Stylogaster kenyensis, Stuke, 2012

Stuke, Jens-Hermann, 2012, A revision of Afrotropical species of Stylogaster Macquart (Diptera: Conopidae), with descriptions of twenty-one new species and an identification key, African Invertebrates 53 (1), pp. 267-267 : 307-310

Stylogaster kenyensis sp. n.

Figs 125–135

Etymology: The species is named after the state of Kenya, from which the type material originates.

Diagnosis: Stylogaster kenyensis sp. n. belongs to a group of species occurring in central and East Africa that lack additional outstanding setulae on the mid femur and have a mainly black mesoscutum ( Fig. 125 ), partly brown tergites and tergite 6 almost completely brown. The other two species belonging to this group, S. kakamegensis sp. n. and S. nitens , differ from S. kenyensis sp. n. in having the mesoscutum black posteriorly to the lateral margin ( Fig. 115 ) and a basal flagellomere longer than the pedicellus ( Fig. 116 ). The ♂ terminalia are typically as illustrated in Figs 129–135 .

Description (based on holotype):

Male.

Overall length: ca 6.0 mm.

Head: 1.3 mm high. Eye dark brown, with a few scattered inconspicuous ommatrichia. Facets on inner side slightly enlarged. Ocelli orange­brown. Ocellar tubercle blackish brown, with 1 pair of ocellar setae. Ocellar triangle occupies virtually entire frons, reaching as far as antennae ( Fig. 127 ). Ocellar triangle dark brown. Frons brown lateral to blackish ocellar triangle, with only 2 small, defined, fronto­orbital setae. Scapus and pedicellus orange­brown, basal flagellomere brown in distal two­thirds. Arista dark brown, 3 segments evident. Arista situated dorsally at apex of basal flagellomere ( Fig. 126 ). Scapus with few orange-brown setulae dorsally. Pedicellus with black setulae. Shape of antenna as illustrated in Fig. 126 . One distinct black vertical seta. Face pale yellow with silver pruinosity. Occiput black to brown, distinctly silver pruinose; with row of regularly-arranged small white setulae dorsally, and several longer white setulae ventrally. Some long black setulae on mouth opening. Proboscis pale brown basally, becoming blackish brown distally, except for yellow-brown distal division of labellum. Labrum ca 2.9 mm, labellum approximately same length.

Thorax: Yellow-brown; mesoscutum (with exception of postpronotum, lateral margins and postalar callus), scutellum and mediotergite black.All setae black. Two notopleural setae, 1 supra-alar seta, 2 postalar setae, 1 praescutellar dorsocentral seta, 1 apical scutellar seta, 1 seta on anepimeron and 1 seta above fore coxa on propleuron. Black semi-adpressed setulae on mesoscutum.

Wing: Length 5.1 mm. Generally clothed in microtrichia, except for base of r 1 and r 2+3, base of br, bm, very narrowly at base of dm and cup. Hind margin of wing with black or brown setulae. Venation as in Fig. 128 . Haltere uniformly yellow­brown basally, knob brown, with areas of sensillae at base.

Legs: Fore and mid legs yellow­brown. Hind leg darker, with brown base and dorsal surface of hind femur, a yellow-white subapical area on hind tibia and conspicuous black hind tarsi. Legs mainly with black or brown setulae and black setae, only fore leg additionally with pale yellow setulae. Fore coxa with 1, mid and hind coxae with 2 distinct black setae. Hind coxa with strong black setulae distally on anterior surface. Hind trochanter without teeth or dense setulae. Mid femur with row of regularly-arranged black setulae posteriorly on basal half. Hind tibia with 1–2 short black spines on the anterior surface. Claws dark brown basally, black distally. Pulvilli white. Empodia short, brown.

Abdomen: Mainly orange-brown, tergite 1 entirely brown, tergites 2–4 with brown posterior margins and brown fascia medially, tergite 5 with brown fascia medially and tergite 6 brown with exception of lateral margins. Tergites with semi-adpressed black setulae. Tergite 1 with long black setulae laterally, tergite 2 with 1 or 2 black setae laterally on either side of anterior margin. Terminalia as illustrated in Figs 129–135 . Cercus elongated ( Fig. 133 ). Dorsal margin slightly concave. Cercus without lappet ventrally. No conspicuous teeth ventrally. No black setae. Surstylus without black teeth or conspicuous black setae ( Fig. 129 ). A few scattered setulae on inner surface. Some long and strong setulae distally. Phallus sheath as illustrated in Fig. 134 .

Female. Unknown.

Holotype: ♂ KENYA: (1) “ KENYA / Western. Prov. / Kakamega Forest / 0°14.13’N, 34°51.87’E / 14. VII.2000 Malaise / trap, R. Copeland ”; (2) “ Holotypus / Stylogaster / kenyensis ♂ / des. Stuke, 2011” ( NMKE). Right fore tarsi, left haltere and some setae damaged, right wing entirely destroyed. Abdomen dissected, macerated and deposited in glycerine in microvial pinned beneath specimen, holotype otherwise in reasonable condition.

Distribution: Known only from Kakamega Forest in western Kenya.

Bionomics: Sampled from Kenyan last remnant of the ancient Pan-African forest.

Figures

Figs 125–128. Stylogaster kenyensis sp. n. (♂ holotype): (125) thorax, dorsal view; (126) antenna, lateral view; (127) frons; (128) wing. Not to scale.

Figs 129–135. Terminalia (♂) of Stylogaster kenyensis sp. n. (♂ holotype): (129) surstylus, lateral view; (130) same, dorsolateral view; (131) same, ventral view; (132) distiphallus; (133) cercus, lateral view;(134) phallus sheath of hypandrium,lateral view; (135) sperm pump and ejaculatory apodeme. Abbreviations: hys – phallus sheath of hypandrium; su – surstylus. Not to scale.

Figs115–118.Stylogaster kakamegensis sp.n.(♂ holotype):(115) thorax,dorsal view; (116) antenna, lateral view; (117) frons; (118) wing. Not to scale.