Wiedemannia ossetiana, Kustov, Semen & Zherebilo, Danil, 2015

Kustov, Semen & Zherebilo, Danil, 2015, New data on the genus Wiedemannia Zetterstedt (Diptera: Empididae) from the Caucasus with description of four new species, Zootaxa 4032 (4), pp. 351-369 : 361-362

Wiedemannia ossetiana sp. nov.

( Fig. 11 )

Type material. HOLOTYPE, ♂ labelled [printed in Cyrillic], [ SOUTH OSSETIA] “Ju. Ossetia Gudiysskiy hrebet [ridge] / zapadnie skloni g. [western slopes of mount] Mangavtsek / rutchei [stream] / [3000 m a.s.l.] / 24.vii.2013, D. Zherebilo ( ZIN). PARATYPES: same data as holotype (1 ♀, KSU); same locality as holotype, 21.vii.2013, D. Zherebilo (1 ♂, 8 ♀, KSU); GEORGIA: Khevsureti, south-western slope of the Mountain Tanie, 2850 m a.s.l., 19.vii.2014, D. Zherebilo (1 ♀, KSU); Khevsureti, the northern slope of Kistanistavi, 2830 m a.s.l., 21.vii.2014, D. Zherebilo (5 ♂, 2 ♀, ZIN, KSU); same locality, western slope of the Mountain Chokismta-Matura, source of River Argun, 2500 m a.s.l., 23.vii.2014, D. Zherebilo (1 ♂, KSU).

Diagnosis. This species differs by acrostichals divergent around the prescutellar depression, 5 pairs of dorsocentrals with interspersed shorter setae, dark brown scutum with blue pruinescence on prescutellar depression, postpronotal lobe and lower margin of notopleuron; proepisternum and laterotergite with pale setulae, fore femur with 3 anterior setae on apical quarter and unilobed, elongated clasping cercus with straight edge dorsally.

Description. Male. Body length 4.2–5.2 mm; wing length 5.2–6.0 mm. Head brown, face, occiput and gena with blue pruinescence, frons and vertex with olive-brown pruinescence. Gena broad, about 1/4 height of eye. Face wide, distinct carina on lower margin. Pair of strong ocellar setae (equal postpronotal setae) and pair of vertical setae, several strong occipitals similarly sized and black, with interspersed shorter postoculars and occipital. Lower postocular setae much finer and paler merging with pale, longer setae on middle and lower occiput. Few dark setulae present on vertex and between ocellar area and eye margin. Antenna dark brown to black, postpedicel and stylus minutely pubescent; scape with setulae dorsally, pedicel slightly shorter than scape, with complete circlet of apical setae; postpedicel triangular, apically pointed, stylus about twice as long as postpedicel, tip blunt. Palpus with numerous dark dorsal setae. Thoracic pleura with blue pruinescence; scutum olive-brown with indistinct darker strips between rows of acrostichals and dorsocentrals; prescutellar depression with blue pruinescence, extending onto concolourous scutellum; postpronotal lobe and lower margin of notopleuron with blue pruinescence. Antepronotum with pair of dark setae and some fine setulae. Proepisternum with pale setulae. Acrostichals small, irregularly biserial, divergent around prescutellar depression; 5 pairs of long dorsocentrals with interspersed numerous shorter setae; 1 postpronotal seta (with 1–2 short setae), 2 notopleural setae (upper stronger), 1 presutural supra-alar seta and several scattered setulae; 1 postalar seta; 1 strong scutellars setae (without weak marginal setae). Laterotergite with patch of fine pale setulae. Legs entirely dark brown to black, coxae with blue pruinescence. All legs with evenly distributed setae; hind tibia with longer dorsal and ventral setae on apical third. Fore femur narrowed apically, with 3 stout anterior setae on apical quarter. All coxae with longer setae anteriorly: hind coxae with pale setae, mid and fore coxae with mixed pale and blackish setae. Wing membrane infuscate, veins brown; pterostigma distinct, elongate, brown; single basal costal seta. Origin of veins M1 and M2 widely separated at end of cell dm. R4 and R5 straight and divergent. Halter dark brown with blue pruinescence. Abdominal sclerites with blue pruinescence. Terminalia ( Fig. 11 ): Hypandrium subequal in length to epandrium, ventrally bearing with numerous setae on apical part. Epandrium rhomboid, covered with numerous dark long setae especially ventrally and laterally. Clasping cercus unilobed, elongate, evenly arched toward tip ventrally, with straight edge dorsally, clothed with moderately long setulae; inner surface of posterior margin with numerous setae, becoming longer on lower third. Phallus more or less linear, brownish; distiphallus without swelling in middle. Female. Similar to male, except terminalia; cercus short ovate and minutely pilose.

Distribution. PALAEARCTIC: South Ossetia, Georgia.

Remarks. Wiedemannia ossetiana sp. nov. is very similar to W. (Chamaedipsia) oredonensis Vaillant, 1967 known from high mountain landscapes of France and Spain. The new species differs from the latter species by almost straight and thinner phallus, very indistinct cercal plate, surstylus not prominent and details of the structure of the clasping cercus: straight dorsal edge, almost rectangular apex and distribution of inner setae (distinct row between angle of rectangular apex and posterior base). In W. (C.) oredonensis , the phallus is rather thick and distinctly S-shaped, cercal plate quite developed, surstylus distinct and clothed with moderately long setae, and details of the structure of the clasping cercus (dorsal edge not straight, apex distinctly rounded) and distribution of inner setae differs.

The new species is known only from high-altitude streams and rivers of Central Caucasus (2500–3000 m a.s.l.), and is active in July.

Etymology. The new species is named in reference to its type locality, South Ossetia.

Figures

FIGURES 7 – 11. Male terminalia of Wiedemannia, lateral view. 7, W. klausnitzeri Joost (from Joost 1981); 8, W. kustovi Sinclair & Shamshev (from Sinclair & Shamshev 2014); 9, W. lota Walker; 10, W. nartshukae sp. nov.; 11, W. ossetiana sp. nov. Scale bar = 0.1 mm. Abbreviations: sur—surstylus.