Cheilosia ( Cheilosia ) confusa, 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 : 45-49

Cheilosia ( Cheilosia) confusa sp. nov.

urn:lsid:zoobank.org:act:

Figs 21–22

Cheilosia melanura Becker, 1889 – Stackelberg & Richter 1968: 246. — Stackelberg 1970: 62. — Peck 1988: 109. — Barkalov 1993: 726. — Mengual et al. 2020: 18. — Speight 2020a: 42.

Cheilosia melanura Becker, 1921 [sic] – Gujabidze 2002: 245.

Differential diagnosis

Cheilosia confusa sp. nov. is confusingly similar to both C. vernalis and extralimital C. melanura , and we could not find differences in the male genitalia between the three species. The male is similar to that of C. vernalis but is larger ( 8.8–9.5 mm vs 5–8 mm), has the frons slightly swollen ( Fig. 22A) (not swollen in C. vernalis ), metasternum bare (usually pilose in C. vernalis ), tarsi dorsally black ( Fig. 21A) (in C. vernalis usually the two basal tarsomeres of the mesoleg are orange), and has the combination of scutum with mixed black and yellow pile and terga entirely yellow pilose (in C. vernalis , if the terga are yellow pilose, then the scutum is also mainly yellow pilose with black pilosity restricted to anterolateral corners). The male of C. confusa is also very similar to C. melanura but C. confusa is smaller ( 8.8–9.5 mm vs 9–12.5 mm) and has slenderer abdomen, pile on terga shorter and metasternum bare (usually pilose in C. melanura ). The male can be confused with C. cynocephala but the body shines black or brown (bluish in C. cynocephala ) and pile on scutum are predominantly yellow (predominantly black in C. cynocephala ). The female is like C. vernalis , but it is on average larger ( 8 mm instead of 7 mm), pile on scutum erect instead of semi-adpressed, posterior anepisternum slightly pruinose instead of shiny, metasternum bare or with one or two pile only (usually more extensive pilose in C. vernalis ), and tarsi dorsally black ( Fig. 21C) (in C. vernalis usually the two basal tarsomeres of mesoleg are orange). The female of C. confusa is very similar to that of C. melanura but the posterior anepisternum is slightly pruinose instead of shiny and the metasternum is bare or with one or two pile only (usually more extensive pilose in C. melanura ). The female can be mistaken for that of C. cynocephala , but the body shine is black or brown (bluish in C. cynocephala ), wing hyaline (usually with faint, black cloud in C. cynocephala ) and pile on scutum predominantly yellow (predominantly black in C. cynocephala ).

Etymology

The species name confusa derives from the Latin word ‘ confusio ’ for ‘mixture, disorder’ ( Brown 1956: 227) and refers to the confusing morphology of this new species, in between the similar C. vernalis and C. melanura . Without DNA, this species would probably have gone unnoticed. Species epithet to be treated as adjective.

Material examined

Holotype

GEORGIA • ♂; Samtskhe-Javakheti, Kodiani ; 41.7268° N, 43.3490° E; 2150 m a.s.l.; 10 May 2023; W. Opdekamp leg.; ZFMK, B016 , ZFMK-TIS-8028459 .

Paratypes

GEORGIA – Adjara Region • 1 ♂; Kintrishi Nature Reserve, Krummholtz Forest ; 41.7553° N, 42.1128° E; 2280 m a.s.l.; 19 May–2 Jun. 2018; GGBC leg.; Malaise trap; ZFMK, ZFMK-TIS-8010426 . – Mtskheta-Mtianeti • 1 ♀; Lutkhubi ; 42.3984° N, 44.7996° E; 2068 m a.s.l.; 8 May 2023; S. Bot leg.; SBA, SB.003123 = ZFMK-TIS-8027995 . – Samtskhe-Javakheti • 2 ♀♀; Borjomi N.P.; 41.824° N, 42.848° E; 2165 m a.s.l.; 10 Jun. 2019; S. Bot leg.; SBA, SB.003121 , SB.003122 = CNC databasing S. Bot 927 • 2 ♀♀; Kodiani ; 41.7300° N, 43.3485° E; 2080 m a.s.l.; 10 May 2023; W. Opdekamp leg.; WOR, A024 = ZFMK-TIS-8028462 , A039 = ZFMK-TIS-8028461 • 1 ♀; Kodiani ; 41.7268° N, 43.3490° E; 2150 m a.s.l.; 10 May 2023; W. Opdekamp leg.; ZFMK, B015 = ZFMK-TIS-8028460 .

Description

Male

LENGTH. Body 8.8–9.5 mm, wing 8 mm.

