Argolepida rivulosa (Kröber)

Irwin, Michael E. & Winterton, Shaun L., 2021, Revision of South American stiletto fly genus Argolepida Metz & Irwin (Diptera: Therevidae: Therevinae), Zootaxa 5068 (2), pp. 151-185 : 170-173

Argolepida rivulosa (Kröber)

( Figs 1 ; 21–24 ; 32K, L ; 34B ; 35 ; 36F ; 37 )

Psilocephala rivulosa Kröber, 1928: 21 [description], 7 [checklist, distribution], 10 [female key], fig. 17 [female frons and antenna] — Metz et al., 2003: 235 [English translation of original description].

Argolepida rivulosa ( Kröber, 1928) — Metz et al., 2003: 235 [new combination, invalid lectotype designation]; Webb et al., 2013: 24 [catalogue].

Diagnosis. Male frontal glabrous area relatively large, surrounded by yellow suffused pubescence; frontal area straight sided in both sexes with dorsal projections (medially and lateral corners); wing with similar markings in both sexes; abdominal tergites 1–5 with white adpressed scale-like setae.

Redescription. Body length: 6.0– 7.5 mm. Head with frons flat (male) or slightly rounded (female) with pubescence light brownish orange dorsally, silver around antennal base, glossy black glabrous area medially with characteristic ‘tulip’ or ‘crown’ shape ( Figs 32K–L ), larger in female, few short pale setae below ocellar tubercle; postocular setae pale or black, pubescence along postocular ridge grey, medial occiput brown, white, scale-like setae abundant medially; antennal scape dark yellow-orange, overlain with grey pubescence; flagellum brownish orange, darker distally with grey pubescence. Thorax with scutal pubescence dark yellowish brown with light-grey dorsocentral stripes, yellow scale-like setae, denser laterally, scutal macrosetae yellow (chaetotaxy as per genus description); pleuron with dense silver-grey pubescence, few white scale-like setae on anepisternum and katepisternum, katatergite with admixed strong filiform and scale-like setae, anepisternum brownish in dorsal half; coxae dark, overlain with silver-grey pubescence, setae white, mid coxa without setae on posterior surface; femora yellow, dense covering of white scale-like adpressed setae; tibiae yellow, dark grey-brown apically; tarsi dark yellow with apices brown; wing hyaline, infuscate along wing veins and apically in cells cu-p, bm and d; venation yellow basally along major veins, darker distally; haltere stem orange-brown, knob yellow. Abdomen base colour dark brown, yellow medially, extensive adpressed setae, yellow medially, black laterally, white posteriorly and ventrally on each segment 1–5; segments 6–8 and terminalia black. Male and female genitalia as per genus description except ejaculatory apodeme broadly spatulate anteriorly, lateral ejaculatory apodeme relatively small.

Comments. The frontal patch is distinctive for this species and its shape is reminiscent of a ‘tulip’ or ‘crown’, and unlike other Argolepida species , the frontal patch is similarly large in both sexes, although slightly smaller and more parallel sided in the male. As noted by Webb et al. (2013), the lectotype designation by Metz et al. (2003) was unjustified as Kröber (1928) clearly distinguished a type and co-type in his original description. Argolepida rivulosa has a relatively broad distribution, being recorded in Argentina, Bolivia and Uruguay.

Type material. Holotype female, ARGENTINA: Mendoza Province: Mendoza [approximated as -32.8958, -68.8837] (MEI134205; MLUH) . Paratype. ARGENTINA: Mendoza Province: male, same data as holotype (MEI134206; MLUH). (Types examined)

Other material examined. ARGENTINA: Catamarca Province: 2 females, Sierra de Ambato, 13 km NW. Chumbicha [-28.8473, -66.3737], Malaise near water in side canyon, 700 m, 6.IX.1999, M.E. Irwin, F.D. Parker (MEI134838; CSCA) ; 21 males, 6 females, Quemado, ca. 30 km SE. San Martin [-29.5475, -65.5886], open dunes, 275 m, 4–10.XI.1999, M.E. Irwin, F.D. Parker (MEI115295–320; CSCA) . Jujuy Province: 1 male, Tumbaya [approximated as -23.8614, -65.4680], sand dunes, 19.III.1967, L.A. Stange (MEI00011; CSCA) . BOLIVIA: Santa Cruz Province: 1 male, 1 female, Rio Seco [-18.6638, -63.2395], reared larvae sieved from white river dunes, 610 m, 7.III.1999, M.E. Irwin, F.D. Parker (MEI114463, 114568; CSCA) ; 1 male, Rio Seco [-18.6638, -63.2395], river dunes, 610 m, Malaise, 7.III.1999, M.E. Irwin, M. Hauser (MEI121858; CSCA) . URUGUAY: Montevideo Department: 1 male, 1 female, Montevideo [approximated as -34.8393, -56.3890], 21–22.I.1927, F. & M. Edwards, B.M. 1927–63 (MEI30234–5; NHM) .

Figures

FIGURE 1. Argolepida rivulosa (Kröber, 1928), live adult female (photo: Anthony O’Toole).

FIGURE 21. Argolepida rivulosa (Kröber, 1928): male, oblique view.

FIGURE 22. Argolepida rivulosa (Kröber, 1928): male, lateral view.

FIGURE 23. Argolepida rivulosa (Kröber, 1928): female, oblique view.

FIGURE 24. Argolepida rivulosa (Kröber, 1928): female, lateral view.

FIGURE 32. Argolepida spp. heads, anterior view. A. Argolepida atacama sp. n., male; B. Argolepida atacama sp. n., female; C. A. camposi sp. n., male; D. A. camposi sp. n., female; E. A. jama sp. n., male; F. A. jama sp. n., female; G. A. oasis sp. n., male; H. A. oasis sp. n., female; I. A. patagonia sp. n., male; J. A. patagonia sp. n., female; K. A. rivulosa (Kröber, 1928), male; L. A. rivulosa (Kröber, 1928), female; M. A. schlingeri sp. n., male; N. A. schlingeri sp. n., female; O. A. telteca sp. n., male; P. A. telteca sp. n., female.

FIGURE 34. Argolepida spp. wings. A. Argolepida patagonia sp. n.; B. A. rivulosa (Kröber, 1928); C. A. schlingeri sp. n.; D. A. telteca sp. n.

FIGURE 35. Argolepida rivulosa (Kröber, 1928). Male genitalia.A. epandrium; B. gonocoxites, ventral view; C. same, lateral view; D. aedeagus, lateral view; E. same, dorsal view. Female genitalia. F. Furca and internal genitalic structures. Scale line: 0.2 mm. Abbreviations: ag, accessory gland; d, distiphallus; da, dorsal apodeme of parameral sheath; ea, ejaculatory apodeme; f, furca; gs, gonostylus; hy, hypandrium; igp, inner gonocoxal process; lea, lateral ejaculatory apodeme; s, spermatheca; sd, spermathecal duct; ss, spermathecal sac; ssd, spermathecal sac duct; va, ventral apodeme of parameral sheath; vl, ventral lobe.

FIGURE 36. Argolepida spp. male aedeagi, dorsal view (upper) and lateral view (lower). A. Argolepida atacama sp. n.; B. A. camposi sp. n.; C. A. jama sp. n.; D. A. oasis sp. n.; E. A. patagonia sp. n.; F. A. rivulosa (Kröber, 1928); G. A. schlingeri sp. n.; H. A. telteca sp. n.

FIGURE 37. Distribution of Argolepida species in Southern South America.