Sphegina (Asiosphegina) inventum, 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 : 106-109

Sphegina (Asiosphegina) inventum sp. nov.

urn:lsid:zoobank.org:act:D1F99D1E-296C-43CF-BEBF-6BF3036E772E

Figs 45E , 49, 50D, 52D, 54C

Differential diagnosis

Similar to Sphegina (Asiosphegina) bifida sp. nov. and S. (A.) collicola sp. nov. Except for the characters given in the key, the species is distinguished from S. (A.) bifida sp. nov. by having the male superior lobe on both sides wider (higher) than long instead of longer than wide; and from S. (A.) collicola sp. nov. by having the more posterior one of the ventral tooth-like projections on the right superior lobe lateral instead of marginal and by having the respective projection on the left side superior lobe large and sharp instead of small and rounded.

Etymology

The specific epithet inventum is composed of the Latin words ‘ in ventum ’, meaning ‘under the wind’. It is a translation of the informal Malayan name of Sabah, ‘ Negeri Di Bawah Bayu ’, meaning ‘land under the wind’ and referring to the type locality of the species. The name is a noun in apposition.

Material examined

Holotype

INDONESIA • ♂; “ Sabah / Mt. Kinabalu / 5000 ft. / 1–5.v.1973 / [leg.] K.M. Guichard ”; NHM.

Description

Male

LENGTH. Body 6.1 mm, wing 4.5 mm.

HEAD. Face in lateral view concave, very weakly projected antero-ventrally; frontal prominence very weakly developed. Ratio width of vertex at anterior ocellus: width of head 1: 6.6; ratio width of ocellar triangle: width of vertex 1: 1.1; ratio length of ocellar triangle: length of frons 1: 2.1. Face black, light grey pollinose, long pilose along eye-margin. Hypostomal bridge black, long pale pilose. Gena and mouth edge black with large subtriangular non-pollinose shiny area. Frons and vertex black, velvet black pollinose, a narrow oval area posterior of lunula shiny and non-pollinose and 2 squarish anterolateral grey pollinose macula along eye-margin; pile short, light yellow. Frons with narrow and weak furrow medially. Occiput black, light grey pollinose, light yellow pilose. Eye without enlarged facets at anterior margin Antennae missing.

THORAX. Colour black, greyish pollinose, postpronotum dark yellow; posterior margin of katepisternum narrowly non-pollinose, shiny; scutum and pleuron with very short adpressed light yellow pile. Scutellum widely sub-triangular, black, greyish pollinose, with pile slightly longer than on scutum, without detectable longer setae at posterior margin, possibly the setae are broken off.

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

1

meeting vein R

4+5

perpendicularly.

Fig. 49 Sphegina (Asiosphegina) inventum s p. nov., holotype, ♂. 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.

LEGS. Pro- and mesoleg yellow, with coxae black; protarsus with tarsomeres 2–5 black; mesotarsus with tarsomeres 3–5 black. Metaleg with coxa black, trochanter yellow; femur black with basal 1/5 yellow, incrassate, ratio width: length 1: 3.5; tibia yellow, apical ⅓ black, with rounded apicoventral dens; tarsus entirely black, basitarsomere very thick, ratio width: length 1: 2.6.

ABDOMEN. Length ratio of terga I: II: III: IV 1: 3.5: 1.6: 1.4; ratio width at posterior margin: medial length of tergum II and III 1: 5.0 and 1: 0.9. Terga black, anterior ⅓ of tergum III with yellow medially widely interrupted fascia; pile pale, on terga short, laterally on terga I and II long; tergum I with 3 evenly separated strong yellow setae at lateral margin; sternum III not well sclerotized; sternum IV, Fig. 49A; sterna VI, VII and VIII with long yellow pile, sternum VI anteriorly with low and weakly rounded process. Genitalia, Fig. 49B–D: note the only slightly asymmetrical surstyli and superior lobes.

Description

Female

Similar to the male except normal sexual dimorphism and the following.

LENGTH. Body 5.2–5.6 mm, wing 3.9–4.2 mm.

HEAD. Ratio width of vertex at anterior ocellus: width of head 1: 4.9–5.1; ratio width of ocellar triangle: width of vertex 1: 1.6–1.8; ratio length of ocellar triangle: length of frons 1: 2.4–2.7 ( Fig. 54C ). Antenna dark brown; basoflagellomere slightly elongate, ratio width: length 1: 1.5–1.7; arista about 2.5 times as long as basoflagellomere.

