Sphegina (Asiosphegina) nigrotarsata Steenis & Hippa & Mutin 2018, sp. nov.

Sphegina (Asiosphegina) nigrotarsata sp. nov. urn:lsid:zoobank.org:act: 2AC19DE0-951E-4CF2-A8E7-A9DF00B00B18 Figs 54 K–L, 59F, 61D, 62, 63D Differential diagnosis Similar to Sphegina (Asiosphegina) atrimanus sp. nov., S. (A.) granditarsis sp. nov., S. (A.) incretonigra sp. nov., S. (A.) nasuta and S. (A.) nigrotarsata sp. nov. For distinguishing characters, see under S. (A.) atrimanus sp. nov. and S. (A.) granditarsis sp. nov. Etymology The specific epithet is from the Latin ‘ nigrotarsata ’, meaning ‘with black tarsus’ and referring to the predominantly black protarsus. Material examined Holotype VIETNAM • ♂; “ Viet Nam Mt. Lang / Bian 1500–2000 / 19.V–8.VI.1961 ”; “ N. R. Spencer / Collector / Bishop”; BPBM. Paratypes VIETNAM • 1 ♂; same data as for holotype; JSA • 1 ♂; “ Viet Nam / Dalat 1500 m / 26–27.IX 1960 ”; “ J.L. Gressitt / collector”; BPBM • 1 ♂; Viet Nam: Fyan / 1200 m / 11.VII–9.VIII.1961 ”; “ N. R. Spencer / collector / Bishop”; BPBM • 1 ♂; same data as for preceding; JSA. Description Male LENGTH. Body 6.7–7.4 mm, wing 5.1–5.9 mm. HEAD. Face in lateral view, Fig. 54K, concave, strongly projected antero-ventrally; frontal prominence strongly developed; mouth edge very narrow. Ratio width of vertex at anterior ocellus: width of head 1: 4.7–4.9; ratio width of ocellar triangle: width of vertex 1: 1.4–1.7; ratio length of ocellar triangle: length of frons 1: 3.0–3.4. Face black, ventral half yellow, light grey pollinose, long pilose along eyemargin. Hypostomal bridge dark brown to black, long pale pilose. Gena and mouth edge yellow with large subtriangular non-pollinose shiny area. Frons and vertex black, frontal prominence long, shiny (Fig. 54L); pile short, light yellow. Frons with deep pit and wide furrow medially. Occiput black, light grey pollinose, ocellar triangle non-pollinose shiny, light yellow pilose. Eye without enlarged facets at anterior margin. Antenna with scape and pedicel dark yellow to brown, basoflagellomere dark brown to black with black setae dorsally on scape and pedicel; basoflagellomere elongate, ratio width: length 1: 2.0–2.3; arista short pilose, about 3.5 times as long as basoflagellomere. THORAX. Colour dark brown to black, postpronotum and dorso-medial part of anepisternum and anepimeron yellow, weakly greyish pollinose, pleuron entirely more heavily grey pollinose; scutum and pleuron with very short adpressed light yellow pile. Scutellum semicircular, black, sub-shiny and weakly pale pollinose, with pile slightly longer than on scutum, with two closely set, very short setae medially at posterior margin, ratio length of scutellum: length of seta 1: 0.6–0.7. WING. Entirely microtrichose; hyaline, stigma yellowish, membrane brown infuscated at junction of veins R2+3 and R4+5, along veins bm-cu, r-m and M1, at apical end of vein R2+3 and apical part of wing around vein R4+5. Crossvein dm-cu meeting vein M perpendicularly and vein M1 meeting vein R4+5 perpendicularly. LEGS. Pro- and mesoleg yellow; protarsus, Fig. 61D, with tarsomeres 2–5 wide and flattened, tarsomere 1 with black sub-apical annulus, tarsomere 2 with apical ⅔ dark brown to black and tarsomeres 3–5 dark brown; mesotarsus with tarsomere 5 dark brown to black. Metaleg with coxa black and trochanter yellow; femur black and yellow biannulate, slender club shaped, ratio width: length 1: 4.7–5.1; tibia black and yellow biannulate with short sharp subtriangular 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: 3.2–3.6: 2.3–2.6: 1.8–2.1; ratio width at posterior margin: medial length of tergum II and III 1: 4.6–5.0 and 1: 1.0–1.3. Terga black, anterior ¼ of tergum III with straight yellow fascia; anterior 1/5 of tergum IV with yellow posteromedially incised fascia; pile pale, on terga short, laterally on terga I and II long; tergum I with horizontal row of 2 strong dark brown to light yellow setae at lateral margin; sternum III rectangular, ratio width: length 1: 2.2–3.4; sternum IV, Fig. 62A; sterna VI, VII and VIII simple, with long yellow pile. Genitalia, Fig. 62 B–D: note the group of long seta-like pile on cercus, nearly symmetrical surstyli and superior lobes and the small setae on the membrane at the surstylar apodemes. Female Unknown.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 128-130, DOI: 10.5852/ejt.2018.489, http://zenodo.org/record/383053