Stigmella sinuosa Remeikis & Stonis

Stonis, Jonas R. & Remeikis, Andrius, 2016, Southern Andean Stigmella sinuosa complex (Lepidoptera, Nepticulidae): unraveling problematic taxonomy with a pictorial key of adults?, Zootaxa 4136 (2), pp. 309-322 : 310-311

Stigmella sinuosa Remeikis & Stonis , sp. nov.

( Figs 1–6 , 11 , 12 , 23 )

Type material (7 Ƌ). Holotype Ƌ: ARGENTINA, Río Negro, S. C. de Bariloche, Colonia Suiza, elevation ca. 800 m, 19.x.1981, Nielsen & Karsholt, genitalia slide no. RA508 ( ZMUC). Paratypes (6 Ƌ): 4 Ƌ, same locality as holotype, 12.x–7.xi.1981, Nielsen & Karsholt, genitalia slide nos RA323, RA527, RA627, RA704; 1 Ƌ, same locality as holotype, elevation ca. 810 m, 29.xi.1978, Mision Cientifica Danesa, genitalia slide no. RA362; 1 Ƌ, Neuquen, San Martin de los Andes, elevation ca. 640 m, 4.x.1981, Nielsen & Karsholt, genitalia slide no. RA520 ( ZMUC).

Other examined material (not included into the type series, 6 Ƌ): 4 Ƌ, ARGENTINA, Río Negro, S. C. de Bariloche, Colonia Suiza, elevation ca. 800 m, 17.x–11.xi.1981, Nielsen & Karsholt, genitalia slide nos RA356, RA526, RA628 ( ZMUC); 1 Ƌ same locality, elevation ca. 810 m, 9.xii.1978, Mision Cientifica Danesa, genitalia slide no. RA330 ( ZMUC); 1 Ƌ, Neuquen, San Martin de los Andes, elevation ca. 640 m, 7–15.xi.1981, Nielsen & Karsholt ( ZMUC).

Diagnosis. S. sinuosa belongs to the Stigmella salicis group (see Remarks). From the most similar S. mevia it differs in the very pale frontal tuft and paler antenna; in contrast to S. mevia , the forewing is usually coarsely speckled and the golden lustre of forewing is weak or absent. In the male genitalia, it differs from S. mevia in the simple-shaped uncus (see fig. 12) and specific shape of cornuti (with a large sinuous cornutus) (see fig. 11).

Male ( Figs 1 , 11 ). Forewing length 3.0–3.1 mm; wingspan 6.5–6.7 mm. Head: palpi cream white; frontal tuft white to cream; collar and scape cream white, glossy; antenna distinctly longer than half the length of forewing; flagellum with 40 segments, pale, brownish on upper side, brownish cream on underside. Thorax and tegula pale grey-brown. Forewing: basal two thirds grey to golden grey, coarsely speckled with pale brown and dark brown scales with some golden gloss (only a very few with purple iridescence); dark brown scales prevail and are more distinct in the wide area before the forewing fascia; fascia silvery shiny, distinctly postmedian or sub-apical, oblique, ill-defined in the holotype, narrowed at tornus; sometimes apex of forewing with some silvery shiny scales forming small irregular apical spots in between dark brown scales; if fascia absent, silvery shiny scales form two subapical spots along costal margin and on tornus; terminal and tornal fringe pale grey or, at certain angle of view, white with silvery gloss; underside of forewing pale brown, with no spots or androconia. Hindwing pale, pale greybrown or, at certain angle of view, white on upper side and underside, with no androconia; fringe cream, at certain angle of view pale brown. Legs cream to brownish cream, with some grey to grey-brown scales on upper side. Abdomen grey on upper side and underside; anal tufts short, cream; genital plates cream.

Female. Unknown.

Male genitalia ( Figs 2–6 , 11 , 12 ). Capsule longer (300–340 mm) than wide (235–240 mm). Vinculum with short triangular lateral lobes; anterior excavation between lobes shallow and wide; ventral plate long. Uncus bilobed, without or with a weakly visible second pair of tiny lateral processes ( Figs 3, 6 , 12 ). Gnathos with two thickened caudal processes ( Figs 3 , 12 ). Valva ( Figs 2, 3, 6 , 12 ) 170–190 mm long, with wide inner lobe and two slender apical processes which can be weakly visible in genitalia mounts; transtilla with short transverse bar but no sublateral processes ( Figs 3 , 12 ). Juxta membranous, indistinct, triangularly shaped. Phallus ( Figs 4, 5 , 11 ) 200– 205 mm long, 105–130 m wide; vesica with 8 to 10 (usually 9) various horn-like cornuti; one of the largest cornuti is distinctly sinuous ( Figs 4 , 11 ).

Bionomics. Host-plant: unknown. Adults fly in October–early December.

Distribution. Known mostly from the western (mountainous) Argentina at elevations about 640–800 m ( Fig. 23 ).

Etymology. The species name is derived from Latin sinuosus (curving, twisting, serpentine) referring to the large sinuous cornutus in the male genitalia.

Remarks. The Stigmella salicis group (= S. fuscotibiella group) was well defined in a few publications dealing with the European ( Johansson et al. 1990), Asian ( Puplesis 1994), and North American fauna ( Newton & Wilkinson 1982). The consequent inclusion of some South American species into the S. salicis group ( Puplesis & Robinson 2000; Puplesis et al. 2002, with subsequent acceptance to the word catalogue (Diškus & Stonis 2003), has significantly extended not only the geographical range but also made the concept of this group less defined. Currently, on the basis of new and abundant material collected in South America, an updated characterization of the S. salicis group is in progress (Stonis et al. in prep.). Therefore, in the present paper, we intentionally avoid providing a more detail characterization of the S. salicis group than it was published earlier, and refrain from discussions on taxonomic diversity, distribution, host-plant preferences and origin of the species group until our detail analysis is finished.

Figures

FIGURE 11. Comparison of Stigmella sinuosa sp. nov. and S. mevia sp. nov.

FIGURE 12. Comparison of male genitalia of Stigmella sinuosa sp. nov. and S. mevia sp. nov.

FIGURE 23. Distribution of Stigmella sinuosa sp. nov. and S. mevia sp. nov.

FIGURES 1 – 6. Stigmella sinuosa sp. nov. 1, male adult, holotype; 2, male genitalia, fragment of capsule with phallus, paratype, genitalia slide no. RA 527; 3, capsule with phallus removed, holotype, genitalia slide no. RA 508; 4, phallus, holotype, genitalia slide no. RA 508; 5, cornuti on vesica, paratype, genitalia slide no. RA 527; 6, male genitalia, paratype, genitalia slide no. RA 526 (ZMUC).