mid tibia with somewhat longer anteroventral spinule-like setulae. Abdomen lacking gland-like structures; tergites completely desclerotised (except segment 8) and abdomen brownish yellow dorsally, with scattered minute setulae; sternites somewhat stronger sclerotised, sternites 3–6 divided medially. Terminalia rather elongate; segment 8 modified, tergite 8 almost entirely pale yellow (except narrow anterior margin), fused with sternite 8 anteriorly; sternite 8 brown; cercus brownish yellow.

Etymology. The specific epithet refers the country D. R. Congo.

Distribution. D.R. Congo.

Remarks. The new species is most similar to S. lomaense but can be readily distinguished from it by having the hind femur brown on about apical two-thirds (vs. entirely yellow).

Figures

FIGURES 76 – 78. Stilpon congoensis sp. nov. 76. Epandrium with cerci; 77. Right surstylus; 78. Left surstylus.