Euxoa (Pleonectopoda) steideli, Kononenko & Behounek & Gyulai, 2018

Kononenko, V. S., Behounek, G. & Gyulai, P., 2018, Descriptions of two new species of Euxoa Hübner, [1821], subgenus Pleonectopoda Grote, 1873, from Siberia (Lepidoptera, Noctuidae), Zootaxa 4483 (2), pp. 258-270 : 260-261

Euxoa (Pleonectopoda) steideli sp. n.

( Figs 1–6, 10–12 , 21–28 , 42–44 )

Type material. Holotype: male, labeled (in German): “NE Russia W Buryatia, Sayangeb. 400 km W Baikal-See, 24 km nr. Sagan-Shuluta a. Irkuta. 51°(53–55) 36′N, 100°43–46′E 9-14.vii.2012 /NN 1850–1950 m, leg. A. Steidel, u. Gruppe ” [ Russia, west of Buryatia Autonomic Respublic , Tunkinsky reg., 24 km from Sagan-Shuluta village , East Sayan Range , 1850–1950 m], slide GB 8446, coll. GB/ ZSM .

Paratypes: 2 males, same data, slide GB 8237, coll. GB/ ZSM ; 8 males 14.vii.2012, same locality and collectors (coll. HSW). The holotype and one paratype mentioned above are preserve in the collection of Gottfried Behounek (Grafing, near Munich, Germany), later to be deposited in ZSM . 1 male, Russia, Tuva, Naryn river 50°08′N, 96°00′E, 1450 m, NN, 6.vii.1996 , leg. J.Krüger, coll. PG, slide PG 730. 1 male (with red brown forewing), labeled as “Russland-Sibirien, Mondy [ Russia, Siberia, Buryatia, Mondy] 1887 m, 54°.36.8′ N, 100°45.41,5′E, 6–14. 0 7. 2012, Klaus Metz ”, coll. PG, slide PG 3347 . 1 male, South Siberia, Chita reg. Kuka vill., 25.v.–10.vi.1999, leg. Chech collector., coll. PG, genitalia slide PG 3424. The series of the paratypes preserve in the collection of Peter Gyulai (Miskolc, Hungary) . 1 male, Russia, South Siberia, Tuva, Naryn River / Arzhan , 50°13′N, 96°15′E, 1900 m, 24–26.vi.1996, leg. J. Krüger ; 1 male same locality, 50°08′N 96°00′E, 1450 m, 6.vii.1996, leg. J.Krüger ; 1 male, same locality, 50° 08′N 96° 00′E, 1450 m, 6.vii.1996, leg. A.Saldaitis (Coll. ZFMK).

Diagnosis. The new species externally looks very similar to Euxoa muldersi Lafontaine & Troubridge, 2010 ( Figs 16, 17 ), recently described from Canada. It differs from the latter in its larger size (forewing length 19–20 mm vs 13–15 mm in E. muldersi ), sharper and less blackish forewing pattern, usually with ash-grey background and very light-brown shading, paler basally, with the terminal band more expressed on the hindwing, and normally developed eyes (reduced in E. muldersi ). The male genitalia of E. steideli ( Figs 42–44 ) differ from those of E. muldersi in the shape of the valva, which is less narrow basally, and with a longer and somewhat narrower saccular extension, nearly equal to the harpe (sensu Forbes 1954) in length, and a larger sub-basal diverticulum. Among the Palaearctic species, E. steideli is most similar to E. hyperborea Lafontaine ( Fig. 20 , 41 , 49 ), from which it differs by more variable wing pattern and coloration and by the structure of the male genitalia, particularly the shape of the valva, which is constricted basally and somewhat extended distally, the narrower harpe-saccular extension complex, and the less well developed medial extension of the vesica.

Description. Adult ( Figs 1–6, 10–12 , 21–28 ). Wingspan 39–43 mm, length of forewing 19–20 mm. Frons with elongate, conical, slightly rojecting dorsally tubercle; eyes round; male antenna shortly biserrate, with segments about 1.3× as wide as shaft, with bristle on each segment; first segment of antennae with ring of white scales. Head and thorax covered with white, grey and black hair-like and strap-like scales, usually covering the frontal tubercle. Thorax dorsally covered with yellowish–grey hair-like scale; abdomen covered with pale grey or reddish-grey scales. Tibiae armed with one row of spines on each leg, typical for Euxoa . Forewing narrow, elongate; ground colour in most cases pale ash grey with a mixture of brown and black scales; darker greyish brown, olive brown or reddish brown in medial, subterminal and terminal areas. Wing pattern ground plan typical for Euxoa , formed by basal, antemedial, postmedial and subterminal lines, a basal dash, orbicular, reniform and claviform stigmata. Basal and subbasal fields in most cases ash grey, the basal line prounounced in the costal area; basal streak distinct, or diffuse; antemedial line dentate, greyish, outlined with black; medial field darker than ante- and postmedial fields, greyish brown, olive brown or reddish brown, bearing pale scales, outlined by blackish scales and sometimes darker in the centre of the orbicular, reniform and claviform stigmata; postmedial line dentate along veins; postmedial field paler than medial field, with pale-grey suffusion along veins and blackish or greyish dashes between veins; subterminal line pale, thin, diffuse; terminal field dark grey or yellowish grey, pale along veins; terminal line as a row or blackish vertical streaks, interrupted opposite veins; fringe yellowish-grey with black scales. Hindwing pale, yellowish-grey, with distinct discal spot, dark-grey veins and broad greyish with pale yellowish scales on terminal band; fringe pale yellowish grey. Underside forewing pale grey, with distinct reniform, broad diffused postmedial band and marked subterminal band; hindwing pale yellowish grey shadowed with grey along costal margin, with distinct discal spot, wide blackish postmedial band and darker yellowish-grey terminal band; fringe yellowish.

