Cheilosia ( Montanocheila ) rufa, Bot & Mengual & Meutter & Skevington, 2025

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 : 123-127

Cheilosia ( Montanocheila) rufa sp. nov.

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Figs 62–63

Differential diagnosis

Cheilosia rufa sp. nov. belongs to the subgenus Montanocheila and is very similar to the sympatrically occurring C. subpictipennis . Males of C. rufa can be distinguished from those of C. subpictipennis by the anterior part of procoxa with only yellow setae on apical half (in C. subpictipennis the anterior part of procoxa has mixed black and yellow setae on apical half) and the dorsal lobe of the postgonite of the male genitalia shorter than ventral lobe, curved inwards and with widening, pointed apex ( Fig. 63C) (in C. subpictipennis dorsal lobe of postgonite as long as ventral lobe, erect and more rectangular, Fig. 68E). Moreover, males of C. rufa have pile on terga more rufous and clypeus longer. Females of C. rufa cannot be distinguished from those of C. subpictipennis , except for the on average longer clypeus; but this character is variable. Hence, females can only de identified with certainty on the basis of DNA barcodes. Cheilosia rufa is also similar to the sympatric C. gorodkovi but our new species is larger ( 10.5–12.5 mm vs 9.5–10 mm) and has the face more protruding ( Fig. 63A–B), facial tubercle less pronounced, face more densely pruinose, veins paler at wing base (veins Rs, M and CuA bright yellow) (in C. gorodkovi veins Rs and M are orange, and CuA brown). Male of C. rufa has anterodorsal pile on metafemur long and dense, almost two times as long as diameter of metafemur in ventral view (in C. gorodkovi these piles are less dense and at most just over diameter of metafemur in ventral view) and the surstylus of the male genitalia is less than two times as long as wide ( Fig. 63D) (in C. gorodkovi the surstylus is more than two times as long as wide. Female of C. rufa has the pile on body and legs longer, e.g., pile on scutellum longer than diameter of metafemur (pile shorter in C. gorodkovi ) and the metafemur with pile longer than diameter of metafemur anteroventrally (in C. gorodkovi the metafemur has pile anteroventral less dense and shorter than the diameter of metafemur).

Etymology

The species name is derived from the Latin ‘ rufus ’ meaning ‘red, reddish’ ( Brown 1956: 672), and it refers to the abdominal pile of the species, which is on average more rufous compared to the paler pile on the very similar and sympatric C. subpictipennis . Species epithet is to be treated as an adjective.

Material examined

Holotype

GEORGIA • ♂; Samtskhe-Javakheti, Sakire; 41.7301° N, 43.3306° E; 1820 m a.s.l.; 10 May 2023; F. Van de Meutter leg.; ZFMK, ZFMK-TIS-8028515 .

Paratypes

GEORGIA – Mtskheta-Mtianeti • 2 ♂♂; Lutkhubi; 42.3797° N, 44.7969° E; 1463 m a.s.l.; 6 May 2023; S. Bot leg.; SBA, SB.003237 = ZFMK-TIS-8027981 , SB.003238 = ZFMK-TIS-8027982 • 1 ♀; same data as for preceding; SBA, SB.003239 = ZFMK-TIS-8027986 • 2 ♂♂; Lutkhubi ; 42.3867° N, 44.79° E; 1580 m a.s.l.; 6 May 2023; F. Van de Meutter leg.; FMT • 1 ♂; same data as for preceding; ZFMK . – Samtskhe-Javakheti • 2 ♂♂; Kodiani ; 41.7300° N, 43.3485° E; 2080 m a.s.l.; 10 May 2023; W. Opdekamp leg.; WOR, A009 , A018 = ZFMK-TIS-8028458 • 1 ♀; same data as for preceding; WOR, A003 = ZFMK-TIS-8028485 ; identified by genetic analysis .

Description

Male

LENGTH. Body 10.5–12.5 mm, wing 8.5–10 mm.

