Sphegina (Asiosphegina) distincta sp. nov.

urn:lsid:zoobank.org:act: 1C09D33C-449F-4C59-B0C8-359C8600C13B

Figs 25E, 27, 28C, 30 H–I, 43B, 47B

Differential diagnosis

Sphegina (Asiosphegina) distincta sp. nov. resembles the ca 30 other Oriental Sphegina which have strong spinose setae at the posterior margin of sternum IV. It is not especially similar to any of them and can easily be distinguished by the characters given in the key.

Etymology

The specific epithet is from the Latin ‘ distincta ’, meaning ‘different’ and referring to the unusually extensive yellow colour of the fly.

Material examined

Holotype

VIETNAM • ♂; “Viet-Nam vi / Ha-noi / Strnad [sic]; 1990”, ZFMK Dipt / QR code / 00011899”; ZFMK.

Paratypes

VIETNAM • 1 ♂; same data as for holotype; ZFMK • 3 ♂♂; “ Vietnam Vihn Phuc prov. Tam Dao / 21°27 ʹ 52 ″ N, 105°38 ʹ 46 ″ E 1.200 m / 19–22.VI.2014 hand collected / leg. M. Hauser & N. von Ellenrieder ”; CSCA • 2 ♂♂; same data as for preceding; JSA • 1 ♂; same data as for preceding; “JSM6918 / CNC 464909”; DNA voucher specimen, in alcohol; CNC .

Description

LENGTH. Body 8.4–9.9 mm, wing 5.8–6.5 mm.

HEAD. Face in lateral view (Fig. 30H) concave, strongly projected antero-ventrally; frontal prominence weakly developed. Ratio width of vertex at anterior ocellus: width of head 1: 4.6–5.0; ratio width of ocellar triangle: width of vertex 1: 1.7–1.9; ratio length of ocellar triangle: length of frons 1: 2.4–3.1. Face dark brown, ventral half light-brown to dark yellow or entirely yellow, light grey pollinose, long pilose along eye-margin. Hypostomal bridge brown to dark brown, long pale pilose. Gena and mouth edge pale pollinose, dark yellow to light yellow with large subtriangular non-pollinose shiny area. Frons and vertex black, predominantly brown-grey pollinose, a squarish area posterior of lunula non-pollinose and shiny and narrow densely grey pollinose fascia posterior of shiny part (Fig. 30I); pile short, light yellow. Frons with rather deep and narrow medial furrow. Occiput black, light grey pollinose, light yellow pilose. Eye with slightly enlarged facets at anterior margin. Antenna brown-yellow to yellow with black setae dorsally on scape and pedicel; basoflagellomere (Fig. 43B) oval, ratio width: length 1: 1.1–1.3; arista long pilose, about 2.5 times as long as basoflagellomere.

THORAX. Colour dark brown to black, weakly greyish pollinose; postpronotum, anterolateral margin and dorso-medial part of anepisternum and anepimeron brown-yellow to yellow, pleuron entirely grey pollinose; scutum and pleuron with very short adpressed light yellow pile. Scutellum sub-rectangular, black, pollinose, with pile longer than on scutum, with two widely set, very short setae medially at posterior margin, ratio length of scutellum: length of seta 1: 0.81–0.89, about 8 additional shorter and weaker setae along posterior margin.

WING. Entirely microtrichose; hyaline, stigma yellowish. Crossvein dm-cu meeting vein M obliquely and vein M 1 meeting vein R

4+5

perpendicularly. Vein CuA 1 slightly extended to vein dm-cu.

LEGS. Pro- and mesoleg yellow, tarsomeres 4 and 5 black. Metaleg with coxa black, trochanter yellow; femur black and yellow biannulate, with black parts narrow, slightly incrassate, ratio width: length 1: 3.7–4.0 and with long pile dorsally; tibia black and yellow biannulate, with short widely rounded apicoventral dens; tarsus black with tarsomeres 2 and 3 dark yellow to brown, basitarsomere thin, ratio width: length 1: 3.9–4.4.

ABDOMEN. Length ratio of terga I: II: III: IV 1: 5.3–5.6: 2.4–2.6: 1.9–2.2; ratio width at posterior margin: medial length of tergum II and III 1: 4.5–4.8 and 1: 0.9–1.1. Terga black, anterior ⅓ –½ of tergum III with brown-yellow fascia; pile pale, on terga short, laterally on terga I and II long; tergum I with 3 strong brown-yellow to black setae at lateral margin (Fig. 47B); sternum III rectangular, ratio width: length 1: 1.4–1.8, or sclerotized part undifferentiated; sternum IV, Fig. 27A; sterna VI, VII and VIII, with long yellow pile, sternum VII, Fig. 22B, with a small tubercle and a hook shaped projection. Genitalia, Fig. 27 C–E: note the asymmetrical surstyli and superior lobes.

Female

Unknown.