Stuckenbergomyia namibiensis, Sinclair, Bradley J., 2019

Sinclair, Bradley J., 2019, Revision of the southern African genus Stuckenbergomyia Smith, 1971 (Diptera, Empidoidea) and proposal of a new subfamily, African Invertebrates 60 (1), pp. 133-145 : 133

Stuckenbergomyia namibiensis sp. nov. Figs 1-2, 3-7, 22

Etymology.

The specific epithet refers to the country of origin, Namibia.

Diagnosis.

This species is characterised by the pair of dark vittae between acrostichals and dorsocentrals; broad wings, yellow legs and 5-7 pairs of long scutellar setae; male terminalia: nearly symmetrical, held at apex of abdomen, surstyli not clearly differentiated.

Description.

Head: Holoptic with enlarged facets on upper two-thirds. Antenna with scape and pedicel paler than dark brown postpedicel; postpedicel length less than 4 × basal width; stylus cylindrical, shorter than basal width of postpedicel; apical mechanoreceptor one-third length of stylus.

Thorax: Mostly brown with grey pruinescence. Scutum with pair of dark vittae between acrostichals and dorsocentral rows (viewed anteriorly); anterior margin of postpronotal lobe shiny, lacking pruinescence. Acrostichals 4-serial anteriorly, biserial anterior to prescutellar depression; dorsocentral setae biserial and short anteriorly, longer and uniserial at prescutellar depression; postpronotal setae numerous, short and pale; numerous pale presutural and postsutural supra-alar setae; 3-4 short pale notopleural setae; 1 pale postalar seta; 5-7 pairs of pale scutellar setae, slightly longer than length of scutellum. Proepisternum with a few short, pale setae.

Legs: Yellow, including at least apical half of coxae; apical tarsomeres increasingly darker.

Wing (2.5-3 mm): Broad, anal lobe nearly right-angled; alula well-developed. Costal margin at humeral crossvein expanded, costal cell broad; costa gradually reduced beyond R4+5; spur vein arising between cells bm and cua or from cell cua. Halter knob pale.

Abdomen: Dark brown, concolorous with thorax; setae pale; sternites paler than tergites; tergite 8 narrow medially, expanded laterally, bearing pair of setae.

Male terminalia (Figs 3-5): Nearly symmetrical, held at apex of abdomen, not arched over abdomen; rotated 45° to right. Cercus thinly sclerotised, weakly pigmented, clothed in slender setae; hypoproct broad with fine setae on posterior margin. Epandrial lamellae narrowly joined anteriorly; narrowed and tapered on posterior half; surstylus undifferentiated, apex with flattened dorsal margin. Postgonite with slender, sickle-shaped apex; ventral apodeme broad, rectangular. Ejaculatory apodeme elongate, apex pointed. Phallus mostly membranous, expanded apically.

Female.

Similar to male, except dichoptic; frons broad with thick grey pruinescence; abdomen truncate apically (Fig. 6) (see generic description).

Type locality.

NAMIBIA: Brandberg, Mason Shelter, 21°04'42"S 14°35'33"E (Fig. 22).

Type material.

Holotype ♂, labelled: "Namibia: BRANDBERG / Mason Shelter / 21°04'42"S 14°35'33"E / 05-14.iii.2002, 1750 m [elev.] / A.H. Kirk-Spriggs / light trap sample"; "HOLOTYPE / Stuckenbergomyia / namibiensis / Sinclair [red label]" (NMNW) (Fig. 1).

Paratypes: NAMIBIA: 1♂, 1♀, same data as holotype (CNC); 3♀, same data as holotype (NMNW).

Remarks.

This species was not included in the original list of Empidoidea from the Brandberg Massif ( Sinclair 2000), because these specimens were collected subsequent to the initial surveys.