Sphegina (Asiosphegina) orientalis Kertész, 1914

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 : 135-141

Sphegina (Asiosphegina) orientalis Kertész, 1914

Figs 61E , 66 , 67 A–B, 68–69, 70C, 84C

Sphegina orientalis Kertész, 1914: 73 . Type locality: Kosempo, Taiwan (lectotype, ♂, NMHB).

Differential diagnosis

Sphegina (Asiosphegina) orientalis is similar to S. (A.) atrimanus sp. nov., S. (A.) granditarsis 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.

Material examined

TAIWAN • 1 ♂; “Formosa / Sauter”; “Taihorin / 1911, VII.”; “ orientalis Kert / det. Kertész”; “coll. Klöcker”; “ Lectotypus Sphegina / orientalis Kertész / design. Thompson” [red label, partly handwritten], “ orientalis / Kertész”; partly destroyed specimen; USNM.

Additional material

TAIWAN • 3 ♂♂, 4 ♀♀; “ Taiwan, Yilan, Datung / Mingchih forest rec. area / 24°39 ʹ 05 ʺ N, 121°28 ʹ 24 ʺ E / 17–5–2016 1182 m / leg. J. van Steenis ”; JSA • 1 ♂, 2 ♀♀; same data as for preceding; NMNS • 1 ♂, 1 ♀; same data as for preceding; NTU • 1 ♀; same data as for preceding; “ 24°38 ʹ 40 ʺ N, 121°27 ʹ 40 ʺ E / 1120 m ”; JSA • 1 ♀; same data as for preceding; NTU • 1 ♀; same data as for preceding; “leg. W. van Steenis ”; NMNS • 3 ♀♀; same data as for preceding; NTU • 4 ♀♀; same data as for preceding; WSB • 1 ♀; same data as for preceding; “ 24°38 ʹ 40 ʺ N, 121°27 ʹ 40 ʺ E / 1120 m / leg. W. van Steenis ”; WSB • 2 ♀♀; same data as for preceding; “leg. A. Ssymank ”; ASW • 1 ♂; same data as for preceding; WSB • 1 ♀; same data as for preceding; “leg. B. Lechner-Ssymank ”; ASW • 1 ♂; same data as for preceding; “ 24°38 ʹ 40 ʺ N, 121°27 ʹ 40 ʺ E / 1120 m / leg. A. Ssymank ”; ASW • 1 ♂, 2 ♀♀; same data as for preceding; “ 24°31 ʹ 46 ʺ N, 121°27 ʹ 43 ʺ E / 1112m.a.s.l. / leg C J Palmer”; CPP • 1 ♀; same data as for preceding; NTU • 1 ♀; same data as for preceding; “ 24°39 ʹ 04 ʺ N, 121°28 ʹ 19 ʺ E / 1157m.a.s.l. / leg C J Palmer”; CPP • 2 ♀♀; same data as for preceding; “leg MP van Zuijen ”; MZW • 2 ♀♀; same data as for preceding; NTU • 1 ♂, 1 ♀; same data as for preceding; “ Roadside / 1050 m a.s.l. / leg MP van Zuijen ”; MZW • 1 ♀; same data as for preceding; “J.H. Skevington, A.D. Young / JSM8411–14 CNC566911–14 ”; DNA voucher specimens, in alcohol; CNC • 1 ♂, 1 ♀; same data as for preceding; NMNS • 1 ♂; “ Taiwan, Mingchih, small rocky valley / Ren’ai , Nantou / 1–6–2016, 1080 m a.s.l. / 24°38 ʹ 43 ʺ N, 121°27 ʹ 20 ʺ E / leg MP van Zuijen”; MZW • 1 ♂; same data as for preceding; NTU • 1 ♂; same data as for preceding; “ J.H. Skevington / JSM7929 CNC569410 ”; DNA voucher specimen, in alcohol; CNC • 1 ♀; same data as for preceding; “A.D. Young , rich fern / vegetation in rocky, forested / creek valley / JSM8078 / CNC569431 ”; DNA voucher specimen, in alcohol; CNC • 1 ♀; “FO: 8996 Taiwan / 24°05 ʹ 12.9 ʺ N, 121°02 ʹ 13.5 ʺ E / Hueisun Forest Reserve steep sl. / Nantou 770 mNN / B / leg B. Lechner-Ssymank 20.05.2016 ”; ASW • 1 ♀; “ Taiwan Hualien, Yuli / Antong traversing trail / ca 12 km SSW of Yuli / 23°16 ʹ 48 ʺ N, 121°21 ʹ 9 ʺ E / 24–5–2016 1182 m / leg. J. van Steenis ”; JSA • 1 ♂; “ Taiwan Taiting / Tenping / 13.III.1990 / C.C. Chiang / Sweeping net ”; “ NMNS ENT / 592–6”; NMNS • 1 ♀; “ Taiwan Ilan / Wufangchi / 16.X.1990 / C.C. Chiang / Sweeping”; “ NMNS ENT / 754–28”; NMNS • 1 ♂; “ VI. 1914 / Arisan / col M. Maki ”; “barcode / 12153014180066”; NTU • 1 ♂; “ Arisan / 1921. X–10 / Col I. Nitobe ”; “barcode / 12153014180069”; NTU • 1 ♂; same data as for preceding; “barcode / 73”; NTU • 5 ♀♀; same data as for preceding; with barcodes 68, 70 to 72 and 74; NTU • 1 ♂; “ Arisan / 21.IV–8.VI. [19]19 / Col T. Shiraki ”; “barcode / 63”; NTU • 1 ♂; “ Kobayasti / Rosti 2.VIII.1923 / Col. T Shiraki ”; “barcode / 99”; NTU • 1 ♂; “ Formosa / Arisan 1918 / X 2– 23 / J. Sonan, / M. Yoshino ”; “barcode / 79”; NTU • 1 ♂; “ Taiheizan / 25 and 29–VIII–1923 / Col. T Shiraki ”; “barcode / 94”; NTU • 1 ♂; same data as for preceding; “barcode / 96”; JSA • 1 ♂, 2 ♀♀; “ Formosa / Shinchiku [19]18 / VII 1– 30; / J. Sonan / M. Miyake ”; with barcodes 80, 81, and 83 respectively; 1 ♀; same data as for preceding; “barcode / 84”; JSA .

