Sphegina (Sphegina) quadriseta Huo & Ren, 2006

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 : 26-27

Sphegina (Sphegina) quadriseta Huo & Ren, 2006

Figs 2E , 3 E–F

Sphegina quadriseta Huo & Ren, 2006: 34 . Type locality: Honghe Valley, Shaanxi province, China (holotype, ♂, depository of type unknown).

Differential diagnosis

Sphegina (Sphegina) quadriseta is dissimilar to other species by the long black pile posterior of posteromedial corner of eye, the scutellum with 4 long black setae at posterior margin and the black and extremely strongly antero-ventrally projected face.

Material examined

CHINA • 1 ♀; “ China Sichuan Daocheng , 37 km / WNW, 29.153° N, 99.930° E, 3400 m / 23. VI. 2009, legit Blank, Liston & / Taeger 054 China”; CSCA .

Description

Female

LENGTH. Body 6.9 mm, wing 7.2 mm.

HEAD. Face in lateral view ( Fig. 3E ), concave, unusually strongly projected antero-ventrally; frontal prominence very strongly developed. Ratio width of vertex at anterior ocellus: width of head 1: 2.8; ratio width of ocellar triangle: width of vertex 1: 3.3; ratio length of ocellar triangle: length of frons 1: 3.1. Head entirely black and grey pollinose; face yellow pilose along eye-margin. Hypostomal bridge long pale pilose. Gena and mouth edge without non-pollinose shiny area. Frons and vertex black, predominantly grey pollinose, a narrow fascia posterior of lunula non-pollinose and shiny ( Fig. 3F ); pile short, black, posterior of posteromedial corner of eye with patch of very long black pile. Frons with very weak medial furrow. Occiput dark brown, 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 slightly oval, ratio width: length 1: 1.2; arista pilose, almost 3 times as long as basoflagellomere.

THORAX. Colour black, greyish pollinose; scutum and pleuron with very short adpressed pale-brown pile, medial part of scutum black pilose. Scutellum subtriangular, black, grey pollinose, with pile slightly longer than on scutum, with four setae at posterior margin, the medial two widely set, short, ratio length of scutellum: length of seta 1: 1.3.

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

1

meeting vein R

4+5

perpendicularly.

LEGS. Legs yellow; all tarsi and apical ⅓ of metatibia black; metatibia without apicoventral dens; metafemur very weakly incrassate, ratio width: length 1: 5.5; metatarsus with basitarsomere very thin, ratio width: length 1: 5.5.

ABDOMEN. Length ratio of terga I: II: III: IV: V 1: 3.3: 2.8: 2.5: 1.3; ratio width at posterior margin: medial length of tergum II and III 1: 0.9 and 1: 0.6. Terga black, tergum III medially yellow and terga IV and V entirely yellow; pile mixed dark brown to light-brown, short, laterally on terga I and II long; tergum I with only normal pile; sternum I squarish, ratio width: length 1: 1.3; sterna II–IV sclerotized, trapezoidal to squarish shaped, sternum V rectangular, ratio width: length respectively 1: 1.1, 1: 0.8, 1: 0.7 and 1: 0.4; sterna VI, VII and VIII with long yellow pile.

Remarks

In the original description the scutellum and pleuron are described as being shiny black. None of the species of Sphegina studied here have an entirely non-pollinose and shiny pleuron, nor do any of the Palaearctic species as far we know. Most likely the pollinosity is not considered in the description of Sphegina (Sphegina) quadriseta and the scutellum and pleuron are, in our terms, ‘slightly pollinose, sub-shiny’, which does not correspond exactly to the female described here. However, although the female described here is more pollinose than the male, as originally described, we have concluded that it is the same species and that the original description of the male is inaccurate. Further material and the examination of the holotype of Sphegina (Sphegina) quadriseta is necessary to confirm this. It is, of course, possible that this female belongs to an undescribed species.

Figures

Fig. 2. Habitus, lateral view. A. Sphegina (Sphegina) angustata sp. nov., paratype, Ƌ, Nepal. B. S. (S.) angustata sp. nov., paratype, ♀, Nepal. C. S. (S.) guptai Mutin, 1998, paratype, ♀, India. D. S. (S.) kumaoniensis Mutin, 1998, Ƌ, Myanmar. E. S. (S.) quadriseta Huo & Ren, 2006, ♀, China. F. S. (S.) uncinata Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar. Scale bars = 1.0 mm.

Fig. 3. Head, lateral view (C, E), and dorsal view (A–B, D, F). A. Sphegina (Sphegina) abbreviata sp. nov., paratype, ♀, Nepal. B. S. (S.) angustata sp. nov., paratype, ♀, Nepal. C. S. (S.) angustata sp. nov., paratype, Ƌ, Nepal. D. S. (S.) guptai, 1998, holotype, Ƌ, India. E–F. S. (S.) quadriseta Huo & Ren, 2006, ♀, China. Abbreviations: a = width of head; b = width of vertex; c = width of ocellar triangle; d = length of frons; e = length of ocellar triangle. Scale bars = 0.5 mm.