Sphegina (Asiosphegina) amplistylus, 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 : 32-34

Sphegina (Asiosphegina) amplistylus sp. nov.

urn:lsid:zoobank.org:act:54E8023E-E4AC-4393-8CE8-66D9AD6BC700

Figs 6D , 8 , 21C

Differential diagnosis

Similar to Sphegina (Asiosphegina) inflata sp. nov., S. (A.) philippina and S. (A.) spathigera sp. nov. For distinguishing characters, see under these three species.

Etymology

The specific epithet is from the Latin ‘ amplistylus ’, meaning ‘large stylus’ and referring to the enlarged left-side surstylus. The name is a noun in apposition.

Material examined

Holotype

PHILIPPINES • ♂; “ Philippines / Camarines Sur: Mt. / Isarog 500 m. / 4. IV. 1963 ”; “ H. M. Torrevillas / Collector / Bishop”; BPBM.

Description

Male

LENGTH. Body 6.4 mm, wing 5.3 mm.

HEAD. Face in lateral view concave, weakly projected antero-ventrally; frontal prominence very weakly developed. Ratio width of vertex at anterior ocellus: width of head 1: 5.3; ratio width of ocellar triangle: width of vertex 1: 1.6; ratio length of ocellar triangle: length of frons 1: 2.4. Face black, ventral half dark yellow to brown; light grey pollinose, long pilose along eye-margin. Hypostomal bridge brown, long pale pilose. Gena and mouth edge dark yellow to brown, weakly pollinose with large subtriangular nonpollinose shiny area. Frons and vertex black, slightly pollinose, a narrow subtriangular area posterior of lunula non-pollinose and shiny; pile short, light yellow ( Fig. 21C ). Frons with weak furrow medially. Occiput black, light grey pollinose, light yellow pilose. Eye with an area of enlarged facets at anterior margin. Antenna brown with black setae dorsally on scape and pedicel; basoflagellomere rectangular, ratio width: length 1: 1.4; arista long pilose, nearly 3 times as long as basoflagellomere.

THORAX. Colour black, weakly greyish pollinose, postpronotum dark brown, grey pollinose, pleuron entirely grey pollinose; scutum and pleuron with very short adpressed light yellow pile. Scutellum short, widely sub-triangular, black, weakly pollinose, long pilose, with pile longer than on scutum, without marginal setae (possibly the setae are broken off).

WING. Entirely microtrichose; hyaline, stigma yellowish; crossvein dm-cu meeting vein M slightly obliquely and vein M

1

meeting vein R

4+5

perpendicularly.

LEGS. Pro- and mesoleg yellow, tarsomeres 4–5 black. Metaleg with coxa black, trochanter yellow; femur black with basal ⅓ yellow, rather strongly incrassate, ratio width: length 1: 3.6; tibia black and yellow biannulate, with large rounded apicoventral dens; tarsus entirely black, basitarsomere thick, ratio width: length 1: 3.3.

ABDOMEN. Length ratio of terga I: II: III: IV 1: 3.5: 1.9: 1.6; ratio width at posterior margin: medial length of tergum II and III 1: 3.9 and 1: 0.8. Terga black, anterior ⅓ of tergum III with dark yellow fascia; pile pale, on terga short, laterally on terga I and II long; tergum I with horizontal row of 3–4 evenly spread brown-yellow setae at lateral margin; sternum III not sclerotized; sternum IV, Fig. 8A ; sterna VI, VII and VIII simple, with long yellow pile. Genitalia, Fig. 8 B–D: cerci unmodified, roundish; surstyli

asymmetrical with the dorsal lobe of left surstylus strongly inflated; superior lobe slightly asymmetrical, with several sublobes of which the anteroventral one very long.

Female

Unknown.

Remarks

In the type material of Sphegina (Asiosphegina) philippina there is a headless specimen (1 ♀, “P.I.: Mindanao / Bukidnon. 1480 m. / Mt. Katanglad / 27–31.X.1959 ”; “L.W. Quate / Collector” (BPBM)), see Fig. 6B . This female is not Sphegina (Asiosphegina) philippina , because the postpronotum is black (yellow in S. (A.) philippina ), the wing is hyaline (slightly infuscated in S. (A.) philippina ) and tergum V has the posterior margin straight (incised in S. (A.) philippina ). This specimen is possibly the female of S. (A.) amplistylus sp. nov., but as even the males of all the similar species are very difficult to distinguish from each other without reference to genitalia, the identity of this female remains doubtful.

Figures

Fig. 6. Habitus, lateral view. A. Sphegina (Asiosphegina) achaeta Hippa, van Steenis & Mutin, 2015, holotype, Ƌ, Myanmar. B. S. (A.) achaeta, ♀, Myanmar. C. S. (A.) albolobata sp. nov., holotype, Ƌ, Vietnam. D. S. (A.) amplistylus sp. nov., holotype, Ƌ, Philippines. E. S. (A.) apicalis Shiraki, 1930, Ƌ, Taiwan. F. S. (A.) apicalis, ♀, Taiwan. Scale bars = 1.0 mm.

Fig. 8. Sphegina (Asiosphegina) amplistylus sp. nov., holotype, Ƌ. A. Sternum IV, ventral view. B. Left surstylus, lateral view. C. Left superior lobe, lateral view. D. Genitalia, right side, lateral view. Scale bars = 0.5 mm.

Fig. 21. Head, lateral view (A, D, F, J–K), dorsal view (B, C, G–H, L), frontal view (E, I). A–B. Sphegina (Asiosphegina) albolobata sp. nov., holotype, Ƌ, Vietnam. C. S. (A.) amplistylus sp. nov., holotype, Ƌ, Philippines. D. S. (A.) apicalis Shiraki, 1930, ♀, Taiwan. E. S. (A.) bifida sp. nov., holotype, Ƌ, Sabah, Malaysia. F–G. S. (A.) bracon sp. nov., paratype, Ƌ, Vietnam. H–I. S. (A.) bispinosa Brunetti, 1915, Ƌ, Nepal. J. S. (A.) brevipilis sp. nov., holotype, Ƌ, China. K–L. S. (A.) collicola sp. nov., paratype, Ƌ, Malaysia. Scale bars = 0.5 mm.