Nexosa hexaphala tamdaoana Heppner & Bae

Heppner, John B. & Bae, Yang-Seop, 2015, Review of Nexosa Diakonoff in Vietnam, with a new species and a new subspecies, and transfer to the tribe Archipini (Lepidoptera: Tortricidae: Tortricinae: Archipini), Zootaxa 3999 (1) : -

Nexosa hexaphala tamdaoana Heppner & Bae , new subspecies

( Figs. 1, 2–3 , 7 )

Type locality. Tam Dao (930 m), Vinh Phuc Prov., Vietnam.

Description. Wing expanse: 13.5– 14 mm (n = 11). Male ( Fig. 1 ). Head ( Figs. 3–4 ): Vertex brown-fuscous; frons brown-fuscous, tan at base; neck tan, white ventrally; antenna black-brown alternating with yellow-tan, ventrally setous but unscaled, and scape dark brown-fuscous; labial palpus cream-white, with some brown-fuscous on apical segment, and mesally the same but less fuscous near apex. Thorax: Brown-fuscous, lighter brown centrally as horizontal border to anterior darker area, with line of yellow-tan horizontal line between tegulae anteriorly, and dark brown on posterior of thorax dorsum and white scale patch posterolaterally; tegulae brownfuscous, lighter posteriorly; venter white; legs white but dorsally yellow-tan on mid- and hind tibia and tarsal segments, with hind tibia having 3 dorsal bars of dark brown and dorsally as alternating bands on tarsal segments. Forewing ( Fig. 1 ) brown, with irrorated white area on dorsal middle, angled to tornus, with basal area brown and with 3 vertically arranged small dark brown spots; costal margin with brown alternating with 6–7 silver or orangeyellow; orange-yellow line at apical 1/4 curved to tornus (less yellow near tornus), margined by iridescent silverfuscous, and orange-yellow also around apical silver fascia; silver subterminal line; black patch near tornus with small white spots; fringe dark fuscous, with white near apex and near tornus; venter of wing like dorsum but duller and more yellow marks on costa and apex. Hindwing white in basal half, brown-fuscous at base and some brownfuscous irrorations near anal margin and angled beyond base; apical 1/3 brown and a large black patch along termen and tornus, with several small yellow and silver spots towards tornus mixed into black areas, and subterminal silver line; fringe white except fuscous near apex and several small fuscous spots along termen to tornus; venter of wing like dorsum but duller. Abdomen: Brown-fuscous with pale white scale row on posterior margin of each tergite; venter cream-white; anal tuft fuscous. Male genitalia ( Fig. 7 ) with uncus elongated, with bulbous emarginated apex and with several very strong somewhat recurved bristle-like setae; uncus on strongly slerotized quadratic base. Tegumen strongly sclerotized and somewhat bulbous, with acutely indented anterior margins, and with quadratic dorsal corners, below which is the elongate, somewhat setose and acutely pointed paired socius extended out posteriorly. Gnathos extended posteroventrally as two convergent abruptly recurved arms without setae. Transtilla a flattened band, emergent from strongly sclerotized spine-like knob at each valval base. Valva triangular but slightly upcurved, setose, with very strongly sclerotized dorsal and saccular margins, apically truncate and angled ventrally to slightly extended ventral apex. Vinculum strong, with small rounded saccus. Anellus a small semicircular plate of concentric margins ventrally and dorsally, slightly emarginate dorsally. Aedeagus ( Fig. 7 a) slender, elongate, with middle convexity; a single large spine-like cornutus. Pregenital plate on abdomen rounded ( Fig. 7 b). Female unknown. The single known female specimen of the nominate subspecies has the abdomen missing ( Clarke 1969).

Specimens recorded. Holotype male: Tam Dao (930 m), Vinh Phuc Prov., Vietnam, 13–15 Oct 2014, J. B. Heppner. Deposited with FSCA/McGuire Center, on indefinite loan from PPRI (Hanoi, Vietnam). Paratypes (9♂): VIETNAM: Vinh Phuc Prov.: Tam Dao [Natl. Pk.] (985 m), 5 May 2005 (1♂), Y.-S. Bae & J.-M. Kim (INUC); Tam Dao (930 m) 25–31 Jul 2010 (3♂), J. B. Heppner (FSCA/McG); 1 Aug 2000 (1♂), Y. S. Bae (INUC); 6–9 Oct 2014 (3♂), 13–15 Oct (1♂), J. B. Heppner (FSCA/McG).

Other specimens (1♂): Tam Dao (930 m), 17 Oct 1995 (1♂), V. Sinaev ( MNHU).

Etymology. The species is named after the type locality, Tam Dao.

Biology. These moths are likely diurnal, as far as is known, as are the true Hilarographini ( Heppner 1982) and some other colorful tortricids (viz. Ceracini ), but most specimens are taken at lights. Otherwise, nothing is known of the life history and biology of the species.

Distribution. This subspecies is known only from northern Vietnam.

Discussion. This subspecies has been found fairly common at Tam Dao, in northern Vietnam, but unfortunately, only males have been taken thus far. The subspecies was first reported for Vietnam (as N. hexaphala ) by Razowski (2008), for a single male from Tam Dao. Nedoshivina (2013) also illustrated the species (as N. hexaphala ) in her Vietnam Tortricidae compendium.

The new species described below cannot be the female of N. hexaphala as it is much darker and differs in maculation, as can easily be seen by comparing the figure shown here for N. tonkinensis with that illustrated by Clarke (1969) of the holotype female of N. hexaphala from Sri Lanka. With the distance from Sri Lanka to Vietnam being significant, it is likely the Vietnam population is a distinct species, particularly given the evident differences and becuase the other Nexosa species all are very similar (except N. picturata ). However, until more Sri Lankan specimens of N. hexaphala are available so that the genitalia can be compared with the Vietnamese specimens, we have named them as a subspecies of N. hexaphala .

Figures

FIGURE 7. Nexosa hexaphala tamdaoana, n. subsp., male genitalia, with details a) aedeagus, b) abdominal pregenital sternal plate (slide JBH 2858).

FIGURES 1 – 2. Nexosa species in Vietnam. 1. N. hexaphala tamdaoana, n. subsp., holotype male (13.8 mm wingspan). 2. N. tonkinensis, n. sp., holotype female (12.3 mm wingspan).

FIGURES 3 – 6. Nexosa species head close-ups (lateral and dorsal views). 3 – 4. N. hexaphala tamdaoana, n. subsp., male. 5 – 6. N. tonkinensis, n. sp., female.