VIETNAM • 1 ♂; “ N. Vietnam Tonkin / Hoang Lien N.P. Pansi Pan Mt / 2320 m prim. Forest 24.iv– / 2.v.2000 [leg] Mai Phu Quy & / Nguyen M. Tam RMNH’00”; NBC .

CHINA • 1 ♂; “ CHINA Sichuan / Mt EMEI / 17–21.IX.1985 ”; “ 4 km N / XIANFENG / 1650 m ”; JSA • 3 ♂♂, 1 ♀; “Fukien, S. China / Shaowu: Tachulan / 1000 m T. Maa ”; “ 24.IV–15.VII.1942 ”; BPBM • 2 ♂♂, 1 ♀; same data as for preceding; JSA • 1 ♂; “Fukien, S. China / Chungan Tsili- / chiao 1000 m / 1942 T. Maa ”; “ 19.X.1942 ”; BPBM .

JAPAN • 1 ♂; “ Ryukyu Is / Iricomote I. / Ushiku-mori 425 m / 11.III.1964 ”; “ C.M. Yoshimoto / G.J. Harrell / Collector”; “ U.S. -Japan / Co-op. Sci. / Programme”; BPBM • 1 ♀; “Ryukyu Is / Iricomote I. / Nakara Gawa / 0–200 m 12.III.’64”; “ C.M. Yoshimoto / G.J. Harrell / Collector”; “ U.S. -Japan / Co-op. Sci. / Programme”; BPBM • 1 ♀; “ Japan : Okinawa Island, / roadside and trail NE of / Mount Yonaha 26.735864° N, 128.230661° E 7.vi.2016 / J.H. Skevington, A.D. Young, / S. Bot JSM8741, / CNC573355 ”; DNA voucher specimen, in alcohol; CNC • 1 ♂, 1 ♀; same data as for preceding; “ 26.735862° N, 128.230659° E / CNC560675–6 ”; CNC .

