Sphegina (Asiosphegina) plautus, Steenis & Hippa & Mutin, 2018

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 : 150-153

Sphegina (Asiosphegina) plautus sp. nov.

urn:lsid:zoobank.org:act:3431A2B3-67BD-4350-B199-C423EC4AFE59

Figs 61F , 70F , 75 A–B, 76, 84H, 95A

Differential diagnosis

Sphegina (Asiosphegina) plautus sp. nov. is very similar to S. (A.) brevipilis sp. nov., both are also similar to Sphegina (Asiosphegina) simplex . For distinguishing characters, see under S. (A.) brevipilis sp. nov.

Etymology

The specific epithet is a Latin cognomen ‘ plautus ’, meaning ‘flat-footed’ and referring to the widened protarsus. The name is a noun in apposition.

Material examined

Holotype

CHINA • ♂; “Fukien, S. China / Shaowu: Tachulan / 1000 m T. Maa ”; “ 6–10.V.1943 ”; BPBM.

Paratypes

CHINA • 1 ♂; same data as for holotype; “ 19.V.1942 ”; JSA • 1 ♀; same data as for holotype; “ 25–30. IV.1943 ”; BPBM .

Description

Male

LENGTH. Body 5.9–6.2 mm, wing 5.0– 5.3 mm.

HEAD. Face in lateral view ( Fig. 84H ) concave, weakly projected antero-ventrally; frontal prominence very weakly developed. Ratio width of vertex at anterior ocellus: width of head 1: 4.0–4.3; ratio width of ocellar triangle: width of vertex 1: 1.6–1.8; ratio length of ocellar triangle: length of frons 1: 1.6–1.8. Face black, light grey pollinose, long pilose along eye-margin. Hypostomal bridge black, long pale pilose. Gena and mouth edge black, pale pollinose, with large subtriangular non-pollinose shiny area. Frons and vertex black, predominantly brown-grey pollinose, a subtriangular area posterior of lunula non-pollinose and shiny and narrow densely grey pollinose fascia posterior of shiny part; pile short, light yellow. Frons with rather deep pit antero-medially. Occiput black, light grey pollinose, light yellow pilose. Eye without enlarged facets at anterior margin. Antenna brown-yellow to brown with black setae dorsally on scape and pedicel; basoflagellomere 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, pleuron entirely grey pollinose; scutum and pleuron with very short adpressed light yellow pile. Scutellum sharply subtriangular, black, pale pollinose, with pile longer than on scutum, with two very widely set, very short setae medially at posterior margin, ratio length of scutellum: length of seta 1: 0.7–0.9.

WING. Entirely microtrichose; hyaline, stigma yellowish, infuscated at junction of veins R 2+3 and R 4+5, along crossveins dm-cu and M 1 and at the apex of vein R 1+2. Crossvein dm-cu meeting vein M obliquely and vein M

1

meeting vein R

4+5

perpendicularly. Vein CuA

1

very slightly extended beyond vein dm-cu.

LEGS. Pro- and mesoleg yellow, tarsomere 5 black; protarsus, Fig. 61F , with tarsomeres 2–5 short and wide, slightly flattened. Metaleg, Fig. 95A , with coxa black and trochanter yellow; femur black and yellow biannulate, very slightly incrassate and club shaped, ratio width: length 1: 6.1–6.4; tibia black and yellow biannulate with light yellow, short, sharply subtriangular apicoventral dens; tarsus entirely black, basitarsomere very thick, ratio width: length 1: 2.5–2.8.

ABDOMEN. Length ratio of terga I: II: III: IV 1: 5.0–5.3: 2.8–3.2: 1.9–2.2; ratio width at posterior margin: medial length of tergum II and III 1: 3.9–4.2 and 1: 1.2–1.4. Terga black, anterior ⅓ of tergum III with brown-yellow fascia; tergum IV with anterolateral squarish brown-yellow macula; pile pale, on terga short, laterally on terga I and II long; tergum I with 3 strong brown-yellow setae at lateral margin; sternum III rectangular, ratio width: length 1: 2.7–3.0; sternum IV, Fig. 76A ; sterna VI, VII and VIII simple, with long yellow pile. Genitalia, Fig. 76 B–C: note the unusually short pilosity of cercus, the unusual sclerite posteriorly from the base of cercus, symmetrical surstyli and slightly asymmetrical superior lobes.

Female

Similar to male except for the usual sexual dimorphism.

LENGTH. Body 6.4 mm, wing 5.8 mm.

