Sphegina (Asiosphegina) crassispina, 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 : 16

Sphegina (Asiosphegina) crassispina sp. n.

Figs 2 E, 4D, H, 7A–G

MALE. Body length 8.3–8.4 mm, wing length 6.5–6.9 mm. Head. Face strongly concave and strongly projected antero-ventrally; frontal prominence weakly developed (somewhat similar to Figs 1J, L). Width of vertex at anterior ocellus 1/4 of width of head; the depth of occipital fossa ca. 1/3 of the width of an eye in dorsal view. Width of face:width of head 1:4. Face black, with a brownish medial fascia on ventral 1/2, weakly pale pollinose. Gena shiny black. Frons and vertex dull black; lunula shiny brown; a trace of a wide medial furrow on frons; the pile erect, dark. Occiput dull black. Antenna brown, basoflagellomere oval, paler than scapus and pedicellus, basoventrally reddish; arista pilose. Thorax. Colour black, postalar callus and lateral part of scutellum brown, weakly brownish-grey pollinose; scutum with rather weakly differentiated submedial stripe of more dense pollinosity; the pile very short and adpressed, dark or reddish; scutellum semicircular (ratio length:width 1:2.2); the pile longer and more erect than that on scutum; a pair of long, thin, yellow setae at apical margin. Wing, Fig. 2 E. Hyalinous to weakly brownish, the infuscated pattern brown, stigma yellowish; apical part of vein R2+3 with appendix into cell r1. Legs. Pro- and mesoleg yellow, tarsomeres 4 and 5 black. Metaleg: coxa brown; trochanter yellow, simple; femur black, the basal 1/3 yellow, slightly curved on basal 1/3, without long erect pile postero-ventrally, without long setae antero-dorsally on apical part; tibia without a distinct apico-ventral tooth-like projection, colour yellow with the apical 1/5 and an annulus on the basal 1/2 brownish; tarsus black, with golden pile. Abdomen, Figs 4 D, H. Length ratio of tergites I, II, III and IV 1:3.3:1.8:1.3; colour of tergites shiny black with weak bluish luster, the anterior 1/4 of tergite III reddish-yellow; the pile of tergites short and adpressed, becoming longer laterally, pale; tergite I with 2 very widely separated strong black setae at lateral margin ( Fig. 4 D); sternite IV ( Figs 7 A–D) black, pile pale, the strong setae and bristles black or intermixed with pale ones on the right side; sternite VI ( Figs 7 A, B) with two processes of which the more anterior one is thin and usually curved, the more posterior one conical, colour black, the pile very long and pale; sternites VII and VIII simple, black, with long pale pile. Genitalia, Figs 7 E–G. Note the asymmetry of the surstyli and the superior lobes and the short finger-like process subbasally on the medial side of the dorsal lobe of surstylus. FEMALE. Body length 6.0– 7.5 mm, wing length 5.4–6.6 mm. Similar to male except for the normal sexual dimorphism. Length ratio of tergites I, II, III and IV 1:2.8:2.2:1.2; tergites II and III with a small oval yellowish macula antero-medially, tergite V yellow with very long pale pile on posterior part, tergite VI medially membranous, laterally shiny brownish, rather bare; sternite II and III strongly reduced, small, elongate, brownish; sternite IV large, trapezoidal, broader than long, brownish, pile pale; sternite V large, longer than broad, posteriorly rounded, yellow, pile pale, long and adpressed, with a pair of very long thin setae postero-laterally.

