Trilocha nicobari N. Singh & Ahmad 2021, sp. nov.

Trilocha nicobari N. Singh & Ahmad, sp. nov.

(Figs 1–3, 7–9, 13–15)

Type material. Holotype, male. India, Andaman and Nicobar Islands, Great Nicobar Island, 4 km South of Vijay nagar, 12.xi.2018 (NZCZSI, 7217/H10).

Paratypes (12 ♂). India, Andaman and Nicobar Islands, Great Nicobar Island: 2 ♂, data same as holotype (NZCZSI, 7218/H10); 1 ♂, Chingam basti, 09.xi.2018 (NZCZSI, 7220/H10); 1 ♂, Gobind nagar, 05.xi.2018 (NZCZSI, 7222/H10); 1 ♂, Gobind nagar, 18.xi.2018 (NZCZSI, 7221/H10); 6♂, Galathea, 07.xi.2018 (NZCZSI, 7219/H10); 1 ♂, Bird watching point, 14.xi.2018 (NZCZSI, 7223/H10), leg. K.C.Gopi & party (NZCZSI).

Diagnosis. T. nicobari, sp. nov. is most closely similar to T. varians, but is distinct by the presence of single postmedial zigzag line, which is double in T. varians. In the male genitalia, T. nicobari, sp. nov. (Figs 7–9) is distinguished by the presence of a small, mid ventral flap of valva, which is absent in T. varians. Additionally, T. nicobari, sp. nov. is distinct from all its congeners by the broadest valva and the smallest saccus.

Description. Adult male (Figs 1–3). Ground colour brownish-ochreous, collar and thorax furnished with brownish scales. Forewing with a basal triangular patch of brownish scales, followed by a c-curved antemedial line of brown scales; an elongated mid-costal patch of brown scale, giving rise to small bar, expanding to an elongated spot on discocellular; discocellular mark varies from almost circular to bar like or irregular circle, below it, irregular lines of brown scale reaching inner margin; postmedial zigzag line of brown scales which is more conspicuous and excurved from costa to radial veins and then inwardly oblique to inner margin; an elongated costal brown bar on apex; a prominent, approximately triangular patch of brown scale at the middle of termen. Hindwing uniformly covered with brown scale, interno-median margin having bands of dark and light scales. Male genitalia (Figs 7–9) with uncus broadest at base, narrowing up to middle, and then having almost parallel edges till slightly squarish apex; tegumen robust, broad, having almost similar length and width, strongly concaved; vinculum forming a deep bowl like structure; saccus thumb like; valva curved, broadest at base, narrowing towards apex, a minute apical spine present, a small flap like structure present mid ventrally; 8 th sternite (Figs 13–15) having deep V or U-shaped posterior depression, two anterior processes narrow finger like, almost straight and of similar length; aedeagus straight, minutely narrowing towards apex.

Remark. Population variation is reported in one paratype, where uncus is minutely notched and swollen at apex (Fig. 9). Variation in 8 th sternite is also reported in different populations of new species.

Etymology. The name of the species belongs to the Great Nicobar Island.

Distribution. Great Nicobar Island, India.