Amphoterus londti, Midgley & Bellingan & Jordaens, 2023

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 londti sp. nov.

Figs 6 , 10 , 14

Material examined.

Holotype: Kenya • 1♀; Eastern Province , Kibwe Forest; 2.41649°S, 37.95560°E; 925 m a.s.l.; 18 Nov.-2 Dec. 2017; R. Copeland leg.; Malaise trap in indigenous forest; RMCA DNA 1300E02; ICIPE 2973, GenBank: OQ706114 (ICIPE).

Diagnosis.

Distinguishable from the other known species in the genus by the narrow alula which is almost three times as long as broad (slightly more than twice as long as broad in others) the long postpedicel, which is about 4.1 times as long as high (2.8-3.1 times in other species); the pedicel is shorter than the postpedicel (0.8:1) (longer in A. cribratus (1.25:1) or equal in length in A. braunsi ), and the white pollinosity of the face (yellow to golden in other species).

Description.

Female: length 9.2 mm, wing: 7.1 mm.

Head: Face black; white pilose; covered with dense white pollinosity but with two vittae of less dense pilosity running from base of antennae to outer oral margin. Gena black; white pilose; with white pollinosity. Oral opening occupies about ⅓ of distance between eyes. Frons black; white pilose; dense white pollinosity restricted to ventrolateral corners and eye margin, though some sparse pollinosity may be present below ocellar triangle, without sutures. Ocellar triangle black; with sparse white to pale yellow pilosity; lacking pollinosity. Ocellar triangle obtuse, distance between posterior ocelli 1.7 times the distance between anterior ocellus and posterior ocellus. Occiput black; white to pale grey pilose, darker dorsally and paler laterally; white pollinose laterally, bare dorsally. Eye bare, facets of equal size across eye. Scape short, dark brown, with a few black spines at the dorsoapical margin and thinner hairs at the ventroapical margin, lateroapical margins bare. Pedicel elongate, 0.8 times as long as postpedicel, 7.5 times as long as high, dark brown, covered in stout black hairs dorsally, ventrally and laterally, with white spines medially, sparser basally, white pollinose. Postpedicel elongate, 4.1 times as long as high, dorsal and ventral margin almost parallel basally, widest at ¾ of length, dorsal margin sloping downwards in final ¼ and rounded venteroapically; dark brown; sparse white pollinose. Arista brown.

Thorax: Scutum black, punctate; postpronotum, the lateral part of the transverse suture and the postalar callus paler, brownish yellow; pale yellow to white 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 with longer white pilosity on the postalar callus; with a horizontal vitta of sparse white pollinosity from the postpronotum to in line with the posterior corner of the eye and a horizontal vitta of sparse white pollinosity along the transverse suture and five vertical vittae of sparse white pollinosity, one medial and two mediolaterally reaching from the anterior margin of the scutum to in line with the suture and two laterally, between postpronotum and postalar calli. Scutellum with flattened apical rim, black, pale yellow to white pilose, pilosity longer on rim. Posterior anepisternum, anterior anepimeron and dorsal katepisternum with white pilosity. All lateral tergites with white pollinosity, sparse on dorsal anepisternum. Metasternum with white pilosity.

Legs: Dark brown, except for the metafemur, which has some black markings, and metatibia, which has a pale brown patch posteromedially; with pale yellow to white pilosity. Metafemur somewhat thickened medially, metatibia expanded apically, with a small groove venteromedially. Metabasitarsus large, as thick as metatibia and as long as other tarsal segments combined.

Wing: grey infuscated in distal region, from subcostal anteriorly to branch of veins R2+3 and R4+5, to crossvein r-m to posterior margin of cell dm, hyaline basally. Cell r1 open for about ¼ 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 two appendices projecting towards the wing margin. Cell dm with a single appendix at posterior corner. Spurious vein developed, though less than other veins. Wing microtrichose over most of the surface, bare only in basal 1/6 of cell r1, anterior margin and posterobasal part of cell br, basal part of cell bm, basal part of cell cua, anterobasal part of cell cup, and anterior part of alula. Allula 2.9 times as long as broad. Calypter white, with long white pilosity. Haltere stem brown basally, becoming lighter distally, knob yellow.

Abdomen: Punctate, black, with pale yellow to white pilosity anteriorly, yellow orange pilosity on apex of final segment. T2 parallel sided, about 2.5 times as wide as long, with longer pilosity at anterior corners, anterolateral and dorsomedial sections raised somewhat, with grooves between these sections; with white pollinosity from the anterior margin to the grooves, posteromedial section without pollinosity. T3 parallel sided, about 4 times as wide as long, with shallower grooves than T2; with a transverse vitta of white pollinosity on the anterior margin and diagonal vittae of white pollinosity from the medial part of the transverse vitta to the margin of the tergite. T4 parallel sided anteriorly, rounded posteriorly, about as long as wide, evenly rounded dorsally, without grooves; with a transverse vitta of white pollinosity on the anterior margin and diagonal vittae of white pollinosity from the medial part of the transverse vitta to the margin of the tergite.

Etymology.

The new species is named in honour of Dr Jason Londt, who not only collected material used in this study, but a wide variety of other Afrotropical Syrphidae . The specific epithet should be treated as a noun in the genitive case.

Comments.

The male of the species is unknown.

Figures

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. (♀).