Sphegina (Asiosphegina) raduloides, Hippa, Heikki, Steenis, Jeroen Van & Mutin, Valeri A., 2015

Hippa, Heikki, Steenis, Jeroen Van & Mutin, Valeri A., 2015, The genus Sphegina Meigen (Diptera, Syrphidae) in a biodiversity hotspot: the thirty-six sympatric species in Kambaiti, Myanmar, Zootaxa 3954 (1), pp. 1-67 : 29-30

Sphegina (Asiosphegina) raduloides sp. n.

Figs 15 A–D

MALE. Body length 6.5 mm, wing length 5.6 mm. Head. Face strongly concave, weakly projected anteroventrally; frontal prominence weakly developed (similar to Fig. 1F). Width of vertex at anterior ocellus:width of head 1:4.1; depth of occipital fossa ca. 1/4 of the width of an eye in dorsal view [1:3.9]. Width of face:width of head 1:4.6. Face yellow, densely pale pollinose. Gena shiny yellow. Frons and vertex shiny black; lunula shiny brown, a narrow pale-pollinose cross band just posterior of the frontal prominence; the pile very short, erect and pale. Occiput dull black. Antenna brownish; basoflagellomere oval [length:width 1:0.8], paler baso-ventrally; arista pilose. Thorax. Colour dull black; postpronotum pale pollinose; scutum with short, adpressed densely placed pale pile; scutellum semicircular, with adpressed pale pile which becomes longer and stronger towards the apex and with a pair of long pale setae at apical margin. Wing. Hyaline, stigma pale. Legs. Pro- and mesoleg yellow; tarsomeres darker toward apex, sometimes 4 and 5 brown. Metaleg: coxa brownish; trochanter brownish, simple; femur brownish, the basal 1/3 yellow, the yellow basal part with 2–3 small black and yellow setulae ventrally, well separated from the black setae on the dark part of the femur; metatibia without apico-ventral tooth, brownish, the basal 1/3 and an annulus on the apical 1/2 yellow; tarsus black or brown (in paler specimens). Abdomen. Length ratio of tergites I, II, III and IV 1:3.3:1.7:1.3. Colour of tergite black, anterior 1/3 of tergite III reddish, pile mainly pale, short and adpressed, becoming longer laterally; tergite I with 3 black (sometimes the first one yellow), strong, well separated setae at lateral margin; sternite IV ( Fig. 15 A) black, posterior margin behind setae yellow, the pile pale, the stronger setae and bristles black, the number and arrangement of the setae and bristles slightly variable; sternites VI–VIII simple, black, the pile dense, long and pale. Genitalia, Figs 15 B–D. Note the asymmetrical surstyli and superior lobes and the concavity on the dorsal margin of the dorsal lobe of the left side surstylus giving it an angulate shape. FEMALE. Unknown.

Type material. HOLOTYPE. ♂, N.E. Burma, Kambaiti, 2000 m, 26.iv. 1934, R. Malaise ( SMNH). PARATYPES. 2♂ with same data as holotype except 7000 ft, 14.v. ( SMNH, NBC); 1♂ with same data except 7000 ft, 23.v. ( SMNH).

Etymology. The name is formed from the name of S. radula by adding the Latin suffix - oides, like or resembling, referring to the similarity to that species.

Discussion. Sphegina raduloides is similar to S. radula , S. subradula and S. trichaeta . Except for the character mentioned in the key it differs from S. trichaeta by lacking three very strong setae on left side of the posterior margin of male sternite IV, greatly deviating from the other setosity, and from all the discussed species by having an unusual concavity on the dorsal margin of the dorsal lobe of the left side surstylus which makes the margin angulate, and by having the right side superior lobe posteriorly bi-lobed. The ventral one of these lobes possibly belongs to the ventral part of sternite IX which in that case is unusually pushed posteriorly. The aedeagus resembles that of S. radula by having the lateral lobe short.

Figures

FIGURE 15. Sphegina (Asiosphegina) raduloides sp. n. (A paratype, B, C, D holotype). A. Posterior part of sternite IV, ventral view; the unmodified pilosity omitted. B. Genitalia, lateral view. C. Left surstylus, lateral view. D. Left superior lobe, lateral view. Scale 0.5 mm.