Sphegina (Asiosphegina) varidissima Shiraki 1930
Creators: name: Steenis, Jeroen Van
name: Hippa, Heikki
name: Mutin, Valeri A.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Syrphidae
Sphegina
Sphegina varidissima

description: Sphegina (Asiosphegina) varidissima Shiraki, 1930
Figs 65D, 88 I–J, 93C, 94, 95E, 97B–C
Sphegina varidissima Shiraki, 1930: 421. Type locality: Taiwan, Horisha (holotype, ♀, NIAES).
Differential diagnosis
Sphegina (Asiosphegina) varidissima is dissimilar to other species of Asiosphegina by the colour and pollinosity of the scutum and the overall brownish colour. It resembles somewhat Sphegina (Asiosphegina) cerina in body colour but differs by the characters mentioned in the key. The male genitalia are unique, especially the symmetrical superior lobes which are basally narrowed, and which are separated from sternum IX by a transverse crest-like lobe posteriorly on the latter.
Material examined
Holotype
TAIWAN • ♀; “ Horisha / 10.V.1913 / col. M. Maki ”; “ Sphegina / striata n. sp. / Det T. Shiraki: “Type” [white round label with red circle]; photo of holotype in lateral and dorsal view studied; NIAES.
Additional material
TAIWAN • 1 ♂; “ Taiwan Taoyuan / Fuhsing / 1992.II.20 / [leg.] C.Y. Lee / Sweeping net ”; “1452–358”; NMNS • 1 ♂; “ Taiwan Nantou / Meifeng; / V.11.2004 / [leg.] C.S. Lin / Sweeping net ”; “ NMNS ENT / 4507 27”; JSA • 1 ♀; “ Taiwan Nantou / Meifeng / 26–28.V.1997 / C.S. Lin & W.T. Yang / UV light trap ”; “ NMNS ENT / 2680–807”; NMNS • 1 ♀; “ Taiwan N-Nantou Co. / Road No. 14, NE Puli / Reyen Shi-Reg., Tsuifeng / ca 24°06 ʹ N, 121°11 ʹ E / 2200 m 28.VI–2.VII.2000 / leg. W. Schacht ”; “ holotype and one third / of paratypes resulting / from this material are / property of Taiwan!”; “ Syrphidae / spec 30 / det. W. Schacht ”; JSA.
Description
Male
LENGTH. Body 6.9–7.4 mm, 5.3–5.9 wing mm.
HEAD. Face in lateral view concave, strongly projected antero-ventrally; frontal prominence strongly developed. Ratio width of vertex at anterior ocellus: width of head 1: 3.7–4.2; ratio width of ocellar triangle: width of vertex 1: 1.8–2.1; ratio length of ocellar triangle: length of frons 1: 2.1–2.3. Face entirely yellow (as in holotype) to predominantly black. Gena and mouth edge yellow, pale pollinose, with large subtriangular non-pollinose shiny area. Frons sub-shiny, slightly grey pollinose with wide but weak medial furrow (Fig. 88I). Scape and pedicel yellow or black. Basoflagellomere black squarish, ratio width: length 1: 1.0–1.1; arista short pilose basally; about 3.5 times as long as basoflagellomere.
THORAX. Colour from dark brown to black to predominantly yellow, pollinose, scutum dark with more densely grey pollinose submedial vitta or scutum yellow with 3 shiny black vittae. Pleuron entirely yellow to predominantly black; posterior margin of katepisternum widely non-pollinose, shiny (Fig. 65D). Scutellum semicircular, black, with posterior margin narrowly pollinose, rest non-pollinose and shiny, long pilose, with two widely set long setae medially at posterior margin, ratio length of scutellum: length of seta 1: 1.8–2.0.
WING. Microtrichose, cell cup with basal 1/10 slightly microtrichose, almost bare; hyaline, stigma yellowish. Crossvein dm-cu meeting vein M obliquely and vein M 1 meeting vein R
4+5
perpendicularly.
