Tactusa nilssoni Fibiger, 2010

FIBIGER, MICHAEL, 2010, Revision of the Micronoctuidae (Lepidoptera: Noctuoidea) Part 3, Taxonomy of the Tactusinae, Zootaxa 2583 (1), pp. 1-119 : 20-21

Tactusa nilssoni Fibiger , new species

( Plate 2 , figure 1, 2; male genit. plate 12, figure 6; female genit. plate 22, figure 2)

Material examined. Holotype: male, Thailand, Phuket, Kata View Point , 200 m, 7–11.vii.2005, leg. & coll. D. Nilsson, later to be deposited in ZMUC.

Paratypes: 36 males and 43 females, with same data as holotype; male and female with genit. preps 5728 and 5729 M. Fibiger. Colls D. Nilsson, M. Fibiger, BMNH, HNHM , and ZMUC.

Taxonomic notes. T. nilssoni is a member of the T. trigonifera species-group, which has a blackish triangular or quadrangular patch between the antemedial and postmedial lines; the typical Tactusa ampulla; and a prominent, long, heavily sclerotised anellus, which is still totally fused to juxta.

Diagnosis. Imago (external). Wingspan: 9–10 mm.

Forewing: ground colour light yellow (holotype) to brownish yellow, with acutely-angled blackish patch in upper medial area and black subterminal area.

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

Reniform stigma: well marked, white, black outlined.

Hindwing: dark grey, with discal spot.

Underside: unicolorous grey.

Male genitalia. Tegumen: narrow.

Vinculum: strongly built.

Saccus: short; strongly built, broadly U shaped.

Fultura superior: membranous.

Valva: slightly asymmetrical; relatively narrow, with thumblike saccular process, setose at tip (apo.).

Ampulla: forming a cross with axis of valva; slightly asymmetrical, broadest by valva; dorsal arm long, tapered, ventral arm short and rounded (apo.).

Digitus: present; large, triangular, setose at tip (apo.).

Juxta and anellus plate: fused; anellar plate triangular and very long; apically bifurcate (apo.).

Phallus: very short, broad, and straight; a very long, upturned carinalike spine present (apo.).

Vesica: with spinules; no cornuti.

Female genitalia. Ovipositor: quadrangular with rounded corners.

Posterior apophyses: longer than anterior apophyses and ovipositor.

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. nilssoni differs from other Micronoctuidae from Oriental region in saccular process, shape of ampulla, short, broad-based digitus, long, distally bifurcate anellus and short, broad phallus, with a long, dorsal carina spine.

Distribution. Known only from S Thailand, Phuket.

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.