Cheilosia ( Cheilosia ) rhynchops Egger, 1860

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 : 121-123

Cheilosia ( Cheilosia) rhynchops Egger, 1860

Fig. 61

Cheilosia rhynchops Egger, 1860: 353 .

Cheilosia rhynchops – Barkalov 1993: 699. — Barkalov & Mutin 2018: 484. — Mengual et al. 2020: 20.

Differential diagnosis

Cheilosia rhynchops is characterized by the combination of a bare face, pilose eye, black legs, posterior margin of scutellum with setae and shiny sterna. In the Caucasus it can be mainly confused with C. caucasi sp. nov. but it has an elongated face ( Fig. 61B, D, with long straight part between antennae and facial tubercle (in C. caucasi sp. nov. face not elongated) and the dorsal and ventral pile patches on the katepisternum are connected or almost so in the Caucasian populations (widely separated in C. caucasi ). In the male the frons is swollen (not swollen in C. caucasi ) and scutum with long black and white pile (scutum usually with mainly black pile in C. caucasi ). In the female scutum with adpressed mainly golden pile (variable in C. caucasi ) and postpedicel dark orange in basoventral corner (black in C. caucasi ).

Material examined

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

Genetics

A well-supported (BS = 100%) cluster is found in our NJ tree with the barcodes of C. lenta Becker, 1894 , C. andalusiaca Torp Pedersen, 1971 , C. siciliana Becker, 1894 , and C. rhynchops . No further grouping appears in our dataset.

Remarks

Cheilosia rhynchops is extremely similar to extralimital C. lenta from Europe and little is known how to differentiate the two species. The absence or presence of pile connecting the dorsal and ventral pile patches on the katepisternum is, however, regarded as the most important difference between the two species: in C. lenta both dorsal and ventral pile patches on the katepisternum are connected or joined with pile, but this pile are absent in C. rhynchops and the dorsal and ventral pile patches on the katepisternum are not connected. All specimens collected in the Caucasus have the dorsal and ventral pile patches on the katepisternum connected. However, dorsal and ventral pile patches on the katepisternum can sometimes also be connected in populations of C. rhynchops (e.g., from the Alps; S. Bot pers. obs.), making certain identification of the two species sometimes impossible. No morphological difference was found between European and Caucasian populations of C. rhynchops . Moreover, our genetic results show C. lenta to be genetically not distinct from C. rhynchops . Given the current uncertainty in the identification of these two species, we here name the individuals from the Caucasus C. rhynchops for the time being, until there is more certainty on the status of C. lenta . We chose the earlier published name of the two. Taxonomy of these two and two other similar European species will be subject of more extensive research in the near future.

Biology

During our expeditions, collected between 9 May and 17 June at an altitude between 920 and 2327 m a.s.l. In the lower montane zone present in forest clearings and herb-rich grasslands with shrubs, in the subalpine and alpine zone present in meadows.

Distribution

Central and Southern Europe, Caucasus ( Georgia, Russia).