Gandaritis stueningi Wen & Cheng, 2025

Wen, Boxin & Cheng, Rui, 2025, A taxonomic study of Gandaritis flavomacularia and related species (Lepidoptera, Geometridae), with description of a new species from western China, ZooKeys 1255, pp. 333-341 : 333-341

Gandaritis stueningi Wen & Cheng sp. nov.

Figs 2–6 , 17–20 , 25 Chinese common name: 斯氏枯叶尺蛾

Type material.

Holotype, ♂, China: Sichuan ( IZCAS): • Pingwu, Wanglang , 2446 m, 21–22.VII.2016, leg. Cui Le, slide no. Geom- 07564, IOZ LEP M 22602 . Paratypes: Shaanxi ( IZCAS): • 1 ♂, 1 ♀, Tiantaishan, Jialingjiang , 1062 m, 8–9.VIII.2014, leg. Xue Dayong, slide no. Geom- 07566, IOZ LEP M 15798 , 15862 ; • 1 ♀, Ningshan, Huoditang , 1550 m, 8.VII.2008, leg. Cui Junzhi ; • 1 ♂, 1 ♀, ( IZCAS, ex. ZFMK), Tapaishan im Tsinling Sued-Shensi , ca. 1700 m, 8.VIII.1936, leg. H. Höne, slide no. Geom- 01949 . Shaanxi ( ZFMK), 3 ♀, Tapaishan im Tsinling Sued-Shensi , ca. 1700 m, 22–26.VII.1935, leg. H. Höne ; • 4 ♂, 2 ♀, ibidem, 6–19.VIII.1935 ; • 6 ♂, 8 ♀, ibidem, 5–19.VIII.1936 ; • 1 ♀, Tapaishan im Tsinling Sued-Shensi , ca. 3000 m, 25.VII.1935, leg. H. Höne ; • 3 ♂, 3 ♀, ibidem, 11–25.VIII.1936 . Gansu ( IZCAS), 8 ♀, Dangchang, Guanegou , 2045 m, 1–3.VIII.2016, leg. Cheng Rui & Jiang Shan ; • 1 ♀, Wenxian, Liziba , 1971 m, 22–24.VIII.2014, leg. Li Xinxin ; • 2 ♀, Wenxian, Qiujiaba , 2200 m, 16–19.VII.2003, leg. Wang Hongjian ; • 1 ♀, Kangxian, Qinghe , 1400 m, 7.VII.1999, leg. Zhu Chaodong . Sichuan ( IZCAS), 1 ♀, Pingwu, Wanglang , 2504 m, 23.VII.2016, leg. Cui Le, slide no. Geom- 07563, IOZ LEP M 22674 ; • 10 ♀, Pingwu, Wanglang , 2410 m, 5.VIII.1999, leg. Zhou Xin.

Description.

Head. Antennae filiform in both sexes, lacking cilia. Head coloration dark grayish-brown to blackish-brown. Labial palpus moderately long, extending beyond frons. Vertex grey-brown, intermixed with grayish-white scales.

Thorax. Dorsally dark grayish-brown to blackish-brown. Leg coxae grayish-white, femora to tarsi pale yellowish-gray, intermixed with dark grayish-brown. Patagia sparsely mixed with yellowish scales. Forewing length: ♂ 26–27 mm, ♀ 29–31 mm. Wings broad; forewing with apex pointed, slightly protruding; outer margin gently curved. Hindwing termen arched. Discocellular of hind wing strongly biangulate; vein D 2 distinctly longer than D 1 and D 3; base of M 2 slightly close to M 3. Wing omit comma color brown to blackish-brown. Forewing with white antemedial, medial, and postmedial lines. Antemedial line oblique outward from costa to discal cell, slightly thickened, bending inward within cell, slightly wavy to inner margin. Median line thickened at costa, forming an outwardly oblique wedge-shaped white patch, angled backward within discal cell and slightly wavy to inner margin. Postmedial line narrow white streak, tapering, extending obliquely to mid-vein M 2, following part inclined to basal 1 / 3 of CuA 2 or often invisible, then slightly thicken and wavy to inner margin. Submarginal and terminal lines absent. Fringes thickened with wing. Hindwing. Costa grayish-white from base to postmedial line; area below often tinged with yellow, sometimes expanding downward forming diffuse yellow patch at mid-wing. Discal spot round, dark brown, faint. Postmedial line stout, yellow, deeply curved, lower half slightly wavy. Submarginal line curved, composed of a series of crescent-shaped yellow spots. Costa yellow from submarginal line to apex. Fringes yellow at apex, remainder concolorous with wing. Forewing underside. Mostly yellowish; costa to discal cell intermixed with grayish-white and dark brown; distal part blackish. Dark brown patch present at middle of anterior margin of discal cell. Discal spot rounded, dark brown. Postmedial line blackish, anterior part very broad, forming a “> ” - shaped angle; posterior part tapering and bent outward near inner margin. Submarginal line blackish, curved, discontinuous on veins, almost merged with blackish distal part near costa. Underside of male forewing without secondary sexual characteristics. Hindwing underside. Grayish-white to pale grayish-yellow, mixed with brown. Postmedial and submarginal lines blackish; the former deeply curved, with posterior part broader; the latter broad and arcuate, interrupted on veins. Discal spot more distinct than upperside. Abdomen. Its dorsal side dark grayish-brown to blackish-brown, intermixed with grayish-white scales; ventral sides grayish-white. Setal patch on male third sternite absent.

