Sphegina (Asiosphegina) gigantea, Steenis & Hippa & Mutin, 2018

Steenis, Jeroen Van, Hippa, Heikki & Mutin, Valeri A., 2018, Revision of the Oriental species of the genus Sphegina Meigen, 1822 (Diptera: Syrphidae), European Journal of Taxonomy 489, pp. 1-198 : 85-88

Sphegina (Asiosphegina) gigantea sp. nov.

urn:lsid:zoobank.org:act:3326F11E-6280-474F-8733-20E6FAF54191

Figs 33F , 37 , 38G , 41A

Differential diagnosis

Sphegina (Asiosphegina) gigantea sp. nov. is similar to those other Sphegina which have strong setae posteriorly on the male sternum IV, especially S. (A.) gigas and S. (A.) trispina with which it shares the hyaline wing in combination with the presence of long sub-apical setae antero-dorsally on the hind femur. Except for the characters appearing in the key, it also differs from S. (A.) gigas and S. (A.) trispina by having male sternum IV with a very narrow posterior submembranous flange (in S. (A.) gigas and S. (A.) trispina very wide). Sternum VII has a conical tubercle with long light pile as in S. (A.) trispina , but the pile is more seta-like; S. (A.) gigas has a long finger-like process with long light yellow pile. Thus, the male genitalia of these three species are significantly different (see also Hippa et al. 2015).

Etymology

The specific epithet is from the Latin ‘ gigantea ’, meaning ‘gigantic’ and referring to the large size of the fly.

Material examined

Holotype

CHINA • ♂; “ Sichuan: / Luding 9 km SE / 29.861° N, 102.314° E / 2100 m / 01.VII.2009 leg. / Blank, Liston, Taeger / 074 China”; CSCA.

Description

Male

LENGTH. Body 8.5 mm, wing 7.3 mm.

HEAD. Face in lateral view concave, strongly projected antero-ventrally; frontal prominence weakly developed. Ratio width of vertex at anterior ocellus: width of head 1: 4.5 ratio width of ocellar triangle: width of vertex 1: 2.0; ratio length of ocellar triangle: length of frons 1: 2.4. Face black, light grey pollinose, long pilose along eye-margin. Hypostomal bridge black, long pale pilose. Gena and mouth edge black with large subtriangular non-pollinose shiny area. Frons and vertex black, slightly pollinose, a wide subtriangular area posterior of lunula non-pollinose and shiny and a wide posterolateral densely grey-pollinose fascia ( Fig. 38G ); pile short, light yellow. Frons with weak pit antero-medially. Occiput black, light grey pollinose, light yellow pilose. Eye without enlarged facets at anterior margin. Antenna brown with black setae dorsally on scape and pedicel; basoflagellomere squarish, ratio width: length 1: 1.1; arista long pilose, slightly more than 3.5 times as long as basoflagellomere.

THORAX. Colour black, weakly greyish pollinose sub-shiny, pleuron entirely and more heavily grey pollinose; scutum and pleuron with very short adpressed light yellow pile. Scutellum subtriangular, black, weakly greyish pollinose, with pile slightly longer than on scutum, with two closely set, long setae medially at posterior margin, ratio length of scutellum: length of seta 1: 2.2.

WING. Entirely microtrichose; hyaline, stigma yellowish. Crossvein dm-cu meeting vein M slightly obliquely and vein M

1

meeting vein R

4+5

perpendicularly. Vein CuA

1

extending beyond vein dm-cu.

LEGS. Pro- and mesoleg yellow; femur black on medial ⅓ –4/5, tibia with apico-medial ⅓ –¼ black, tarsomeres 4 and 5 black. Metaleg, Fig. 33F , with coxa black, trochanter yellow; femur black with basal ⅓ yellow, slightly incrassate, ratio width: length 1: 4.7, with a row of 3 long black setae anteriorly on basal yellow part and two long sub-apical setae antero-dorsally; tibia black and yellow biannulate with pointed apicoventral dens; tarsus entirely black, basitarsomere very thin, ratio width: length 1: 5.0.

ABDOMEN. Length ratio of terga I: II: III: IV 1: 3.5: 1.8: 1.5; ratio width at posterior margin: medial length of tergum II and III 1: 5.8 and 1: 1.0. Terga black, anterior ⅓ of tergum III with yellow fascia; pile pale, on terga short, laterally on terga I and II long; tergum I with 3 evenly spaced strong black setae at lateral margin; sternum III rectangular, ratio width: length 1: 1.9; sternum IV, Fig. 37B ; sterna VI, VII and VIII with long yellow pile, sternum VII with a low conical tubercle with long light setae-like pile. Genitalia, Fig. 37 C–E: note the asymmetrical surstyli and superior lobes and the short subbasal finger-like lobe on the medial side of the right surstylus.

Female

Unknown.

Figures

Fig. 33. Metaleg, anterior view. A. Sphegina (Asiosphegina) crassispina Hippa, van Steenis & Mutin, 2015, paratype, ♀, Myanmar. B. S. (A.) crucivena Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar. C. S. (A.) exilipes sp. nov., holotype, Ƌ, Java. D. S. (A.) forficata Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar. E. S. (A.) ghatsi sp. nov., holotype, Ƌ, India. F. S. (A.) gigantea sp. nov., holotype, Ƌ, China. G. S. (A.) gigas Hippa, van Steenis & Mutin, 2015, paratype, ♀, Myanmar. Scale bars = 0.5 mm.

Fig. 37. Sphegina (Asiosphegina) gigantea sp. nov., holotype, Ƌ. A. Posterior part of abdomen, left side lateral view. B. Sternum IV, ventral view. C. Left surstylus, lateral view. D. Left superior lobe, lateral view. E. Genitalia, right side, lateral view. Scale bars = 0.5 mm.

Fig. 38. Head, lateral view (C, K), dorsal view (A–B, D, F–J, L) and frontal view (E). A. Sphegina (Asiosphegina) farinosa sp. nov.,holotype, Ƌ, Sabah, Malaysia. B. S. (A.) fimbriata sp. nov., holotype, Ƌ, Thailand. C–D. S. (A.) forceps Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar. E. S. (A.) furva Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar. F. S. (A.) ghatsi, sp. nov., holotype, Ƌ, India. G. S. (A.) gigantea sp. nov., holotype, Ƌ, China. H. S. (A.) granditarsis sp. nov., paratype, Ƌ, Thailand. I. S. (A.) hamulata sp. nov., holotype, Ƌ, India. J. S. (A.) hansoni Thompson, 1966, holotype, Ƌ, Nepal. K–L. S. (A.) hauseri sp. nov., paratype, Ƌ, Nepal. Scale bars = 0.5 mm.

Fig. 41. Habitus, lateral view. A. Sphegina (Asiosphegina) gigantea sp. nov., holotype, Ƌ, China. B. S. (A.) gigas Hippa, van Steenis & Mutin, 2015, paratype, ♀, Myanmar. C. S. (A.) granditarsis sp. nov., paratype, Ƌ, Thailand. D. S. (A.) hamulata sp. nov., holotype, Ƌ, India. E. S. (A.) hansoni Thompson, 1966, holotype, Ƌ, Nepal, Malaysia. F. S. (A.) hauseri sp. nov., paratype, Ƌ, Nepal. Scale bars = 1.0 mm.