Tactusa ostium Fibiger, 2010

FIBIGER, MICHAEL, 2010, Revision of the Micronoctuidae (Lepidoptera: Noctuoidea) Part 3, Taxonomy of the Tactusinae, Zootaxa 2583 (1), pp. 1-119 : 21

Tactusa ostium Fibiger , new species

( Plate 2 , figure 3; female genit. plate 26, figure 6)

Material examined. Holotype: female, Thailand, Prov. Nakhon Naoyk, Khao Yai Nat. Park , ca. 700 m, 29.ix.– 6.x.1984, leg. O. Karsholt et al., genit. prep. 2938 M. Fibiger, coll. ZMUC.

Paratypes: 2 females. 1 with same data as holotype, genit. prep. 2937 M. Fibiger, coll. MF ; 1 female, Thailand, Khao Yai Nat. Park , 1200 m, 17.iv.1987, leg. M.G. Allen, genit. prep. 3193 M. Fibiger, coll. BMNH .

Taxonomic notes. T. ostium is a member of the trigonifera species-group, which has a blackish triangular patch between the antemedial and postmedial lines; and the typical Tactusa antrum: cylindrical, short, narrow, and heavily sclerotised.

Diagnosis. Imago (external). Wingspan: 11 mm.

Forewing: ground colour yellow, with acutely-angled blackish patch in upper medial area and black subterminal area.

Crosslines: only subterminal and terminal lines indicated, former inwardly outlined by light yellow, latter with interneural black spots.

Reniform stigma: well marked, white, black outlined.

Hindwing: dark grey with discal spot.

Underside: unicolorous grey.

Male genitalia. Unknown.

Female genitalia. Ovipositor: quadrangular with rounded corners.

Posterior apophyses: longer than both anterior apophyses and ovipositor.

Anterior apophyses: slightly shorter than 8 th abdominal segment.

Ostium: displaced to left, round, extremely broad, as broad as 8 th abdominal segment; with ventral plate (apo.).

7 th segment ventrally shorter than 8 th segment (apo.).

Antrum: short, tapered.

Ductus bursae: membranous, long, narrow, coiled; 1.5 times longer than corpus bursae.

Appendix bursae: arising medially from ductus bursae (apo.).

Corpus bursae: ovoid.

Signum: cross shaped.

Differential diagnosis. T. ostium differs from other Micronoctuidae from SE Asian and Oriental regions in prominent ostium, long 8 th abdominal segment and relatively short 7 th segment.

Distribution. Known from one female specimen from Thailand.

Figures

PLATE 2. Figures 1–8. Tactusa species, adults. 1, 2, T. nilssoni, male holotype, Thailand, Phuket, and female paratype, with same data; 3, T. ostium, female holotype, Thailand, Nakhon Naoyk; 4, T. peregovitsi, male holotype, Vietnam N, Nghe Aniwan; 5, T. flavoniger, female holotype, Laos, Vientiane; 6, T. nieukerkeni, male holotype, Vietnam, Vinh Phuc; 7, T. topi, male holotype, China, Guangdong, Canton; 8, T. incognita, male holotype, Thailand, Nakhon Naoyk.