Stylogaster acanthocercus, 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 : 275-279

Stylogaster acanthocercus sp. n.

Figs 11–24

Etymology: From latinized Greek akantha (thorn) and kerkos (tail), referring to the diagnostic spines on the cercus.

Diagnosis: The occurrence and arrangement of spines on the cercus ( Fig. 21 ) is unique and distinguishes S. ancanthocercus sp. n. from all other Afrotropical Stylogaster species.

Description (based on holotype):

Male.

Overall length: ca 6.3 mm.

Head: 1.5 mm high. Eye brown, with a few scattered inconspicuous ommatrichia. Facets on inner side of eye slightly enlarged. Ocelli pale brown. Ocellar tubercle blackish brown, with 1 pair ocellar setae (1 damaged). Ocellar triangle occupying almost entire frons, reaching as far as antennae ( Fig. 16 ). Ocellar triangle brown. Frons black lateral to ocellar triangle, with 1 or 2 fronto-orbital setae distinguishable. Scapus and base of pedicellus yellow­orange, basal flagellomere and pedicellus apex blackish brown. Arista blackish brown, 2 segments evident. Arista situated dorsally at apex of basal flagellomere ( Fig. 15 ). Scapus with a few black setulae dorsally. Pedicellus with black setulae. Shape of antenna as illustrated ( Fig. 15 ). One vertical seta (both damaged). Face pale yellow with silver pruinosity. Occiput black, distinctly silver pruinose; with line of regularly-arranged small white setulae dorsally, and with several longer white setulae ventrally. Some long white setulae at mouth opening. Proboscis yellow-brown basally, becoming dark brown distally, except for yellow-brown distal, divided part of labellum. Labrum ca 3.2 mm, labellum approximately same length.

Thorax: Yellow-white; mesoscutum (with exception of postpronotum and postalar calli), scutellum, mediotergite and laterotergite blackish brown to brown. All setae damaged, with exception of 2 black notopleural setae and 2 white setae on propleuron. Scars of 2 notopleural setae evident, 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. Some black setulae on the anepimeron. Black semi-adpressed setulae on mesoscutum.

Wing: Length 5.2 mm. Generally clothed in microtrichia, except for base of br, bm, base of dm and cup. Hind margin with black or brown setulae. Venation as in Fig. 17 . Haltere uniformly pale yellow, knob brown, with areas of sensillae at base.

Legs: Fore and mid legs pale yellow­white. Hind leg pale brown dorsally, hind tibia white distally. Hind tarsi damaged. Legs mainly with black or brown setulae, only fore and mid tibiae with pale yellow setulae. Setae on fore coxa white, setae on mid and hind coxae black. Fore coxa without distinct setae, but with strong white setulae distally. Mid coxa with 1 black seta laterally and some black setulae anteriorly. Hind coxa with 1 short lateral black seta and also distally on anterior surface with strong black setulae. Hind trochanter without teeth or dense setulae. Mid femur with row of regularly-arranged black setulae posteriorly on basal half and black setulae ventrally that are slightly longer than diameter of mid tibia. Mid tibia with short, dense black setulae ventrally. Hind femur with long black setulae posteriorly. Hind tibia with 3 short black spines on anterior surface. Claws dark brown basally, black distally. Pulvilli pale brown. Empodia short, pale brown.

Abdomen: Pale yellow, tergite 1 mainly brown, tergites 2–3 with brown posterior margin and brown medial fascia, tergites 5–6 with wide brown medial fascia, epandrium mainly brown ( Fig. 12 ). Tergites with semi­adpressed black setulae. Tergite 1 with long black setulae laterally, tergite 2 with 6 black lateral (and mostly damaged) setae on either side of the anterior margin. Terminalia as illustrated in Figs 18–24 . Cercus rounded distally ( Fig. 20 ). Dorsal margin concave. Cercus with long black tooth and 3 or 4 black spines ( Fig. 21 ). Surstylus with 2 black teeth distally, no setulae on inner surface. Phallus sheath as illustrated in Fig. 23 .

Female. Unknown.

Holotype: ♂ MADAGASCAR: (1) “ Madagascar, Fianarantsoa Prov., / Belle Vue, 1.2 km S Ranomafana / Nat’l Park entrance, malaise / in rainforest, 21.III­12.IV.2003, / 1095 m, R Harin, M E Irwin, / 21°15.99’S. 47°25.21’E. MG 9C­57”; (2) “ Holotypus / Stylogaster / acanthocercus ♂ / des. Stuke, 2011” ( CAS). Left hind tarsi and right hind leg damaged, some setae and right haltere damaged, left wing torn. Abdomen dissected, macerated and deposited in glycerine in a microvial pinned beneath specimen . Holotype otherwise in reasonable condition.

Paratypes: MADAGASCAR: Fianarantsoa: 1♂ Parc National Ranomafana , radio tower at forest edge, 21°15.05'S 47°24.43'E, 1130 m, 5–18.iii.2006, M. Irwin & R. Harin’Hala, Malaise trap ( CAS) ; 1♂ same, except 13–28.iii.2005 ( J-HS) .

Distribution: Endemic to Madagascar.

Bionomics: Found in primary rainforest at moderately high elevation (1095–1130 m).

Figures

Figs 11–17. Stylogaster acanthocercus sp. n. (♂ holotype): (11) habitus, lateral view; (12) abdomen, dorsal view; (13) base of hind femur; (14) mid femur; (15) antenna, lateral view; (16) frons; (17) wing. Not to scale.

Figs 18–24.Terminalia (♂) of Stylogaster acanthocercus sp. n. (paratype):(18) surstylus, lateral view; (19) same, ventral view;(20)cercus, lateral view;(21) same, lateral view, focused on ventral conjunction; (22) apex of cercus, ventrolateral view; (23) phallus sheath of hypandrium, lateral view; (24) sperm pump and ejaculatory apodeme. Abbreviations: ce – cercus; hys – phallus sheath of hypandrium; su – surstylus. Not to scale.