Prosoeca parva, Theron & Ellis & Midgley, 2025

Theron, Genevieve L., Ellis, Allan G. & Midgley, John M., 2025, A revision of a spring-active clade of Prosoeca Schiner, 1867 (Diptera, Nemestrinidae), keystone pollinators from the Greater Cape Floristic Region in South Africa, with descriptions of three new species, ZooKeys 1257, pp. 249-284 : 249-284

publication ID	https://doi.org/10.3897/zookeys.1257.155954
publication LSID	lsid:zoobank.org:pub:7D8BD25C-6BBF-44AE-8E5F-0B055043E470
DOI	https://doi.org/10.5281/zenodo.17485619
persistent identifier	https://treatment.plazi.org/id/D1A60800-C15D-5E3D-A470-7CAC3442E8E8
treatment provided by	ZooKeys by Pensoft
scientific name	Prosoeca parva
status	sp. nov.

Treatment

Prosoeca parva sp. nov.

Figs 1 View Figure 1 , 3 F View Figure 3 , 4 F View Figure 4 , 5 F View Figure 5 , 6 F View Figure 6 , 8 E, F View Figure 8

Type material.

Holotype: South Africa: • 1 ♂ Northern Cape, Calvinia: Hantamsberg ; 3 Sep. 1994; 30; Felicia ; NMSA -DIP 76671 ; NMSA . Paratype: South Africa: • 1 ♀ Northern Cape: Calvinia: Hantamsberg ; 3 Sep. 1994; 30; Felicia ; NMSA -DIP 76670 ; NMSA . • 1 ♀ Northern Cape: Hantamsberg ; 31.39563°S, 19.78919°E; 15 Sep. 2018; F. Grenier leg.; # FG 46; RMCA -ENT 000056705 ; RMCA GoogleMaps . • 1 ♂, Northern Cape: Hantamsberg ; 31.39563°S, 19.78919°E; 15 Sep. 2018; F. Grenier leg.; # FG 48; RMCA -ENT 000056706 ; RMCA GoogleMaps .

Diagnosis.

Relatively small species (length 8–11 mm), thorax dark without distinct central markings, thorax and scutellum with a conspicuous grey border, abdomen uniformly black, proboscis length 0.57 ± 0.04 × the length of the body (range of un-extended proboscis length 4 mm – 6 mm), femora very dark with pale red-brown tibia and tarsi and conspicuously short antennal style. Prosoeca parva sp. nov. can be distinguished from all other species in the clade by the apparent lack of patterning on the abdomen (Fig. 3 F View Figure 3 ), largely hyaline wings (Fig. 5 F View Figure 5 ) and the dark femora which contrast the paler tibia and tarsi. Prosoeca parva sp. nov. is notably smaller than P. marinusi , P. peringueyi , and P. torquata with a proboscis shorter than the length of its body, usually not reaching past the hind legs when folded beneath body.

Description.

Male. Body length: mean 9.8 mm; range 8–11 mm ( n = 4). Intertegular width: mean 3.8 mm; range 3–4 mm ( n = 4). Proboscis length: mean 5.6 mm; range 4–6 mm ( n = 4). Wing length: mean 11.2 mm; range 11–12 mm ( n = 4).

Head. (Figs 4 F View Figure 4 , 6 F View Figure 6 ) Ground colour generally grey to black. Ocellar tubercle somewhat bulbous and developed, just evident above upper eye margin in profile, with dense silvery pruinescence; width between eyes at the anterior ocellus 3.8 × the length of the anterior ocellus; anterior ocellus separated from posterior ocelli by shallow transverse groove; pile generally long, black. Frons trapezoid; width anterior to ocellar tubercle 0.7 × the width above antennal insertions; slightly to moderately swollen between antennal insertions and anterior ocellus; swelling recedes strongly towards eye margin; pruinescence relatively dense, silver to brown; pile black and white, dense on entire frons. Antenna with scape 1.5–2 × the length of pedicel; first flagellomere shorter than the length of scape + pedicel; style shorter than scape + pedicel + flagellomere 1; ground colour dark brown to black, style darker than remainder of antenna; scape, pedicel and flagellomere 1 with irregular silver to brown pruinescence; pedicel with mostly elongate pile, black pile, flagellomere 1 with short black pile basally on the dorsal side. Facial area bulbous in profile, with horizontal groove present; with silver to brown pruinescence, evenly distributed across face; pile mostly white, elongate, dense, similar to that of frons. Gena with pile a mixture of black and white to pale yellow, elongate, and dense, forming the beard. Proboscis 0.5–0.7 × the length of the body, dorsal and ventral side black. Palpus with first segment significantly longer than that of second segment, second segment much narrower than first segment; colour generally dark brown to black; pile long on both segments.

