Cyana, Walker, 1854

Volynkin, Anton V. & Ivanova, Maria S., 2021, Cyana fossi, a new species from Vietnam (Lepidoptera: Erebidae: Arctiinae Lithosiini), Zootaxa 4938 (5), pp. 595-600 : 595-596

Cyana fossi sp. n.

( Figs 1, 2 , 9 , 13 )

Type material. Holotype ( Figs 1 , 9 ): male, “S. Vietnam, Plato [ Plateau ] Tay Nguyen, Mt. Ngoc Linh, 900–1400m, 15°02’N 107°59’E, 10–25.VIII.1996, leg. Sinjaev [Sinyaev] & Afonin”, gen. slide No.: MWM 34520 (prepared by Volynkin) (MWM/ ZSM).

Paratypes. VIETNAM: 8 males, with the same data as the holotype, gen. slide No.: MWM 34479 (prepared by Volynkin) (MWM/ ZSM) ; 3 males, 2 females, X.2013, South Vietnam, Lam Dong Province, Lac Duong District, Tay Nguyen Highlands , Bidoup Nui Ba National Park , leg. local collector, gen. slide No.: AV5890 (female) ( CAV) .

Diagnosis. The new species is similar externally to C. bellissima ( Figs 3–6 ), but the males ( Fig. 1 ) can be distinguished by the pale ochreous dorsal part of the thorax (which is off white in its congener), the dark brown-white striped legs (those are uniformly pale brown in C. bellissima ), the fully fused, teardrop-shaped distal black spots (in C. bellissima these spots may be connected ( Fig. 5 ), but never fully fused), and the broader subcostal postmedial dash of the forewing; the female specimens of C. fossi ( Fig. 2 ) differ from those of C. bellissima by the dark brown-white striped legs (those are uniformly pale brown in C. bellissima ), the broader transverse lines, the slightly larger black cell spots and the much darker, pale red hindwing which is pale pinkish in C. bellissima . The male genital capsule and the aedeagus of the new species ( Fig. 9 ) display no noticeable differences from those of C. bellissima ( Figs 11, 12 ). However, the everted vesica of C. fossi has a broader and bilobate subbasal diverticulum (which is unilobate in its congener), larger distal diverticulum bearing a conspicuously more extensive cluster of larger spinules and a medial cluster of more robust spinules than in C. bellissima . In comparison with C. stresemanni ( Fig. 10 ), the male genital capsule of C. fossi has medially broader and apically narrower valvae with a slightly longer medial crest and a slightly shorter distal saccular process. The everted vesica of the new species is distinguished from that of C. stresemanni by the bilobate subbasal diverticulum with the broader distal lobe, and the presence of the medial and distal clusters of spinules which are absent in C. stresemanni . The female genitalia of C. fossi ( Fig. 13 ) are similar to those of C. bellissima ( Fig. 14 ), but the posterior section of the corpus bursae is slightly less sclerotized, the basal section of the appendix bursae is more weakly sclerotized, the subbasal section of the appendix bursae is narrower and the main chamber of the appendix bursae is slightly shorter than in C. bellissima . The female genitalia of C. fossi differ from those of C. stresemanni ( Fig. 15 ) in the structure of the appendix bursae: in C. fossi, the basal section is more weakly sclerotized, the subbasal section is narrower, the main chamber is markedly narrower and the distal section is much shorter and narrower compared to those characters of C. stresemanni .

