Merodon robustus, Veselić, Sanja, Vujić, Ante & Radenković, Snežana, 2017

Veselić, Sanja, Vujić, Ante & Radenković, Snežana, 2017, Three new Eastern-Mediterranean endemic species of the Merodon aureus group (Diptera: Syrphidae), Zootaxa 4254 (4), pp. 401-434 : 424-430

Merodon robustus sp. n.

Figs 11 , 21–24

Type material. HOLOTYPE: Greece: ♂, Samos , Pyrgos, 15.iv.2011, leg. A. Vujić ( FSUNS) . PARATYPES: Greece: 19 ♂ + 6 ♀, Samos , Pyrgos, 15.iv.2011, leg. A. Vujić ( FSUNS) ; 3 ♂ + 13 ♀, Samos , Pyrgos, 500m, 21– 22.iv.1988, leg. J. A. W Lucas (NBC) ; 5 ♂ + ♀, Samos, Platanos , 600m, 23.iv.1988, leg. J. A. W. Lucas (NBC) ; ♂, Samos, Spatharaioi-Paghondhas , 15.iv.2011, leg. A. Vujić ( FSUNS) ; ♀, Samos, Karvuni , 26.v.1997, leg. J. P. Duffels (NBC).

Diagnosis. Species with stocky abdomen without any trace of mictrotrichose stripes and the visible black background colour of tergites because of the scarce shortlight yellow pilosity ( Figs 21 a, 23a); frons above antennae swollen and striated, with median tubercle above lunulae; metatarsus of hind leg with small dorsal depression. This species is similar to Merodon chalybeus Wiedemann and Merodon minutus Strobl , except for the following differences: M. robustus sp. n. with whitish to yellowish pile at wing basis, black in M. minutus and M. chalybeus ; M. robustus sp. n. with pale pilosity on hind femur, in M. minutus and M. chalybeus with many black pile in the apical half; M. robustus sp. n. with shiny tergites without any trace of microtrichia, contrary to M. minutus and M. chalybeus with microtrichose stripes at least on tergite II.

Body size. Length: body = 8–12 mm; wing 6–8 mm (n = 50).

Description. MALE ( Fig. 21 , 22 ). Head ( Fig. 22 c, 22d). Antenna from brown to reddish-brown; basoflagellomere 1.3–1.5 times longer than pedicel, dorsal margin concave between arista and apex, apex acute; arista brown, as long as pedicel and basoflagellomere together. Face and frons shiny black, except indistinct brown microtrichia on facial median stripe and along eye margin; covered in whitish to light yellow pile. Frons above antennae swollen and striated, with median tubercle above lunulae. Oral margin without setae or microtrichia, black and lustrous. Vertical triangle isosceles, 1.5–2.0 times longer than eye contiguity, shiny black without microtrichia and covered with long black pile anteriorly and light yellow pile posteriorly. Ocellar triangle slightly isosceles, covered with mixed black and light yellow pile. Eye contiguity about 10–15 ommatidia long. Eye pile long and pale except for upper eye corner with black pile. Occiput shiny, except stripe of white microtrichia along eye margin; covered with pale pile. Thorax ( Fig. 21 b, 21c). Mesonotum black with bronze metallic reflections, covered in long, erect yellowish pile, without any trace of microtrichia. Posterior anepisternum, anepimeron, dorsal part of katepisternum and postalar callus with whitish-yellow long pile. Wing brownish, with veins light brown to dark brown; densely covered with brown microtrichia. Dorsal and ventral calypters light yellow. Haltere with light brown pedicel and dark brown capitulum. Legs black except for pale apex of femora, orange basal half (or less) and apex of tibiae, and orange ventral surface of tarsi (first two tarsomeres of fore and mid legs dorsally can be paler). Fore and mid femur covered posteriorly with long light yellow pile and both dorsally and anteriorly with short black pile ( Fig. 22 a); hind femur with light yellow pilosity. Tibiae and tarsi covered with short yellow-orange pile, except hind tarsi dorsally with black pile ( Fig. 22 b). Hind trochanter with an inner spike ending in two angular points; metatarsus of hind leg with small dorsal depression. Abdomen. Stocky abdomen; black, with bronze reflection, except for tergite II that is laterally bluish and lustrous. Tergites without any trace of mictrotrichose stripes. Tergites covered with adpressed short light yellow pile, except for a few intermixed black pile medially and more black pile postero-medially on tergites II and III. Sternites brown and shiny; covered with long light yellow pile, except for posterior half of sternite IV with a few black pile. Genitalia. Similar to all other species of the M. aureus group.

FEMALE ( Fig. 23 ). Similar to the male except for normal sexual dimorphism and in the following characteristics: ocellar triangle equilateral. Vertex with yellow pile and a few intermixed black ones ( Fig. 23 b, 23c). Hind trochanter without spike. Pilosity on abdomen shorter than in male; tergites II and III with more black pile in female than in male ( Figs 24 a, 24b).

Etymology. The Latin adjective robustus means solid and robust, and refers to the robust body form of this species.

Range and preferred habitat. Aegean island of Samos (Greece) ( Fig. 11 ); open areas in evergreen Mediterranean oak forest and maquis.

Figures

FIGURE 11. Distribution of Merodon nisi sp. n. (●), Merodon robustus sp. n. (■) and Merodon quercetorum (▲).

FIGURE 21. Merodon robustus sp. n., male: a—dorsal view; b—thorax, dorsal view; c—thorax, lateral view (anterior part of the thorax on the right side, posterior part on the left side). Scale 0.5 mm.

FIGURE 22. Merodon robustus sp. n., male: a—hind leg, lateral view (scale 1 mm); b—hind tarsi, lateral view (scale 1 mm); c—head, lateral view (scale 0.5 mm); d—head, anterior view (scale 0.5 mm).

FIGURE 23. Merodon robustus sp. n., female: a—dorsal view (scale 1 mm); b—head, lateral view (scale 0.5 mm); c—head, anterior view (scale 0.5 mm).

FIGURE 24. Merodon robustus sp. n.: a—male, abdomen, lateral view; b—female, abdomen, lateral view. Scale 1 mm.