Thorax (Fig. 3 F View Figure 3 ). Scutum dark grey to black; pruinescence mostly brown, with pale grey to silvery pruinescence complete along the lateral sides of the scutum, joining on scutellum; median and paired sublateral vittae absent; pile mixture of black and pale to golden, sparse, shorter than the pile on the posterior of the scutellum; postalar callus with black pile dorsally, ventral side with a tuft of golden pile. Scutellum anterior margin covered by brown pruinescence; posterior margin with a dark, black border; pile on disc of scutellum golden or black, relatively long, of similar density to that on the scutum; pile along posterior margin elongate, a mixture of black and pale, white or yellow, same density as on disc of scutellum; with some pale yellow to golden pile laterally. Pleuron mostly blackish; with silver pruinescence, sparser than on scutum; pile generally a mixture of black and white to yellow, relatively long, of intermediate density; most dense and elongate in two tufts, ventral and anterior to the base of the wing and between postalar callus and posterior spiracle; tuft of pile anterior to wing base directed posteriorly, mostly white to golden with some black pile; tuft of pile on katatergite directed posteriorly, black and golden; katepimeron with pile absent. Legs. Coxae dark brown to black; with pile mostly off-white to golden, elongate, dense. Trochanters mostly blackish, with some yellow-brown colouring; pile short, very sparse. Femora dark brown to black, with dark marking on dorsal side of the distal end present; pile mostly black, mostly short, dense; ventral pile typically longer, sparse; hind femur with short pile (may have very sparse elongate pile on hind femur) more evenly distributed than on fore and mid femora. Tibiae yellow-brown to dark brown; with mostly short pile, most dense on hind tibia. Tarsi red-brown to dark brown, hind tarsi tend to be darker. Wings (Fig. 5 F View Figure 5 ). Shape relatively slender; broadest just basal to termination of CuP on posterior margin; alula broad; costal margin close to straight, without distinct anteriorly curved flexure; Sc termination on C aligned with termination of M 4 on posterior margin of wing; R 1 terminated closer to R 2 + 3 than to Sc; termination of Sc and R 1 well separated; short appendix just beyond fork on R 4 + 5 always absent; cross vein between M 1 and M 2 absent; cross vein just beyond fork between R 4 and R 2 + 3 absent; R 1 relatively straight; R 4 deep bowing upward; R 5 shallow bowing upward; M 1 and M 2 slightly curved upward; cell cua open at margin; CuA and CuP well separated. Dark marking on R 1 positioned just basal to humeral cross vein; membrane without smoky brown infuscation; appearing almost entirely hyaline; isolated darker patches absent. Tuft of pile on base of wing white. Haltere with pale brown to yellow stalk; bulb dark brown.

Abdomen (Fig. 3 F View Figure 3 ). Colour of abdomen generally black; T 2 with posterior margin stout and relatively broad; abdomen tapering abruptly after T 3. Tergites with pruinescence largely absent; membrane between T 1 and T 2 dark brown to black; medial brown pruinescent vitta indistinct, extending from the posterior margin of T 1 to terminalia. Pile on tergites mostly black, both long and short, of intermediate density; along anterior margins of T 2 white to pale yellow, elongate, sparse; posterolateral pile on T 2 – T 4 black, elongate, dense; T 5 with pile along lateral margins more evenly distributed than that of T 2 – T 4. Sternites typically paler than tergites; grey to black; pruinescence silvery, relatively sparse. Sternites with pile mostly black, mostly long, sparse; pile on S 1 and S 2 noticeably longer, white; pile on membrane adjacent to lateral margins of S 2 – S 4 typically with profuse, decumbent, elongate, pale yellow to golden.

Genitalia (Fig. 8 E, F View Figure 8 ). Hypandrium triangular in shape; broad, tapering gradually towards the apex; laterally convex; 2.1 × longer than basal width; with apical 1 / 5 projecting past the top of the gonocoxites. Pile on apical 1 / 3 of the hypandrium. Gonocoxite apical 1 / 2 not parallel sided; gonocoxites widest in apical 1 / 3, narrowing apically; rounded apically. Gonocoxite vestiture on the lateral 1 / 2, of apical 1 / 3. Gonostylus narrowed medially; and globular apical section. Phallus near parallel sided; narrowing apically.

Female. Same as male, except for genitalia dimorphism and the following characters: Head. Ocellar tubercle width between eyes at the anterior ocellus 3.8–4.5 × the length of the anterior ocellus. Frons width anterior to ocellar tubercle 0.8 × the width above antennal insertions. Wings. Sharp short appendix just beyond fork on R 4 sometimes present.

Geographical distribution.

Known from only a single locality on the Hantamsberg near Calvinia (Fig. 1 View Figure 1 )

Biology.

Known to be on the wing in September and has been recorded visiting flowers in the Asteraceae genus Felicia . A male and a female were caught mating on a mountain peak, potentially hill-topping ( RMCA -ENT 000056705 ; RMCA -ENT 000056706 ; RMCA.

Etymology.

From the Latin parva = little; referring to the small size of this species compared to all other species in this clade. To be treated as a noun in apposition.