THORAX. Scutellum semi-circular, rather long pilose.

WING. Crossvein dm-cu meeting vein M slightly oblique.

LEGS. Metafemur, Fig. 52D , slightly incrassate, ratio width: length 1: 3.5–3.6, yellow on basal ¼; metatarsus with basitarsomere very thick, ratio width: length 1: 2.7–3.0.

ABDOMEN. Length ratio of terga I: II: III: IV: V 1: 3.1–3.4: 2.1–2.3: 1.9–2.1: 1.0–1.2; ratio width at posterior margin: medial length of tergum II and III 1: 2.1–2.3 and 1: 0.6–0.7. Tergum I black with 2 or 3 strong yellow setae at lateral margin; tergum II with dark yellow fascia on antero-medial ⅓; tergum III with yellow upturned V-shaped fascia on anterior ⅓ –¼; tergum IV with oval lateral yellow macula on anterior ¼; tergum V with anterior half yellow and posterior half black; sternum III elongated, ratio width: length 1: 1.9–2.1; sternum IV rectangular with slightly concave posterior margin, ratio width: length 1: 0.8–0.9; sternum V oval with concave posterior margin, ratio width: length 1: 1.4–1.7.

Distribution and biology

Collected in a Malaise trap which stood in a partially disturbed primary forest along a tributary of the Ritan river close to Long Pa Sia village. The trap was placed on the river bank and was in full shade under the forest canopy (C. van Achterberg, pers. comm).

Remarks

The following females may belong to Sphegina (Asiosphegina) inventum sp. nov. based on the velvet black pollinosity on medial part of the frons, the yellow postpronotum, extensively yellow abdomen and relatively dark pro- and mesotarsus with respectively tarsomeres 2–5 and 3–5 black (in the similar S. (A.) bifida sp. nov. the postpronotum is black; pro- and mesotarsus with tarsomeres 4 and 5 black; abdomen with narrow brown fascia on tergum III): 1 ♀, “ Malaysia: Sabah: / 1 km S. Kundasang / el 1530 m. 11 Sept. 1983 / G.F. Hevel & W.E. Steiner” (BPBM); 1 ♀, “Malaysia-SW, Sabah / along Ritan river / c. 1170 m. 8–10.IV.1987 / Mal. trap 10, RMNH ’87 / C. v. Achterberg” (NBC).

Figures

Fig. 45. Habitus, lateral view. A. Sphegina (Asiosphegina) incretonigra sp. nov., holotype, Ƌ, Vietnam. B. S. (A.) index Hippa, van Steenis & Mutin, 2015, holotype, Ƌ, Myanmar. C. S. (A.) inflata sp. nov., holotype, Ƌ, Philippines. D. S. (A.) cf. inflata sp. nov., ♀, Philippines. E. S. (A.) inventum sp. nov., holotype, Ƌ, Sabah, Malaysia. F. S. (A.) javana de Meijere, 1914, lectotype Ƌ, Java, Indonesia. Scale bars = 1.0 mm.

Fig. 54. Head, lateral view (D, F, I, K) and dorsal view (A–C, E, G–H, J, L). A. Sphegina (Asiosphegina) incretonigra sp. nov., holotype, Ƌ, Vietnam. B. S. (A.) inflata sp. nov., holotype, Ƌ, Philippines. C. S. (A.) inventum sp. nov., paratype, ♀, Sabah, Malaysia. D–E. S. (A.) karnataka sp. nov., paratype, Ƌ, India. F–G. S. (A.) licina sp. nov., holotype, Ƌ, Thailand. H. S. (A.) lucida sp. nov., paratype, Ƌ, Vietnam. I–J. S. (A.) nigerrima Shiraki, 1930, Ƌ, Taiwan. K–L. S. (A.) nigrotarsata sp. nov., paratype, Ƌ, Vietnam. Scale bars = 0.5 mm.

Fig. 52. Metaleg, dorsal view (A) and anterior view (B–F). A. Sphegina (Asiosphegina) hansoni Thompson, 1966, holotype, Ƌ, Nepal. B. S. (A.) index Hippa, van Steenis & Mutin, 2015, ♀, Kambaiti. C. S. (A.) cf. inflata sp. nov., ♀, Philippines. D. S. (A.) inventum sp. nov., paratype, ♀, Sabah. E. S. (A.) javana de Meijere, 1914, paralectotype, Ƌ, Java. F. S. (A.) karnataka sp. nov., paratype, Ƌ, India. Scale bars = 0.5 mm.