Cheilosia ( Taeniochilosia ) longifacies, 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 : 81-84

Cheilosia ( Taeniochilosia) longifacies sp. nov.

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Fig. 41

Differential diagnosis

Cheilosia longifacies sp. nov. belongs to the caerulescens species group within the subgenus Taeniochilosia . This species group is recognized by typically having bicoloured legs (yellow and black) and infuscate wing cross-veins. The caerulescens species group has recently been revised ( Ståhls & Barkalov 2017) and when using their key, C. longifacies keys out to C. circassica , which also occurs in the Caucasus (but is synonymized in this publication with C. armeniaca ). Compared to C. armeniaca , C. longifacies has a larger body size ( 8.5–11 mm vs 8.5–9 mm) and the face further protruding, with the facial tubercle much lower relative to the ventral side of the eye, giving a snout-like appearance ( Fig. 41B) (in C. armeniaca the face is less protruding; Fig. 6B), face with lateral stripe less pruinose, parafacia shiny except for the dorsal corners pruinose (in C. armeniaca parafacia has the dorsal half pruinose), eye contiguity ca 0.8 times as long as frons in C. longifacies (ca 0.6 times in C. armeniaca ), frontal triangle shiny in C. longifacies instead of pruinose in C. armeniaca , frontal triangle with predominantly erect pile (in C. armeniaca frontal triangle with short erect pile only medially, laterally with dense forwardly directed pile with wavy apex Fig. 6B), dorsal margin of occiput with long yellow pile and some sparse black pile intermixed (only with yellow pile in C. armeniaca Fig. 6B), scutum with black pile intermixed with yellow pile (scutum with yellow pile in C. armeniaca ), on body pile wavy apices more pronounced and more commonly occurring in C. armeniaca (e.g., on frons, posterior part of scutum and posterior katepisternum), tibiae with narrower black ring in C. longifacies ( Fig. 41A) leaving apex of metafemur distinctly yellow (black ring reaching apex in C. armeniaca ), tarsi paler with tarsomeres 2–4 of proleg dorsally yellow (protarsus dorsally dark brown to black in C. armeniaca ), short ventral pile on metafemur black except for the yellow pile on basal 1/5 (in C. armeniaca metafemur with ventral pile yellow, except for the apical 1/4 with black pile), terga II–III partly pruinose (entirely shiny in C. armeniaca ), abdomen more elongated, less oval compared to C. armeniaca , pile on sternum III medially predominantly adpressed ( C. armeniaca has pile on sternum III medially predominantly erect) and surstylus with a less distinct kink halfway on the ventral margin. Although C. longifacies keys out to C. armeniaca in the identification key provided by Ståhls & Barkalov (2017), it is morphologically closer to C. caerulescens ( Meigen, 1822) , but it differs in several ways including more protruding and less pruinose face and tergum III with yellow pile only (tergum III partly black pilose in C. caerulescens ).

Etymology

The species name is derived from the Latin word ‘ longus ’ meaning ‘long’ ( Brown 1956: 494) and the Latin word ‘ facies ’ meaning ‘face’ ( Brown 1956: 313) and it refers to its distinctly protruding face. Species epithet to be treated as a noun in apposition.

Material examined

Holotype

GEORGIA • ♂; Mtskheta-Mtianeti, Lutkhubi ; 42.3984° N, 44.7996° E; 2068 m a.s.l.; 8 May 2023; S. Bot leg.; ZFMK, SB.003148 = ZFMK-TIS-8027991 .

Paratypes

GEORGIA – Mtskheta-Mtianeti • 1 ♂; Lutkhubi ; 42.3936° N, 44.7923° E; 1760 m a.s.l.; 8 May 2023; F. Van de Meutter leg.; FMT, ZFMK-TIS-8027953 .

Description

Male

LENGTH. Body 8.5–11 mm, wing 7–8.5 mm.

HEAD. Face bare, with facial tubercle, black, protruding downwards, shiny except for a pruinose band below antennae and slightly pruinose oblique stripe at lateral parts of face. Mala shiny. Parafacia black, at widest point ca 0.8 times as wide as width of postpedicel, shiny except dorsal corners, with yellow pile. Length of eye contiguity ca 0.8 times as long as frons. Angle of approximation of eyes ca 95°. Frontal triangle black, shiny, long yellow pilose, with medial frontal sulcus. Ocellar triangle with ca anterior ⅔ black pilose, ca posterior ⅓ yellow pilose. Dorsal margin of occiput with long yellow pile and some sparse black pile intermixed. Lunule black, medial arm on lunule absent, antennal fossa present. Scape black with predominantly yellow setae; pedicel basally black, apically dark orange, with predominantly yellow setae; postpedicel about as high as wide, rounded, entirely orange or basally orange, apically dark orange. Arista black, with short pile, pile 0.5 times as long as width of arista at base. Eye bare.

THORAX. Scutum black, shiny, finely punctured, with long erect yellow pile, medially and in between wing bases intermixed with sparse black pile; lateral margin of scutum with some black setae, postalar callus with or without black setae. Scutellum black, shiny, entirely with yellow pile, posterior margin with yellow not so strong setae. Pleura black, slightly pruinose, with yellow pile, dorsal and ventral pile patches on katepisternum connected. Haltere with pedicellum yellow, capitulum dark or orange.

WING. Wing including alula entirely microtrichose; veins black, all cross-veins infuscated; stigma yellow-brown; vein R

4+5 not distinctly curved.

LEGS. Coxae and trochanters black. Femora black except apical 1/10 yellow. Tibiae black except ca basal 1/3 and apical 1/5 yellow. Tarsi yellow except basitarsomere and fourth tarsomere dorsally brown and fifth tarsomere black. Legs mainly yellow pilose, metafemur ventrally with long and short pile; of short pile, basal 1/5 yellow, remainder of pile predominantly black.

ABDOMEN. Terga I–IV with erect yellow pile, pile laterally longer, terga I–IV shiny except medial half of terga I–II and tergum III anteromedially pruinose. Sternum I pruinose, sterna II–IV shiny, sterna I–II with erect yellow pile, sterna III–IV with yellow erect pile laterally, pile medially adpressed and yellow, except posteromedial on sternum IV where also with black adpressed pile. Genitalia with surstylus longer than wide, tapering. Dorsal lobes of postgonite pointed, ventral lobes rounded.

Genetics

DNA barcodes of C. longifacies sp. nov. were resolved into a cluster with high support (BS = 100%) together with the barcodes of C. armeniaca and C. caerulescens . All sequences of C. caerulescens cluster together, while C. longifacies barcodes are grouped with those of C. armeniaca .

Remarks

Genetically indistinguishable from C. armeniaca , despite the many consistent distinct morphological differences between the two species.

Biology

In mountains between 1760–2068 m a.s.l. The holotype was collected with a hand net when flying through a flowering willow along a mountain stream just below the snow line, the paratype was feeding on male willow catkins a bit lower along the same mountain stream.

Distribution

So far only known from the type locality in the Greater Caucasus.