Cheilosia ( Cheilosia ) gigantea ( Zetterstedt, 1838 )

Bot, Sander, Mengual, Ximo, Meutter, Frank Van de & Skevington, Jeffrey H., 2025, Review of the genus Cheilosia Meigen, 1822 (Diptera: Syrphidae) from the Caucasus, with the description of 14 new species, European Journal of Taxonomy 1023, pp. 1-181 : 62-64

Cheilosia ( Cheilosia) gigantea ( Zetterstedt, 1838)

Fig. 31

Eristalis gigantea Zetterstedt, 1838: 612 .

Cheilosia gigantea – Stackelberg & Richter 1968: 245. — Stackelberg 1970: 62. — Peck 1988: 103. — Barkalov 1993: 724. — Barkalov & Mutin 2018: 483. — Mengual et al. 2020: 16. — Speight 2020a: 35.

Cheilosia gigantean [sic] – Gujabidze 2002: 245.

Differential diagnosis

Cheilosia gigantea is a member of a group of closely related species, called the proxima group ( Vujić et al. 2013) in which the pilose eyes, posterior margin of scutellum with setae, usually partly yellow legs, continuously pilose katepisternum, pruinose sterna and the shape of postgonite are distinctive characters. For a full diagnosis of the Cheilosia proxima group see Vujić et al. (2013). Within the proxima group, C. gigantea is particularly similar to C. ushguliensis sp. nov. and C. proxima . The male genitalia of C. gigantea are figured in Vujić et al. (2013). The male can be identified from that of C. ushguliensis by having the abdomen usually partly with black pile (usually all yellow in C. ushguliensis ) and by having the facial tubercle well-developed (poorly developed in C. ushguliensis ). The male can be separated from that of C. proxima by on average larger body size ( 7–12 mm vs 7–9 mm), basal two thirds of metafemur with the anterodorsal pile as long as or shorter than the anteroventral pile (basal two thirds of metafemur with the anterodorsal pile longer than the anteroventral pile in C. proxima ) and dorsal lobe of postgonite simple (with a more or less distinct hook on its dorsal margin in C. proxima ). In the female Cheilosia gigantea differs from C. ushguliensis by the more extensive pruinose terga (shiny except pruinose along anterior margin of tergum III in C. ushguliensis ) and pile on scutum often partly black and semi-adpressed (with erect golden pile in C. ushguliensis ). The female can be separated from that of C. proxima by on average larger body size ( 7–12 mm vs 7–9 mm), basal two thirds of metafemur with the anteroventral pile long, usually obviously longer than diameter of metafemur (without anteroventral pile, occasionally with few individual pile anteroventrally which are shorter than, or rarely as long as, the diameter of the metafemur in C. proxima ) and apex of metafemur ventrally with some black setae (usually absent in C. proxima ).

Material examined

Collected in 2018, 2019, 2021 and 2023; see Mengual et al. (2020) for detailed records from 2018.

Genetics

DNA barcodes of C. gigantea from Europe and the Caucasus cluster together with high support (BS = 100%).

Biology

During our expeditions, collected between 9 May and 13 July at an altitude between 1090 and 2807 m a.s.l. in montane, subalpine and alpine meadows.

Distribution

Palaearctic. Within the Caucasus known from Armenia, Georgia and Russia.