LEGS. Colour yellow. Pro- and mesotibia dark yellow; pro- and mesobasitarsus dark brown, other tarsomeres dark brown to black. Metaleg, Fig. 95E, with coxa and trochanter yellow; femur predominantly yellow or biannulate, slightly incrassate, ratio width: length 1: 4.1–4.3; tibia black and yellow biannulate, without apical dens; tarsus with basitarsomere thin, ratio width: length 1: 3.8–4.0.
ABDOMEN. Length ratio of terga I: II: III: IV 1: 3.8–4.1: 1.8–2.2: 1.2–1.4; ratio width at posterior margin: medial length of tergum II and III 1: 3.5–3.9 and 1: 1.0–1.1. Tergum III black with sub-anterior fascia covering ⅓ of the tergum; pile pale, on terga short, laterally on terga I and II long; tergum I with oblique row of 4–5 light yellow setae laterally; sternum III rectangular, ratio width: length 1: 2.5–2.7; sternum
IV, Fig. 94A; sterna VI, VII and VIII simple, with long yellow pile. Genitalia, Fig. 94 B–C: note the almost symmetrical surstyli and superior lobes.
Redescription of female
Similar to the male except normal sexual dimorphism.
LENGTH. Body 7.4–7.8 mm, wing 6.1–6.7 mm
HEAD. Lateral view, Fig. 88J; ratio width of vertex at anterior ocellus: width of head 1: 3.0–3.4; ratio width of ocellar triangle: width of vertex 1: 2.6–2.9; ratio length of ocellar triangle: length of frons 1: 4.1–4.5. Mouth edge yellow. Face entirely yellow (as in holotype) to predominantly black. Frons subshiny, slightly grey pollinose, with wide but weak medial furrow. Scape and pedicel yellow or black. Basoflagellomere black squarish, ratio width: length 1: 0.86–0.98; arista short pilose basally; about 3 times as long as basoflagellomere.
THORAX. Scutellum black with posterior margin narrowly pollinose, rest non-pollinose and shiny, with two very widely set, long setae medially at posterior margin, ratio length of scutellum: length of seta 1: 2.0–2.3.
WING. Microtrichose, cell cup with basal 1/10 bare.
LEGS. Pro- and mesotibia dark yellow; pro- and mesobasitarsus dark brown, other tarsomeres dark brown to black; metafemur ratio width: length 1: 4.1–4.3; metatarsus with basitarsomere thin, ratio width: length 1: 3.8–4.1.
ABDOMEN. Length ratio of terga I: II: III: IV: V 1: 3.0–3.4: 2.4–2.7: 2.2–2.5: 1.1–1.3; ratio width at posterior margin: medial length of tergum II and III 1: 1.2–2.4 and 1: 0.6–0.7. Tergum II black or with posterolateral orange subtriangular macula; tergum III black to orange-brown with small black anteromedial macula; tergum IV yellow with anteromedial black macula to entirely orange-brown; tergum V entirely orange-brown; sternum III trapezoidal, ratio width: length 1: 2.5–2.7; sternum IV rectangular, ratio width: length 1: 0.9–1.1; sternum V rectangular with concave posterior margin, ratio width: length 1: 0.4–0.5.
Remarks
The species is, as several Palaearctic species (e.g., Sphegina (Asiosphegina) fasciata Shiraki, 1968 and S. (A.) sibirica), unusually variable in colouration but otherwise there is nothing to indicate that there is more than one species involved.
description: Published as part of Steenis, Jeroen Van, Hippa, Heikki & Mutin, Valeri A., 2018, Revision of the Oriental species of the genus Sphegina Meigen, 1822 (Diptera: Syrphidae), pp. 1-198 in European Journal of Taxonomy 489 on pages 184-187, DOI: 10.5852/ejt.2018.489, http://zenodo.org/record/3830537