Afroxanthandrus comorosensis, Midgley & Goergen & Jordaens, 2024

Midgley, John M., Goergen, Georg & Jordaens, Kurt, 2024, A revision of the Afrotropical hover fly genus Afroxanthandrus Kassebeer, 2000 (Diptera, Syrphidae), with the description of two new species and one new synonymy, European Journal of Taxonomy 968, pp. 60-85 : 64-68

Afroxanthandrus comorosensis sp. nov.

urn:lsid:zoobank.org:act:2105F4F0-C786-41FD-A40C-A4EE6886063F

Figs 1–2 , 7 , 13 , 18–19 , 24

Diagnosis

Differs from other species of Afroxanthandrus in having a broad yellow fascia on tergite 4 (absent in A. congensis and A. longipilus , narrow in A. conopeum sp. nov.) and from A. congensis and A. longipilus in the straight posterior margin of the yellow marking on tergite 2. Male genitalia small (0.5 mm long), surstyli with a ventral projection in lateral view (genitalia large without ventral projection in A. conopeum and A. congensis ).

Etymology

Named after the Comoros Archipelago from where the type was collected.

Type material examined

Holotype

COMOROS • ♂; Nzwani Island [= Anjouan], Koni-Djodjo ; 30 Nov. 2010; M. Jocque leg.; RMCA DNA 1024C07; GenBank: PP828581 ; RMCA, RMCA ENT 000056900 .

Description

MEASUREMENTS. Body: 9.7 mm; wing: 8.8 mm.

Male

HEAD ( Fig. 2 ). Dark brown to black, with medium sized facial tubercle and a medium sized antennal prominence. Face straight in profile; widest just above the tubercle, where approximately 40% of the maximum head width, with slightly curved sides, about as narrow just below antennae and just above the oral margin, approximately 38% of maximum head width; laterally with dense, yellowish gold pollinosity, completely obscuring the black ground colour, thinner pollinosity on the oral margin, gena and medial strip between the tubercle and antennal base, facial tubercle bare; with long, light yellowish pilosity and a few brown pili just below the antennae, medial region bare from oral margin to antennal base. Frons with dense yellowish-gold pollinosity, reaching from the eye contiguity to the base of the antennal prominence. Antennal prominence and lunule bare, the lunule orange in ground colour while the prominence is dark brown to black. Frons with long light yellow pilosity laterally, some brown pile on antennal tubercle, medial pile yellow with brown tips. Vertex short, eye contiguity almost touching ocellar triangle, angle at eye contiguity approximately 35°; ocellar triangle acutely angled, clearly raised, with long and medium length brown pile anteriorly and long golden pile with brown tips posteriorly, anterior ocellus round, posterior ocelli oval, about 1.5 times as long as wide. Occiput with golden pile dorsocentrally, brown pile dorsolaterally and white pile laterally. All pile of similar thickness; with pale yellow white pollinosity laterally, bare dorsally. Eyes bare, kidney-shaped in lateral view. Frontal ommatidia slightly enlarged in a large area above the antennae.Antennae orange-brown, darker dorsally; elongate, slightly shorter than the maximum width of the face, narrow, parallel sided in lateral view, on dorsal side pedicel about as long as the scape, postpedicel 2.5 times the length of the pedicel; scape and pedicel with short thick dark brown pilosity, postpedicel bare, with sparse brown pollinosity; arista bare, inserted basally, about 1.3 times the length of the postpedicel.

THORAX ( Fig. 7 ). Scutum evenly rounded, except for a medium sized raised oval bump on each side, anterior to the suture; black with bronze sheen, postalar callus and surrounding scutum brownish. Scutum covered in short and long pilosity, slightly shorter dorsomedially and slightly longer laterally, yellowish with dark brown tips on long pile over most of the scutum, anterolaterally some pili yellowish for entire length, each pilus on a tiny, rounded, raised, non-pollinose base. Scutal pollinosity densest between the postpronotum and transverse suture, a small area along the suture and posteromedial to the postalar calli, yellow-brown. The remainder of the scutum without pollinosity. Scutellum broad and large, ~60% the width and ~35% the length of the scutum; dark brown to black; pilosity long and short, denser and longer than on the scutum, pile yellowish, the longer pile with dark tips. The relatively smaller size of the raised bases makes the scutellum look smoother (particularly on the margin) than in other species; base narrowly bare (may be obscured by the scutal pile), smooth, with a long, multi-rowed, light subscutellar fringe. Pleura black with bronzy sheen; evenly rounded except for a moderate bulge on the posterolateral anepisternum; yellow to white pollinose, most dense on the anterior anepisternum, bare on the triangular part of the anepimeron, evenly spread over other pleurae; pilosity yellowish, bases smaller than on scutum. Dense pilosity limited to patches on the posterior anepisternum, anepimeron, katepisternum and katatergite, pilosity on katepimeron long but less dense. Metasternum bare. Plumule long, yellowish orange.

