binominatus

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 : 93-94

Species subgroup binominatus

Diagnosis.

Eyes densely whitish, pilose. Basoflagellomere relatively small, only about twice size of pedicel, oval to squarish in shape, with only a few short radial wrinkles. Male eyes holoptic or narrowly dichoptic. Abdomen short and stout (Fig. 4C). Posterior lobe of surstylus simple, well developed.

Remarks.

The Eumerus binominatus subgroup shares all characters of the tricolor group ( Grković et al. 2017) but can easily be recognized within this group by the extremely long and slender legs in males, especially obvious in the metaleg, where the width of the widest part of metafemur is equal or less than one fifth of the length of the metafemur (Fig. 4 D–F). Eumerus niveitibia is a Mediterranean species from the tricolor group which shares several characters with members of binominatus subgroup, e.g. long pilosity on eyes and thorax, similar heart-shaped abdomen with large white pollinose maculae on tergites, but it is clearly differentiated by the long eye-contiguity in male, metafemur clearly thickened and by characteristic snow-white pilosity dorsally on metatibia. Furthermore, the posterior lobe of the surstylus in E. niveitibia is much smaller than in E. binominatus species subgroup. Females of E. niveitibia are similar in appearance with the females of binominatus subgroup, but can be differentiated by a slenderer metafemur and characteristic curvature on the metatibia in the binominatus subgroup females.

E. selevini Stackelberg, 1949 is a middle-Asian species similar to the binominatus subgroup, based on the slender metafemur. The head of this species is very similar to that in E. binominatus and E. tadzhikorum but with smaller, equilateral ocellar triangle, placed medially on vertex, which is in the other two species large, elongated and placed closer to the upper eye margins. It differs by the normal shaped metatarsus, not elongated as in binominatus subgroup; elongate abdomen in comparison to the length of head and thorax together and with a characteristic lateral notch in the second metatarsal segment; the pilosity on the thorax is very short in E. selevini in contrast to species in the binominatus subgroup which makes this species easily recognizable.

The following species belong to the binominatus subgroup:

E. binominatus Hervé-Bazin, 1923 (Fig. 1A, B)

= E. maculipennis Becker, 1921 preocc. Bezzi, 1915

E. grallator sp. nov. (Fig. 3A, B)

E. longitarsis Peck, 1979

E. tenuitarsis sp. nov. (Fig. 3C, D)

E. tadzhikorum Stackelberg, 1949 (Fig. 1C, D)