Sphegina (Asiosphegina) verrucosa, 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 : 187-189

Sphegina (Asiosphegina) verrucosa sp. nov.

urn:lsid:zoobank.org:act:33C0BA9B-A7AD-40E0-86E0-A5F4867DE075

Figs 88K , 93D , 96 , 97D

Differential diagnosis

Similar to Sphegina (Asiosphegina) distincta sp. nov. and S. (A.) trichaeta . It is distinguished from both species by the male sternum IV having at the posterior margin on the left side, in addition to the three very strong and long setae, two elongated but shorter ones. In the male genitalia, Sphegina (Asiosphegina) verrucosa sp. nov. is distinguished from S. (A.) trichaeta by having the dorsal lobe of the right surstylus wider than the left one, not vice versa; and from S. (A.) distincta sp. nov. by having the dorsal lobe of surstyli narrow, narrower than the superior lobes, instead of wider than the superior lobes. The scraper-like surface baso-dorsally on the hypandrium is a unique character of this species

Etymology

The specific epithet is from the Latin ‘ verrucosa ’, meaning ‘warty or rough’ and referring to the rough scraper-like baso-dorsal part of male hypandrium.

Material examined

Holotype

VIETNAM • ♂; “ Viet Nam Dak Song / 76 km SW of / BanMeThuot 870 m / 19–21.V.1960 ”; “ L.W. Quate / Collector”; BPBM.

Paratypes

VIETNAM • 1 ♂; same data as for holotype; JSA • 1 ♂; “ Viet Nam : Fyan / 900–1000 m / 11. VII – 9.VIII.1961 ”; “ N. R. Spencer / Collector”; BPBM • 1 ♂; “ Viet Nam / BanMeThuot 900 m / 16– 18.V.1960 ”; “ L.W. Quate / Collector”; JSA .

Description

Male

LENGTH. Body 5.3–5.6 mm, wing 3.9–4.3 mm

HEAD. Face in lateral view concave, weakly projected antero-ventrally; frontal prominence weakly developed. Ratio width of vertex at anterior ocellus: width of head 1: 3.8–4.1; ratio width of ocellar triangle: width of vertex 1: 1.8–1.9; ratio length of ocellar triangle: length of frons 1: 1.7–2.0. 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 grey pollinose, a semi-circular area posterior of lunula non-pollinose and shiny and a wide densely grey pollinose fascia posterior of shiny area ( Fig. 88K ); pile short, light yellow. Frons with weak medial furrow. Occiput black, light grey pollinose, light yellow pilose. Eye with an area of enlarged facets at anterior margin. Antenna with scape and pedicel dark brown to black, basoflagellomere light- to dark brown, with black setae dorsally on scape and pedicel; basoflagellomere squarish, ratio width: length 1: 1.1–1.2; arista long pilose, nearly 3 times as long as basoflagellomere.

THORAX. Colour dark brown to black, weakly greyish pollinose, pleuron entirely more heavily grey pollinose; scutum and pleuron with very short adpressed light yellow pile. Scutellum semicircular, black, grey pollinose, with pile slightly longer than on scutum, with two closely set very short setae medially at posterior margin, ratio length of scutellum: length of seta 1: 0.5–0.6.

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

1

meeting vein R

4+5

perpendicularly.

LEGS. Pro- and mesoleg yellow, femora with dark brown medial annulus, tarsomeres 4 and 5 black. Metaleg with coxa black, trochanter yellow; femur black with basal ¼ yellow, incrassate, ratio width: length 1: 4.0–4.2; tibia black and yellow biannulate with short wide and rounded apicoventral dens; tarsus entirely black, basitarsomere thick, ratio width: length 1: 3.2–3.5.

ABDOMEN. Length ratio of terga I: II: III: IV 1: 3.9–4.1: 1.8–2.0: 1.7–1.9; ratio width at posterior margin: medial length of tergum II and III 1: 4.2–4.5 and 1: 0.8–0.9. Terga black, anterior 2/5 of tergum III with brown-yellow fascia; pile pale, on terga short, laterally on terga I and II long; tergum I with 2 light to dark brown setae at posterolateral margin; sternum III oval with incised anterior margin, ratio width: length 1: 2.4–2.6; sternum IV, Fig. 96B ; sterna VI, VII and VIII with long yellow pile, sternum VII anteroventrally with subtriangular lobe and postero-ventrally with conical process. Genitalia, Fig. 96 C–E: note the asymmetrical surstyli, subbasal lobe on the medial side of surstyli and asymmetrical superior lobes.

Female

Unknown

Remarks

We have one specimen (1 ♀, “ Viet Nam: Fyan / 900–1000 m / 11. VII–9.VIII.1961 ”, “N. R. Spencer / Collector” (BPBM)) which possibly belongs to this species. The differences amongst females of similar species are so subtle that it does not seem wise to include this female in the type series, nor give a description.

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. 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. 96. Sphegina (Asiosphegina) verrucosa 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 with associated parts, lateral view. E. Genitalia, right side, lateral view. 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.