Periacma mediacantha Wang, 2024

Wang, Shuxia & Xu, Zhixin, 2024, Taxonomy of the genus Periacma Meyrick (Lepidoptera: Autostichidae) from China, with a checklist of the world species, Zootaxa 5399 (2), pp. 101-129 : 114

Periacma mediacantha Wang , sp. nov.

( Figs 12 , 27 )

Type material. CHINA, Hainan: Holotype ♂, Lizudadian (18.53ºN, 109.40ºE), Shuiman Town, Wuzhishan , 766 m, 31.VII.2016, leg. X Bai et al., slide No. ZXJ18476 . Paratype: 1♂, Wuzhishan , 738 m, 25.VII.2016, leg. X Bai et al., slide No. XZX20849 .

Diagnosis. The new species is similar to P. nakhonnayokensis Moriuti, Saito et Lewvanich, 1985 . It can be distinguished by the costa with a large spine-shaped process near the middle, and the aedeagus with a spine arising from beyond the middle and produced to a spine-like process distally. In P. nakhonnayokensis , the costa has a spine-like process near the apex, and the aedeagus lacks a spine beyond the middle and is produced to a digitate process distally.

Description. Adult ( Fig. 12 ). Wingspan 15.0 mm.

Head. Vertex and frons yellow. Labial palpus yellow, with scattered black scales on outer side; second segment ringed with black near apex. Antenna with scape yellow, covered with brown scales on dorsal surface; flagellum yelloe, annulated with yellowish brown on dorsal surface.

Thorax. Mesonotum brown, mixed with pale yellow scales; tegula black basally, yellow distally. Forewing yellow, with scattered brownish yellow scales; greyish black spot at base of costal margin and dorsum respectively; discal, discocellular, plical and tornal spots greyishblack, plical spot smallest, tornal spot largest; greyish black scales from distal 1/4 of costal margin diffused obliquely inward to discocellular spot; apical spot greyish black; terminal dots greyish black, ranging from below apex and along termen to tornal spot; fringe yellow, greyish black distally around apex. Hindwing deep grey; fringe yellowish grey. Legs pale yellow, except three distal tarsomeres of fore- and midlegs black; on ventral surface, foreleg with black scales on coxa; on dorsal surface, foreleg black on femur, tibia with dense black scales at base and near apex, midleg with blackish grey scales on femur, tibia black at base and with a few black scales on distal half, tarsus black at middle of first tarsomere and at base of second tarsomere; on outer surface, tarsus of hindleg with black scales.

Male genitalia ( Fig. 27 ). Uncus sub-rectangular, sclerotized laterally, obtuse apically. Gnathos with basal arm slender, half length of ventral plate; ventral plate gradually narrowed to 1/2, thereafter slightly widened to rounded apex. Valva with costal part gradually widened from base to basal 3/5, then narrowed to obtusely rounded apex, convex at middle on ventral margin; costa straight, medially with a large triangular process that is spine-shaped distally; dorso-proximal process small, rod-like, setose; sacculus slightly shorter than costal part of valva, basal 2/3 broad, narrowed from distal 1/3 to apex, strongly sclerotized distinctly. Saccus sub-triangular. Aedeagus almost as long as sacculus, heavily sclerotized from basal 2/5 to apex, expanded and forming a large sclerotized circle from basal 2/5 to distal 1/6, its inner edge finely serrate in part and with a large distinct spine, outer edged with two denticles opposite to large spine, distal 1/6 produced to a spine-shaped process.

Female unknown.

Distribution. China (Hainan).

Etymology. The specific epithet is from the Latin media- and acanthus, referring to the costa medially produced to a triangular process that is spine-like distally.

Figures

FIGURES 10‒18. Adults of Periacma spp. 10. P. platygnatha sp. nov., holotype; 11. P. ludingensis sp. nov., holotype; 12. P. mediacantha sp. nov., holotype; 13. P. nakhonnayokensis; 14. P. nepalensis; 15. P. rectignatha; 16. P. securiformis sp. nov., holotype; 17. P. solitaridens sp. nov., holotype; 18. P. subaequalis sp. nov., holotype. Scales = 2.0 mm.

FIGURES 25‒28. Male genitalia of Periacma spp. 25. P.platygnatha sp. nov., holotype, slide No.LiSR16014; 26. P. ludingensis sp. nov., holotype, slide No. XZX20613; 27. P. mediacantha sp. nov., holotype, slide No. ZXJ18476; 28. P. nakhonnayokensis, slide No. ZXJ18211. Scales = 0.2 mm.