Thylacosceles cuneiformis, Guan, Wei & Li, Houhun, 2016

Guan, Wei & Li, Houhun, 2016, Thylacosceles Meyrick new to China, with descriptions of four new species (Lepidoptera: Stathmopodidae), Zootaxa 4158 (2), pp. 213-220 : 218-219

Thylacosceles cuneiformis sp. nov.

( Figs. 6 , 12, 13 )

Type material. CHINA: Holotype ♀, Tropical Botanical Garden (102°39′E, 25°1′N), Xishuangbanna , Yunnan Province, 560 m, 5.viii.2010, leg. Yinghui Sun and Lixia Li, genitalia slide No. GW 14005 . Paratype: 1 ♂, same data as holotype, genitalia slide No. GW 14004.

Description. Adult ( Fig. 6 ) with wingspan 7.0− 7.5 mm. Head silvery white; face yellowish white. Labial palpus silvery white on inner side, pale brown on outer side. Antenna with scape silvery white; flagellum silvery white basally, deepening to brown distally. Thorax and tegula silvery white. Forewing with basal 4/5 silvery white mottled pale brown scales, with bluish purple metallic luster, distal 1/5 pale ochreous brown; costal margin blackish brown along basal 1/3; cilia silvery gray. Hindwing brown; cilia pale brown. Legs dominantly silvery white; fore femur pale brown on outer surface, tibia blackish brown on outer surface, tarsus grayish brown, ringed with a blackish brown band at apex of each tarsomere; mid tibia dorsally with long creamy white scales, apically ringed with a blackish brown band, with whorls of silvery white bristles, tarsus with whorls of yellowish white bristles at apexes of basal three tarsomeres, distal two tarsomeres tinged with yellowish brown scales; hind tibia dorsally with long silvery white bristles, except medially with long blackish brown bristles, apically with whorls of black scales, tarsus dark brown on inner and outer surfaces, with silvery white bristles at apex of each tarsomere. Abdomen grayish white on dorsal surface, silvery white on ventral surface.

Male genitalia ( Fig. 12 ). Uncus broad at base, gradually narrowed to 3/4, distal 1/4 subrectangular, straight apically, rounded posterolaterally, with long hairs laterally. Gnathos broad at base, slightly narrowed to 2/3, distal 1/3 clubbed, blunt apically. Tegumen broad, about 1.5 times length of uncus, branched from posterior 1/3, gradually narrowed anteriorly. Valva with basal half subparallel ventral-dorsally; ampulla hook-shaped; sacculus heavily sclerotized, about half length of valva, narrowly banded, basal 4/5 uniformly wide, distal 1/5 slightly narrow, apically free from valva, pointed, reaching basal 1/5 of ventral margin of cucullus; cucullus nearly cuneal, narrow at base, slightly broadened to bluntly rounded apex, dorsal margin heavily sclerotized. Vinculum narrowly banded; saccus semi-elliptical, about 1/3 length of uncus. Juxta broad at base, slightly narrowed to 1/3, posterior 2/3 nearly uniform, narrowly rounded on posterior margin, protruded medially on anterior margin; anellus lobes short clubbed, shorter than juxta, with a few long setae. Aedeagus about same length as valva, narrow at base, slightly arched in dorsal 2/3; cornutus consisting of dense microtrichia, located between basal 1/2 and 3/4.

Female genitalia ( Fig. 13 ). Papilla analis with dense short setae; intersegmental membrane between papilla analis and eighth abdominal segment about twice length of papilla analis. Apophysis posterior about 1.5 times length of apophysis anterior. Eighth segment straight on posterior margin, with long setae; eighth sternite with anterior half subtriangular, eighth tergite straight anteriorly. Antrum inverted trapezoidal, waved posteriorly, with several longitudinal wrinkles; approximately 2.5 times length of ductus bursae. Ductus bursae uniform in width, approximately 1/4 length of corpus bursae. Corpus bursae elongate elliptical, posterior 1/3 with dense granules; two signa located at posterior 1/3, triangular, one side sclerotized, forming an arched ridge. Appendix bursae arising from posterior 1/4 of corpus bursae, long narrow tube shaped, about four times length of corpus bursae, with small teeth at base, roundly dilated at middle, broad in distal 1/4, with dense micro granules.

Diagnosis. This new species is similar to T. acridomima Meyrick, 1889 by the forewing without any spot. It can be distinguished by the forewing silvery white in basal 4/5 and pale ochreous brown in distal 1/5, and in the male genitalia by the apex-blunted gnathos and cucullus, and the cornutus of several microtrichia. In T. acridomima , the forewing is uniformly brown; the gnathos is hooked ventrad at apex, the cucullus is obliquely straight on anterior half at apex, and the cornutus is a large spine (see Kasy 1973: 246). This new species is also similar to T. angareuta Meyrick, 1922 , but can be distinguished by the flagellum silvery white basally, deepening to brown distally, and the absence of the costal spot on the forewing. In T. angareuta , the flagellum is dark gray except distal six flagellomeres ochreous white, and the forewing has a yellowish white spot between costal 3/5 and 4/5.

Distribution. China (Yunnan).

Etymology. The specific name is derived from the Latin cuneiformis (cuneal), referring to the shape of the cucullus in the male genitalia.

Figures

FIGURES 1 − 7. Adults of Thylacosceles species. 1 − 4, T. nephroides sp. nov., holotype, ♂: 1, head (dorsal view); 2, head (lateral view, paratype, ♂); 3, hindleg; 4, adult; 5, T. clavata sp. nov., holotype, ♂; 6, T. cuneiformis sp. nov., holotype, ♀; 7, T. ellipsoidala sp. nov., holotype, ♂. (Scale bars = 2.0 mm).

FIGURES 10 − 14. Genitalia of Thylacosceles species. 10, T. nephroides sp. nov., holotype, ♂, slide No. GW 14002; 11, T. clavata sp. nov., holotype, ♂, slide No. GW 14006; 12, T. cuneiformis sp. nov., paratype, ♂, slide No. GW 14004; 13, ditto, holotype, ♀, slide No. GW 14005; 14, T. ellipsoidala sp. nov., holotype, ♂, slide No. GW 14003. (Scale bars = 0.2 mm, 13 = 0.5 mm).