Sphegina (Asiosphegina) apicalis 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 apicalis

description: Sphegina (Asiosphegina) apicalis Shiraki, 1930
Figs 6 E–F, 9, 10B, 21D
Sphegina apicalis Shiraki, 1930: 423. Type locality: Musha, Taiwan (holotype, ♀, NIAES).
Differential diagnosis
Sphegina (Asiosphegina) apicalis is similar to S. (A.) nubicola sp. nov. Except for the characters mentioned in the key, the species is distinguished by the very different male genitalia: in S. (A.) apicalis the surstyli are angular (curved in S. (A.) nubicola sp. nov.), the ventral lobe of the right surstylus has a prominent sublobe at posterior margin (weak sublobe) and the superior lobes are complicated, with several sublobes (simple, only with posteroventral claw-like sublobe). The female of S. (A.) apicalis differs from that of S. (A.) nubicola sp. nov. by the squarish basoflagellomere (oval in S. (A.) nubicola sp. nov.) and the shape of sterna IV and V which are squarish and slightly rectangular in S. (A.) apicalis but widely to very widely rectangular in S. (A.) nubicola sp. nov.
Material examined
Holotype
TAIWAN • ♂; “ Formosa / Musha 1919 / V 18 – VI 15 / T. Okuni / J. Sonan / K. Miy, M. Yosh. ”; “ Sphegina / apicalis n. sp. / Det T. Shiraki ”; “Type” [white round label with red circle]; photos of the holotype in lateral and dorsal view studied; NIAES.
Additional material
TAIWAN • 1 ♂; “ Taiwan Nantou / Jenai Meifen / V.1 –20.1998 / [leg] C.S. Lin & W.T. Yai / UV light”; “ NMNS ENT / 2889–148”; NMNS • 1 ♂; “ Taiwan N-Nantou Co. / Road No. 14, NE Puli / Reyen Shi-Reg. E. Tsuifeng / to Yuanfeng ca 2500–2700 m / ca 24°07 ʹ N, 121°13 ʹ E / 1.VII.2000 leg. W. Schacht ”; JSA • 1 ♀; same data as for preceding; “ Tsuifeng / ca 24°06 ʹ N, 121°11 ʹ E / 2200m, 28.VI–2.VIII.2000 ”; ZSM • 1 ♂; “FO: 9006 Taiwan / 23°14 ʹ 50.5 ʺ N, 120°59 ʹ 09.3 ʺ E / Siangyang National forest Recreat / Taichung 2820 mNN / A. Astilbe sp. / leg. A. Ssymank, 29.05.2016 ”; ASW.
Description
Male
LENGTH. Body 5.2–5.5 mm, wing 4.4–4.7 mm.
HEAD. Face in lateral view concave, weakly projected antero-ventrally; frontal prominence weakly developed. Ratio width of vertex at anterior ocellus: width of head 1: 3.7–4.0; ratio width of ocellar triangle: width of vertex 1: 2.0–2.3; ratio length of ocellar triangle: length of frons 1: 2.0–2.3. Face black, light grey pollinose, long pilose along eye-margin. Hypostomal bridge yellow to dark yellow, long pale pilose. Gena black, mouth edge brown to dark yellow with large triangular non-pollinose shiny area. Frons and vertex black, predominantly grey pollinose, a very narrow semi-circular area posterior of lunula non-pollinose and shiny; pile short, light yellow. Frons with deep pit and weak medial furrow. Occiput black, light grey pollinose, light yellow pilose. Eye with enlarged facets at anterior margin.
Antenna black with black setae dorsally on scape and pedicel; basoflagellomere squarish, ratio width: length 1: 1.0–1.1; arista with basal ¼ short pilose, about 3 times as long as basoflagellomere.