HEAD. Face bare, black, with facial tubercle, shiny, except laterally slightly pruinose and with dense pruinose band below lunule, below lunule narrower than an eye. Parafacia black, slightly pruinose, yellow pilose, about 0.8 times as wide as postpedicel. Frontal triangle black, slightly swollen, shiny, except pruinose along eye margin, with long black pile, with medial frontal sulcus. Length of eye contiguity equals the length of frons. Angle of approximation of eyes 80–90°. Vertical triangle and ocellar triangle shiny, long black or black and yellow pilose. Occiput pruinose, dorsally yellow or mixed black and yellow pilose. Lunule dark orange to blackish, with distinct medial arm, separating acetabula. Scape and pedicel black; postpedicel small, rounded, about as high as wide, dark brown, basoventral corner orange; arista black, bare, except basal third with very short pile, not exceeding half the width of arista at base. Eye with long dark brown pile.

THORAX. Scutum black, shiny, finely punctured, with long erect pile, pile mixed black and yellow, in posterior half with piles of two lengths, with a short erect black and yellow pile and a long erect black or black and yellow pile. Scutellum black, medially shiny, with long erect black and yellow and short erect black and yellow pile, with thin black setae along posterior margin. Pleura black, pruinose, with mixed black and yellow pile; dorsal and ventral pile patches on katepisternum widely separated; metasternum bare. Haltere pedicellum orange, capitulum dark brown to blackish.

WING. Wing including alula entirely microtrichose, hyaline, veins dark brown to blackish.

LEGS. Coxae, trochanters black. Femora black except apices narrowly yellow; with black and yellow pile; metafemur ventrally with seta-like hairs. Tibiae black except basal third and apical quarter yellow. Tarsi dorsally black, basitarsomere of metaleg not swollen, about 3 times as long as second tarsomere of metatarsus.

ABDOMEN. Terga I–IV with erect yellow pile, except medially on terga II–III where pile is adpressed; shiny except tergum I and terga II–III medially pruinose. Sterna yellow pilose, sternum I with long erect pile medially, laterally with shorter and semi-adpressed pile, sternum II with long erect pile, sterna III–IV medially with adpressed pile, laterally with semi-adpressed pile. Genitalia with surstylus 1.5 times as long as wide, with small keel, surface above keel with large field of microtrichia ( Fig. 22D); dorsal lobe of postgonite short and wide with inwards facing tip ( Fig. 22C).

Female

LENGTH. Body 8–9 mm, wing 7.5–8.5 mm.

Similar to the male, except for normal sexual dimorphism and the following characters. Frons shiny except anterolateral corners along eye margin pruinose, with erect mixed black and yellow pile, with wide paravertica. Pile on vertex and ocellar triangle erect, predominantly black. Postpedicel variable, ranging from entirely black to predominantly orange. Colour of pile on eye variable, ranging from entirely yellow to only ventral half of eye with yellow pile, dorsal half with black pile. Scutum with erect pile, in posterior part also with sparse longer erect pile, colour of pile yellow, sometimes medially between wing bases mixed with some black pile. Colouration of tibiae as described in the male or sometimes only base yellow, apex black or only one tenth yellow. Pile on abdomen yellow, except sometimes anteromedially on terga II–III with black pile, pile on terga II–III medially adpressed, on tergum IV medially semi-adpressed.

Genetics

Molecular data for C. triamilia Ballester-Torres et al., 2024 , C. melanura , C. bracusi , C. gemmula sp. nov., C. vernalis and C. confusa sp. nov. cluster together without high support (BS <90%) and relatively low interspecific p-distance (<0.022), except for the specimen of C. vernalis ZFMKDIP-00093901 (= ZFMK-TIS-8014645) that reaches interspecific p-distances of 0.0285 (see Supp. file 3: Table S2). Nevertheless, all C. confusa barcodes cluster together (BS <90%), the same for all DNA sequences of C. gemmula (BS<90%).

Remarks

Specimens from the Caucasus published under the name C. melanura are considered to be records of C. confusa sp. nov.

Two specimens which look intermediate between C. vernalis and C. confusa sp. nov. end up in the molecular tree near C. confusa (ZFMK-TIS-8009292, ZFMK-DIP-00093672 = ZFMK-TIS-8014649), but forming a different cluster (BS<90%). We leave these specimens unidentified.

Biology

Seemingly mainly a spring species with most records in May and the last date on 10 June. Collected in high mountains between 2068–2280 m a.s.l., specimens from May were found on flowering willow Salix sp. or on low flowers.

Distribution

Endemic to the Caucasus, known from Georgia and Russia.