Sphegina (Asiosphegina) bracon, 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 : 49-52

Sphegina (Asiosphegina) bracon sp. nov.

urn:lsid:zoobank.org:act:0A45A27E-8BD9-4371-B219-9A348B37A659

Figs 15A , 17 , 21 F–G, 25A–B

Differential diagnosis

Sphegina (Asiosphegina) bracon sp. nov is similar to S. (A.) furcillata sp. nov. and S. (A.) vietnamensis sp. nov., the only reliable differences being the characters in the male genitalia mentioned in the key. In S. (A.) furcillata sp. nov. the pile dorsally of wing base is all black (at least partly yellow to dark brown in S. (A.) bracon sp. nov. and S. (A.) vietnamensis sp. nov.) and the metafemur is slightly less incrassate than in S. (A.) vietnamensis sp. nov. Also similar to S. (A.) spenceri sp. nov. but easily distinguished by the characters mentioned in the key. The females of S. (A.) spenceri sp. nov. differ from the supposed females of S. (A.) bracon sp. nov. and S. (A.) vietnamensis sp. nov. by the wider vertex with a shiny ridge medially and pollinosity laterally of the ridge more velvet textured than the other pollinosity (in S. (A.) bracon sp. nov. and S. (A.) vietnamensis sp. nov. vertex narrower and without ridge, anteromedially only a weak pit and medio-lateral pollinosity the same colour as the rest of the pollinosity).

Etymology

The specific epithet ‘ bracon ’ refers to the species of Bracon ( Hymenoptera , Braconidae ) to which the fly has a superficial similarity. The name is a noun in apposition.

Material examined

Holotype

VIETNAM • ♂; “ Viet Nam : Dalat / 6 km S. 1400–1500 m. / 19.VI–7.VII. 1961 ”; “ N.R. Spencer / Collector / Bishop”; BPBM.

Paratypes

VIETNAM • 5 ♂♂; same data as for holotype; BPBM • 3 ♂♂; same data as for holotype; JSA • 1 ♂; same data as for holotype; “ 1550 m, 11.IX.1960 ”; BPBM • 2 ♂♂; “ Viet Nam / DiLinh / 1200 m 22–28. IV.[19]60”; “ S. Quate / Collector”; BPBM • 1 ♂; same data as for holotype; “ L. W. Quate ”; BPBM • 35 ♂♂; “ Viet Nam : Fyan / 900–1000 m / 11.VII–9.VIII.1961 ”; “ N. R. Spencer / Collector; / Bishop”; BPBM • 24 ♂♂; same data as for preceding; JSA • 4 ♂♂; same data as for preceding; “ 1200 m ”; BPBM • 2 ♂♂; same data as for preceding; JSA .

Description

Male

LENGTH. Body 5.9–7.4 mm, wing 4.2–5.0 mm

HEAD. Face in lateral view concave, Fig. 21F , weakly projected antero-ventrally; frontal prominence weakly developed. Ratio width of vertex at anterior ocellus: width of head 1: 4.6–5.0; ratio width of ocellar triangle: width of vertex 1: 1.9–2.1; ratio length of ocellar triangle: length of frons 1: 2.4–2.6. Face black, ventral half brown-yellow, light grey pollinose, long pilose along eye-margin. Hypostomal bridge yellow, long pale pilose. Gena and mouth edge yellow with large subtriangular non-pollinose shiny area. Frons and vertex black, predominantly grey pollinose, a semi-circular area posterior of lunula non-pollinose and shiny; pile short, light yellow ( Fig. 21G ). Frons with deep medial furrow. Occiput black, light grey pollinose, light yellow pilose. Eye with an area of enlarged facets at anterior margin. Antenna yellow to brown-yellow with black setae dorsally on scape and pedicel; basoflagellomere oval, ratio width: length 1: 1.2–1.4; arista pilose, about 3 times as long as basoflagellomere.

THORAX. Colour dark brown to black, weakly greyish pollinose; postpronotum and dorso-medial part of anepisternum and anepimeron yellow, pleuron entirely grey pollinose; scutum and pleuron with very short adpressed light yellow pile. Scutellum semicircular, black, with slightly concave lateral margin, entirely shiny, with pile slightly longer than on scutum, with two widely set, short setae medially at posterior margin, ratio length of scutellum: length of seta 1: 1.2–1.4.

