Atherigona (Acritochaeta) tsumeb Deeming, 2024

Deeming, John C. & Kirk-Spriggs, Ashley H., 2024, A contribution to the knowledge of Namibian Atherigona Rondani (Diptera: Muscidae), with the descriptions of four new species and two new subspecies, Zootaxa 5536 (4), pp. 501-535 : 528-529

Atherigona (Acritochaeta) tsumeb Deeming , sp. nov.

Fig. 22

Etymology: The specific epithet tsumeb is a noun in apposition and is named after the type locality, the Tsumeb District of Namibia.

Description: Male. Body length: ca 3.0 mm; wing length: 3.2 mm. All setae and setulae black.

Head: Colouration yellow on frons, parafacial and gena, infuscate on occiput, ocellar triangle and upper fronto-orbital plate, face creamy white, darker parts with grey pruinescence; palpus and prementum of proboscis infuscate, the latter shiny; lower parafacial very narrow, gena scarcely deeper; antenna with scape and pedicel ferruginous, postpedicel black throughout, arista brown.

Thorax: Colouration black, dorsally with grey pruinescence, bearing brown fascia medially and along dorsocentral lines; postpronotal lobes and entire margin of scutellum yellow; pleura black in ground colour, but anteriorly yellow to a point level with hind insertion of fore leg; prosternum black and shiny. Legs: Yellow, but fore leg black in apical 2 / 5 of length, on tibia and tarsus, tarsus without specialised chaetotaxy. Wing: Membrane hyaline, veins yellow, calypters and basicosta similar, haltere creamy yellow.

Abdomen: Colouration yellow, with conspicuously short setulae and short setae limited to apices of tergites 3–5, syntergite 1 + 2 with basal pair of brown lateral maculae, remaining tergites with small black paired maculae inserted preapically, those on tergite 3 separated by 3 × their own width, on tergite 4 similarly and on tergite 5 by their individual width; cercal plate ( Fig. 22 ) centrally with surface granulose, with small granules centrally and increasingly courser granules laterally, dorsolaterally with pair of upwardly directed setae, on lower margin with pair on either side of dorsomedially directed setae.

Female: Unknown.

Differential diagnosis: The species is very similar to A. (Ac.) gracilipalpis Deeming, 1971 (recorded from Ghana, Nigeria, Republic of Congo and Sierra Leone), sharing with it the same linear, narrow male palpus, with a ventral adornment of fine setulae and also wing vein R 4+5 being apically strongly divergent from vein R 2+3, converging strongly with vein M 1. Whereas in A. (Ac.) gracilipalpis the radial–medial crossvein (r–m) is situated at 0.42 the length of the discal medial cell (dm), it is situated just beyond mid length in the new species (see Table 2 for characters to differentiate the two species).

Type material examined: Holotype ♂ “Ghaub 47 / 19°28'S, 17°00'E / TSUMEB DISTRICT / 16–26 Jul. 1986 / J. Irish / Malaise trapping [printed] // Namibian National / Insect Collection / National Museum / P.O. Box 1203 / Windhoek, Namibia [printed; blue card] // HOLOTYPE ♂ / Atherigona (Acritochaeta) / tsumeb sp. nov. / J.C. Deeming 2024 [printed; red border]” ( NMNW; type series #665). In fair condition, fore leg detached and glued to card beneath; direct-pinned, dissected, terminalia in micro-vial pinned beneath specimen.

Atherigona (Acritochaeta) gracilipalpis Deeming Atherigona (Acritochaeta) tsumeb sp. nov.

Head with frontal vitta brownish black. Head with frontal vitta yellow.

Fore femur without dorsoapical excision and preapical seta Fore femur with dorsoapical excision not developed, but posteriorly. its position marked by compact forwardly directed setulae; preapical posteroventral seta well-developed, with similar but weaker seta situated a tibia width basad to it. Legs black, with knees and apical two tarsal segments dirty Legs yellow, with apical 1 / 3 of fore femur black; fore tibia yellow. becoming increasingly infuscate towards tip, knee yellow.

Wing veins brown. Wing veins yellow.

Wing with radial–medial crossvein (r–m) situated at 0.42 of Wing with radial–medial crossvein (r–m) situated at slightly length of discal medial cell (dm). beyond mid-point of discal medial cell (dm).

Abdominal tergites velvety black laterally, some with dark Abdominal tergites yellow, with paired small black maculae, median vittae. those on tergite 3 separated by 4 × their own width, slightly less on tergite 5 and by their own width on tergite 6.

Figures

FIGURES 1–23. Male terminalia of Atherigona spp. (1–4) A. (s. str.) australis Deeming, sp. nov. 1. Trifoliate process, dorsal view. 2. Same, lateral view. 3. Hypopygial prominence, dorsal view. 4. Same, lateral view. (5–8). A. (s. str.) maraisi Deeming, sp. nov. 5. Trifoliate process, dorsal view. 6. Same, lateral view. 7. Hypopygial prominence, dorsal view. 8. Same, lateral view. (9–12). A. (s. str.) mulleri Deeming, sp. nov. 9. Trifoliate process, dorsal view. 10. Same, lateral view. 11. Hypopygial prominence, dorsal view. 12. Same, lateral view. (13–16). A. (s. str.) jordaensi Magoai & Muller. 13. Trifoliate process, dorsal view. 14. Same, lateral view. 15. Hypopygial prominence, dorsal view. 16. Same, lateral view. (17–20). A. (s. str.) robertsi okavango Deeming, ssp. nov. 17. Trifoliate process, dorsal view. 18. Same, lateral view. 19. Hypopygial prominence, dorsal view. 20. Same, lateral view. (21). A. (s. str.) fumivenosa Deeming, trifoliate process, lateral view. (22). A. (Acritochaeta) tsumeb Deeming, sp. nov., cercal plate, ventral view. (23). Atherigona (Acritochaeta) yorki ssp. yorki Deeming, epandrium and surstyli, left oblique view. All not to scale. Abbreviations: epand—epandrium; sp—spines; sur—surstylus.