Male genitalia (Figs 17–20 ). Uncus very long, narrow, apex pointed. Tegumen simple. Juxta broad, bearing well sclerotized conical process medially on posterior margin. Anellus lobe developed, extremely robust, truncate at apex, densely covered with long hairs, tip swollen. Saccus short and broad. Valva wide and simple. Aedeagus stout, large, its middle part broad; vesica large, membranous, lacking cornuti. Manica with a short, tongue-like process, surrounding membrane finely spined.

Female genitalia (Fig. 25 ). Papilla anales simple. Apophyses posteriores and anteriores slender and elongate. Lamella antevaginalis narrow, semicircular, sclerotized band. Ductus bursae approximately two-thirds length of elliptical corpus bursae; colliculum present at lower half. Corpus bursae bears an irregularly shaped signum, located at middle area and ventral side, composed of numerous spinules.

Diagnosis.

This species is morphological similar to G. flavomacularia (Figs 7–10 ). Compared to G. flavomacularia , the wing color of G. stueningi sp. nov. is darker; the white streak along the forewing postmedial line is narrower, straighter, and more steeply inclined. In G. stueningi sp. nov., the submarginal and terminal lines are absent, whereas in G. flavomacularia , the submarginal line consists of a series of white spots of various sizes, and the terminal line forms a series of yellow dots at the end of veins. On the underside, G. stueningi sp. nov. is darker, and the postmedial line is more strongly protruding, forming a “> ” shape, while in G. flavomacularia , the postmedial line is less convex, and connected to the submarginal line by a black-brown spot. The genitalia also differ: the male saccus in the new species is narrower than that in G. flavomacularia (Figs 21 , 22 ) and in the female of the new species, the antrum is shorter and the signum more slender than in G. flavomacularia (Fig. 26 ). Unlike G. tristis (Figs 13–16 ), which has a yellow costal patch extending to the wing apex, G. stueningi sp. nov. shows white spots along the upper half of the postmedial line. Although molecular evidence supports the closest relationship of this new species with G. flavescens (Figs 11 , 12 ), G. stueningi sp. nov. can be distinguished by the absence of secondary sexual characteristics.

Distribution.

China ( Shaanxi, Gansu, Sichuan).

Etymology.

The species is named after Dr Dieter Stüning (Bonn, Germany), former curator of Lepidoptera at the Zoological Research Museum Alexander Koenig, Bonn, and a well-known specialist, for his significant contributions to Geometridae taxonomy.

Molecular data.

Gandaritis stueningi is clearly separated from closely related species based on COI barcode sequences (Fig. 1 ). The genetic distance between G. stueningi and G. flavescens is 2.11 % to 2.77 %, and between G. stueningi and G. flavomacularia is 5.13 % to 5.30 %. The mean intraspecific distance of G. stueningi is 0.68 % (range 0–1.07 %; N = 4).

Figures

Figure 1. Neighbour-joining (NJ) tree of selected Gandaritis based on the Kimura two-parameter model.

Figures 2–16. Wing pattern of Gandaritis species. 2–6 G. stueningi sp. nov. 2. Holotype, male, upperside (in: IZCAS); 3. Ibidem, underside; 4, 5. Paratype, female, upperside (in: IZCAS); 6. Ibidem, underside; 7–10. G. flavomacularia. 7. Male, upperside (in: IZCAS); 8. Ibidem, underside; 9. Female, upperside; 10. Ibidem, underside; 11, 12. G. flavescens. 11. Holotype, male, upperside (in: IZCAS); 12. Ibidem, underside; 13–16. G. tristis. 13. Male, upperside (in: ZFMK); 14. Ibidem, underside; 15. Female, upperside (in: ZFMK); 16. Ibidem, underside. Scale bars: 1 cm.

Figures 17–26. Male and female genitalia. 17–24. Male genitalia. 17–20. G. stueningi sp. nov.; 17, 18. Holotype (slide no.: 07564); 19, 20. Paratype (slide no.: 01949); 21, 22 G. flavomacularia (slide no.: 07562); 23, 24. G. flavescens (slide no.: 02073); 25–26. Female genitalia. 25. G. stueningi sp. nov., paratype (slide no.: 07563); 26. G. flavomacularia Leech (slide no.: 07561). Scale bars: 0.5 mm.