Atherigona (s. str.) nigrithorax Stein, 1906

Deeming, John C., 2022, Some Afrotropical species of Atherigona Rondani (Diptera: Muscidae) revisited and a new species described, European Journal of Taxonomy 847 (1), pp. 121-144 : 130-131

Atherigona (s. str.) nigrithorax Stein, 1906

Fig. 1c–d

Described from a female from Togo ( Stein 1906: 66) and not since reported. The holotype appears in the material discovered in the Smithsonian Institution and has been returned to MNB. The type is in good condition and mounted on a black steel pin with the following labels:

1) rectangular grey label “ Togo, Bismarckburg, 17-23.XII.92, L. Conradt S.”

2) rectangular red label “ Type ”.

3) rectangular white label “Mus. Berol.”

4) rectangular grey label “ Atherigona nigrithorax sp. n. Stein ♀ ”.

The first three labels are machine-printed and the fourth is in the handwriting of Stein.

Redescription

MEASUREMENTS. Body length, female 4.0 mm; wing 3.0 mm.

Female

HEAD. Frontal vitta deep velvety black; frontal plate undusted from base of second inferior orbital seta to level of posterior ocellus; parafacialia, facialia and gena white dusted, this most strongly developed on frontofacial angle; occiput and ocellar prominence dark grey dusted, the postorbital strip paler grey; width of parafacialia at narrowest part equal to diameter of an ocellus; antenna black, somewhat brownish on extreme apex of pedicel and on arista; palpus black.

THORAX. Scutum and scutellum black in ground colour and weakly grey dusted, the former without apparent darker dusted longitudinal vittae; postpronotal lobe infuscate dorsally; pleura ranging from yellow on propleuron to yellowish brown elsewhere, more heavily and yellowish dusted than scutum; propleuron with one long and one moderate and one fine seta; one moderate prostigmatical and a fine seta; lower katepisternal seta equidistant from the two upper setae (these lacking on both sides, but the scars of their attachment visible).

WING. Hyaline with brown veins; anterior crossvein at 0.4 of length of discal cell. LEGS. All tarsi more or less infuscate; fore tibia black, but obscurely yellowish on basal one third of its length; fore femur somewhat infuscate on apical two fifths of its length and hind tibia somewhat infuscate on apical two thirds.

ABDOMEN ( Fig. 1d ). Yellow with black markings and tergites very weakly yellowish dusted; 8 th tergite ( Fig. 1c ). The abdomen is contained in a van Doesburg vial of glycerine pinned under the specimen.

Male

Unknown.

Remarks

In the structure of the head and thorax this species is almost identical to A. bimaculata Stein, 1910 but the area of infuscation of the fore femur is much more restricted than in that species, the abdominal pattern is quite different and the eighth tergite has more heavily sclerotised basal lobes and their pair of separated sclerites triangular, rather than slug-shaped.

Distribution

Togo.

Figures

Fig. 1. a–c. Female eighth tergite, dorsal. a. Atherigona bifida Deeming, 1971. b. Atherigona contrastiloba Deeming, 1987. c. Atherigona nigrithorax Stein, 1906. d. Atherigona nigrithorax, preabdomen, dorsal.