LEGS. Hind coxae with a small tuft of pile at posteromedian angle and with scattered long, yellow-white pile. Mid coxae with shorter, scattered yellow-white pile, fore coxae with sparse yellow pile. Trochanters with scattered yellow pile. Fore and mid femur orange brown, hind femur orange brown basally and dark brown distally, fore femur curved, mid femur with a slight medial swelling, hind femur swollen in distal ⅔. Fore femur with long pile on the posterior and ventral surfaces, shorter on the anterior and dorsal surfaces, pile ranges in colour from yellow to brown, shorter pile generally darker, longer pile paler. Pile also somewhat paler basally. Mid femur with long pile posteriorly, shorter on other surfaces; long pile as long as femur thickness; short pile generally brown, long pile golden yellow, but basal pile also paler. Hind femur with shorter pile than other femora, slightly shorter than femur width; mostly brown, though golden basally. Fore tibia orange in basal ½, brown in distal ½, mid tibia orange in basal ⅔, brown distally, hind tibia brown. Tibial pile short and brown, slightly paler brown basally. Tarsi brown with brown pile.

WINGS. Extensively microtrichose, small bare patches at base of c and cup cells. Cell bm bare basally only, with a small patch of denser microtrichia in the distal region, in line with the knot (the thickened part of the vein in br) of the spurious vein. Cell br bare basally, with a small bare patch basomedially. Cell cua bare basally only. Calypters yellow to orange, darker dorsally, with fringe of very long yellowish orange pile. Halteres whitish.

ABDOMEN ( Fig. 13 ). Elongate, broadly oval. Shorter than the wings, about as wide as the thorax. tergite 1 yellow, with a thin posterior black margin; tergite 2 yellow, with a thin black posterior margin, extending on the lateral margin for a very short distance. Tergites 3–4 yellow, with thin black borders on all sides. Tergite 5 yellow. Tergite 2 slightly shorter than tergite 3, tergite 2 and tergite 4 of the same length, and tergite 5 about 1/5 the length of tergite 3. Pile on dorsal surface short, brown centrally and light brown laterally, somewhat longer lateral to tergite 1 and basolateral to tergite 2. Pile on margin longer, pale yellow on tergites 1–2, dark brown on posterior of tergite 2 and tergites 3–5. Sternites yellow, pile long, thin and yellow on sternites 1–2, shorter, thicker and brown on sternites 3–5.

MALE GENITALIA ( Figs 18–19 ). Small (0.5 mm long). Superior lobes projecting posteriorly, slightly shorter than surstyli, somewhat truncated apically, with a ventral projection in lateral view. Surstyli small, about twice as long as wide, rounded apically and covered in small hairs. Hypandrium shorter than superior lobes.

Female

Unknown.

Distribution

Known only from Nzwani Island in the Comoros Archipelago.

Figures

Fig. 1. Map of the known distribution of species of Afroxanthandrus Kassebeer, 2000 in the Afrotropical region.

Figs 2–6. Frontal view of the head of species of Afroxanthandrus Kassebeer, 2000. 2. A. comorosensis sp. nov., holotype, ♂ (RMCA ENT 000056900). 3. A. congensis (Curran, 1938), ♂ (ANHRTUK 00282353). 4. A. conopeum sp. nov., holotype, ♂ (NMSA-Dip 219971). 5. A. congensis, ♀ (ANHRTUK 00282352). 6. A. longipilus Kassebeer, 2000, ♀ (ANHRTUK 00282356). Scale bars = 1 mm.

Figs 7–8. Lateral view of species of Afroxanthandrus Kassebeer, 2000. 7. A. comorosensis sp. nov., holotype, ♂ (RMCA ENT 000056900). 8. A. congensis (Curran, 1938), ♂ (ANHRTUK 00282353). Scale bars = 1 mm.

Figs 13–17. Dorsal view of the abdomen of species of Afroxanthandrus Kassebeer, 2000. 13. A. comorosensis sp. nov., holotype, ♂ (RMCA ENT 000056900). 14. A. congensis (Curran, 1938), ♂ (ANHRTUK 00282353).15. A. conopeumsp. nov., holotype, ♂ (NMSA-Dip 219971). 16. A. congensis, ♀ (ANHRTUK 00282352). 17. A. longipilus Kassebeer, 2000, ♀ (ANHRTUK 00282356). Scale bars = 1 mm.

Figs 18–23. Male genitalia of species of Afroxanthandrus Kassebeer, 2000. 18–20. Dorsal views. 18. A. comorosensis sp. nov., holotype (RMCA ENT 000056900). 19. A. congensis (Curran, 1938) (RMCA ENT 000028396). 20. A. conopeum sp. nov., paratype (NMSA-Dip 086809). 21–23. Lateral views. 21. A. comorosensis sp. nov., holotype (RMCA ENT 000056900). 22. A. congensis (RMCA ENT 000028396). 23. A. conopeum sp. nov., paratype (NMSA-Dip 086809). Scale bars = 0.5 mm.

Fig. 24. Neighbour-Joining tree generated from DNA barcode data for four species of Afroxanthandrus Kassebeer, 2000.