Idaea khankaensis, Beljaev, Eugene A., 2006

Beljaev, Eugene A., 2006, Descriptions of a new species of Idaea Treitschke and the female of Scopula vojnitsi Inoue (Lepidoptera: Geometridae, Sterrhinae) from the Russian Far East, Zootaxa 1364, pp. 51-57 : 51-55

Idaea khankaensis sp. n.

( Figs 1, 2 )

Diagnosis. The new species is comparatively robust; the ground color of the wings is monochromatic pale grayish-yellow, with indistinct, grayish, gently curved transverse lines; the discal spot is lacking; and the forewing apex is not elongated. The male genitalia differ from those of other species of Idaea Treitschke by the possession of a simple, almost rectangular valva with strongly developed setae of the cucullus, and a simple aedeagus with a scobinate vesica lacking cornuti. The female genitalia differ by the distinct median narrowing of the ventral sclerotization of ductus bursae and by the possession of a band of 2–3 rows of teeth around the bottom of the corpus bursae, which form a sclerotized plate on the dorsal wall of corpus bursae that is acute-angled posteriorly.

Description. Male. Wingspan 16 mm. Labial palpi fine, short, not extending beyond frons, covered with blackish scales. Proboscis well developed. Frons black, vertex and basal segments of antenna white. Basal segments of antenna simple, thickened, flagellum ciliate with prismatic segments, thickened from the base approximately to the middle. Occiput, patagia, thorax, tegulae, wings, and abdomen pale grayish-yellow (light-buff) with sparse blackish scales. Forewing wide with rounded outer margin; weak, almost inconspicuous subterminal transverse line, and indistinct sinuous postmedial, medial, and antemedial grayish lines. Discal spot absent. Fringe concolorous with wing. Hindwing as forewing, but subterminal transverse line almost inconspicuous, antemedial line absent, and slightly marked angle at the end of M3. Retinaculum large, frenulum strong. Hind leg with tibia slightly thickened, spurs lacking, tarsus length almost same as tibia.

Male genitalia ( Figs 4, 5 ). Uncus conical, moderately long, rounded at the apex. Gnathos broad, rectangular, with concave (in holotype) or nearly straight (in paratype) posterior margin. Valve long, with almost parallel dorsal and ventral margins, distally subrectangular, simple, without any processes but with strongly developed setae on cucullus. Transtilla narrow, ribbonlike. Juxta simple, wide, joined to aedeagus. Saccus small, rounded. Aedeagus large, thick; vesica evenly and densely scobinate, without cornuti.

Female. Wingspan 18 mm. As described for male, except antenna filiform; forewing more rounded at the apex, transverse lines more distinct, and frenulum well developed, consisting of several long setae in a dense tuft. Hind tibia simple, about same length as tarsus, with one pair of long spurs.

Female genitalia ( Fig. 6 ). Papillae anales with additional papillae ventrally. Posterior apophyses long, anterior apophyses half as long as posterior ones. Ductus bursae long, moderately wide, ventrally with long, ribbonlike sclerotization narrowed at the middle; ostial area simple, not dilated. Corpus bursae oval, approximately as long as ductus bursae, membranous, weakly wrinkled longitudinally, with dense ring of conical teeth around membranous bottom and triangular, acute-angled posterior sclerotized zone of similar teeth on the dorsal wall of corpus bursae. Ductus seminalis arising from right side of corpus bursae; basal part of ductus seminalis (appendix bursae) broad and long, C-shaped, arched on the left; proximal half of the appendix bursae sclerotized, longitudinally wrinkled, with several irregular longitudinal rows of small spines on the wrinkles, distal portion membranous, inflated.

Types. Holotype: 1 ɗ, Russia, Primorsk Territory, 17 km W Pokrovka, plateau West from Orlikha River, 43°56'37" N 131°25'13", 31.vii–2.viii.2005 (E. Beljaev leg.). Paratypes: 1 Ψ, same locality and data (E. Beljaev leg.); 1 ɗ, Russia, Primorsk Territory, 50 km West Ussuriisk, Gorelaya Pad’, 43°49'02" N, 131°21'58" E, 25, 26.vii.2003 (E. Beljaev leg.).

Distribution. Russia, southwest of Russian Far East ( Fig. 8 ), probably also distibuted in northeastern China.

Habitat. All specimens were collected on insolated dry stony glades with sparse grass in the Manchurian and Siberian apricot communities ( Prunus manchurica , Prunus sibirica ).

Biology. Probably univoltine; imago recorded in late July and early August.

Etymology. The specific epithet is derived from the name "Khanka", the lake for which the neighboring plains south and southwest of it are named.

Remarks. The species probably is closely related to Idaea tanakai Sato, 1994 , which was described from 2 females from southern Honshu (Aichi Prefecture, Japan). Females of Idaea tanakai differ from those of the new species by more distinct postmedial transverse line of the forewing, which is less curved inward beyond the vein M1; however, the diagnostic significant of this character requires confirmation. In the genitalia it differs by the ventral sclerotization of the ductus bursae which is narrower and with almost parallel lateral sides without narrowing at the middle; by the possession of a large, heavy extended dilation of the left side of corpus bursae; by the narrower band of spines around the bottom of the corpus bursae which consists of 1–2 rows of teeth (whereas in the new species the band consists of 2–3 rows of teeth); and by strongly curved appendix bursae. In Idaea tanakai the band of spines on the dorsal wall of the corpus bursae forms a wide bend, not a whole, acute-angled, sclerotized plate as in the new species.

No other known species (except I. tanakai ) are closely related to I. khankaensis . The male genitalia somewhat resemble those of Idaea sylvestraria Hübner ; however, the valva is distally broader and more rectangular, the saccus is much narrower, the aedeagus is larger, and the vesica is more heavily scobinate; in the female genitalia the corpus bursae is quite different. We do not associate I. khankaensis with any species-group of Idaea as proposed by Sterneck (1940) or Hausmann (2004).

Figures

FIGURE 8. Distribution of Idaea khankaensis sp. n. (rings) and Scopula vojnitsi Inoue (squares): black symbol — type locality; white symbol — other collection localities.

FIGURES 1 – 3. Adults. 1 – 2, Idaea khankaensis sp. n.: 1, male; 2, female; 3, Scopula vojnitsi Inoue, female.

FIGURES 4 – 7. Genitalia. 4 – 6, Idaea khankaensis sp. n.: 4, male genitalia, ventral view; 5, aedeagus, lateral view; 6, female genitalia; 7, Scopula vojnitsi Inoue, female genitalia.