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 4–5 black. Metaleg with coxa black, trochanter yellow; femur and tibia black and yellow biannulate; tarsus black with tarsomeres 2 and 3 sometimes dark brown; femur slightly incrassate, ratio width: length 1: 3.9–4.2; tibia with weak and short apicoventral dens, basitarsomere rather narrow to thin, ratio width: length 1: 3.8–4.2.

ABDOMEN. Length ratio of terga I: II: III: IV 1: 3.9–5.0: 1.9–2.2: 1.7–1.9; ratio width at posterior margin: medial length of tergum II and III 1: 3.9–4.4 and 1: 0.8–0.9. Terga black, anterior ⅓ of tergum III with yellow fascia and posterior 1/7 of tergum IV with brown-yellow fascia; pile pale, on terga short, laterally on terga I and II long; tergum I with 2–3 strong dark brown to black setae at lateral margin; sternum III roundish to rectangular, ratio width: length 1: 1.3–2.1; sternum IV, Fig. 17A ; sternum VII, Fig. 17B with a large rounded yellow pilose widely conical process with a sharp subtriangular medial projection; sterna VI, VII and VIII simple, with yellow pile. Genitalia, Fig. 17 C–E: note the asymmetric surstyli, the bifid ventral lobe of the right-side surstylus and the asymmetric superior lobes with a strong curved finger-like lobe posteroventrally on the left-side one.

Female

Unknown.

Distribution and biology

Collected together with Sphegina (Asiosphegina) lucida sp. nov., S. (A.) nigrotarsata sp. nov., S. (A.) spenceri sp. nov., S. (A.) verrucosa sp. nov. and S. (A.) vietnamensis sp. nov.

Remarks

Among the material studied, the following females were found: 20 ♀♀; “ Viet Nam: Fyan / 900–1000 m. / 11.VII–9.VIII.[19]’61”, “N.R. Spencer / Collector / Bishop” (BPBM); 11 ♀♀, same data as for preceding, JSA; 3 ♀♀, same data as for preceding, “ 1200 m ” (BPBM); 2 ♀♀, same data as for preceding (JSA); 2 ♀♀, “ Viet Nam: Dalat / 6 km S, 1400–1500 m / 9. VI – 7. VII 1961 ”, “N. R. Spencer / Collector / Bishop” (BPBM); 1 ♀, same data as for preceding (JSA); 2 ♀♀, “ Viet Nam (34 km SE) / Ban Me Thuot 500 m / 16–18.V.1960 ”, “S. Quate / collection” (BPBM); 1 ♀, “ Viet Nam Kontum / N. of Pleiku 550m / 13.V.1960 ”, “L.W. Quate / collection” (BPBM).

These females most likely belong to either Sphegina (Asiosphegina) bracon sp. nov. or to S. (A.) vietnamensis sp. nov. The males of these species are only separable by the characters of the genitalia and so the females are not identifiable.

Figures

Fig. 15. Habitus, lateral view. A. Sphegina (Asiosphegina) bracon sp. nov., paratype, Ƌ, Vietnam. B. S. (A.) brevipilis sp. nov., paratype, Ƌ, China. C. S. (A.) brevipilis sp. nov., paratype, ♀, China. D. S. (A.) carinata Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar. E. S. (A.) cerina Hippa, van Steenis & Mutin, 2015, paratype, ♀, Myanmar. F. S. (A.) clavigera sp. nov., holotype, Ƌ, Vietnam. Scale bars = 1.0 mm.

Fig. 17. Sphegina (Asiosphegina) bracon sp. nov., paratype, Ƌ. A. Sternum IV, ventral view. B. Sternum VII, 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. 21. Head, lateral view (A, D, F, J–K), dorsal view (B, C, G–H, L), frontal view (E, I). A–B. Sphegina (Asiosphegina) albolobata sp. nov., holotype, Ƌ, Vietnam. C. S. (A.) amplistylus sp. nov., holotype, Ƌ, Philippines. D. S. (A.) apicalis Shiraki, 1930, ♀, Taiwan. E. S. (A.) bifida sp. nov., holotype, Ƌ, Sabah, Malaysia. F–G. S. (A.) bracon sp. nov., paratype, Ƌ, Vietnam. H–I. S. (A.) bispinosa Brunetti, 1915, Ƌ, Nepal. J. S. (A.) brevipilis sp. nov., holotype, Ƌ, China. K–L. S. (A.) collicola sp. nov., paratype, Ƌ, Malaysia. Scale bars = 0.5 mm.