THORAX. Colour dark brown to black, weakly greyish pollinose, with denser grey pollinose vitta submedially; posterior margin of katepisternum narrowly non-pollinose, shiny; scutum and pleuron with very short adpressed light yellow pile. Scutellum subtriangular, black, shiny, with pile slightly longer than on scutum, with two closely set, short setae medially at posterior margin, ratio length of scutellum: length of seta 1: 0.9–1.2.
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, incrassate, ratio width: length 1: 4.0–4.5; tibia black and yellow biannulate, without apicoventral dens; tarsus entirely black, basitarsomere very thick, ratio width: length 1: 2.7–3.1.
ABDOMEN. Length ratio of terga I: II: III: IV 1: 3.6–4.0: 1.8–2.1: 1.5–1.7; ratio width at posterior margin: medial length of tergum II and III 1: 2.9–3.2 and 1: 0.7–0.8. Tergum IV slightly skewed to the right. Terga black; tergum III with sub-anterior yellow fascia with upturned V-shaped posterior margin; pile short and pale; tergum I with an oblique row of 4 light yellow setae at lateral margin; sternum III rectangular, ratio width: length 1: 2.3–2.8; sternum IV, Fig. 9A; sterna VI, VII and VIII simple, with long yellow pile. Genitalia (Fig. 9 B–E): cerci unmodified, subtriangular; surstyli asymmetrical, the ventral lobe on the right side with subtriangular lobe on posterior margin, on the left side with a long vertical lobe laterally; superior lobe with several sublobes.
Redescription
Female
Similar to male except for the usual sexual dimorphism.
LENGTH. Body 5.0 mm, wing 3.9 mm.
HEAD. Face in lateral view Fig. 21D. Ratio width of vertex at anterior ocellus: width of head 1: 3.0; ratio width of ocellar triangle: width of vertex 1: 2.4; ratio length of ocellar triangle: length of frons 1: 3.4. Basoflagellomere squarish, ratio width: length 1: 0.9; arista long pilose; about 3 times as long as basoflagellomere.
THORAX. Scutellum with two closely set, very short setae medially at posterior margin, ratio length of scutellum: length of seta 1: 0.8.
LEGS. Metafemur, ratio width: length 1: 3.9, metatarsus with basitarsomere thick, ratio width: length 1: 3.2.
ABDOMEN. Length ratio of terga I: II: III: IV: V 1: 2.9: 2.5: 1.9: 1.3; ratio width at posterior margin: medial length of tergum II and III 1: 1.0 and 1: 0.8. Tergum II with postero-lateral large triangular orange-brown maculae; terga III and IV on anterior ½–¾ with orange-brown fascia; tergum V anterior ¾ to entirely orange-brown; sternum III rectangular with slightly wider posterior part, ratio width: length 1: 2.3; sternum IV squarish, ratio width: length 1: 1.2; sternum V rectangular, ratio width: length 1: 0.7.
Distribution and biology
Widely distributed in Taiwan at an altitude between 2200–2820 m and collected between the 1 st of May and the 2 nd of August. The holotype could, however, have been collected at an altitude of 1150 m (Kojima et al. 2011). Flower visiting Astilbe longicarpa (Saxifragaceae) near a small brook with water percolating on a steep rocky slope within a mainly older Pinus taiwanensis afforestation and at Siangyang collected together with Sphegina (Asiosphegina) dentata sp. nov., S. (A.) orientalis and S. (A.) taiwanenis sp. nov. (van Steenis et al. in prep).
Remarks
The species was until now only known from the female holotype. The conspecificity of the males studied here with the holotype is supported by the yellowish mouth edge, the squarish basoflagellomere, the scutum with pollinose pattern, the shiny scutellum, the hyaline wing with crossvein dm-cu meeting vein
M obliquely and vein M 1 meeting vein R 4+5 perpendicularly, the biannulate incrassate metafemur, and the oblique row of 4 light yellow setae at lateral margin of tergum I.
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 34-38, DOI: 10.5852/ejt.2018.489, http://zenodo.org/record/3830537