Cheilosia ( Cheilosia ) vernalis ( Fallén, 1817 )

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 : 153

Cheilosia ( Cheilosia) vernalis ( Fallén, 1817)

Fig. 79

Eristalis vernalis Fallén, 1817: 55 .

Cheilosia vernalis – Stackelberg & Richter 1968: 250. — Peck 1988: 120. — Barkalov 1993: 721. — Gujabidze 2002: 245. — Barkalov & Mutin 2018: 484. — Mengual et al. 2020: 22. — Żóralski 2022: 68.

Differential diagnosis

Cheilosia vernalis is a small (body size: 5–8 mm) and variable species ( Ståhls et al. 2008). In the Caucasus, mainly to be confused with C. confusa sp. nov., see the Differential diagnosis of that species to distinguish the two taxa. Also, see Prokhorov et al. (2020) for a key to distinguish C. vernalis from similar species. Cheilosia vernalis is similar to C. cynocephala , but on average smaller (body size 5–8 mm vs 7–9 mm), body with brown or black shine (with blue shine in C. cynocephala ), wing hyaline (female C. cynocephala usually with faint blackish median spot), pile on scutum often predominantly yellow (black in C. cynocephala ) and with the two basal tarsomeres of mesoleg often dark orange (black in C. cynocephala ). In our tree (Supp. file 1: Fig. S1), there are two specimens genetically in between C. vernalis and C. confusa which we call ‘ Cheilosia sp. ’ (ZFMK-TIS-8009292 and ZFMKTIS-8014649). They are morphologically very close to C. vernalis , but slightly different. Our sample size and the differences are too small to draw firm conclusions on the identity of these two specimens. They could belong to the variation within C. vernalis or represent a new species; thus, we decided to leave them unidentified.

Material examined

Collected in 2018, 2019, 2022 and 2023; see Mengual et al. (2020) for detailed records from 2018.

Genetics

DNA barcodes of C. vernalis cluster together without high support (BS <90%) with the DNA sequences of C. confusa sp. nov., C. gemmula sp. nov., C. melanura , C. bracusi , C. triamilia , and two specimens left as Cheilosia sp.

Biology

During our expeditions, collected between 6 May and 2 August at an altitude between 1250 and 2885 m a.s.l., both on low flowers and on willow Salix sp. catkins.

Distribution

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