Cheilosia angusta, Barkalov & Ståhls, 2022

Barkalov, Anatolij V. & Ståhls, Gunilla, 2022, Cheilosia (Diptera, Syrphidae: Rhingiini) of Nepal with descriptions of 29 new species, European Journal of Taxonomy 829 (1), pp. 1-127 : 21-24

Cheilosia angusta sp. nov.

urn:lsid:zoobank.org:act:55095AEB-7AE4-4D44-8E3E-43595D6B8E9F

Figs 7–8

Differential diagnosis

Cheilosia (Cheilosia) angusta sp. nov. can be discerned from all other Nepalese Cheilosia by the following combination of characters: eye black pilose, basoflagellomere and arista orange-yellow to dusky orangebrown in colour and scutellum margin black pilose.

Etymology

The specific epithet is from the Latin ‘ angusta ’ meaning ‘narrow’, and refers to the slender habitus of the species.

Material examined

Holotype NEPAL • ♂; Distr. Humla, 18 km NW Simikot Brücke am Chuma Khola [18 km NW of Simikot Bridge on Chuma Khola]; 30°02′25″ N, 81°39′06″ E; 2950 m a.s.l.; 20–22 Jun. 2001; F. Creutzburg leg.; yellow trap; IBSJW / NME.

Paratype NEPAL • ♂; same data as for holotype; IBSJW / NME .

Description

Male

LENGTH. Body 10.2–11 mm, wing 10.0– 10.5 mm.

HEAD. Face in lateral view distinctly protruded forward in ventral part; black, shiny but with fine grey pollinosity; non-pilose; facial tubercle small, distinctly compressed laterally; parafacia moderate in width, in broadest part about ¾ to ⅘ of basoflagellomere width, grey pollinose and with short, white pilosity; genae narrow, finely grey pollinose, with moderately long white pilosity; lower occiput with fine grey pollinosity and white pilosity. Frons slightly inflated, shiny, grey pollinose near eye, long black pilose; frontal angle acute; lunule dusky yellow; antennal pits distinctly separated. Scape and pedicel dark-brown to black, basoflagellomere oval, orange to dusky orange (orange-brown); arista long, orange-yellow, with very short pilosity. Eye contiguity about 1.3 times as long as frons without lunule. Eye completely covered with comparatively long, dense, yellow pilosity. Vertex slightly inflated, shiny, covered with long black pilosity; ocellar triangle isosceles; upper occiput with long black pilosity.

THORAX. Postpronotum black, grey pollinose and yellow pilose. Scutum with fine puncturation, shiny, with finely grey pollinose laterally and on hind ⅓ part; long, erect, black and yellow pilose, on posterior part longer black pilosity of which some pile is apically wavy. Postalar callus white pilose and with some long, but fine, black bristles. Scutellum black, with long, erect, black pilosity and shorter erect yellowish pilosity, on hind margin with many long black bristles or bristle-like pilosity as long as or longer than scutellum length; subscutellar fringe with long white pilosity. Pleurae grey pollinose, without shiny spots, yellow pilose; posterior anepisternum and anterior anepimeron yellow pilose mixed with some fine black pile; katepisternum with dorsal and ventral yellow pile patches widely separated.

LEGS. Mostly black, only basal ⅓–½ and tips of tibiae brownish; fore coxa without baso-lateral spur; long pilosity on posterior side of fore femur mostly black with some yellow pilosity; long pilosity on posterior side of mid femur yellow with some black pilosity near tip; hind femur with long yellowish pilosity antero- and postero-ventrally, longer than width of hind femur, some long yellow apically wavy pilosity. Metasternum with long yellow pilosity.

WING. Elongated, slightly brownish, completely microtrichose; inner angle between M 1 and R 4+5 almost right. Rs basally with 3–4 very short pile. Haltere yellow with darker (brownish) knob; calypter yellow with yellow pilosity.

ABDOMEN. Black, narrow, distinctly narrower that mesonotum at level of wing base; pollinose and matte medially and weakly pollinose and shiny laterally; covered with comparatively long but not dense, erect, yellow pilosity which is longest on lateral parts of tergites I–II, hind margin of tergite IV also with some black pilosity. Sternites I–II with long erect yellow pilosity, pilosity longest on sternite II. Sternites III–IV laterally with erect yellow pilosity, sternites III–IV medially with short appressed black pilosity. Pre-genital segments black pilose.

Female

Unknown.

Distribution

Nepal.

Figures

Fig. 7. Cheilosia (Cheilosia) angusta sp. nov., holotype, ♂ (IBSJW/NME). A. Head, lateral view. B. Antenna, lateral view of pedicel and basoflagellomere. C. Tip of wing. D. Superior lobe of hypandrium, lateral view. E. Surstylus and gonocercus, lateral view. F. Aedeagus and aedeagal apodeme, lateral view. Scale bars indicated in drawings.

Fig. 8. Cheilosia (Cheilosia) angusta sp. nov. A–B. Holotype, ♂ (IBSJW/NME); dorsal and lateral views. C. Oblique view of scutellum of ♂, paratype (IBSJW/NME).