Atherigona albicornis, Muller, 2015

Muller, B. S., 2015, Illustrated key and systematics of male South African Atherigona s. str. (Diptera: Muscidae), African Invertebrates 56 (3), pp. 845-845 : 857-858

Atherigona albicornis sp. n.

Fig. 31

Etymology: From the Latin albus (white) and cornu (horn), i.e. “white-horned” referring to the characteristically white apical half of the trifoliate process with median piece having two long hyaline setulae appearing as horns.

Diagnosis: This species is most similar to A. flavifinis sp. n. and A. binubila van Emden, 1940 and also keys to the latter in Deeming (1971) and Dike (1989 a). It differs, however, in having its trifoliate process’ median piece dilated, with long white apical setulae and having its lateral plates expanded ( Fig. 31a ), compared to that of A. binubila ( Fig. 26a ) which appear narrow. A. albicornis also has a tridentate hypopygial prominence ( Fig.31c ) compared to that of A. binubila ( Fig. 26c ).

Description:

Male.

Measurement s: Body length: 3.38 mm; wing: 2.87 mm; r­m crossvein ratio: 0.447.

Head: Ground colour dark. All head setae and setulae infuscated. Occiput grey dusted posteriorly and laterally with narrow median part glossy. Ocellar triangle grey dusted, sub-shining. Frontal vitta wholly infuscated. Frontal plate grey dusted, sub-shining around bases of three pairs of proclinate frontal and two pairs of orbital setae; first pair of frontal setae only two thirds the length of the other two pairs. Parafacial silver-grey dusted, narrow. Scape, pedicel, postpedicel and arista infuscated. Palpus infuscated; apically dilated and truncated, with hyaline setulae.

Thorax: Ground colour dark. Postpronotal lobe grey dusted, with three setae and 13 setulae. Pleura grey dusted, except for area where anepisternum, anepimeron and katepisternum meet which is golden dusted. Proepisternum not conspicuously protruding. Scutum grey dusted, with three dark and clearly visible 2-4 dorsocentral vittae, extending and merging over a third the width of the scutellum. Scutellum grey dusted; one pair of basal setae, one pair of discal setae and nine discal setulae; one pair of subbasal setae and one pair of apical setae, equal in length.

Legs: All legs entirely infuscated.

Leg chaetotaxy: Apical three fore tarsal segments with long dorsal setulae, at least as long as segments are wide.

Wings: Hyaline, except for slight brown smoky suffusion at apex of Sc­R 1 and around humeral cross-vein. Veins dark-brown. Knob of halteres white with stalk yellow. Calypters white.

Abdomen: All tergites yellow, grey dusted on all dorsal surfaces; tergite 1+2 with dark-brown median trapezoidal mark, reaching the apical margins, appearing to flow into tergite 3 markings; tergite 3 with two large dark-brown oblong marks taking up two thirds of dorsum width; dark clearly visible median vitta that extends to basal-half of tergite 4; tergite 4 with two small round markings, taking up a third of dorsal surface; tergite 5 with two faint small brown markings. Hypopygial prominence tridentate, with two anterior projecting processes and one medial, somewhat upwards directed process. Trifoliate process stem 2.5× the length of the apical process, hyaline on basal half, infuscated on apical half with the exception of the area surrounding the hood which is also hyaline; median piece hyaline on apical half, with slight rounded bifurcation, dilated in both posterior and lateral views, with one pair of long hyaline setulae (longer than median piece); lateral plates infuscated, wider than median piece in profile, inner lobes present. Surstylus infuscated on majority of dorsal surface.

Female. Unknown.

Holotype ♂: SOUTH AFRICA : KwaZulu­Natal: Royal Natal National Park, Tiger Falls area, 28°41.341'S 28°56.047'E, Protea caffra woodland, 17–18.ii.2010, A.H. Kirk-Spriggs, Malaise trap (BMSA(D) 19841). Paratypes 2♂: KwaZulu­Natal: Giant’s Castle Game Reserve - Injasuti area, 29°07'08.57"S 29°26'19.60"E, 5–11.xii.1983, J.G.H. Londt (NMSA; Type no. 2502).

Distribution: South Africa.

Figures

Figs 28–36. Atherigona spp.: trifoliate process and hypopygial prominence of (28) A. oblonga sp. n.; (29) A. libertensis sp. n.; (30) A. angustiloba van Emden; (31) A. albicornis sp. n.; (32) A. occidentalis Deeming; (33) A. kirkspriggsi sp. n.; (34) A. perfida Stein; (35) A. chirinda Dike; (36) A. cinarina Séguy. Not to scale.

Figs 19–27. Atherigona spp.: trifoliate process and hypopygial prominence of (19) A. marginifolia van Emden; (20) A. erectisetula sp. n.; (21) A. humeralis (Wiedemann); (22) A. bundongoana van Emden; (23) A. falcata (Thomson); (24) A. ndumoensis sp. n.; (25) A. decempilosa Dike; (26) A. binubila van Emden; (27) A. piscatoris sp. n. Not to scale.