Sphegina (Asiosphegina) spenceri, 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 : 165-169

Sphegina (Asiosphegina) spenceri sp. nov.

urn:lsid:zoobank.org:act:104143FD-884E-4527-A2E9-8E42D0DA2F79

Figs 85 , 86 A–B, 88B–C

Differential diagnosis

Similar to Sphegina (Asiosphegina) bracon sp. nov., S. (A.) furcillata sp. nov. and S. (A.) vietnamensis sp. nov., but should be easily distinguished by the characters given in the key. The male is easily distinguished by having the two most lateral setae on the left side of sternum IV about twice as long as

the other strong seta rather than about ten times as long. Also, by the normal undivided ventral lobe of surstylus instead of a bifid one.

Etymology

The species is named after Mr Neal Spencer, an entomologist specialising in the biocontrol of weeds and director of the USDA ARS Pest Management and Agricultural Systems Research Unit at Sidney, USA. He has been a great collector of Diptera and collected the type material of this species.

Material examined

Holotype

VIETNAM • ♂; “ Viet Nam : Dalat / 6km S. 1400–1500 m / 9.VI–7.VII.1961 ”; “ N. R. Spencer / Collector / Bishop”; BPBM.

Paratypes

VIETNAM • 6 ♂♂, 1 ♀; same data as for holotype; BPBM • 4 ♂♂; same data as for preceding; JSA • 9 ♂♂, 5 ♀♀; “ Viet Nam : Fyan / 900–1000 m / 11.VII–9.VIII 1961 ”; “ N. R. Spencer / collector / Bishop”; BPBM • 8 ♂♂, 3 ♀♀; same data as for preceding; JSA • 6 ♂♂, 1 ♀; same data as for preceding; “ 1200 m ”; BPBM • 4 ♂♂, 1 ♀; same data as for preceding; JSA • 1 ♂; “ Viet Nam / BanMeThuot 500 m / 16–18.V.1960 ”; “ L.W. Quate / Collector”; BPBM • 1 ♂; “ Viet Nam : Mt. Lang / Bian 1500–2000 / 19. V– 8.VI 1961 ”; “ N. R. Spencer / collector / Bishop”; BPBM .

Description

Male

LENGTH. Body 6.1–7.8 mm, wing 4.4–6.1 mm.

HEAD. Face in lateral view, Fig. 88C , concave, weakly projected antero-ventrally; frontal prominence very 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: 1.9–2.1; ratio length of ocellar triangle: length of frons 1: 3.1–3.5. Face with dorsal half dark brown to black and ventral half orange-brown to dark brown, light grey pollinose, long pilose along eye-margin. Hypostomal bridge dark brown, long pale pilose. Gena and mouth edge orange-brown to dark brown, pale pollinose with large subtriangular non-pollinose shiny area. Frons and vertex black, pale pollinose with narrow subtriangular area posterior of lunula nonpollinose and shiny, with grey-brown pollinose macula posterolaterally of shiny part ( Fig. 88B ); pile short, light yellow. Frons with very weak pit antero-medially and weak shiny ridge postero-medially towards ocellar triangle, laterally of this ridge the pollinosity is more velvet-black than other pollinosity. Occiput black, non-pollinose and shiny, light yellow pilose. Eye with enlarged facets at anterior margin. Antenna brown to orange-brown with black setae dorsally on scape and pedicel; basoflagellomere short oval to slightly elongate, ratio width: length 1: 1.3–1.5; arista long pilose, about 3 times as long as basoflagellomere.

THORAX. Colour dark brown to black, postpronotum, postalar callus, proepimeron and medio-dorsal part of pleuron yellow to brown-yellow; weakly greyish pollinose, pleuron sub-shiny; scutum and pleuron with very short adpressed light yellow pile. Scutellum sub-rectangular, brown-yellow to brown, entirely grey pollinose, in some specimens sub-shiny, with pile slightly longer than on scutum, with two very widely set, short setae medially at posterior margin, ratio length of scutellum: length of seta 1: 1.0–1.2.

WING. Entirely microtrichose; 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, tarsomeres 4 and 5 black. Metaleg with coxa black, trochanter yellow; femur black and yellow biannulate, slightly incrassate, ratio width: length 1: 3.3–3.9; tibia black and yellow biannulate with wide and short rounded apicoventral dens; tarsus black with tarsomeres 2 and 3 brownish, basitarsomere rather thin, ratio width: length 1: 3.6–3.9.

ABDOMEN. Length ratio of terga I: II: III: IV 1: 5.5–5.9: 2.3–2.6: 1.8–2.1; ratio width at posterior margin: medial length of tergum II and III 1: 4.0–4.3 and 1: 1.0–1.2. Terga black, anterior ⅓ of tergum III with orange-brown fascia; pile pale, on terga short, laterally on terga I and II long; tergum I with 2–3 strong light-brown setae at lateral margin; sternum III rectangular, ratio width: length 1: 1.6–1.8; sternum IV, Fig. 85B ; sternum VI with long yellow pile; sternum VII short pilose, posteriorly with elongate cone shaped process with curved apex. Genitalia, Fig. 85 C–E: note the asymmetrical surstyli and superior lobes.

Female

Similar to male except for the usual sexual dimorphism.

LENGTH. Body 5.1–7.0 mm, wing 4.2–5.7 mm.

HEAD. Ratio width of vertex at anterior ocellus: width of head 1: 3.7–4.2; ratio width of ocellar triangle: width of vertex 1: 1.9–2.1; ratio length of ocellar triangle: length of frons 1: 3.5–3.9. Basoflagellomere oval, ratio width: length 1: 1.2–1.4; arista long pilose, 2.5 to 3 times as long as basoflagellomere.

THORAX. Scutellum with two widely set, very short setae medially at posterior margin, ratio length of scutellum: length of seta 1: 0.8–0.9.

LEGS. Metafemur, ratio width: length 1: 3.6–3.8; metatarsus with basitarsomere rather thin, ratio width: length 1: 3.7–3.9.

ABDOMEN. Length ratio of terga I: II: III: IV: V 1: 3.6–4.0: 2.5–2.7: 2.3–2.8: 0.9–1.1; ratio width at posterior margin: medial length of tergum II and III 1: 2.1–2.3 and 1: 0.66–0.75. Anterior ¼ of tergum III with sub-anterior yellow fascia, lateral margin dark yellow to yellow on anterior 3/5; terga III and IV with antero-medial small oval to very large rectangular yellow macula; sternum III elongate, ratio width: length 1: 1.7–1.9; sternum IV trapezoidal with concave anterior margin, ratio width: length 1: 0.5–0.6; sternum V widely rectangular, ratio width: length 1: 0.5–0.6.

Figures

Fig. 85. Sphegina (Asiosphegina) spenceri sp. nov., holotype, Ƌ (B–D) and paratype, Ƌ (A–B). A. Posterior part ofabdomen, 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. 86. Habitus, lateral view. A. Sphegina (Asiosphegina) spenceri sp. nov., paratype, Ƌ, Vietnam. B. S. (A.) spenceri sp. nov., paratype, ♀, Vietnam. C. S. (A.) subradula Hippa, van Steenis & Mutin, 2015, paratype, ♀, Myanmar. D. S. (A.) taiwanensis sp. nov., paratype, Ƌ, Taiwan. E. S. (A.) taiwanensis sp. nov., paratype, ♀, Taiwan. F. S. (A.) trichaeta Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar. Scale bars = 1.0 mm.

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.