HEAD. Ventral half of face and anterior half of mouth edge brown. Basoflagellomere short oval, ratio width: length 1: 1.2; arista long pilose, about 3 times as long as basoflagellomere.

THORAX. Scutellum with two very widely set, short setae medially at posterior margin, ratio length of scutellum: length of seta 1: 1.2.

LEGS. Metafemur ratio width: length 1: 5.9; metatarsus with basitarsomere thick, ratio width: length 1: 3.1.

ABDOMEN. Length ratio of terga I: II: III: IV: V 1: 3.5: 2.9: 1.9: 0.8; ratio width at posterior margin: medial length of tergum II and III 1: 1.6 and 1: 0.9. Tergum I with 3 large brown setae at lateral margin. Tergum III on anterior 2/5 with yellow fascia; tergum IV antero-laterally with large lunulate macula; sternum III rectangular, ratio width: length 1: 3.0; sternum IV trapezoidal with anterior part thinner, ratio width: length 1: 1.9; sternum V rectangular with convex posterior margin, ratio width: length 1: 0.9.

Figures

Fig. 61. Protarsus, dorsal view. A. Sphegina (Asiosphegina) atrimanus sp. nov., holotype, Ƌ, Vietnam. B. S. (A.) granditarsis sp. nov., holotype, Ƌ, China. C. S. (A.) incretonigra sp. nov., holotype, Ƌ, Vietnam. D. S. (A.) nigrotarsata sp. nov., paratype, Ƌ, Vietnam. E. S. (A.) orientalis Kertész, 1914, Ƌ, Taiwan. F. S. (A.) plautus sp. nov., holotype, Ƌ, China. Scale bars 0.5 mm.

Fig. 70. Habitus, dorsal view. A. Sphegina (Asiosphegina) nubicola sp. nov., paratype, ♀, Thailand, dark form. B. S. (A.) nubicola sp. nov., paratype, ♀, Thailand, light form. C. S. (A.) orientalis Kertész, 1914, Ƌ, Taiwan. D. S. (A.) philippina Thompson, 1999, holotype, Ƌ, Philippines. E. S. (A.) philippina, paratype, ♀, Culasi, Philippines. F. S. (A.) plautus sp. nov., paratype, Ƌ, China. Scale bars = 1.0 mm.

Fig. 75. Habitus, lateral view. A. Sphegina (Asiosphegina) plautus sp. nov., paratype, Ƌ, China. B. S. (A.) plautus sp. nov., paratype, ♀, China. C. S. (A.) pollinosa Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar. D. S. (A.) prolixa, sp. nov., paratype, Ƌ, Thailand. E. S. (A.) radula Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar. F. S. (A.) setosa sp. nov., paratype, Ƌ, Nepal. Scale bars = 1.0 mm.

Fig. 84. Head, lateral view (E, H), dorsal view (A–D, F, I, K–L) and frontal view (G, J). A. Sphegina (Asiosphegina) nasuta Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar. B. S. (A.) nubicola sp. nov., holotype, Ƌ, Thailand. C. S. (A.) orientalis Kertész, 1914, ♀, Taiwan. D. S. (A.) parvula Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar. D–E. S. (A.) perlobata sp. nov., holotype, Ƌ, Taiwan. F. S. (A.) philippina, Thompson, 1999, paratype, ♀, Philippines. G. S. (A.) philippina, holotype, Ƌ, Philippines. H. S. (A.) plautus sp. nov., holotype, Ƌ, China. I–J. S. (A.) prolixa sp. nov., holotype, Ƌ, Malaysia. K. S. (A.) cf. spathigera sp. nov., ♀, Philippines. L. S. (A.) taiwanensis sp. nov., paratype, Ƌ, Taiwan. Scale bars = 0.5 mm.

Fig. 95. Metaleg, anterior view. A. Sphegina (Asiosphegina) plautus sp. nov., holotype, Ƌ, China. B. S. (A.) setosa sp. nov., holotype, Ƌ, Nepal. C. S. (A.) strigillata sp. nov., holotype, Ƌ, Vietnam. D. S. (A.) umbrosa sp. nov., holotype, Ƌ, China. E. S. (A.) varidissima Shiraki, 1930, Ƌ, Taiwan, yellow form. Scale bars = 0.5 mm.

Fig. 76. Sphegina (Asiosphegina) plautus sp. nov., holotype, Ƌ. A. Sternum IV, ventral view. B. Posterior part of genitalia, left side, lateral view. C. Genitalia, right side, lateral view. Scale bars = 0.5 mm.