Stigmella hylomaga ( Meyrick, 1931 )

Stonis, Jonas R., Remeikis, Andrius, Diškus, Arūnas & Megoran, Nick, 2017, New species of leaf-mining Nepticulidae (Lepidoptera) from the Neotropical and Ando-Patagonian regions, with new data on host plants, Zootaxa 4272 (1), pp. 1-39 : 19-20

Stigmella hylomaga ( Meyrick, 1931)

( Figs 1 , 78–83 )

Material examined. 1 (holotype; sex unknown, see Remarks), ARGENTINA, Río Negro Province, San Carlos de Bariloche, Lake Correntoso , 15–25.xi.1926, F. & M. Edwards ( BMNH) ; 2 ♂, 3 ♀ (not type series), San Carlos de Bariloche , Colonia Suiza, elevation 800–810 m, 29.xi–11.xii.1978, Mision Cientifica Danesa, genitalia slide RA 286♂, RA 288♂, RA 300♀, RA 301♀ ( ZMUC) ; 2 ♂, 3 ♀ (not type series), same locality, 4.x–23.xii.1981, Nielsen & Karsholt, genitalia slide RA 279♀, RA 287♂, RA 289♂, RA 304♀, RA 310♀ ( ZMUC) ; 3 ♀ (not type series), Neuquen Province, San Martin de los Andes , elevation ca. 640 m, 17.x–6.xi.1981, Nielsen & Karsholt, genitalia slide RA 281♀, RA 311♀, RA 320♀ ( ZMUC) .

Diagnosis. The combination of an unique set of cornuti in the phallus (see fig. 81), very long lateral lobes of vinculum, and a very wide golden glossy postmedian fascia distinguishes S. hylomaga (Meyrick) from all other Stigmella species, including the most similar species of the S. sinuosa complex of S. marmorea group.

Male ( Figs 78, 79 ). Forewing length about 2.4–2.8 mm; wingspan 5.3–6.0 mm. Head: palpi grey cream; frontal tuft orange beige to pale beige; collar and scape golden cream; antenna significantly longer than half the length of forewing; flagellum with 37–39 segments, brown-grey on upper side, grey cream on underside, with little or no purple iridescence. Thorax and tegula grey-brown with little or no purple iridescence. Forewing: grey-brown with little purple (sometimes also blue) iridescence on basal part (before fascia), dark grey-brown with strong purple and some bright blue iridescence on apical third (beyond fascia); fascia postmedian, very wide, golden shiny; fringe grey-brown; underside of forewing grey-brown, without spots. Hindwing grey to grey-brown on upper side and underside, without spots or androconia; fringe grey-brown. Legs dark grey-brown on upper side, grey cream on underside. Abdomen glossy, dark grey to grey on upper side, distinctly yellowish cream on underside.

Female. Similar to male. Flagellum with 33–34 segments. Apex of forewing with weak purple or strong purple & blue iridescence. Fascia of forewing silvery to golden shiny. Abdomen also distinctly yellowish cream as with the male.

Male genitalia ( Figs 80, 81 ). Capsule longer (380 µm) than wide (230 µm). Uncus with two small caudal lobes each possessing two papillae. Gnathos with two caudal processes. Valva 225–230 µm long, 90–95 µm wide, with two small apical processes; transtilla with weakly developed sublateral processes. Vinculum with very long lateral lobes and very short ventral plate. Phallus ( Fig. 81 ) 270 µm long, 130 µm wide; vesica with 8 large spine-like cornuti.

Female genitalia ( Figs 82, 83 ). Total length 800–815 µm. Anterior and posterior apophyses almost equal in length. Vestibulum without sclerites. Corpus bursae with very large folded part and smaller, 280 µm long, 200–210 µm wide basal part; pectinations indistinctive; signa absent. Accessory sac very large; ductus spermathecae with one sclerite. Abdominal apex greatly narrowed but rounded distally.

Bionomics. Adults fly from October to December. Otherwise biology unknown.

Distribution ( Figs 1 ). This species occurs in the southern Andes ( Argentina: Rio Negro and Neuquen Provinces) at altitudes around 640– 810 m.

Remarks. The species was described by Edward Meyrick as Nepticula hylomaga from a single specimen with both hindwings and abdomen missing (mentioned in the original description) and, therefore, sex was unknown ( Meyrick 1931: 415). The appendages of the head are hardly visible and the left forewing is abraded (also see Discussion).

Figures

FIGURE 1. Distribution map to the species treated in the current paper.

FIGURES 78 – 83. Stigmella hylomaga (Meyrick, 1931). 78, male adult, RA 286; 79, same, left side; 80, male genitalia, slide no. RA 286, capsule with phallus removed; 81, same, phallus; 82, female genitalia, slide no. RA 304; 83, same, slide no. RA 310 (ZMUC).