Tactusa artus, Fibiger, 2010

FIBIGER, MICHAEL, 2010, Revision of the Micronoctuidae (Lepidoptera: Noctuoidea) Part 3, Taxonomy of the Tactusinae, Zootaxa 2583 (1), pp. 1-119 : 29

Tactusa artus a Fibiger, new species

( Plate 3 , figure 6; male genit. plate 13, figure 4)

Material examined. Holotype: male, Thailand NW, Chang Mai , Samoeng / Hang Dong Rd, 15 km, 750 m, 3.ii.1989, leg. A.M. Cotton & I.J. Kitching, BM 1989-57 , genit. prep. 3519 M. Fibiger, coll. BMNH.

Diagnosis. Imago (external). Wingspan: 12 mm.

Forewing: long and narrow; ground colour yellowish, with basal-costal patch and dorso-medial triangular patch; yellowish between basal and antemedial lines; all subterminal and terminal areas, except for four small beige costal dots, blackish brown, including fringes; subterminal and terminal lines beige (apo.).

Crosslines: subterminal and terminal lines beige.

Reniform stigma: invisible (apo.).

Hindwing: whitish grey, with indistinct discal spot.

Underside: unicolorous grey.

Abdomen: grey with black crest dorsally on first segment.

Male genitalia. Tegumen: relatively strongly built.

Vinculum: even more strongly built.

Saccus: short, strongly built, U shaped.

Fultura superior: membranous.

Valvae: slightly asymmetrical, left one broader.

Ampulla: forming a cross with axis of valva; slightly asymmetrical; broadest by valva; arms narrow, dorsal arm shorter, broader, upturned, apically with small, stout spines; ventral arm longer, narrower, tapered (apo.).

Digitus: present; asymmetrical, triangular, narrow, pointed apically (apo.).

Juxta and anellus plate: fused, slightly asymmetrical, almost quadrangular, slightly constricted medially (apo.).

Phallus: strongly enlarged at ductus ejaculatorius; tapered from middle, and distally forming a long, narrow, curved, smoothly upturned cylinder.

Vesica: unarmed.

Female genitalia. Unknown.

Differential diagnosis. T. artus differs from T. biartus in narrower ampulla, constricted juxta-anellus plate, absence of a digitus in T. biartus , and similar phallus, which is straighter and narrower. These two species differ from other members of species-group in combination of three characters: shape and outer edges of very large patch on forewing, and in male genitalia narrow and smoothly curved ampulla, and shape of juxtaanellus plate. General features of these three character states also separate them from other Micronoctuidae from E and SE Asia and Oriental region.

Distribution. Known from one specimen from NW Thailand.

Figures

PLATE 3. Figures 1–8. Tactusa species, adults. 1, T. jeppeseni, female holotype, India NE, Assam; 2, T. bechi, female holotype, India NE, Assam; 3, T. dohertyi, male holotype, Indonesia, Java Centr.; 4, T. minor, female holotype, Thailand N, Chiang Mai; 5, T. tranumi, female holotype, Vietnam N, Vinh Phuc; 6, T. artus, male holotype, Thailand N, Chiang Mai; 7, 8, T. biartus, male holotype, Thailand N, Chiang Mai, and wing prep. 3198, with same data.