Nannopterix choreutes Gibbs

Gibbs, George W., 2010, establishment of five new genera from Australia, New Caledonia and New Zealand, Zootaxa 2520, pp. 1-48 : 44-46

Nannopterix choreutes Gibbs , sp. nov.

( Figs 2 C, 3A&H, 5B, 6G, 15A–E, 21)

Type material. Holotype: ɗ, New Caledonia, Mt Rembai, 800 m, 30 Nov 1978, G.W. Gibbs. Collected on forest floor leaf litter in a shady ravine. Genital prep G875. ( MNHN). Paratypes: New Caledonia. 82 ɗ. 75 ɗ from type locality, Mt Rembai, 800 m. 21 Oct 1978, J.S. Dugdale; 30 Nov 1978, G.W. Gibbs; 24 Oct 1981, G.W. Gibbs; 16 Nov, 2002, G.W. Gibbs; 1 ɗ Riviere Bleue, 800–900 m, 7 Nov 1988, J.S. Dugdale. 1 ɗ Table Unio, 800 m, 1 Dec 1978, G.W. Gibbs; 1 ɗ Mt Humboldt, 1500 m, 12 Nov 1982, W.J. Winstanley; 4 ɗ Rivière Bleue, 180–200 m, 7 Nov 1988, J.S. Dugdale. ( MNHN, ZMUC, ANIC, NZAC)

Material examined. Type series only.

Diagnosis New Caledonia. A very small (fw 2.5 mm) shining pale ochreous species with indistinct brownish costal and anal margins ( Fig. 2 C). Male tergum 10 a simple arching sclerite orientated across the dorsum, with slightly concave posterior margin ( Fig. 15 A).

Description. Head capsule brown with dense tufts of moderately long piliform scales on frons and dorsum but absent from the area between antennal base and ocellus; scales of head, mouthparts, and antennae uniformly pale ochreous except on posterior surface of scape and pedicel where the scales are pale brown, contributing to the brown lateral line formed by the compound eyes, the naked areas of the head capsule and the costal margin of the forewing.

Tegula with tuft of long ochreous lamellar scales. Dorsum with ochreous lamellar scales but grading to a grey patch in the centre of mesonotum; remainder of thorax, femora and legs shining ochreous but with darker brownish scales on fore-tibia, mid-femur and banding of all tarsal joints.

Abdomen brownish ochreous scaled above and below.

Forewing length of male 2.4 mm (2.1–2.7); Note: an alcohol-preserved specimen from Mt Humboldt, 1500 m, with forewing length 3.1 mm, appears conspecific. Ground colour uniform; a narrow brown costal streak from base to about the end of Sc2; another slightly broader brown anal streak to end of CuP; a small brown patch of scales around the end of CuA2; an irregular area of brown scales in the apex in the vicinity of the fork of R s3-R s4; fringes ochreous except for a tuft of brown scales between R s1 and R s2.

Hindwing with 1 frenular bristle; pale ochreous with ochreous fringes.

Male genitalia. [G875] ( Figs. 15 A–E) S8 remnants lenticular, lying along thickened anterior border of sclerite 9, bearing 1–2 fine setae. Sclerite 9 dorsal arms finely tapering to virtually meet at dorsal mid-line; slightly thickened along antero-lateral margin. Valvae with arms 2.5x longer than broad, curving upwards slightly with rounded apex; lacking spines or ornamentation but with a field of recurved setae on inner surface toward apex. Median plate a short rod. Tergum 10 wide and hood-like, slightly indented in the mid-line, just sufficient to be described as bilobed; dense fields of recurved setae along lateral and posterior margins of lobes. Anal cone sclerites triangular. Phallus short, straight, 1.9x length of S6; gonopore occupies entire apex, circular, with radial folds slightly elongated dorsally to overhang the gonopore. Phallocrypt micro-scales acutely pointed.

Female. Unknown.

Etymology. The species name is derived from the Greek choreutai (the dancers who took part in a troupe of singers or dancers) and refers to the graceful flying behaviour of this tiny golden moth, as it flits around on the forest floor, amongst the dead leaves.

Remarks. This species is the smallest micropterigid yet known from the southern hemisphere. Males have been taken in large numbers (65 on one occasion), flitting about amongst dead leaves on the damp forest floor in a shaded ravine. On one occasion it was found to be active at dusk. In this regard it may be worth noting that the male interocular index is the lowest for any species in this lineage, indicating somewhat reduced compound eyes. In spite of diligent searches for females, using both Malaise traps and leaf litter heat extractions, to date none have been found. This species has not been captured in Malaise traps, nor has it come to light.

Distribution. (Fig. 27) New Caledonia: Table Unio south to Rivière Bleue, with a wide altitude range from 200–1500 m. Collected between 21 October and 1 December.

Figures

FIGURE 2. Adult moths from life: A, Austromartyria porphyrodes (Turner), female; B, A. porphyrodes feeding on dehiscing spores of Blechnum cartilagineum, at The Crater, Atherton Tableland; C, Nannopterix choreutes sp. nov., male; D, Aureopterix micans sp. n., male; E, Aureopterix sterops (Turner), female; (A, C – E to scale, white scale bars = 1 mm)

FIGURE 15. Nannopterix choreutes sp. nov. Genitalia: A – E. male: A, dorsal; B, lateral; C, ventral; D, phallus, lateral view; E, distal apex of phallus enlarged, lateral.