Amygdalops acer, Jindr & Rohác & ek, 2004

Jindr, Rohác, ich & ek, 2004, Revision of the genus Amygdalops Lamb, 1914 (Diptera: Anthomyzidae) of the Afrotropical Region, African Invertebrates 45, pp. 157-221 : 186-189

Amygdalops acer sp. n.

( Figs 61–65 , 87, 127)

Type material: Holotype male, labelled: ‘ Kilembe , 4,500 ft. F. W. Edwards. ’, ‘ UGANDA: Ruwenzori Range. xii. 1934 – i. 1935, B. M. E. Afr. Exp., B. M. 1935-203’ ( BMNH, genit. prep.) . Paratypes: UGANDA: S.W., Semiliki Forest , 1250 m, 8.i.1996, 1 male, I. Yarom & A. Freidberg leg. ( TAUI, specimen with faded and damaged wings) . MADAGASCAR: Mandraka , ca 19ºS 48ºE, 11–13.x.1987, 2 males; Andasibe, 19ºS 48ºE, 13–15.x.1987, 1 male, all SFMcE, JRD, SA leg. ( AMSA, one specimen headless). All paratypes with genit. prep .

Etymology: The name ‘acer’ (= Lat. sharp) is derived from sharp, edge-like keel on the male gonostylus of the new species.

Description: Male.

Total body length 1.98–2.30 mm; bicolorous, brown and yellow.

Head: Slightly longer than high. Occiput uniformly brown. Most of frons brown to dark brown, with only anterior fifth ochreous brown and foremost part of orbits orange ochreous. Frontal triangle (including ocellar triangle) shiny and bare, reaching about half of frons (thus shorter than in related species); rest of frons dull and microtomentose, only posterior half of orbit subshiny. Face and gena yellowish white, gena and parafacialia along eye margin silvery white microtomentose; postgena also yellow and sharply contrasting with brown occiput. Mouthparts including palpus yellow. Cephalic chaetotaxy: pvt small but crossed; vti unusually short, only about half length of vte; vte longest of setae on frons; oc also short, slightly longer than vti; 2 long ors (posterior almost as long as vte, anterior only slightly shorter) and 2 usual setulae in front of anterior ors; microsetulae medially in front of frontal triangle almost invisible or absent; 1 long vi and 1 subvibrissa only half length of vi; peristomal setulae small and few in number; postocular setulae very minute. Subapical seta on palpus as long as subvibrissa. Eye convex; its longest diameter 1.45 times as long as shortest one. Gena narrow; its smallest height about 0.1 times as long as shortest eye diameter. Antenna generally yellow; pedicel more orange on inner side and 1st flagellomere somewhat darkened around insertion of arista. Arista about 1.7 times as long as antenna, long pectinate, particularly dorsally.

Thorax: Distinctly narrower than head, brown dorsally and yellow ventrally. Mesonotum including scutellum completely brown to dark brown as also is dorsal band across the pleural part of thorax; humeral and notopleural areas at most slightly paler than mesonotum, never yellow or ochreous. Postscutellum dark brown as scutellum, both these parts separated by a pale ochreous transverse stripe. Ventral portion of pleura yellow to pale yellow. Thoracic chaetotaxy: all macrosetae relatively weak; 1 small prs; 2 dc but anterior very short (only as long prs), posterior dc long though distinctly shorter than apical sc; 2 sc, apical longest of thoracic setae, laterobasal small, as long as anterior dc; ppl indistinct; 2 stpl, anterior distinctly shorter and weaker; ventral setae on sternopleuron few and weak, hair-like. Scutellum rounded subtriangular, with slightly convex dorsal surface. Legs entirely yellow to yellowish ochreous. Chaetotaxy of legs as in related species including posteroventral row of setae on f 3 becoming short and thicker in distal third of femur. Wing ( Fig. 127 ) with similar pattern as in A. thomasseti although the whitish longitudinal area between R 2+3 and R 4+ 5 in front of dark subapical spot less light and poorly delimited. Subapical dark spot more elongate than that of A. thomasseti . R 4+5 and M subparallel, only apically slightly convergent. Discal cell short and narrow; r-m situated distinctly in front of its middle. Wing measurements: length 2.20–2.26 mm; width 0.67–0.72 mm, Cs 3:Cs 4 = 2.04–2.32, r-m\dm-cu: dm-cu = 3.35–3.61. Haltere with ochreous brown stem and darker brown knob.

