Sphegina (Asiosphegina) furcillata, 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 : 80-83

Sphegina (Asiosphegina) furcillata sp. nov.

urn:lsid:zoobank.org:act:870892C9-D28F-4E43-8F8B-92289D8C49AB

Figs 25F , 34 , 35 C–D

Differential diagnosis

Similar to Sphegina (Asiosphegina) bracon sp. nov. and S. (A.) vietnamensis sp. nov. For distinguishing characters, see under S. (A.) bracon sp. nov.

Etymology

The specific epithet is from the Latin ‘ furcillata ’, meaning ‘forked’ and referring to the forked ventral lobe of male surstylus.

Material examined

Holotype

VIETNAM • ♂; “ C. Vietnam: Thua Thien Hué / Phong Dién N. R., near base-camp / 50–100 m; 3.iv.2001 / [leg] R. de Vries. RMNH’01”; NBC.

Description

Male

LENGTH. Body 7.1 mm, wing 4.7 mm

HEAD. Face in lateral view concave, weakly projected antero-ventrally; frontal prominence very weakly developed. Ratio width of vertex at anterior ocellus: width of head 1: 4.8; ratio width of ocellar triangle: width of vertex 1: 1.8; ratio length of ocellar triangle: length of frons 1: 2.9. 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. 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; 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, dorsally of wing base with some black pile. Scutellum semicircular, black, with slightly concave lateral margin, 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.

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 black and yellow biannulate, slightly incrassate, ratio width: length 1: 3.7; tibia black and yellow biannulate with weak and short apicoventral dens; tarsus dark brown with tarsomeres 2 and 3 dark yellow, basitarsomere very thin, ratio width: length 1: 4.6.

ABDOMEN. Length ratio of terga I: II: III: IV 1: 3.5: 1.7: 1.8; ratio width at posterior margin: medial length of tergum II and III 1: 3.9 and 1: 0.9. Terga black, anterior ½.5 of tergum III with 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 rectangular, ratio width: length 1: 1.4; sternum IV, Fig. 34B ; sterna VI, VII and VIII with long yellow pile, sternum VII with a large yellow-pilose crescent-like process with a sharp tooth-like medial projection. Genitalia, Fig. 34 C–E: note the asymmetrical surstyli with bifid ventral lobe on the right side and the asymmetrical superior lobes.

Female

Unknown.

Distribution and biology

The habitat of the holotype was a secondary forest regrown after devastation during the Vietnam war in the 1960’s, with many streams and some small rivers. The Malaise trap was placed close to one of the smaller streams in an open, partially shaded, wooded area. The habitat where the female specimen (see below) was collected was at 500 m a.s.l. in a disturbed lowland forest close to a river with large bamboo thickets. Due to the construction of a dam it was partly flooded (C. van Achterberg, pers. comm).

Remarks

We have also studied a female which possibly belongs to this species: 1 ♀, “S. Vietnam Dak Lak / Chu Yang Sin N.P., nr dam / c. 500 m. 3–9.vi.2007 / Mal.[aise] traps [leg] C. v. Achterberg / & R. de Vries, RMNH ‘07” (NBC). This female has all the diagnostic characters of Sphegina (Asiosphegina) furcillata sp. nov. but has no enlarged setae at lateral margin of tergum I.

Figures

Fig. 25. Habitus, dorsal view. A. Sphegina (Asiosphegina) bracon sp. nov., paratype, Ƌ, Vietnam. B. S. (A.) cf. bracon sp. nov., ♀, Vietnam. C. S. (A.) clavigera sp. nov., paratype, ♀, Vietnam. D. S. (A.) crassispina Hippa, van Steenis & Mutin, 2015, paratype, ♀, Myanmar. E. S. (A.) distincta sp. nov., paratype, Ƌ, Vietnam. F. S. (A.) cf. furcillata sp. nov., ♀, Vietnam. Scale bars = 1.0 mm.

Fig. 34. Sphegina (Asiosphegina) furcillata 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. 35. Habitus, lateral view. A. Sphegina (Asiosphegina) forficata Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar.B. S. (A.) forficata, paratype, ♀, Myanmar. C. S. (A.) furcillata sp. nov., holotype, Ƌ, Vietnam. D. S. (A.) cf. furcillata sp. nov., ♀, Vietnam. E. S. (A.) furva Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar. F. S. (A.) ghatsi sp. nov., holotype, Ƌ, India. Scale bars = 1.0 mm.