Sphegina (Asiosphegina) umbrosa, 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 : 182-184

Sphegina (Asiosphegina) umbrosa sp. nov.

urn:lsid:zoobank.org:act:1DC2CEBB-9E6D-4DC3-A4E5-562C914D0756

Figs 88H , 92 , 93A , 95D , 97A

Differential diagnosis

Similar to Sphegina (Asiosphegina) dentata sp. nov. and S. (A.) tricoloripes . For distinguishing characters, see under the latter. In the male genitalia the species is reminiscent of a few other Sphegina (Asiosphegina) which have the cerci as large or larger than the surstyli. It differs from all these by the unusually large and humpbacked tergum IX.

Etymology

The specific epithet is derived from the Latin ‘ umbrosus ’, meaning ‘dark-shaded’ and referring to the overall dark brown colour of the body and especially the dark-shaded legs.

Material examined

Holotype

CHINA • ♂; “ CHINA: Zhejiang Province, / Qingliangfeng National Nature / Reserve , ex: Malaise trap / 4–11.v.2012 ”; CSCA.

Description

Male

LENGTH. Body 6.2 mm, wing 4.5 mm.

HEAD. Face in lateral view concave, very weakly projected antero-ventrally; frontal prominence weakly developed. Ratio width of vertex at anterior ocellus: width of head 1: 3.7; ratio width of ocellar triangle: width of vertex 1: 2.4; ratio length of ocellar triangle: length of frons 1: 3.0. Face black, light grey pollinose, long pilose along eye-margin. Hypostomal bridge black, long pale pilose. Gena and mouth edge black, pale pollinose with large subtriangular non-pollinose shiny area. Frons and vertex black, slightly pollinose, a wide fascia posterior of lunula and a large round macula anterior of ocelli nonpollinose and shiny, with wide densely grey-pollinose fascia medially ( Fig. 88H ); pile short, light yellow. Frons flat, without any depression medially. Occiput black, light grey pollinose, light yellow pilose. Eye without enlarged facets at anterior margin. Antenna dark brown with black setae dorsally on scape and pedicel; basoflagellomere round, ratio width: length 1: 1.0; arista short pilose only basally, nearly 3.5 times as long as basoflagellomere.

THORAX. Colour black, slightly pollinose, scutum sub-shiny with submedial light grey pollinose vitta and grey-pollinose lateral margin, pleuron entirely more heavily grey pollinose; scutum and pleuron with very short adpressed light yellow pile. Scutellum sub-triangular, black, shiny medially, laterally

weakly pollinose, with pile slightly longer than on scutum, with two widely set very long setae medially at posterior margin, ratio length of scutellum: length of seta 1: 2.4.

WING. Microtrichose, basal ⅓ of cell cup bare; hyaline, stigma yellowish. Crossvein dm-cu meeting vein M obliquely and vein M

1

meeting vein R

4+5

perpendicularly.

LEGS. Pro- and mesoleg yellow; medial ¾ of femur, apico-medial half of tibia and tarsomeres 3–5 black. Metaleg, Fig. 95D , with coxa black, trochanter yellow; femur black with basal ⅓ yellow, incrassate, ratio width: length 1: 4.0; tibia black and yellow biannulate, without apicoventral dens; tarsus entirely black, basitarsomere rather thin, ratio width: length 1: 3.8.

ABDOMEN. Length ratio of terga I: II: III: IV 1: 3.8: 1.9: 1.8; ratio width at posterior margin: medial length of tergum II and III 1: 3.4 and 1: 0.8. Terga black, tergum III with sub-anterior yellow fascia on anterior half; pile pale, on terga short, laterally on terga I and II long; tergum I with a horizontal row of 4 white setae at lateral margin; tergum IV with posterior margin skewed to the right; sternum III not sclerotized; sternum IV, Fig. 92A ; sterna VI, VII and VIII simple, with long yellow pile. Genitalia, Fig. 92 B–C: note the large humpbacked tergum IX, enlarged slightly asymmetrical cerci and slightly asymmetrical surstyli; superior lobe on the left side is deformed and not drawn, it is similar to the right side one.

Female

Unknown.

Figures

Fig. 88. Head. lateral view (C, E, F, J) and dorsal view (A–B, D, G–I, K–L). A. Sphegina (Asiosphegina) spathigera sp. nov., holotype, Ƌ, Philippines. B–C. S. (A.) spenceri sp. nov., paratype, Ƌ, Vietnam. D–E. S. (A.) strigillata sp. nov., holotype, Ƌ, Vietnam. F. S. (A.) tricoloripes, Brunetti, 1915, ♀, India. G. S. (A.) tricoloripes, Ƌ, India. H. S. (A.) umbrosa sp. nov., holotype, Ƌ, China. I. S. (A.) varidissima Shiraki, 1930, Ƌ, Taiwan. J. S. (A.) varidissima, ♀, Taiwan. K. S. (A.) verrucosa sp. nov., paratype, Ƌ, Vietnam. L. S. (A.) vietnamensis sp. nov., paratype, Ƌ, Vietnam. Scale bars = 0.5 mm.

Fig. 92. Sphegina (Asiosphegina) umbrosa sp. nov., holotype, Ƌ. A. Posterior part of sternum IV, ventral view. B. Left cercus and surstylus, lateral view. C. Genitalia, right side, lateral view. Scale bars = 0.5 mm.

Fig. 93. Habitus, lateral view. A. Sphegina (Asiosphegina) tricoloripes Brunetti, 1915, Ƌ, India. B. S. (A.) umbrosa sp. nov., holotype, Ƌ, China. C. S. (A.) varidissima Shiraki, 1930, Ƌ, Taiwan, yellow form. D. S. (A.) verrucosa sp. nov., paratype, Ƌ, Vietnam. E. S. (A.) vietnamensis sp. nov., paratype, Ƌ, Vietnam. Scale bars = 1.0 mm.

Fig. 95. Metaleg, anterior view. A. Sphegina (Asiosphegina) plautus sp. nov., holotype, Ƌ, China. B. S. (A.) setosa sp. nov., holotype, Ƌ, Nepal. C. S. (A.) strigillata sp. nov., holotype, Ƌ, Vietnam. D. S. (A.) umbrosa sp. nov., holotype, Ƌ, China. E. S. (A.) varidissima Shiraki, 1930, Ƌ, Taiwan, yellow form. Scale bars = 0.5 mm.

Fig. 97. Habitus, dorsal view. A. Sphegina (Asiosphegina) umbrosa sp. nov., holotype, Ƌ, China. B. S. (A.) varidissima Shiraki, 1930, Ƌ, Taiwan. C. S. (A.) varidissima, ♀, Taiwan, yellow form. D. S. (A.) verrucosa sp. nov., paratype, Ƌ, Vietnam. E. S. (A.) vietnamensis sp. nov., paratype, Ƌ, Vietnam. Scale bars = 1.0 mm.