Abdomen: Preabdominal terga large, broad, all completely dark brown. T6 very small, short, weakly sclerotised and pale. Preabdominal sterna narrow, all pale ochreous except darker S5 which is markedly broader than S4, posteriorly widened and distinctly emarginate on posterior margin. The specimens from Madagascar have preabdominal sterna pale brown and S5 darker brown, although not as dark as preabdominal terga. S6–S8 asymmetrical, dark brown, fused laterodorsally as usual in the genus. S6 short, with ventral part strip-like.

Genitalia: Distinctive. Epandrium hemispherical but relatively short ( Figs 61, 62 ), sparsely setose, with a pair of long dorsomedial setae and small subtriangular anal opening. Cercus moderate, finely setulose. Medandrium ( Fig. 61 ) narrow but comparatively high. Gonostylus ( Fig. 65 ) unusually small, subtriangular, with acute, anteriorly bent apex (less acute in paratypes from Madagascar) and with sharp, longitudinal, edge-like keel on outer side; no micropubescence, only a few setae on its outer side; inner side of gonostylus with more longer setae. Hypandrium (Fig. 87) robust, high in proximal half, with unpigmented membranous internal lobes; transandrium ( Fig. 63 ) robust, provided by transverse ridges and ventrally emarginate, with a pair of slender weak sclerites of caudal process that are almost meeting dorsally and diverging ventrally. Pregonite (Fig. 87) fused with hypandrium, incurved but separated posteriorly from hypandrium by a deep rounded incision, each with about 7 setae, 1 of them longer. Postgonite (Fig. 87) slender, very slightly sinuous, apically pointed and with 1 small anterolateral setula in proximal fourth; basal sclerite attached to postgonite dark, slender and hidden internally behind postgonite. Aedeagal part of folding apparatus attached to base of phallapodeme ( Fig. 64 ) pale even dorsally, provided by flat rounded tubercles; connecting sclerite slender and pale pigmented. Basal membrane with only fine transverse tubercles ( Fig. 63 ). Aedeagal complex ( Fig. 64 ) with unusually slender phallapodeme having basally besides usual fork strongly laterally projecting curved wing-like processes; fulcrum and apex of phallapodeme pale pigmented and the latter strongly tuberculate. Aedeagus with short frame-like phallophore and large distiphallus. Base of distiphallus probably bare. Saccus of distiphallus not very large, rather uniformly finely spinulose (similarly as in A. thomasseti ). Filum of distiphallus formed by 2 dark stripe-like twisted sclerites which are apically tapered and terminate in membranous, somewhat dilated apex. Ejacapodeme small, with usual slender projection.

Female unknown.

Discussion:This distinctive species is externally similar to A. major sp.n. (for differences see under that species) but its wing pattern most resembles that of A. simplicior sp.n. However, it differs from all other Amygdalops species in having peculiar gonostylus (with sharp keel on outer side), base of phallapodeme (with wing-shaped lateral processes) and transandrium (sculptured by transverse ridges). The paratypes from Madagascar are somewhat aberrant; they differ from E. African specimens by darker preabdominal sterna and less acute apex of gonostylus. More material is necessary to evaluate these differences taxonomically; the possibility that the Madagascan population represents a different taxon (probably of subspecific level) cannot be excluded.

Biology: Specimens examined were collected in October, and from December to January.

Distribution: Only known from Uganda and Madagascar.

Figures

Figs 61–65. Amygdalops acer sp.n., male holotype. 61. External genitalia, caudal view. 62. Same, lateral view. 63. Transandrium, caudal view. 64. Aedeagal complex, lateral view. 65. Gonostylus, sublateral view (widest extension). Scales: Fig. 65 = 0.05 mm, others = 0.1 mm. For abbreviation see text.

Figs 126–128. Wings of Amygdalops species. 126. A. major sp.n., male paratype (Madagascar). 127. A. acer sp.n., male holotype. 128. A. nigrinotum Sueyoshi & Rohácek, male (Seychelles). Scales = 0.5 mm.