Periscelis stuckenbergi, Mathis & Freidberg TAU, 2012

Mathis, Wayne N. & Freidberg, Amnon, 2012, Periscelis stuckenbergi sp. n., the first record of the genus from the Afrotropical Region (Diptera: Periscelididae: Periscelidinae), African Invertebrates 53 (1), pp. 231-231 : 235-237

Periscelis stuckenbergi sp. n.

Figs 1–7

Etymology: It is a pleasure to dedicate this new species to the late Brian R. Stuckenberg who was an indefatigable student of Afrotropical Diptera . Brian not only conducted excellent research himself on the taxonomy of Diptera from the Afrotropics and elsewhere, but he also very actively promoted study of this diverse fauna, and we were often the direct recipients of his encouragement and enthusiasm.

Description:

Generally dark brown; body length 2.25–2.60 mm; wing length 2.20–2.60 mm; wing width 0.75–1.00 mm.

Head ( Figs 1–3 ): Frons dark brown, shiny. Antenna generally brown, especially dorsally, yellowish brown to yellow ventrally; arista ( Fig. 2 ) with 6 or 7 dorsal rays; 3 or 4 long ventral rays and 3 much shorter rays between longer rays. Face ( Figs 1, 3 ) with dorsal three quarters generally brown, parallel­sided, with lateral and especially ventral margins yellowish, generally flat, ventral margin of this portion distinctly convex; ventral and ventrolateral portions shiny to subshiny, subshiny portions greyish microtomentose; gena with thin area immediately ventrad of eye whitish to silvery white, microtomentose; postoccipital thin area immediately posterior to posterior margin silvery white, microtomentose. Clypeus thin and narrow, colouration similar to ventral portion of face.

Thorax: Mesonotum ( Fig. 5 ) mostly dark brown, mostly shiny, sparsely invested with grey microtomentum, postpronotum slightly lighter brown; pleura dark brown.Thoracic chaetotaxy: 1 postpronotal; 2 notopleurals; 1 supra­alar; 1 postalar; 2 dorsocentrals (0+2); 2 scutellars, apical 3–4× length of basal; 2 katepisternals, both near dorsal margin.

Wing ( Fig. 4 ): Generally lightly brown on anterior portion and hyaline posteriorly; veins dark brown to ochreous; wing proportion 0.35–0.42 (last proportion from flattened, slide­mounted wing); 1 st costal proportion 0.10–0.14; 2 nd costal proportion 0.46–0.58; costal section I (humeral– R 1) 0.70–1.00 mm; costal section II (R 1 –R 2+3) 0.90– 1.10 mm; costal section III (R 2+3 –R 4+5) 0.09–0.15 mm; costal section IV (R 4+5 –M) 0.20–0.30 mm; subcosta short, length about equal to width of cell, attenuated apically; vein R 2+3 conspicuously arched; cell R 2+3 with semiquadrate spot near middle; cell M with large, semiquadrate spot at basal third, aligned slightly basad of spot in cell R 2+3; crossvein dm–cu short, subequal to length of crossvein r–m; vein M straight, nearly parallel with vein R 4+5.

Legs: Except tarsi, generally dark brown except for yellowish ventral portion of coxae, trochanters and bases of femora; fore tarsus with basitarsomere and sometimes tarsomere 2 dark brown, apical tarsomeres yellow, but becoming slightly darker apically; tarsomeres of mid and hind legs yellowish basally, apical 2 or 3 tarsomeres sometimes darkened, colouration variable.

Abdomen: Dark brown.

Male terminalia ( Figs 6, 7 ): Generally reduced, apparently through fusion. Epandrium as an inverted U ( Fig. 6 ), wider than high, lateral margin in posterior view shallowly arched, in lateral view ( Fig. 7 ) somewhat rectangular but widest just ventrad of midheight, thereafter tapered ventrally; surstylus apparently fused to ventral margin of epandrium as a tapered, ventral projection; cerci robustly developed, 2× as high as wide in posterior view ( Fig. 6 ), digitiform, bearing numerous setulae, these elongate along ventral margin and very stoutly developed, spine­like medially and medioventrally; aedeagus (phallus) in lateral view ( Fig. 7 ) greatly elongate, slender, somewhat membranous, deeply Ushaped, arched medially, basal and apical sections nearly straight; gonite in lateral view slipper­like, tapered apically; subepandrial plate a narrow arch that is projected medially; ejaculatory apodeme well developed with narrow stem, distal portion fan­like; phallapodeme and hypandrium apparently fused indistinguishably, forming a relatively well­sclerotized, deep pocket or pouch ( Fig. 7 ).

Holotype: ♂ “ ETHIOPIA: GAMO GOFA, Arba Minch ‘forest’ [6°02’N 37°33’E], 1300m at tree resin 9.ii. 2000. I. YAROM & A. FREIDBERG / Holotype ♂ Periscelis stuckenbergi Mathis & Freidberg TAU [red].” The holotype is double mounted (minuten in a block of plastic) and is in excellent condition ( TAU).

Paratypes: ETHIOPIA: Gamu-Gofa : 5♂ 6♀ same label data as holotype ( TAU, USNM); 1♀ 3 km NE Ārba Minch, 1300 m, 5.ii.2000, A. Freidberg & I. Yarom ( TAU) .

Remarks: The type locality is in southern Ethiopia, near the town of Ārba Minch. The specimens were collected in a disturbed habitat, just outside the Ārba Minch forest reserve, while they were moving around resin sap from a tree wound located 1.5–2.0 m above the ground.

ACKNOWLEDGMENTS

We gratefully acknowledge the assistance and cooperation of many organisations and individuals who contributed to the field work and production of this paper. We thank I. Yarom for assistance with fieldwork. We also thank Alessandra Rung and an anonymous reviewer for reviewing an earlier draft of the paper. Illustrations of the new species, especially Figs 1–5 , were expertly produced by Karolyn Darrow who is gratefully thanked.

Figures

Figs 1–5. Periscelis stuckenbergi sp. n.: (1–3) head, anterior (1), lateral (2) and anteroblique (3) views; (4) wing, dorsal view; (5) mesonotum, dorsal view.

Figs 6, 7. Genitalia of Periscelis stuckenbergi sp. n.: (6) epandrium and cerci, posterior view; (7) epandrium (and fused surstylus), cerci, ejaculatory apodeme, hypandrium (and fused phallalpodeme) and aedeagus, lateral view.