Sphegina (Sphegina) uncinata, 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 : 13

Sphegina (Sphegina) uncinata sp. n.

Figs 1A, 2A, 5A–C

MALE. Body length 4.5–5.8 mm, wing length 4.7–5.5 mm. Head. Face strongly concave, strongly projected antero-ventrally; frontal prominence large (Fig. 1A). Width of vertex at anterior ocellus:width of head 1:2.9; depth of occipital concavity less than 1/3 of the width of an eye in dorsal view. Width of face:width of head 1:2.9. Face dorsally blackish, ventrally paler yellowish or brownish, densely pale pollinose dorsally. Gena yellow. Frons and vertex brownish to blackish, more or less densely pollinose; lunula brown or yellow; the rather dense pile short, erect and pale. Occiput dull black. Antenna brown, scapus and pedicellus usually not darker than the basoflagellomere; basoflagellomere oval, large; arista short pilose. Thorax. Colour dark brown, postpronotum and postalar callus yellow or brownish, usually pleura paler than the dorsal parts of thorax, all parts more or less densely pale pollinose, the pile rather dense dorsally, adpressed, reddish; scutellum semi-triangular, ratio of length:width 1:0.4, pollinosity similar to scutum, the pile similar to that on the posterior part of scutum, with a pair of long, thin, pale setae at apical margin. Wing. ( Fig. 2 A). Hyaline or entirely more or less intensively darkened, stigma yellow. Legs. Pro- and mesoleg: yellow, tarsus entirely yellow or tarsomeres 4 and 5 darker than the more basal ones. Metaleg: coxa brown; trochanter simple, yellow; femur brownish, except basal 1/3 to basal 1/2 yellow; tibia rather straight, without apico-ventral tooth-like projection, brown with a yellowish annulus medially; tarsus dark brown. Abdomen. Gradually broadening from the posterior 1/2 of tergite II to the anterior 1/2 of tergite III; length ratio of tergites I, II, III and IV 1:2.8:2.3:2.0. Tergites shiny, unicolorous dark brown or blackish or tergite III paler on the anterior part, the pile of tergites mainly pale, becoming longer towards the lateral margin; tergite I laterally with long pale pile, without stronger setae; sternite I semicircular or semi-quadrangular, yellow or reddish; sternites II and III elongated; sternite IV ( Fig. 5 C) large, membranous postero-medially, yellow entirely or brownish anteriorly and yellow posteriorly, the pile dense, rather long and pale; sternites VI–VIII simple, brown, the pile long and pale. Genitalia, Figs 5 A, B. Symmetrical. FEMALE. Body length 5.5–6.2 mm, wing length 5.8– 6.5 mm. Similar to male except the normal sexual dimorphism. Width of face:width of head 1:2.9. Width of vertex at anterior ocellus:width of head 1:3.0. Gena more or less brownish, moderately pale pollinose. Frons and vertex uniformly pollinose, the pile reddish. Protarsus more or less darkened, tarsomeres 4 and 5 darker than the others. Length ratio of tergites I, II, III and IV 1:2.8:2.0:1.8; sternite I yellow, semi-rectangular; posterior margin of sternite III narrower than anterior margin of sternite IV; sternite IV short, transverse.

Type material. HOLOTYPE. ♂, N.E. Burma, Kambaiti, 7000 ft., 9.vi.1934, R. Malaise ( SMNH). PARATYPES. 2♂ with same data as holotype except 25.iv. ( SMNH, NBC); 1♂ with same data except 2.v. ( BMNH); 1♂ with same data except 5.v. ( BMNH); 1♂ with same data except 7.v. ( BMNH); 2♂ with same data except 11.v. ( SMNH, NBC); 1♂ with same data except 12.v. ( SMNH); 3♂ with same data except 14.v. ( SMNH, NBC); 7♂ with same data except 9. vi. ( SMNH, NBC); 1♂ with same data except 8000 ft., 12.v. ( SMNH); 1♂ with same data except 2000 m, 19.iv. ( SMNH); 1♂ with same data except 2000 m, 28.iv. ( SMNH); 1♂ with same data except 2000 m, 10.v. ( SMNH); 5♂, 1♀ with same data except 2000 m, 11.v. ( SMNH, NBC); 1♂ with same data except 2000 m, 7.vi. ( SMNH); 1♂ with same data except 2000 m, 7– 9.vi. ( SMNH); 1♀ with same data except 2000 m, 12–17.vi. ( SMNH).

Etymology. The name is Latin, uncinata , hooked, referring to the hooked posterior part of the male superior lobe.

Discussion. Sphegina uncinata is very similar to S. kumaoniensis Mutin, 1998a and they may be difficult and uncertain to distinguish without reference to the male genitalia. Except for the characters mentioned in the key S. uncinata also has a more ventrally projecting face, a larger basoflagellomere and the occiput along dorsal margin behind the vertex has longer and denser pile. These latter characters apply to both sexes, but the differences are small and difficult to quantify. In the male genitalia the two species differ greatly and can be distinguished by e.g. the following characters: in S. uncinata the baso-dorsal part of the superior lobe is simple (in S. kumaoniensis there is a horn-like process), the apical part of the superior lobe is narrow and curved dorsally (broad and curved lateroventrally), and the surstylus is shorter and in dorsal view evenly broad with a straight medial margin (narrowed on the apical half and with a concave medial margin). S. uncinata and S. kumaoniensis are not especially similar to any other Sphegina (Sphegina) . Their dark pollinose brownish colour and the short and rather narrow abdomen distinguish the species from other described Sphegina (Sphegina) .

Figures

FIGURE 2. Wing. A. Sphegina (Sphegina) uncinata sp. n. (paratype). B. S. (Asiosphegina) furva sp. n. (paratype). C. S. (A.) nasuta sp. n. (paratype). D. S. (A.) crucivena sp. n. (paratype). E. S. (A.) crassispina sp. n. (paratype). F. S. (A.) bidens sp. n. (paratype). G. S. (A.) carinata sp. n. (paratype). H. S. (A.) index sp. n. (paratype). I. S. (A.) simplex sp. n. (paratype). Scale 0.5 mm.

FIGURE 5. Sphegina (Sphegina) uncinata sp. n. (holotype). A. Genitalia, lateral view. B. Surstyli and postero-dorsal part of aedeagus, dorsal view. C. Male sternites IV and V, ventral view. Scale 0.5 mm. 1 = tergite IX, 2 = sternite IX, 3 = surstylus, 4 = superior lobe, 5 = cercus, 6 = aedeagus, 7 = sternite IV, 8 = sternite V.