Stictane trigonica Bayarsaikhan & Černý, 2022

Bayarsaikhan, Ulziijargal, Cha, Yeong-Bin, Černý, Karel, Kwon, Hyung-Wook & Bae, Yang-Seop, 2022, Review of the genus Stictane Hampson (Lepidoptera, Erebidae, Arctiinae) in Thailand with description of a new species, Zootaxa 5138 (4), pp. 481-491 : 489-490

Stictane trigonica Bayarsaikhan & Černý , sp. n.

( Figs 11 , 19 , 24 )

Type materials. HOLOTYPE: 1 ♂, SW Thailand, Chumphon-prov., Pa Toh distr. , Ban Lang Tang, 162m, 7.XII.2005 (N9˚46′5″, E98˚46′59″) (leg. K. Černý), Gen. Slide No. INU˗10363 Thailand . PARATYPES (2 ♂, 1 ♀) SW Thailand: 1 ♂, same data as for the holotype ; 1 ♂, 1 ♀, Ranong, 543m (N10˚02′1″, E98˚40′17.66″), 7.IV.2013 (leg. K. Černý), Gen. Slide No. INU˗10353 Thailand (Coll. CKC) .

Diagnosis. The new species has no remarkable external differences from other members of the genus in the antemedial series of three large dark spots (fourth small dark spot presented near tornus in S. trigonica sp. n.), more or less curved dark medial band, 1–3 discoidal dark spots (two dark spots in S. trigonica sp. n., figs 7a, b), and a curved postdiscal series of dark small spots of whitish forewing.

According the subapical spine on outer margin of cucullus in male genitalia, the present new species is similar to S. fractilinea ( Snellen, 1880) , S. muara Holloway, 2001 , S. heppneri Bayarsaikhan & Bae, 2019 , and S. bayarsaikhanae Bucsek, 2020 . But the new species can be distinguished from those similar species by the short (shorter than apex of uncus), roundly stout valva with a short subapical spine on outer margin of cucullus medially, it is above the tip of saccular spine, and aedeagus vesica has an area of thin, diverse sized spines and one large-wrinkled spine. In S. fractilinea , slender valva is longer than apex of uncus, with a short (almost same size to S. trigonica sp. n.) subapical spine on outer margin of cucullus, it is arising immediately near the tip of saccular spine, and aedeagus vesica has a bundle of thin spines and a straight larger one ( Kirti et al. 2013: 4, figs 4–7). In S. muara , stout valva is shorter than apex of uncus, with a long (almost four times longer than S. trigonica sp. n.) subapical spine on outer margin of cucullus, it is arising immediately near the tip of saccular spine, and aedeagus vesica with numerous cornuti ( Holloway 2001: 418, figs 8d-e). In S. heppneri , stout valva is shorter than apex of uncus, with a long (almost two times longer than S. trigonica sp. n.) subapical spine on outer margin of cucullus, it is above the tip of saccular spine, and aedeagus vesica has two bundles of thin, short spines and a long, slender, strongly waved one ( Bayarsaikhan et al. 2019: 260, fig 24a-b). In S. bayarsaikhanae , slender valva is shorter than apex of uncus, with a short (almost same size to S. trigonica sp. n.) subapical spine on outer margin of cucullus, it is arising immediately near the tip of saccular spine, and aedeagus vesica has a bundle of thin, same sized spines and a weakly waved, larger one ( Bucsek 2020: 44, figs 89–92, Bayarsaikhan et al. 2021: 142, figs 14a-b).

The female genitalia structure of the present new species is similar to S. munda (De Joannis, 1928) ( Bayarsaikhan & Bae 2021: 91, fig. 4B), and S. imorod Chen, Hsu, Chen & Buchsbaum, 2018 ( Chen et al. 2018: 41, fig. 4). But the new species can be distinguished from two other species by the globular corpus bursae membranous and bent appendix bursae strongly sclerotized whole of length. In S. munda , corpus bursae is irregularly ovoid and strongly sclerotized, except membranous medial area, and membranous appendix bursae with strongly sclerotized plate in cervix area. In S. imorod , globular, membranous corpus bursae has strongly sclerotized plate, its covered spines and appendix bursae is weakly sclerotized along whole length.

