Stylogaster kroeberi, 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 : 313-316

Stylogaster kroeberi sp. n.

Figs 151–162 , 181

Etymology: This species is named in honour of the late Otto Kröber (1882–1969). He was a German dipterist, whose contribution to the study of Conopidae , especially the Afrotropical species, was considerable.

Diagnosis: Stylogaster kroeberi sp. n. belongs to a species-group with darkened posterior margins to the tergites ( Fig. 153 ) and a white­setulose area on the distal part of the hind tibia ( Fig. 155 ). It differs from the two other species in this group ( S. rinhaii sp. n. and S. malgachensis Camras ) in the presence of the small orange-brown ocellar triangle bordered by the orange­brown frons ( Fig. 156 ), and in having only slightly enlarged eye facets ( Fig. 181 ). The ♂ terminalia ( Figs 157–162 ) are also diagnostic.

Description (based on holotype):

Male.

Overall length: ca 7.1 mm.

Head: 1.5 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. 156 ). Ocellar triangle yellow­brown. Frons orange­brown lateral to ocellar triangle, with 4 fronto-orbital setae. Scapus and pedicellus yellow­brown, basal flagellomere orange­brown. Arista dark brown, base of 3 evident segments orange­brown, situated dorsally at apex of basal flagellomere ( Fig. 154 ). Scapus with few black setulae dorsally. Pedicellus with black setulae. Shape of antenna as illustrated in Fig. 154 . 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 white 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 pale brown medially. All discernible setae black, with exception of golden seta on anepimeron. Two notopleural setae (1 damaged at right side), 1 damaged supra-alar seta, 2 damaged postalar setae, 1 damaged 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 4.9 mm. Generally clothed in microtrichia, but base of sc, base of r 1, r 2+3 and r 4+5, part of br, bm, base of dm and cup without microtrichia. Hind margin of wing with black or brown setulae. Venation as in Fig. 152 . Haltere uniformly yellow­brown, with areas of sensillae at base.

Legs: Pale yellow, hind femur brown basally, with brown areas on hind tibia, a conspicuous white distal area on hind tibia and conspicuously black hind tarsi. Legs with white and black setulae and golden setae; only left hind coxa with black setae. Fore and mid coxae without distinct setae, but with strong golden setulae distally. Hind coxa with strong golden setulae distally on anterior surface, laterally with smaller golden setulae, without outstanding lateral seta. Hind trochanter without teeth, but with dense golden setulae. Mid femur with row of regularly-arranged golden setulae along entire length posteriorly. Hind tibia with single short black spines on anterior surface. Claws brown basally, black distally. Pulvilli brown. Empodia short, brown.

Abdomen: Mainly orange-brown, tergites 2–5 with indistinct darker posterior margins, tergite 6 pale brown ( Fig. 153 ). Tergites with semi­adpressed black setulae. Tergite 1 with long golden setulae laterally, tergite 2 with 5 black lateral setae on either side at anterior margin. Terminalia as illustrated in Figs 157–162 . Cercus triangular ( Fig. 160 ). Dorsal margin straight. Cercus with lappet ventrally. No conspicuous teeth ventrally. No black setae. Surstylus with 1 black tooth medially on distal margin ( Fig. 159 ). No setulae on inner surface. Phallus sheath as illustrated in Fig. 161 . Strong black setulae conspicuous basally.

Female. Unknown.

Holotype: ♂ MADAGASCAR: (1) “ Madagascar , Toliana Prov. / Fiheren, 5.­10. VII.2003, / 23°13.351'S 43°52.853'E / elev 65m, coll. Cal. Acad. of Sci. / ex: malaise trap MGF076”; (2) “CASLOT 044926”; (3) “ Holotypus / Stylogaster / kroeberi ♂ / des. Stuke, 2011” ( CAS). Some tarsi and setae damaged. Abdomen dissected, macerated and deposited in glycerine in a microvial pinned beneath specimen, holotype otherwise in good condition.

Distribution: Endemic to Madagascar.

Bionomics: Sampled in primary rainforest at low elevation (65 m).

Figures

Figs 151–156. Stylogaster kroeberi sp. n. (♂ holotype): (151) habitus, lateral view; (152) wing; (153) abdomen, dorsal view; (154) same, lateral view; (155) hind tibia; (156) frons. Not to scale.

Figs 157–162. Terminalia (♂) of Stylogaster kroeberi sp. n. (holotype): (157) surstylus, lateral view; (158) same, dorsolateral view; (159) same, ventral view; (160) cercus, lateral view; (161) phallus sheath of hypandrium,lateral view; (162) hemispherical extension of hypandrium.Abbreviations:ce – cercus; su – surstylus. Not to scale.

Figs 180, 181. Enlarged facets of Stylogaster spp.: (180) S. malgachensis Camras (♂ Madagascar, 46 km NE of Ankazobe); (181) S. kroeberi sp. n. (holotype). Not to scale.