Sympycnus stackelbergi, Negrobov & Grichanov & Selivanova, 2017

Negrobov, Oleg P., Grichanov, Igor Ya. & Selivanova, Olga V., 2017, Review of East Palaearctic species of Sympycnus Loew, 1857, with a key to species, Zootaxa 4277 (4), pp. 531-548 : 541-543

Sympycnus stackelbergi sp. nov.

( Figs 32–38 )

Diagnosis (male). Fore tibia with anterodorsal row of weak setae on apical 1/2 or 2/3, nearly as long as width of tibia; posterodorsal and posteroventral rows of short white hairs along entire length; hind tarsus simple, without remarkably modified setae; only tarsomere 3 of hind tarsus with erect setae (MSSC).

Description. Male. Body length: 1.7–2.4 mm; wing length: 1.8–2.5 mm, wing width: 0.8–0.9 mm. Head: Frons mat, dark green, dusted grey. Face silvery white, narrowing below antennae, in middle nearly as wide as height of postpedicel (0.3/0.4). Palpus yellow, white haired; proboscis dark brown. Antenna ( Fig. 32 ) black; postpedicel short, triangular with rounded apex, slightly shorter than high; arista-like stylus middorsal. Ratio of postpedicel length to postpedicel height to stylus length, 1.1/1.2/8.7. Lower postocular bristles white. Thorax dark green. Mesonotum metallic, dusted brown-grey, with pleura densely dusted greyish. Thoracic bristles black; 6 pairs of strong dorsocentrals; acrostichals uniserial, weak, reaching 5th dorsocentrals, in irregular row; both upper and lower proepisternum with group of small white setae. Scutellum with 2 strong median bristles, 2 minute laterals. Legs variable in colour. Coxae mainly brown with apices yellow or mainly yellow with brown base, with white hairs and setae. Fore coxa with very dense pubescence of white anterior bristles and equal-sized white apical bristles. Mid coxa with pubescence of inclined white setae on anterior face, and one strong white bristle and a few setae on outer margin of anterior face. Hind coxa with one straight, yellow external bristle, as long as coxa, inserted at about basal 2/5. Trochanters yellow. Fore femur yellow, slightly darkened dorsally, or mainly brown, with yellow apices; mid femur usually yellow, rarely darkened; hind femur mainly yellow, brownish dorsally, or almost entirely blackish or brown. Tibia usually yellow, hind tibia often brown. Tarsi mainly black or brown; fore and mid basitarsi mainly yellow with dark tip. Fore femur with 1–2 preapical posteroventral bristles, without venrtal bristles. Mid femur with 1 strong anterodorsal preapical bristle, with posteroventral setae at apex about as long as width of femur. Hind femur with 1 strong anterodorsal bristle. Fore tibia ( Fig. 33 ) with anterodorsal row of weak setae on apical 1/2 or 2/3, nearly as long as width of tibia; posterodorsal and posteroventral rows of short white hairs along entire length; weak posterodorsal bristle, inserted at basal 1/5. Mid tibia with 2–3 anterodorsal bristles; 2–3 weaker posterodorsal bristles; 1 posteroventral bristle; 4 strong apical bristles. Hind tibia with 3 strong anterodorsal bristles; 5–6 small posterodorsal bristles; 5 apical bristles. Fore tarsus with tarsomeres 2–5 short; tarsomeres 2–4 thickened; tarsomere 5 slightly broadened, with 1 posterior claw, with white enlarged pulvilli. Mid basitarsus with short ventral setae. Hind tarsus simple ( Fig. 34 ), without long spine or long bristles, with segment 3 bearing short erect ventral bristles on apical 1/2. Tibia and tarsomere (from first to fifth) length ratio: fore leg: 5.1/2.1/0.9/0.5/0.5/ 0.8, mid leg: 5.8/2.8/1.2/0.8/0.7/0.6, hind leg: 6.3/2.0/1.5/0.9/0.6/0.6. Wing: Hyaline, slightly darkened, without anal lobe; anal vein only weakly indicated. R4+5 convex anteriorly, M1+2 with smooth bend, both parallel near wing apex. Apical section of CuA1 3.6 times longer than dm-cu. Halter yellow, lower calypter with white fringe. Abdomen: Six abdominal segments pubescent, with segment 6 as long as segment 5. Tergites and sternites entirely dark green with bronze tint, with short black inclined setae on disc of tergites; tergite 1 with strong bristles on posterior margin (brown on disc, and pale on sides. Sternites with white pubescence. Hypopygium ( Figs 35–38 ) with epandrium black-brown; hypandrium broad, subtriangular (ventral view), with small apical excavation (ventral view), without serration; phallus narrow, with apical hook; apicoventral epandrial lobe long, projected, with 1 ventral seta at middle, with several apical setae as figured; surstylus apparently lacking; cercus yellow, short, swollen at base, narrow on apical half, covered with white hairs and setae, which rather long apically; postgonites concealed, with bifurcate ventral structure arising at base, and forming two long and broad appendages, running alongside the phallus, curved at apex; each appendage bearing lateroventral row of about 8 thick teeth, swollen at base, with inner and outer triangular projections. Female. Unknown.

Type material examined. HOLOTYPE ♂, labelled: Tajikistan: Gissar Ridge , Takob Gorge , 1800 m, 29.VII.1979, Grichanov ( ZIN). PARATYPES: 18♂, same labels with collecting dates 29.VII, 30.VII and 1.VIII.1979, Grichanov ; 1♂, [ Tajikistan:] Gissar Ridge , southern slope, Ziddy, 15.VI.1944, Stackelberg ; 4♂, [ Tajikistan:] “ Obburden / 5” [Oburdon, 39.4053°N, 69.0833°E] ; 7♂, [ Tajikistan:] “ Fan / 19” [Fan Darya River, 39.38°N, 68.55°E] ; 1♂, [ Tajikistan:] “ Yagnob / 22” [Yaghnob River, 39.18°N, 68.53°E] ; 3♂, [ Tajikistan:] “ Iskander / 15” [Iskander Darya River, 39.19°N, 68.54°E] ; 5♂, [South Kazakhstan Region:] Karjantau [mountain ridge] upper Su-Singan River, on grass at riverbed, 6.VIII.1959, Obukhova ( ZIN, ZMUM, VSU).

Identification. Males of Sympycnus stackelbergi sp. nov. are very close to those of S. changaicus , both species having hind tarsomere 3 with erect setae. Nevertheless, S. changaicus males have numerous erect setae along the entire length of tarsomere 3, and several erect setae at the base of tarsomere 4, while S. stackelbergi sp. nov. males have only a few erect setae on the apical 1/2 of tarsomere 3, and no erect setae at base of tarsomere 4. Sympycnus changaicus males differ from S. stackelbergi sp. nov. also in the broad hind tarsomere 3.

Etymology. The species is named after the famous Soviet dipterist, Prof. A.A. Stackelberg (1897–1975).

Distribution. Palaearctic: S Kazakhstan, Tajikistan.

Figures

FIGURES 32 – 38. Sympycnus stackelbergi sp. nov., male holotype. 32, antenna, lateral view; 33, fore leg, lateral view; 34, hind tarsus, lateroventral view; 35, hypopygium, left lateral view; 36, hypopygium, ventral view; 37, cerci, dorsal view; 38, apicoventral epandrial lobe, dorsal view.