Xestia (Megasema) ashworthii centralaltaica Volynkin & Dvořák, 2016

Volynkin, Anton V. & Dvořák, Marek, 2016, A new subspecies of Xestia ashworthii (Doublebay, 1855) from Russian Altai (Lepidoptera, Noctuidae), Zootaxa 4114 (1), pp. 95-100 : 96

Xestia (Megasema) ashworthii centralaltaica Volynkin & Dvořák , ssp. n.

( Figs 1–4 , 9, 11, 12 )

Type material. Holotype: male, 07–12.vii.2010, Russia, Altai Republic, Ulagan district, Aktash village, bottom of southern steppe stony slope, h= 1350 m, by light-trap. 50º19' N, 87º35' E. Volynkin A.V. leg. (Coll. ZISP, ex coll. AVB). Slide AV0399 Volynkin.

Paratypes: 1 male, Russia, Altai Mts., 50º14–16' N, 87º50–55' E, Kuraiskaja step [Kurai steppe], 1500–1700 m, 27.vi.2000, T. & K. Nupponen leg. (Coll. KNE); 2 females, 08.vii.2009, Russia, Altai Republic, Ulagan district, 26 km S of Balyktuyul' village, Chulyshman valley, bottom of steppe stony slope, h= 500 m. 51º00' N, 88º01' E. By light-trap. Volynkin A.V. & Černila M. leg. Slides AV0360, AV1755 Volynkin. (Coll. AVB); 1 male, 8 females, 27–28.vi.2015, Russia, Altai Republic, Ulagan District, Ulagan vill. (45km N), Chulyshman valley, 600 m, 51°01’54’’N; 88°00’44’’E, Dvořák M. leg. (Coll. MDS); 1 male, 3 females, the same data, but Šumpich J. leg. (Coll. NMPC).

Diagnosis. The new subspecies ( Figs 1–4 ) differs externally from X. ashworthii candelarum ( Figs 5–7 ) in the narrower forewing (like X. a. ashworthii , Fig. 8 ) having darker ground colour without brown suffusion. The new subspecies differs clearly from X. a. candelarum in the female genitalia structure: in X. a. centralaltaica ( Figs 11, 12 ) the posterior sclerotised part of the ductus bursae is longer and narrower than in X. a. candelarum ( Fig. 13 ), the antevaginal plate is narrower and more or less V-shaped (in X. a. candelarum the antevaginal plate is more or less U-shaped), the corpus bursae is somewhat smaller. The male genitalia of X. a. centralaltaica ( Fig. 9 ) are very close to those of X. a. candelarum ( Fig. 10 ) and differ only in the somewhat longer and narrower pollex and the much larger apical process of the juxta.

Molecular data. Two specimens of X. a. centralaltaica from different isolated localities of Central Altai (Aktash vill. and Chulyshman valley) were compared with two specimens of X. a. candelarum from Europe ( Switzerland Alps) and Northeastern Kazakhstan ( Fig. 14 ). The comparison was made also with sequences of other Megasema species free available on the BOLD Systems website (www.boldsystems.org). Distance between a specimen of X. a. candelarum from Switzerland Alps and a specimen from NE Kazakhstan is 0.17 %. Distance between two specimens of X. a. centralaltaica collected in two isolated localities also is 0.17 %. Minimal distance between specimens of X. a. candelarum (NE Kazakhstan) and X. a. centralaltaica (Aktash) is 0.52 %. Maximal distance between specimens of X. a. candelarum ( Switzerland) and X. a. centralaltaica (Chulyshman valley) is 0.87 %. Distance between the two specimens of X. a. candelarum and specimens of a closely related species X. wockei (samples from Canada with incomplete sequences 609 and 641 bp) is 1.75 % ( Fig. 14 ).

