Amphoterus braunsi van Doesburg, 1956

Midgley, John, Bellingan, Terence & Jordaens, Kurt, 2023, A revision of the hover fly genus Amphoterus Bezzi, 1915 (Diptera, Syrphidae) with the description of one new species, African Invertebrates 64 (2), pp. 149-163 : 149

Amphoterus braunsi van Doesburg, 1956

Figs 2 , 3 , 4 , 7 , 8 , 11 , 12 , 15-17

Amphoterus braunsi van Doesburg, 1956, 22: 517.

Amphoterus braunsi van Doesburg - Smith and Vockeroth 1980: 497; Dirickx 1998: 4.

Eumerus braunsi (van Doesburg) - Whittington 2003, 10: 592. [citation only]

Material examined.

Holotype: South Africa • 1♂; Mpumalanga, Barberton; Dr Brauns leg.; NMSA-Dip 051409, NMSA type number 731.

Other material: South Africa • 1♂; Eastern Cape, Katberg ; 15-30 Jan. 1933; R.E. Turner leg. (NHMUK) . • 1♂; KwaZulu-Natal, Karkloof nr Mount Alida, Geekies Farm ; 1500 m a.s.l.; 3 Jan. 1962; B. & P. Stuckenberg leg.; NMSA-Dip 052854 (NMSA) . • 3♀♀; KwaZulu-Natal, Royal Natal National Park ; 2828DB; late Jan. 1971; H. Townes leg.; NMSA-Dip 059707, 059708, 051873 (NMSA) . • 1♂; KwaZulu-Natal, Karkloof, Geekies Farm ; 2930AB; 21 Dec. 1983; B.R. Stuckenberg leg.; NMSA-Dip 056083 (NMSA) . • 2♀♀; KwaZulu-Natal, Karkloof Nature Reserve ; 29°18'10"S, 30°13'40"E; 1260 m a.s.l.; 10 Dec. 1987; J. & H. Londt leg.; Mixed Podocarpus forest edge; NMSA-Dip 059706, 064223 (NMSA) . • 1♀; KwaZulu-Natal, Vernon Crookes Nature Reserve near Umzinto ; 30°16'S, 30°36'E; 2-7 Nov. 2008; G. Davies leg.; RMCA DNA 165C02; NMSA-Dip 75216, GenBank: OQ706113 (NMSA) . • 1♀; KwaZulu-Natal, Karkloof, near Benvie Farm ; 29°15'36.8"S, 30°21'08"E; 1392 m a.s.l.; 10 Jan. 2015; M. Reemer leg.; MRSA078; (RMNH) . • 1♂ 1♀, KwaZulu-Natal, Karkloof Canopy tour forest; 29°19'18"S, 30°15'43"E; 03 Dec. 2017; G. Ståhls & E. Rättel leg.; http://id.luomus.fi/GJ.2928, Stahls _Y2423, GenBank: OQ706109 (MZHC) . • 1♀; KwaZulu-Natal, Karkloof, Shawswood ; -29.30356, 30.30606; 12 Nov. 2020; J. Midgley leg.; NMSA-Dip 206396 (NMSA) . • 1♂ 2♀♀; KwaZulu-Natal, Karkloof, Shawswood ; -29.30356, 30.30606; 24 Nov. 2020; J. Midgley leg.; RMCA DNA 1370E 06, 1370E 07, 1370E 08; NMSA-Dip 206389, 206390, 206391, GenBank: OQ706110, OQ706111, OQ706112 (NMSA) . • 2♀♀; KwaZulu-Natal, Karkloof, Shawswood ; 9 Jan. 2021; L. Mva leg.; NMSA-Dip 209856, 209857 (NMSA) . • 1♂ 1♀ KwaZulu-Natal, Didima, Rainbow Gorge forest , -28.959933, 29.226848; 22 Jan. 2023; T. Bellingan, K. Jordaens & J. Midgley leg. (RMCA) . • 1♂ 1♀ KwaZulu-Natal, Didima, Rainbow Gorge forest , -28.959933, 29.226848; 23 Jan. 2023; T. Bellingan, K. Jordaens & J. Midgley leg. (AMGS) .

Description.

Male: length 9.5-9.7 mm, wing: 7.5-8 mm.

Head: Eyes broadly dichoptic. Face dark brown; golden yellow pilose; evenly dense golden yellow pollinose. Gena dark brown; golden yellow pilose; sparse golden yellow pollinose. Oral opening occupies about ½ of width between eyes. Frons dark brown; golden yellow pilose; golden yellow pollinose, with a bare patch above the antennae and a bare band between the eyes about ⅔ of the way to form the antennal bases to the anterior ocellus, with a short suture from the angle of the eye extending about 1/6 of the width of the frons on the bare band. Ocellar triangle dark brown; bare anteriorly, with golden brown to dark brown pilosity posteriorly; lacking pollinosity. Ocellar triangle obtuse, distance between posterior ocelli 1.5 times the distance between anterior ocellus and posterior ocellus. Occiput dark brown; golden yellow to golden brown pilose, darker dorsally and paler laterally; golden yellow pollinose laterally, bare dorsally. Eye bare, facets of equal size across eye. Scape short, brown, with a few thick dark brown hairs at the dorsoapical and ventroapical margins, lateroapical margins bare. Antenna with pedicel elongate, about as long as postpedicel, 4.1 times as long as high, brown, covered in stout dark brown hairs, sparser basally, some white pollinosity near apex. Postpedicel elongate, 3.1 times as long as high, dorsal and ventral margin almost parallel basally, widest at ¾ of length, rounded apically; slightly darker brown than basal antennal segments and darker at apex; sparse white pollinose. Arista brown.

