Eumerus tenuitarsis Grkovic & Vujic

Grkovic, Ana, Smit, John, Radenkovic, Snezana, Vujic, Ante & Steenis, Jeroen van, 2019, Two new European long-legged hoverfly species of the Eumerusbinominatus species subgroup (Diptera, Syrphidae), ZooKeys 858, pp. 91-108 : 99-102

Eumerus tenuitarsis Grkovic & Vujic sp. nov. Figs 3C, D; 4 A–D; 5C, E, F, H; 7

Type material.

Holotype. GREECE • ♂, Lesvos , Agiassos. Original label: "Agiassos, 601 m / Lesbos, Greece / 39°4'16"N / 26°22'23"E / 23.vi.2003 / leg. M. Hull " . Paratype. GREECE • 1♀, Evros , Dadia, 26-28.vii.2013, 40,9943N 26.0933E leg. M. Kourtidou ( FSUNS) .

Diagnosis.

Male. Ocellar triangle isosceles (Fig. 4A). Abdomen black, without any red markings (Fig. 3C). Constriction of elongated metafemur is located in anterior half (Fig. 4D). Metatibia with characteristic curvature in posterior half, also well noticeable in female. Ventral margin of hypandrium with oval medial protuberance (Fig. 5C: vp). Anterior lobe of surstylus with a single row of pilosity (Fig. 5E).

Description.

Male. Body length (excluding antennae): 12 mm; wing length: 8 mm. Head. Eyes slightly dichoptic, separated by width of two ommatidia (Fig. 4A); covered in long dense white pilosity. Eye margins in anterior view almost parallel, slightly broadening ventrally. Face completely black pilose, gently pollinose, with distinctive thin line of silvery-white pollinosity in middle, slightly narrower in upper part. Frons, vertical triangle and occiput black; silvery-white pollinosity well expressed along eye margin on frons, on vertex anteriorly and dorsally on occiput behind eye margin, on the posterior margin as a patch, but most distinctive laterally. Ocellar triangle isosceles and predominantly black pilose, becoming intermixed with white pile in front of the ocellar triangle and turning predominantly white behind it. Vertical triangle and occiput with metallic blue reflection. Distance from anterior to posterior ocellus same as distance from latter one to upper eye corner. Lower facial margin in lateral view not protruding (Fig. 4B). In lateral view, white pilosity on eyes make contrast to black long pile on face, reaching one third to half of their length. Scape and pedicel dark colored, almost black. Basoflagellomere lacking in the holotype. Ventral pile of pedicel black, longer than its depth. Thorax. Scutum and scutellum densely punctate, covered in long dense white pilosity. Scutum with pair of white vittae of pollinosity, along almost two thirds of scutum length. Scutellum and lateral area of scutum with metallic blue tinge. Pleurae black. Anepisternum predominantly covered in long white pilosity, except behind anterior spiracle with patch of black pilosity. Katepisternum, anepimeron and katepimeron black pilose. Wing. Hyaline with pterostigma the same color as wing. Vein R4+5 slightly curved. Wing covered in microtrichia except for basal cells mostly bare. Costal setae black. Halter blackish. Legs. Metaleg slender with all segments very elongated (Fig. 4D). Femora black with yellowish tips covered in black pilosity; metafemur very narrow in apical half with only few scattered inconspicuous setae. Tibiae white pilose. Pro- and mesotibia mostly black, yellowish in basal third and with yellowish apices; metatibia in the basal half yellowish, the apical half black turning lighter towards apex. Metatibia with characteristic curvature in posterior half (Fig. 4D). Tarsi brown to black; metatarsus longer than tibia. Abdomen. Black, punctate, pilose, tapered (Figure 3C; 4C). Terga 2-3 with pairs of wide white pollinose maculae, slightly obscured towards medial part of terga; tergum 4 with pair of white pollinose maculae with apices upwards. Tergum 2 with long white pile laterally; pilosity adpressed, in area of pollinose maculae white, black on rest of terga. Punctures are visible through pollinose maculae. Sterna entirely black pilose; sternum 4 flat with uniformly long pilosity (Fig. 5H). Terminalia. (Fig. 5C, E, F). Posterior surstyle lobe simple, beak-like in lateral view, with long strong setae laterally on outer surface (Fig. 5E: ps); in ventral view, outer margin slightly convex, pilose (Fig. 5F: om). Cerci oval (Fig. 5E: c), uniformly pilose. Interior accessory lobe of surstyle lobe densely pilose (Fig. 5F: in). Hypandrium curved, broad with folded thecal ridge near base (Fig. 5C: th); medially with oval protuberance on ventral margin (Fig. 5C: vp) and wide notch dorsally near base (Fig. 5C: dn). Female. Body length (excluding antennae): 11 mm; wing length: 7 mm. Similar to male except normal sexual dimorphism and for following characteristics: Head. White pilose except on ocellar triangle, with black pilosity. Basoflagellomere oval, dark, reddish anteriorly, with three radial wrinkles (Fig. 7B). Width of the frons in narrower part is narrower than one fourth of width of head in anterior view. (Fig. 7A). Thorax. Bluish sheen not noticeable. White pollinose vittae present along almost entire length of scutum. Pleurae white pilose. Segments of metaleg only slightly elongated. Metatibia with characteristic curvature (Fig. 7C). Abdomen. Tergum 4 with longer white pile posteriorly. Sterna black pilose except sternum 4 which is covered in white pile.

Etymology.

The species name is derived from the Latin words “tenui” and “tarsus” and refers to the extremely long and slender tarsi, especially obvious in the male metalegs.

Distribution.

Only known from the holotype and female paratype taken on Lesvos and Evros ( Greece) respectively.