Type material. HOLOTYPE. ♂, N.E. Burma, Kambaiti, 2000 m, 11.v.1934, R. Malaise ( SMNH). PARATYPES. 1♀ with same data as holotype except 4.iv. ( SMNH); 2♂ with same data except 10.iv. ( SMNH, NBC); 1♂ with same data except 19.iv. ( SMNH); 1♂ with same data except 23.iv. ( SMNH); 1♂ and 1♀ with same data except 11.v. ( SMNH, NBC); 2♂ with same data except 4.vi. ( SMNH, NBC); 2♂ with same data except 12– 17.vi. ( SMNH, NBC); 2♂ with same data except 1800 m, 28.v. ( SMNH, NBC); 1♀ with same data except 7000 ft., 19.iv. ( SMNH); 1♂ with same data except 7000 ft., 7.v. ( BMNH); 1♀ with same data except 7000 ft., 12. v. and Sphegina nigrifacies Dsb ( SMNH); 1♂ and 1♀ with same data except 7000 ft., 14. v. and Sphegina nigrifacies Dsb ( SMNH, NBC); 1♂ with same data except 7000 ft., 15. v. and Sphegina nigrifacies Dsb ( SMNH); 1♂ with same data except 7000 ft., 16. v. and Sphegina nigrifacies Dsb ( SMNH); 1♀ with same data except 17.v. ( SMNH); 1♀ with same data except 7000 ft., 18. v. and Sphegina nigrifacies Dsb ( SMNH); 1♀ with same data except 29.v. ( SMNH); 1♀ with same data except 7000 ft., 2.vi. and ( SMNH); 1♂ and 3♀ with same data except 7000 ft., 7.vi. ( BMNH, NBC).

Etymology. The name is composed of the Latin words crassus, big, and spina, thorn, referring to the strong spine-like setae on the male sternite IV.

Discussion. Sphegina crassispina is similar to S. carinata , S. index and S. malaisei . Except for the characters mentioned in the key it differs from these by the vestiture of male sternite IV: the four enlarged setae on the left side are steadily diminishing in length towards the medial line instead of being two longer + two shorter ones. Further, right side surstylus is broader than in the other species and the arrangement of sublobes on the superior lobe is different in all these species. S. crassispina is also similar to S. bispinosa Brunetti, 1915 , and S. hansoni Thompson, 1966 . It is distinguished from S. bispinosa by the hyaline wing (with infuscated pattern in S. bispinosa ), 3 short stout setae on left side of male sternite IV (7 long and strong setae in S. bispinosa ), and by having the metafemur without long setae subapically on the prolateral side (2–3 setae in S. bispinosa ); from S. hansoni by the hyaline wing (infuscated pattern in S. hansoni ), by 3 short stout setae on left side of male sternite IV (3 long and strong setae in S. hansoni ), by lacking a long seta subapically on the prolateral side of metafemur (present in S. hansoni ), and by the asymmetrical surstyli (in S. hansoni they are nearly symmetrical).

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 4. Tergite I (A – E), lateral view, abdomen (F, G, H), dorsal view. A, F. Sphegina (Asiosphegina) simplex sp. n. (paratype). B. S. (A.) gigas sp. n. (paratype). C. S. (A.) radula sp. n. (paratype). D, H. S. (A.) crassispina sp. n. (paratype). E, G. S. (A.) parvula sp. n. (paratype). Scale 0.5 mm for A – E, 1 mm for F, G, H.

FIGURE 7. Sphegina (Asiosphegina) crassispina sp. n. (A, B, D paratype, C, E, F, G holotype). A, B. Posterior part of abdomen, lateral view; the unmodified pilosity omitted. C, D. Posterior part of sternite IV, ventral view; the unmodified pilosity omitted. E. Genitalia, lateral view. F. Left surstylus, lateral view. G. Left superior lobe, lateral view. Scale 0.5 mm. 1 = tergite IV, 2 = sternite IV, 3 = sternite V, 4 = sternite VI, 5 = sternite VII, 6 = finger-like process, 7 = conical process, 8 = tergite IX, 9 = sternite IX, 10 = dorsal lobe of surstylus, 11 = ventral lobe of surstylus, 12 = lobe on the medial side of surstylus, 13 = superior lobe, 14 = sublobe of superior lobe, 15 = cercus, 16 = aedeagus.