Variability. E. steideli is rather variable by wing coloration and pattern. Most specimens collected in the upper Irkut valley (Sagan-Shuluta) have ash-grey wings and body ( Figs 1–3 , 21–24 ), similar to E. muldersi . Beside these typical ash-grey specimens with differentiated wing pattern elements, one examined male specimen has reddishbrown ground forewing colouration with the subcostal area and veins suffused with grey scales, a dark-brown subbasal field, and the main wing pattern elements brown ( Figs 3 , 24 ). The specimens from Tuva populations have dull-grey or reddish-grey wing colouration with non-contrast the main elements visible as or thin borders ( Figs 4–6 , 25–28 ) (ante- and post medial lines, orbicular and reniform stigmata represented by thin, sometimes indistinct lines or by pale, dentate borders).

Male genitalia. ( Figs 42, 43 ). Similar to those of E. muldersi ( Fig. 40 ) in most details, but valva somewhat broader; saccular extensions thinner and longer, left extension is almost equal to harpe in length and slightly thinner; the angle between harpe and saccular extension broader; subbasal diverticulum in vesica larger, medial diverticulum smaller. Compared with E. hyperborea , it differs by the shape of valva more constricted basally and markedly extended distally, rounded cucullus and narrower harpe – saccular extension complex and less developed medial extension of vesica in the aedeagus.

Female unknown.

Etymology. The species is named for German geologist and insect collector Axel Steidel who collected the species in the Sayan Mts. (upper reach of Irkut River) in South Siberia and brought it to the attention of authors.

Distribution and bionomics ( Fig. 39 ). The species is known only from mountains of South Siberia: Russia, Tuva, Naryn River valley; southwest of Buryatia, Tunkinsky region, East Sayan Range, upper reach of Irkut River, near Sagan-Shuluta village; Mondy village; south Transbaikalia, Kuka village. Specimens were collected by light in the montane steppe, and river banks at elevation 1850–1950 m. Larva and larval biology unknown.

Figures

FIGURES 1–15. Euxoa (Pleonectopoda) spp., adult (1–9), head capsule, lateral and frontal views (10–15). 1–6, 10–12, E. steideli sp. n., males; (1, holotype, genitalia slide 8237 GB; 2, 3 – paratypes, genitalia slide 8237 GB, all west Buryatia, Sagan- Shuluta; 4–6, ditto, paratypes, 4—Buryatia, Mondy, genitalia slide 3347; 5, 6 Tuva, Naryn valley). 7–9, 13–15, E. kodara sp. n. (male, holotype, genitalia slide 3347, Northern Transbaikalia, Kodar Range, coll. PG; 8, male, paratype, same locality, coll. GB; 9, female, paratype, same locality, coll. ABr.

FIGURES 16–39. Euxoa (Pleonectopoda) spp., adult (16–36), habitat of E. steideli sp.n. (37, 38), distribution map of E. steideli sp. n. and E. kodara sp. n. (39). 16, 17, E. muldersi, Canada, after Lafontaine & Troubridge; 18, E. churchillensis, Canada; 19, E. churchillensis, Russia, Chukchi Autonomy; 20, E. hyperborea, Russia, Magadan reg. Upper Kolyma; 21–26, E. steideli sp. n., (holotype and paratypes) Russia, west, Sagan-Shuluta (21–24), Tuva (25–26), Buryatia, Mondy (27, 28); 29–34 E. kodara sp. n. (paratypes), 29, 31–34, Northern Transbaikalia, Kodar Range; 30, Yakutia; 35, 36, E. culminicola, Austria; 37, 38 montane steppe at altitude 1200–1500 m, habitat of E. steideli sp. n.; 39, distribution map: black circle—E. steideli sp. n., black quadrat E. kodara sp. n.

FIGURES 40–43. Euxoa spp., male genitalia. 40, E. muldersi, Canada (after Lafontaine & Troubridge 2010); 41, E. hyperborea, Russia, Magadanskaya oblast, JK9/15111997 (coll. FNHM);42, E. steideli sp. n., HT, Russia, west Buryatia; Sagan-Shuluta, 8237GB (coll. GB/ZSM); 43, Ditto, PT, 8446GB (coll. GB/ZSM).

FIGURES 44–47. Euxoa spp., male genitalia. 44, E. steideli sp. n., PT, Russia, Buryatia; Mondy, 3347PG (coll. PG/HNHM); 45, E. kodara sp. n., HT, Russia, Northern Transbaikalia, Kodar Range, 3344PG (coll. PG/HNHM); 46, Ditto, PT, Russia, Northern Transbaikalia, Kodar Range, 12191GB (GB/ZSM); 47 Ditto, PT, Russia, Northern Transbaikalia, Kodar Range, 8438GB (GB/ZSM).

FIGURES 48–51. Euxoa spp., male (48) and female (49-51) genitalia. 48, E. culminicola, Austria 8449GB (coll. GB/ZSM); 49, E. hyperborea, Magadan reg. IBP76/VK; 50 E. kodara sp. n., HT, Russia, Northern Transbaikalia, Kodar Range, 8440GB (GB/ZSM); 51, E. culminicola, Austria, 8450GB (GB/ZSM).