Wiedemannia pseguashae, 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 : 362-364

Wiedemannia pseguashae sp. nov.

( Fig. 12 )

Type material. HOLOTYPE, ♂ labelled [printed in Cyrillic], [ SOUTH OSSETIA]: “C. Kavkaz, Ju. Ossetia, hr. [ridge] Britauli / C-B skloni g. [north-east slopes of Mountain Britavtsak / lev.bereg r. [left bank of River] Britadon / Vis. [high] 2500 m [a.s.l.] / 42°29'13.4"N, 044°10'34.6" E / 21.vii.2013, D. Zherebilo” ( ZIN). PARATYPES: SOUTH OSSETIA: same data as holotype (7 ♂, 5 ♀, ZIN; 7 ♂, 5 ♀, KSU); Central Caucasus, South Ossetia, Gudiysskiy ridge, source of River Britadon, northern slope of the Mountain Mangavtsek, 2700 m a.s.l., 21.vii.2013, D. Zherebilo (2 ♂, 5 ♀, KSU). GEORGIA: Khevsureti, south-western slope of Mountain Tanie, 2850 m a.s.l., 19.vii.2014, D. Zherebilo (8 ♂, 3 ♀, KSU); Khevsureti, the northern slope of Kistanistavi, 2830 m a.s.l., 21.vii.2014, D. Zherebilo (7 ♀, KSU); same lokality, 2900 m a.s.l., 21.vii.2013, D. Zherebilo (104 ♀, KSU).

Diagnosis. This species is distinguished by acrostichals divergent around the prescutellar depression, 6–7 pairs of dorsocentrals with interspersed numerous shorter setae, dark brown scutum with light brown pruinescence on prescutellar depression; 2 anterior setae on fore femur and unilobed, elongate, narrowed apically clasping cercus with inner numerous setae on posterior margin, becoming longer on lower third.

Description. Male. Body length 4.5–5.1 mm; wing length 5.0–6.0 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. 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 almost equal in size to scape, with complete circlet of apical setae; postpedicel longer, apically pointed, stylus twice as long as postpedicel, tip blunt. Palpus with numerous dark dorsal setae. Thoracic pleura with blue pruinescence; scutum dark brown with indistinct darker strips between rows of acrostichals and dorsocentrals; prescutellar depression with light brown pruinescence, extending onto concolourous scutellum; postpronotal lobe and lower margin of notopleuron with lighter pruinescence. Antepronotum with pair of dark setae and some fine setulae. Proepisternum with whitish fine setulae. Acrostichals small, irregularly biserial, divergent around prescutellar depression; 6–7 pairs of dorsocentrals with numerous interspersed shorter setae; 1 postpronotal seta (with several short setae), 2 notopleural setae (upper stronger), 1 presutural supra-alar seta and with numerous scattered setulae; 1 postalar seta; 1 strong scutellar setae and 2 weak marginal setae. Laterotergite with patch of fine, dark 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. All coxae with longer setae anteriorly. Fore femur narrowed apically, with 2 stout, closely approximated anterior setae on apical third and 1 same seta near tip. 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 (some specimens with veins M1 and M2 form additional cell after dm). R4 and R5 straight and divergent. Halter dark brown with blue pruinescence. Abdominal sclerites with blue pruinescence. Terminalia ( Fig. 12 ): Hypandrium subequal in length to epandrium, bearing several setae. Epandrium rhomboid, covered with numerous dark long setae especially ventrally and laterally. Clasping cercus unilobed, elongated, narrowed apically clothed with fine 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 pseguashae sp. nov. is most similar to W. (Chamaedipsia) pyrenaica Vaillant 1967 and W. (Chamaedipsia) beckeri , but differs by the structure of the male terminalia, especially the form of the clasping cercus and distribution of inner setae. Wiedemannia pseguashae sp. nov. can be differentiated from related new species described in this article as outlined in the key.

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 epithet refers to “Pseguash” (maid of rivers), a pagan goddess in the mythology of ancient Cherkessian.

Figures

FIGURES 12 – 17. Male terminalia of Wiedemannia, lateral view. 12, W. pseguashae sp. nov.; 13, W. pseudovaillanti Joost; 14, W. shamshevi Kustov & Zherebilo; 15, W. sinclairi Kustov & Zherebilo; 16, W. vaillanti Joost; 17, W. zetterstedti (Fallén). Scale bar = 0.1 mm.