Redescription

Male

LENGTH. Body 6.3–7.2 mm, wing 5.1–5.9 mm.

HEAD. Face in lateral view concave, strongly projected antero-ventrally; frontal prominence weakly developed. Ratio width of vertex at anterior ocellus: width of head 1: 4.0–4.4; ratio width of ocellar triangle: width of vertex 1: 1.6–1.9; ratio length of ocellar triangle: length of frons 1: 2.4–2.8. Face black, ventral half yellow, light grey pollinose, long pilose along eye-margin. Hypostomal bridge black, long pale pilose. Gena and mouth edge yellow with large subtriangular non-pollinose shiny area, posterior part of mouth edge dark brown to black. Frons and vertex black, frontal prominence long, shiny with grey pollinose subtriangular macula antero-laterally at eye-margin ( Fig. 84C ); pile short, light yellow. Frons with deep anteromedial pit and wide medial furrow. 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: 2.1–2.3; arista short pilose, about 3 times as long as basoflagellomere.

THORAX. Colour dark brown to black, postpronotum, and dorso-medial part of anepisternum and anepimeron yellow, weakly greyish pollinose; katepimeron at least medially non-pollinose and shiny (the specimens from the Ryukyu Islands with almost entirely pollinose katepimeron); scutum and pleuron with very short adpressed light yellow pile. Scutellum subtriangular, black, weakly pollinose

sub-shiny and, 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: 0.7–0.8.

WING. Entirely microtrichose; hyaline, stigma yellowish, membrane brown infuscated at junction of veins R 2+3 and R 4+5, along veins bm-cu, r-m and M 1, at apical end of vein R 2+3 and apical part of wing around vein R 4+5. Crossvein dm-cu meeting vein M perpendicularly and vein M 1 meeting vein R 4+5 perpendicularly.

LEGS. Pro- and mesoleg yellow; protarsus ( Fig. 61E ) with tarsomere 1 with black sub-apical annulus, tarsomere 2 with apical ⅔ dark brown to black and tarsomeres 3–5 dark brown; mesotarsus with tarsomeres 3–5 dark brown to black. Metaleg with coxa black and trochanter yellow; femur black and yellow biannulate, slender, ratio width: length 1: 5.0–5.4; tibia black and yellow biannulate with short sharp subtriangular apicoventral dens; tarsus entirely black, basitarsomere thick, ratio width: length 1: 3.1–3.5.

ABDOMEN. Length ratio of terga I: II: III: IV 1: 3.0–3.5: 1.9–2.2: 1.5–1.8; ratio width at posterior margin: medial length of tergum II and III 1: 8.9–9.6 and 1: 4.8–5.3. Terga black, anterior ¼ of tergum II and anterior ⅔ of tergum III with straight yellow fascia; anterior 1/5 of tergum IV with posteromedially incised yellow fascia; pile pale, on terga short, laterally on terga I and II long; tergum I with row of 2–3 strong dark brown setae at lateral margin; sternum III elongate, ratio width: length 1: 3.7–4.1; sternum IV, Figs 66A , 68A ; sterna VI, VII and VIII simple, with long yellow pile. Genitalia, Figs 66 B–D, 68B–E, 69A–F: 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 and the slight differences in the shape of surstyli and the superior lobes between the specimens from Taiwan and Vietnam.

Female

Similar to male except for the usual sexual dimorphism.

LENGTH. Body 5.1–5.6 mm, wing 3.8–4.3 mm.

HEAD. Ratio width of vertex at anterior ocellus: width of head 1: 3.8–4.3; ratio width of ocellar triangle: width of vertex 1: 1.8–2.0; ratio length of ocellar triangle: length of frons 1: 3.0–3.4. Frons sub-shiny slightly grey pollinose with wide but weak furrow. Basoflagellomere elongate, ratio width: length 1: 1.6–1.9; arista long pilose; about 3 times as long as basoflagellomere.