HEAD. Face bare, black, slightly protruding downwards, with facial tubercle, pruinose except facial tubercle shiny, below lunule narrower than an eye. Mala black, shiny. Parafacia black, thinly pruinose, yellow pilose except ventral quarter black pilose, about 0.9 times as wide as postpedicel. Clypeus about 2.5 times as long as wide. Frontal triangle black, shiny, except narrowly pruinose along eye margin, with long mixed black and yellow or yellow pile, sometimes with yellow pile intermixed, with medial frontal sulcus. Length of eye contiguity about 0.7–0.9 times the length of frons. Angle of approximation of eyes 90–100°. Vertical triangle black, ocellar triangle pruinose, long mixed black and yellow pilose. Occiput pruinose, short yellow and long mixed black and yellow or yellow pilose. Lunule dark orange to blackish, with distinct medial arm, separating acetabula. Scape black, anteriorly with black and yellow setae; pedicel blackish or dark orange anteriorly with mixed black and yellow setae; postpedicel orange, sometimes dorsal outer corner darkened, rounded except in dorsal outer corner where often more angular, pruinose, about as wide as high; arista black, almost bare, pile much shorter than diameter of arista at base. Eye with long, dense yellow or brown pile. Haltere pedicellum orange, capitulum orange or dark brown.

THORAX. Scutum black, shiny, finely punctured, with long erect pile, pile yellow, except medially between wing bases with a field of shorter black pile. Scutellum black, medially shiny, with long erect yellow pile, sometimes medially shorter black pile intermixed, without setae along posterior margin. Pleura black, pruinose, with yellow pile; dorsal and ventral pile patches on katepisternum connected; metasternum yellow pilose. Haltere pedicellum orange, capitulum ranging from orange to brown.

WING. Wing including alula entirely microtrichose, hyaline except with a more or less clear brown central spot between cell sc and base of cell dm, wing veins orange in the basal part and black in the apical part of the wing.

LEGS. Coxae, trochanters black, anterior part of procoxa with yellow setae on apical half. Femora black except apices narrowly yellow, with black and yellow pile, metafemur with very long anterodorsal and anteroventral yellow pile, metafemur anteriorly with very long yellow pile, pile longer than diameter of metafemur, ventrally basal two third with predominantly yellow setae. Tibiae yellow with indistinct brown ring in apical part, with yellow pile except sometimes ventrally with some black pile. Protarsus dorsally black, ventrally yellow except fifth tarsomere which is black; mesotarsus yellow except fourth tarsomere dorsally and fifth tarsomere black; metatarsus yellow except basitarsomere and often fourth tarsomere ventrally and fifth tarsomere black.

ABDOMEN. Black. Terga I–IV shiny except tergum I, tergum II medially and tergum III anteromedially slightly pruinose; covered with long yellow erect pile, laterally longest, more rufous on terga II–III, exceptionally with a few black pile on posterolateral margin of tergum IV. Sternum I pruinose, with long yellow erect pile; sternum II shiny except anterolateral corners, with very long erect yellow pile, posteromedially with a few semi-adpressed pile amongst the erect pile; sterna III–IV shiny, with long erect yellow pile, pile medially less dense, where intermixed with short adpressed yellow or mixed black and yellow pile. Genitalia with surstylus ca 1.7 times as long as wide, with keel ( Fig. 63D); postgonite with spike between ventral and dorsal lobe, ventral lobe of postgonite with widening rounded apex, slightly but distinctly longer than dorsal lobe of postgonite ( Fig. 63C); dorsal lobe of postgonite curved inwards and with widening black pointed apex ( Fig. 63C); sclerite of the distiphallus with two ventral spurs.

Female

LENGTH. Body 11.5 mm, wing 9 mm.

Similar to the male, except for normal sexual dimorphism and the following characters: parafacia entirely yellow pilose. Frons shiny. Postpedicel brown, rounded. All pile on head, thorax, legs and abdomen yellow. Terga shiny except tergum I medially and tergum II anteromedially narrow pruinose.

Genetics

DNA barcodes of C. rufa sp. nov. cluster together with the sequences of C. contrasta sp. nov. with low support (BS<90%), although all DNA barcodes of C. rufa are grouped together as do all sequences of C. contrasta .

Biology

Collected in mountains between 1463 and 2080 m a.s.l. Most specimens were found feeding on willow Salix sp. catkins, or drinking at mud puddles.

Distribution

So far only known from the type series localities in the Greater and Lesser Caucasus in Georgia.