Thorax: Scutum dark brown, punctate; postpronotum, the lateral part of the transverse suture and the posterior part of the postalar callus paler, brownish yellow; golden yellow pilose, with denser patches at the posterior margin between the postalar calli, with some darker brown pilosity on the margin between the suture and the postalar callus and on the postalar callus; with a horizontal vitta of sparse golden yellow pollinosity from the postpronotum to in line with the posterior corner of the eye and a horizontal vitta of dense golden yellow pollinosity along the transverse suture and three vittae of sparse white pollinosity, one medial and two mediolateral, reaching from the anterior margin of the scutum to in line with the suture. Scutellum with flattened apical rim, dark brown, golden yellow pilose. Posterior anepisternum, anterior anepimeron and dorsal katepisternum with pale pilosity which is golden yellow dorsally gradually becoming white ventrally. Katatergite with thin, fine golden pilosity. Anterior anepisternum, katepisternum, katepimeron and meron with sparse white pollinosity, which extends slightly onto the posterior anepisternum and anepimeron. Metasternum with white pilosity.

Legs: Reddish brown, except for the coxa, which is dark brown and the metafemur and metatibia, which have some darker markings; golden yellow pilose and a few darker pile on the tarsus. Metafemur somewhat thickened medially, with a shallow, darkened suture posteroventrally at middle of length; metatibia expanded apically, with a small groove ventrally at middle of length. Metabasitarsus large, as thick as metatibia and as long as other tarsal segments combined.

Wing: Brown infuscated, darker anterior to the spurious vein, sometimes with a small hyaline patch at the base of cell r1. Cell r1 open for about ⅓ of its length. Vein R2+3 straight for most of its length, turning sharply upwards as it joins the wing margin. Vein R4+5 straight. Crossvein r-m with a bend posteriorly, at about ⅔ of length of vein where the spurious vein would cross crossvein r-m. Vein M1 recessive, with one or two appendices projecting towards the wing margin. Cell dm usually with a single appendix at posterior corner. Spurious vein weak, indistinct, only visible as a thickened fold. Entire wing microtrichose. Alula about 2.2 times as long as broad. Calypter yellowish, with long golden yellow pilosity. Haltere stem brown basally, becoming lighter distally, knob white.

Abdomen: Punctate, dark brown, with yellow golden pilosity. Tergite (hereafter “T”) 2 somewhat trapezoidal, about half as long as wide, with longer pilosity at anterior corners, anterolateral and dorsomedial sections raised somewhat, with diagonal vittae of golden yellow pollinosity in the grooves between these sections. T3 parallel sided, about half as long as wide, with diagonal vittae of golden yellow pollinosity in shallower grooves than T2. T4 parallel sided anteriorly, rounded posteriorly, about as long as wide, evenly rounded dorsally, diagonal golden yellow pollinose vittae not in grooves.

Genitalia: Hypandrium broad in lateral view, cerci trapezoid (Figs 15-17 ).

Female (as for male, except as noted): length 8.3-10.4 mm, wing 6.7-8.5 mm.

Head: Dense golden yellow pollinosity over most of the face, but with two vittae of less dense pollinosity running from base of antennae to outer oral margin. Ocellar triangle obtuse, distance between posterior ocelli 1.6 times the distance between anterior ocellus and posterior ocellus. Frons more extensively bare than in male, golden yellow pilosity limited to lateral margins and a thin vitta bellow ocellar triangle, without sutures. Pedicel similar colour brown to basal antennal segments.

Thorax: Entire postalar calli pale.

Wing: Vein M1 often with a third appendix projecting into cell r4+5. Allula 2.1 times as long as broad.

Abdomen: T2 parallel sided.

Comments.

Compared to other species in the genus, a large number of specimens of A. braunsi are available for study. This is likely due to higher collecting effort in South Africa than in other African countries and not necessarily an indication of relative abundance. Several collecting events resulted in multiple specimens, suggesting that adults of this species may be abundant at particular times or in particular habitats. In specimens where habitat information is available, individuals were collected from indigenous forests. From our own observations, they are collected in sunny patches with or without flowers, where they rest on leaves or flowers (Fig. 2 ). Detailed flower visiting information is not available at present.

Figures

Figure 2. Live Amphoterus braunsi, collected from sunny patch in indigenous forest at Rainbow Gorge, KwaZulu-Natal, South Africa. Specimen at AMGS.

Figures 3 - 6. Amphoterus species, dorsal view 3 A. braunsi (♂) 4 A. braunsi (♀) 5 A. cribratus (♂) 6 A. londti sp. nov. (♀).

Figures 7 - 10. Amphoterus species, lateral view 7 A. braunsi (♂) 8 A. braunsi (♀) 9 A. cribratus (♂) 10 A. londti sp. nov. (♀).

Figures 11 - 14. Amphoterus heads, frontal view 11 A. braunsi (♂) 12 A. braunsi (♀) 13 A. cribratus (♂) 14 A. londti sp. nov. (♀).

Figures 15 - 20. Amphoterus male genitalia 15 - 17 A. braunsi 15 apical view 16 ventral view 17 lateral view 18 - 20 A. cribratus 18 apical view 19 ventral view 20 lateral view.