THORAX. Scutellum with two widely set, very short setae medially at posterior margin, ratio length of scutellum: length of seta 1: 0.7–0.9.

LEGS. Protarsus with tarsomere 2–5 with apical half dark-grey coloured; metafemur, ratio width: length 1: 4.7–5.3; metatarsus with basitarsomere thick, ratio width: length 1: 3.2–3.6.

ABDOMEN. Length ratio of terga I: II: III: IV: V 1: 3.0–3.4: 2.5–2.8: 2.1–2.4: 0.9–1.0; ratio width at posterior margin: medial length of tergum II and III 1: 2.0–2.5 and 1: 0.8–0.9. Terga II, III and IV with yellow to dark yellow fascia on respectively anterior 1/10, ⅓ and 1/5; sternum III short oval, ratio width: length 1: 1.6–1.9; sternum IV rectangular with strongly concave posterior margin, ratio width: length 1: 1.6–1.9; sternum V rectangular, ratio width: length 1: 1.2–1.5.

Distribution and biology

Widely distributed throughout Taiwan and also recorded from N. Vietnam, S. China and the Ryukyu Islands, Japan. Lowland to high montane (50–2820 m) species collected from the end of April until the end of July and between the 17 th and 21 st of September. In Taiwan abundantly collected on a cold misty day along a lakeshore and roadside in semi-shady humid forest margins with a dense herb layer dominated by Oenanthe javanica Blume (DC). Other habitats were humid semi-shady roadsides in wide-leaved forests, oil palm plantations or afforestations dominated by Pinus taiwanensis Hayata. Flower visiting has been observed on Oenanthe javanica , Astilbe longicarpa Hayata (Hayata) , Bidens pilosa L., Cyclospermum leptophyllum (Pers.) Sprague , Erigeron annuus (L.) Pers. and Ranunculus spp. Flies were also seen flying low through the vegetation (van Steenis et al. in prep). The specimen from Vietnam was collected in a Malaise trap near Fan Si Pan mountain at about 2300 m a.s.l. The Malaise trap was set up in an area of open and low montane forest partly grazed by buffalos, containing muddy areas and small streams. Despite the cold and wet weather insects were still rather abundantly flying (C. van Achterberg, pers. comm).

Remarks

Sphegina (Asiosphegina) orientalis is a variable species based on external and genital characters. The Okinawa population differ from the Taiwanese population by the partly non-pollinose and shiny katepimeron; the genitalia, however, fall within the range found in this species. The genitalia from the Okinawa population are more similar to those from Taiwan compared with those from China. We think these differences are due to geographical variation rather than different speciation and have refrained from creating additional new species. Only if more material becomes available with extensive DNA sampling could another conclusion be drawn.

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. 66. Sphegina (Asiosphegina) orientalis Kertész, 1914, Ƌ Vietnam. A. Sternum IV, ventral view. B. Left surstylus, lateral view. C. Left superior lobe with associated parts, lateral view. D. Genitalia, right side, lateral view. Scale bars = 0.5 mm.

Fig. 67. Habitus, lateral view. A. Sphegina (Asiosphegina) orientalis Kertész, 1914, Ƌ, Taiwan. B. S. (A.) orientalis, ♀, Taiwan. C. S. (A.) parvula Hippa, van Steenis & Mutin, 2015, paratype, Ƌ, Myanmar. D. S. (A.) bispinosa Brunetti, 1915, Ƌ, India. E. S. (A.) perlobata sp. nov., holotype, Ƌ, Taiwan. F. S. (A.) philippina Thompson, 1999, paratype, ♀ from Culasi, Philippines. 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. 68. Sphegina (Asiosphegina) orientalis Kertész, 1914, Ƌ, Taiwan, specimen 1 (A), Ƌ, Taiwan, Mingchih, specimen 2 (B–E). A. Sternum IV, ventral view. B. Right surstylus, postero-lateral view. C. Left surstylus, lateral view. D. Left superior lobe with associated parts, lateral view. E. Genitalia, right side, lateral view. Scale bars = 0.5 mm.