Description. External morphology of adults. Male. Forewing length 19–21 mm. Antenna blackish brown, weakly ciliate. Head white. Collar crimson with white fringe. Patagia white with large crimson spot medially. Dorsal part of thorax ochreous yellow with crimson spot medially and crimson fringe posteriorly. Abdomen pale red. Forewing ground color off white. Subbasal transverse line crimson, angled and strongly constricted at vein R. Antemedial line crimson, oblique, narrow at costa, constricted at vein R and dilated towards the anal margin. Costal margin crimson from wing base to antemedial line. Medial line absent. Medial black spot large, circular. Distal black spots fused into one teardrop-like spot. Postmedial area with a long and broad longitudinal black dash along vein R1. Postmedial line crimson, constricted at costa, then dilated towards anal margin, its costal third slightly undulate. Subterminal area gold, broad, inner margin wavy. Cilia white. Hindwing pale red, with gold suffusion at apex; discal spot broadly semilunar, greyish brown, diffuse; cilia pale red with admixture of gold. Female. Forewing length 28 mm. Antenna blackish brown, filiform. Head white. Collar crimson with white fringe. Patagia white with large crimson spot medially. Dorsal part of thorax white with a crimson spot medially and two crimson spots posteriorly. Abdomen pale red. Forewing ground color creamy white. Subbasal line crimson, interrupted, represented by two spots between costa and vein R and veins R and A1. Costal margin crimson between wing base and antemedial line. Ante- and postmedial lines crimson, relatively narrow, slightly undulate. Medial line absent. Medial cell black spots large, distal ones separated from each other. Subterminal area pale gold, narrow, slightly curved. Terminal area white, broadened at apex. Cilia white. Hindwing pale red, white along costa; discal spot broadly semilunar, greyish brown, diffuse; cilia whitish at apex and along outer margin, pale red along anal margin. Male genitalia. Uncus short, narrow, dorso-ventrally flattened, apically pointed. Tuba analis moderately broad, scaphium absent, subscaphium setose. Tegumen short and narrow. Anellus weakly setose. Juxta large, rectangular with shallow posterior and deep anterior medial depressions. Vinculum short, broad, evenly arcuate. Valva broad basally, narrowed distally, rounded apically. Costal margin strongly curved medially, medial crest of costa long and narrow. Sacculus narrow, moderately sclerotized, its distal process long, robust, curved dorsally, with apex not reaching the valva tip. Aedeagus short, dilated distally; coecum short and narrow, rounded apically. Vesica thick, curved ventrally; dorsal subbasal diverticulum broad, bilobate; its distal lobe slightly narrower and more elongated than dorsal lobe. Ventral subbasal diverticulum very short, bearing an elongate cluster of numerous short spinules. Medial section of vesica with an elongate cluster of numerous short but robust spinules. Distal diverticulum globular, with a circular cornuti field, consisted of numerous short spinules. Distal plate of vesica narrow, stick-like, with irregularly sinuous anterior margin and gently arched posterior margin. Female genitalia. Papillae anales broad, trapezoidal, with rounded corners. Apophyses anteriores and posteriores long, thin, equal in length. Ostium bursae broad. Ductus bursae short, membranous, longitudinally wrinkled. Posterior section of corpus bursae more or less globular, sclerotized. Anterior section of corpus bursae globular, membranous, with a small rounded signum medially. Appendix bursae originating from posterior section of corpus bursae, its basal section tapering, weakly sclerotized, rugose, directed anterio-laterally. Subbasal section of appendix bursae narrow, membranous, curved laterally. Main chamber of appendix bursae broad and long, rounded sack-like, membranous, directed anteriorly. Distal section of appendix bursae narrow, membranous, S- curved.

Distribution. The new species is known so far from the Tay Nguyen Highlands in southern Vietnam.

Etymology. The species is dedicated to the memory of Mr. Grigory G. Foss, friend of the authors.

Figures

FIGURES 1–8. Cyana spp., adults. Depositories of specimens: 1, 3–8 in MWM/ZSM; 2 in CAV.

FIGURES 9–12. Cyana spp., male genitalia. Specimens are deposited in MWM/ZSM. Genital slides prepared by A.V. Volynkin.

FIGURES 13–15. Cyana spp., female genitalia. Depositories of specimens: 13 in CAV; 14 and 15 in MWM/ZSM. Genital slides prepared by A.V. Volynkin.