Propebrevitrichia serowensis, Winterton, Shaun L., 2005

Winterton, Shaun L., 2005, A new species of Propebrevitrichia Kelsey (Diptera: Scenopinidae: Scenopininae) from Botswana, Zootaxa 818, pp. 1-8 : 2-7

Propebrevitrichia serowensis sp. n. ( Figs 1–3 )

Etymology. The specific epithet refers to the locality (Serowe) where this species was collected.

Type Material: Holotype male, BOTSWANA: [Central District:] Serowe: Farmer’s Brigade, August 1986, Malaise trap, Per Forchhammer ( USNM). Paratypes, BOTSWANA: 22 males, 3 females, same data as Holotype ( USNM); 5 males 1 female, same data as Holotype ( CSCA).

Diagnosis. Wing translucent milky­white in colour, venation yellow anteriorly; haltere stem brown basally, white distally, knob brown with pale band; male sternite 9 without elongate setal comb; aedeagus with relatively short distiphallus; aedeagus with large lateral aedeagal bulbs; gonocoxite with paired dorsal projections.

Description. Body length: Male 2.4–2.8 mm; female 3.5–3.8 mm. Head ( Figs 1 B–E). Male frons narrowly contiguous (eyes rarely touching), separated by less than width of median ocellus, female frons much wider than ocellar tubercle; head black but densely overlain with grey to brown pruinescence (= microtrichia), male face, frons and ocellar tubercle with silver pruinescence, vertex around ocellar tubercle glabrous, black (barely evident as ocellar tubercle occupies most of area between eyes); female frons with brown pruinescence, frons with narrow dark medial stripe in both sexes; occiput with silver pruinescence in male, grey­brown pruinescence in female; female postocular ridge raised, both sexes with minute, sparse and pale coloured postocular setae; eye colour tan; antenna orange brown, flagellum deeply emarginate apically; mouthparts pale orange to cream.

Thorax. Base colouration dark, overlain with grey or brown pruinescence; male scutum grey pruinescent with two diffuse stripes of brown pruinescence, brown pruinescent laterally, posterior half of scutum and anterior portion of scutellum slightly darker, postpronotal lobe, postalar callus and posterior portion of scutellum tan to dark yellow, minute pale setae on scutum with longer pale setae on notopleuron and postpronotal lobe; pleuron dark brown to dark yellow, overlain with grey pruinescence, meron with dark area; legs dark yellow, femora brown in male, pale setae on femora longer in male; wing ( Fig. 1 A) translucent milky white, venation dark yellow, posterior veins pale yellow to white in male; haltere stem brown basally, white distally, knob brown to orange with a pale cream to white band.

Abdomen. Brown with segment one and posterior margin of other segments cream coloured, sparse pale setae in male, brown in female; modified setal patches on T2 rounded, setae projecting medially; male terminalia rotated 180 degrees, (ventral surface appearing dorsal) terminalia pale cream coloured in male, dark yellow in female; some males with paired, heavily sclerotised gonads in segments 4–5 (described as a “spermatocyst” in Yeates et al. (2003)).

Male genitalia ( Fig 2 ). Epandrium split medially and widely separated, lobes truncate anteriorly, ovate posteriorly; cerci and hypoproct elongate with small apical setae, tergite 10 small, thin, located anterior to hypoproct; gonocoxite irregularly shaped with microtrichia on ventral surface, ventral lobe with fine transverse ridges, dark sclerotised dorsal projection with anterodorsal flange, flange covered with setae; gonostylus with microtrichia on outer surface, margin toothed, dark sclerotised on lower tooth; gonocoxal apodeme elongate and dark sclerotised, curved inwards along length; hypandrium medially emarginate with raised medial ridges, ventral setal comb absent; aedeagus shape and internal structure complex, distiphallus relatively short, bifid, curved ventrally and recurved posteriorly near apex, pair of large, sclerotised lateral aedeagal bulbs flanking aedeagus, bulbs ovate, projecting anteriorly just beyond base of ejaculatory apodeme, lateral aedeagal bulbs connect to aedeagus ventrally at point of bifurcation of aedeagus, aedeagus with blunt anterodorsal projection.

Female genitalia ( Fig 3 ). Acanthophorite with five A1 setae, furca elongate, complex, tapered anteriorly and triangular in overall shape with narrow longitudinal bridge, connected to tergite 10 posteriorly; sternite 8 projecting posteriorly beyond tergite 8, posterior margin with dense elongate setae, two sclerotised lateral ridges internally; spermathecal ducts thickened basally with large valve structures, narrow distally, two sclerotised spermathecae, rounded to ovoid, membranous basally; accessory glands narrow, bulbous distally, accessory gland ducts joined to bursa copulatrix on longitudinal bridge anteromedially of spermathecal ducts, just posterior of spermathecal sac duct; spermathecal sac small, tapered distally.

Comments. Propebrevitrichia serowensis sp. n. is known from a single series from Serowe, Botswana. This species is clearly placed in the species group defined by a relatively short distiphallus and the setal comb being absent on sternite 9 (hypandrium) (including species such as P. bonnieana Kelsey , P. botterkloofensis Kelsey , P. canuta Kelsey , and P. patersonensis Kelsey ) (see Kelsey 1976). In the dichotomous key to Propebrevitrichia species in Kelsey (1976), P. serowensis keys out to P. canuta Kelsey , but can be differentiated by the presence of sclerotised dorsal processes on the gonocoxites and straight gonocoxal apodemes in P. serowensis while P. c a n u t a lacks pronounced sclerotised dorsal processes and has upward turned gonocoxal apodemes. Propebrevitrichia serowensis sp. n. is closely related to P. patersonsensis as both species have similar shaped male genitalia but can be easily separated based on body colouration. Yeates (1992, 1994) used specimens from this series as Propebrevitrichia sp. in his phylogenetic studies on Bombyliidae and Scenopinidae .

Figures

FIGURE 1. Propebrevitrichia serowensis sp. n. (A) Wing. (B) Male head, anterior view. (C) Same, lateral view. (D) Female head, anterior view. (E) Same, lateral view. Scale line: 0.1 mm.

FIGURE 2. Propebrevitrichia serowensis sp. n. Male genitalia. (A) Epandrium, dorsal view. (B) Gonocoxites and aedeagus, ventral view. (C) Same, dorsal view. (D) Epandrium, lateral view. (E) Aedeagus, ventral view. (F) Same, dorsal view. (G) Same lateral view. (H) Gonocoxites and aedeagus, oblique view (epandrium removed). Scale line: 0.1 mm. Abbreviations: c, cercus; d, distiphallus; e, epandrium; ea, ejaculatory apodeme; g, gonocoxite; ga, gonocoxal apodeme; gs, gonostylus; h, hypandrium; hy, hypoproct; lab, lateral aedeagal bulb; t 10, tergite 10; va, ventral apodeme of parameral sheath.

FIGURE 3. Propebrevitrichia serowensis sp. n. Female genitalia. (A) Dorsal view, tergite 8 cut away to show internal reproductive structures. (B) Same, lateral view. Scale line: 0.1 mm. Abbreviations: A 1, acanthophorite spines; ac, accessory gland; c, cercus; f, furca; s, spermatheca; sd, spermathecal duct; ss, spermathecal sac; ssd, spermathecal sac duct; s 8, sternite 8; s 10, sternite 10; t 8, tergite 8; t 9 + 10, tergites 9 and 10.