Description. Adult ( Figs 11a, b ). Male and female are superficially similar. Length of forewing 6 mm in male ( Fig 11a ) and female ( Fig 11b ). Head and frons pale gray; labial palpus dark, slender, upturned. Patagium, tegula and thorax pale gray. Ground color of forewing pale gray; basal and costal area tinged with fuscous; antemedian series of three large, dark spots distinct and last smaller one indistinct near tornus; dark brown medial band distinctly convex, interrupted or clouded in cell; a pair distinct discoidal dark spots of discal area different sized, which lower one two times bigger than upper; postdiscal series of dark spots curved outward; before apex with one fuscous patch; terminal series of small spots dark. Hindwing fuscous gray; costal and terminal area narrowly fuscous. Male genitalia ( Fig 19 ). Uncus slender, hook˗shaped, with a small spine at tip, same length with tegumen. Tegumen weakly sclerotized. Valva symmetrical, weakly sclerotized whole of length, basal half of valva broader than rounded apical half, its heavily covered with setose; costa with an angled swollen projection medially; slender, curved cucullus with a subapical spine, which almost six times shorter than saccular spine. Sacculus stout, and blunt apical saccular process with a slender, sickle˗shaped spine, that not extend into small spine on outer margin of cucullus. Juxta arched and apical lobe of juxta heart˗shaped. Aedeagus stout and vesica with a large, wrinkled, tapering spine and an area of thin, diverse sized spines, and finely scobinate. Female genitalia ( Fig 24 ). Papillae anales triangular, weakly sclerotized. Apophyses posteriores about three times as long as apophyses anteriores, both apophyses slender. Ostium broadly waved, weakly sclerotized. Ductus bursae broad funnel-shaped, weakly sclerotized, two times shorter than corpus bursae. Corpus bursae globular, membranous, with a broad area of strongly sclerotized spines in cervix. Bent appendix bursae strongly sclerotized whole of length.

Distribution. SW Thailand (Chumphon and Ranon provinces).

Etymology. The specific name is derived from the Latin “ trigonicus ” meaning “triangles”, refers to the shape of dark brown medial band of forewing.

Figures

FIGURES 2–11. General view of the body of adults of the genus Stictane from Thailand. 2. S. fractilinea, female (INU˗10364T). 3. S. gemina, male (INU˗10356T). 4. S. mlcochi, male (INU˗10355T). 5a. S. pectenicorniculum, male (OPU˗009T). 5b. ditto, female (OPU˗008T). 6a. S. fuscus, male (OPU˗001T). 6b. ditto, female (OPU˗017T). 7a. S. cambodiensis, male (INU˗10358T). 7b. ditto, female (INU˗10362T). 8a. S. bokorensis, male (OPU˗014T). 8b. ditto, female (OPU˗018M). 9. S. kualabohi, female (INU˗10351T). 10. S. transversana, male (OPU˗015T). 11a. S. trigonica sp. n., male (holotype, INU˗10363T). 11b. ditto, female (paratype, INU˗10353T).

FIGURES 12–19. Male genitalia of the genus Stictane from Thailand. 12. S. gemina (INU˗10354T). 13. S. mlcochi (INU˗10355T). 14. S. pectenicorniculum (OPU˗009T). 15. S. fuscus (OPU˗016T). 16. S. cambodiensis (INU˗10358T). 17. S. bokorensis (OPU˗014T). 18. S. transversana (INU˗10350T). 19. S. trigonica sp. n. (holotype, INU˗10363T).

FIGURES 20–26. Female genitalia of the genus Stictane from Thailand. 20. S. fractilinea (INU˗10364T). 21. S. pectenicorniculum (OPU˗008T). 22. S. fuscus (OPU˗011T). 23. S. bokorensis (OPU˗018Malaysia). 24. S. trigonica sp. n. (paratype, INU˗10353T). 25. S. kualabohi (INU˗10351T). 26. S. cambodiensis (INU˗10362T).