Sphegina (Asiosphegina) forceps, 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 : 42-43

Sphegina (Asiosphegina) forceps sp. n.

Figs 3 B, 25A–C

MALE. Body length 5.0– 5.5 mm, wing length 4.2–4.6 mm. Head. Face strongly concave and strongly projected antero-ventrally; frontal prominence moderately developed (somewhat similar to Figs 1J, L). Width of vertex at anterior ocellus:width of head 1:4.1; depth of occipital fossa 1/5 of the width of an eye in dorsal view. Width of face:width of head 1:3.9. Face with the ventral 1/2 yellow, dorsal 1/2 black and both densely pale pollinose. Gena shiny yellow, usually darkened posteriorly. Frons and vertex shiny black; lunula shiny brown; frons with a narrow pale-pollinose band just posterior to the frontal prominence; the pile very short, erect and pale. Frontal prominence with rather deep medial depression. Occiput dull black. Antenna brownish; basoflagellomere elongated [length:width 1:2.5]; arista almost bare basally and distinctly pilose apically. Thorax. Colour black, postpronotum yellow, postalar callus brown, overall slightly pale pollinose (in 2 specimens pleura more or less extensively yellow); scutum mainly black with yellow sides, with the pile adpressed, golden; scutellum shiny black, rather semitriangular, the pile short, pale and adpressed, with a pair of thin, long, yellow setae at apical margin. Wing. Hyaline, stigma yellow. Legs. Pro- and mesoleg yellow, tarsomeres 4 and 5 obscure dark. Metaleg ( Fig. 3 B) coxa brownish; trochanter simple, yellow; femur yellowish to pale yellowish-brown, the apical 1/3 blackish, the submedial darker annulus brownish; tibia without apico-ventral tooth, brown, on apical 1/4 black, at extreme base yellow and the annulus (on the apical 1/2) pale yellowish; tarsus black entirely. Abdomen. Length ratio of tergites I, II, III and IV 1:3.0:1.6:1.4. Colour of tergites shiny black, tergite III reddish or yellow on anterior 1/3–1/6, tergite IV with a narrow transverse yellowish macula at anterior margin; the pile reddish, short and adpressed, becoming longer laterally; tergite I with an oblique row of 3–4 thin, long, pale setae laterally; sternite IV ( Fig. 25 C) unusually symmetrical, black, the pile and the stronger postero-medial setae reddish or brown; sternite VI simple, black, the pile dark and short; sternites VII and VIII black, the pile dark. Genitalia. Figs 25 A, B. Note the symmetrical surstyli, the unusual cercus with a long posterior prong which is apically sclerotized, as well as the unusual aedeagus. The superior lobes are symmetrical. FEMALE. Unknown.

Type material. HOLOTYPE. ♂, N.E. Burma, Kambaiti, 2000 m, 4.vi.1934, R. Malaise ( SMNH, strongly damaged). PARATYPES. 1♂ with same data as holotype except 4.vi. ( NBC); 1♂ with same data except 7000 ft, 12.v. ( SMNH).

Etymology. The name is Latin, forceps , pincers, referring to the pincer-like cerci.

Discussion. Sphegina forceps is not especially similar to any other species. It may recall such species as S. forficata , S. nasuta and S. simplex but is at once distinguished by having an oblique row of slightly strengthened setae postero-laterally on sternite I instead of two or three strong setae in a longitudinal row at the actual lateral margin of the tergite. The male genitalia are quite unique: the cerci which are posteriorly elongated as a curved apically sclerotized lobe and the aedeagus with posteriorly directed ejaculatory hood, ejaculatory tube and aedeagal lobes are much unlike any other species.

Figures

FIGURE 3. Metaleg, prolateral view (A, D female, B, C, E male). A. Sphegina (Asiosphegina) bilobata sp. n. (paratype). B. S. (A.) forceps sp. n. (paratype). C. S. (A.) minuta sp. n. (paratype). D. S. (A.) gigas sp. n. (paratype). E. S. (A.) carinata sp. n. (paratype). Scale 1.0 mm.

FIGURE 25. Sphegina (Asiosphegina) forceps sp. n. (holotype). A. Genitalia, lateral view. B. Left surstylus and posterior part of cercus, lateral view. C. Posterior part of sternite IV, ventral view. Scale 0.5 mm.