Eumerus muratovi Barkalov, 2020

Barkalov, A. V., 2022, Description of a new hoverfly species of the genus Ferdinandea and the female of Eumerus muratovi from Tajikistan (Diptera: Syrphidae: Eristalinae), Zoosystematica Rossica (Zoosyst. Rossica) 31 (1), pp. 66-73 : 71-72

Eumerus muratovi Barkalov, 2020

( Fig. 3A–D )

Material examined. Tajikistan, Gorno-Badakhshan Autonomous Prov. : 1 female, Ishkashim Distr. , near Yamchun Vill., 36°59′N 72°16′E, 2256 m, 23.VII.2021, V. Zinchenko leg.; 1 female, Rushan Distr. , Khufdara Gorge, Khuf Vill., 37°50′N 71°39′E, 2860 m, 6.VII.2021, V. Zinchenko leg.

Description. Female. Body length 14 mm; wing length 10 mm.

Head. Face narrow, parallel-sided, black with dense silver pollen and pile; cheeks very narrow, without pollen, covered with silver pile ( Fig. 3D ). Frons narrow, in narrowest part narrower than width of basoflagellomere, shiny black in middle part, with vittae of dense silver pollen along eyes, covered with comparatively short silver pile being semierect laterally and erect medially; lunula black. Antenna: scape and pedicel black with grey pollen; basoflagellomere very large, irregular in shape ( Fig. 3B ), with 4–5 longitudinal brown furrows being more distinct on inner side; arista black, strongly thickened in basal third. Vertex shiny, with black and white pile. Vertical triangle isosceles. Occiput shiny, with white pile. Eye covered with comparatively short, dense white pile.

Thorax. Scutum with bluish reflection, in anterior half with indistinct grey vittae; pile of scutum comparatively short, erect, dense, white. Pleura bluish with very dense yellow pile. Legs almost completely black, only extreme tips of femora brown. Posterior sides of femora with long erect white pile, anterior sides of femora with short adpressed black pile. Fore and mid tibiae with short adpressed pile; hind tibia with adpressed and semidepressed black pile, only basal third of tibia dorsally with short adpressed white pile. Tarsi black, with white pile; segments of fore and mid tarsi with short but distinct black bristles posteroventrally; hind tarsus flattened dorsoventrally, covered with black pile; hind basitarsus equal in length to segments 2–4 combined. Wing with small brown spot medially; veins black or dark brown. Calypter white with white cilia; halter brown with black knob.

Abdomen ( Fig. 3A, C ) broad, distinctly broader than scutum at level of wing bases. Abdomen black with bluish reflection, covered with erect and semierect, mostly white pile; median parts of terga III–IV with black pile; tergite II with small reddish spots laterally and elongate spots of white pollen; terga III–IV with small spots of white pollen, tergite IV with narrow brown vitta posteriorly; sterna black with white pile.

Comparison. The female of E. muratovi is easily differentiated from females of all other Palaearctic species of the genus Eumerus in the large size, completely black legs and characteristic structure of the basoflagellomere. In the Stackelberg’s key to the genus Eumerus ( Stackelberg, 1961) , the female of E. muratovi runs to E. kozlovi Stackelberg, 1952 , from which it differs in the completely black legs, larger size of the body (14 mm) and presence of brown spot on the wing (in E. kozlovi , the apex of femora and the basal third of tibiae are yellowish brown, body length is 11–12 mm and the wing has no brown spot medially).

Taxonomic position. According to the presence of radial furrows and apical ellipsoidal fossa on the basoflagellomere of antenna, the presence of yellow spots on terga II–III and structure of the male genitalia, E. muratovi should be assigned to the Eumerus tricolor species–group.

Distribution. Eumerus muratovi is known only from high mountains of the West Pamirs in Tajikistan ( Fig. 4 ).

Note. Both females and males were collected from rocks and bare ground but were not found on flowering plants growing around. Typically, many other species of the genus Eumerus can be seen on bare ground and mountain roads. In these species, males and females probably use open space for mating.

Figures

Fig. 3. Eumerus muratovi Barkalov, 2020, female. A, general appearance, in dorsal view; B, antenna, in lateral view; C, scutellum and abdomen, in dorsal view; D, head, in anterior view. Scale bars: 2 mm (A), 0.5 mm (B), 1 mm (C, D).

Fig. 4. Collecting localities in Tajikistan. 1, Ferdinandea volkovae sp. nov. (holotype); 2, 3, Eumerus muratovi Barkalov, 2020 (females).