Description. Adult ( Figs 1–4 ). Wingspan 39–41 mm. Antennae ciliate in males and filiform in females. Head, thorax and abdomen dark ashy grey. Ground colour of forewing monotonous dark ashy grey. Subbasal line thin, blackish, dentate; antemedial line thin, blackish, irregularly dentate, with large dark spot on the costa; postmedial line dentate, with large dark spot on the costa; subterminal line dark, strongly diffuse; terminal line thin, dark grey, wavy. Orbicular and reniform stigmata somewhat paler than ground colour, cell between them dark grey. Cilia dark ashy grey. Hindwing ashy grey, somewhat paler basally. Discal spot semilunar, dark grey, strongly diffuse. Cilia grey. Male genitalia ( Fig. 9 ). Uncus long, narrow, curved, apically pointed; tegumen short, penicular lobes broad; vinculum short, U-shaped. Juxta narrow, hearth-like, its apical process very large, lobe-like. Valva elongated, basally broadened, slightly curved, its apical part narrowed, rounded, strongly setose; pollex long, narrow; harpe relatively long, trigonal slightly curved, apically rounded; sacculus broad. Aedeagus moderately long, broad, carina ventrally armed with a pointed spine; vesica tubular, curved dorsally, with large, sack-like dorsal subbasal diverticulum, bulbous medio-lateral diverticulum and dorsal sclerotised band. Female genitalia ( Figs 11, 12 ). Ovipositor short, conical. Apophyses posteriores long, thin; apophyses anteriores about half as shorter, thin. Antevaginal plate large, strongly sclerotised, horseshoe-like. Posterior part of ductus bursae strongly sclerotised, broad, moderately long; anterior part of ductus bursae about half as shorter, membranous, with a very small membranous lateral pouch. Corpus bursae very broad, sack-like, slightly wrinkledsclerotised; appendix bursae large, sack-like, distally broadened.

Distribution and bionomics. The new subspecies is known from Central Altai province of the Russian Altai Mts. (Volynkin 2012) ( Fig. 15 ). X. a. centralaltaica inhabits rocky slopes and steppe valleys at medium high altitudes ( Fig. 16 ), the moths fly from late June to mid July.

Etymology. The subspecies name is toponymical.

Figures

FIGURES 1 – 8. Xestia ashworthii sspp.: adults. 1, X. a. centralaltaica, holotype, male, Russian Altai, Aktash (ZISP); 2, X. a. centralaltaica, paratype, female, Russian Altai, Chulyshman valley (AVB); 3, X. a. centralaltaica, paratype, female, Russian Altai, Chulyshman valley (MDS); 4, X. a. centralaltaica, paratype, female, Russian Altai, Chulyshman valley (MDS); 5, X. a. candelarum, male, Germany, Dresden (ZSM); 6, X. a. candelarum, male, NE Kazakhstan, Dmitrievka (AVB); 7, X. a. candelarum, Mongolia, male, Töv aimak (PGM); 8, X. a. ashworthii, male, Great Britain, Wales (ZSM).

FIGURES 9 – 13. Xestia ashworthii sspp.: male (9, 10) and female (11 – 13) genitalia. 9, X. a. centralaltaica, holotype, Russian Altai, Aktash, slide AV 0399 Volynkin; 10, X. a. candelarum, West Siberian Plain, Novosibirsk reg., slide AV 0748 Volynkin; 11, X. a. centralaltaica, paratype, Russian Altai, Chulyshman valley, slide AV 0360 Volynkin; 12, ditto, slide AV 1755 Volynkin; 13, X. a. candelarum, East Siberia, Minusinsk, slide AV 0011 Volynkin.

FIGURES 14 – 16. Xestia ashworthii: barcoding tree, distribution map and habitat. 14, Diagram of DNA barcoding tree for Xestia ashworthii sspp. and X. wockei; 15, Distribution map of X. a. centralaltaica and X. a. candelarum in southern Siberia; 16, Russia, Altai Republic, Ulagan district, Chulyshman valley, 51 º 00 ' N, 88 º 01 ' E, the habitat of X. a. centralaltaica.