Atherigona (Acritochaeta) yorki Deeming, 1971

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 : 530

Atherigona (Acritochaeta) yorki Deeming, 1971 , namibiensis Deeming, ssp. nov.

Etymology: The subspecific epithet namibiensis is a noun in apposition and relates to Namibia, the country of origin of the type material.

Description: Male. Body length: ca 3.0 mm, wing length: ca 3.0 mm. All setae and setulae black, other than curved setulae on truncate apex of palpus.

Head: Colouration black; deeper than long (as ratio 4: 3), with grey pruinescence and setae and setulae black; frontal vitta ferruginous (in one paratype strongly infuscate posteriorly); frontofacial angle forming right angle; parafacial broad above, tapering to 2–3 × width of base of arista at level of vibrissa, gena barely wider; 3–4 inferior orbital setae present, followed by 2 erect and 1 long reclinate superior orbital setae; upper postocular setae noticeably long and strong; antenna ferruginous, with dorsoapical extremity of postpedicel angulate; proboscis brown; palpus yellow, with apical truncated surface occupying 1 / 2 length and covered in short yellow pruinescence, dorsally with row of tiny black studs, basally with only short, weak, yellow seta.

Thorax: Colouration black, with heavily grey pruinescence throughout, only postpronotal callus exhibiting faint yellow hue; 2 long proepisternal setulae and 1 weaker proepimeral, ventral katepisternal seta inserted very much closer to base of more posterior of two dorsal setae. Legs: Without specialised chaetotaxy, yellow, but fore leg infuscate, except coxa, trochanter and basal 1 / 2 of femur, this latter bearing strong posteroventral seta. Wing: Membrane yellowish hyaline, veins yellow; radial–medial crossvein (r–m) situated at mid length of discal medial cell (dm); calypters similar, with yellow rims; halteres yellow.

Abdomen: Colouration yellow, with weak grey pruinescence; tergites 2 – 4 with pair of small, rounded black maculae preapically; terminalia without medial double row of tooth-like projections apparent in nominate subspecies.

Female: Unknown.

Remarks: The below-listed material is distinct and unique, in that in the male the double row of four sharp projections on the edges of the incurved margins of the epandrium (see Deeming 1971, figs 8, 9), are absent and the lower 1 / 2 of the surstylus is bent forwards.

Affinities: The only other species of this subgenus to have a truncate male palpus is the oriental species A. (Acritochaeta) tau Pont, 1981 . It has a very different shape of cercal plate, which bears a brush of long setae on either side. A further description and figures were provided by Pont & Magpayo (1995), which show four compact rows of studs on the inner side of the surstylus, both of these characters being absent in the present species and subspecies.

Type material examined: Holotype ♂ “ Namibia: WEST CAPRIVI PK / Kwando River Susuwe / 17°45'37''S 23°20'55''E / 28.ix–02.x.1998 / A. H. Kirk-Spriggs / Malaise trap in dry woodland [printed] // Namibian National / Insect Collection / National Museum / P.O. Box 1203 / Windhoek, Namibia [printed; blue card] // HOLOTYPE ♂ / Atherigona / (Acritochaeta) yorki / namibiensis ssp. nov. / J.C. Deeming 2024 [printed; red border]” ( NMNW; type series #666). In poor condition, some legs missing, ex ethanol, point-mounted, dissected with terminalia in micro-vial pinned beneath specimen . Paratypes: 2♂, same data as holotype, except “ PARATYPE ♂ / Atherigona / (Acritochaeta) yorki / namibiensis ssp. nov. / J.C. Deeming 2024 [printed; red border]” (1♂, NMNW; type series #666; 1♂, NMWC) .