Stigmella magnispinella Remeikis & Stonis, sp. nov.

(Figs 2, 4, 5, 17–20, 29–32, 38, 39)

Type material. Holotype: ♂, PERU, Dept. Ayacucho, 35 km W Puquio, 14°47'31"S, 74°27'19"W, elevation about 3370 m, 10.iii.1987, O. Karsholt, genitalia slide no. RA 544♂ (ZMUC) .

Other material (not type). 2 ♀, PERU, Dept. Ancash, 35 km SE Huaraz, Cerro Cahuish, Quabrada Puvadvado, 9°39'05"S, 77°13'34"W, elevation about 3870 m, 18.ii.1987, O. Karsholt, genitalia slide no. RA 548♀ (ZMUC) (see Remarks).

Diagnosis. The combination of a deeply divided uncus with wide lateral lobes, large apical processes of valva, long sublateral processes of transtilla, short vinculum, and a specific set of cornuti distinguishes S. magnispinella sp. nov. from all other Stigmella including the species of the S. magnispiella group (also see the pictorial key to the S. magnispinella group provided in figs 4, 5).

Male (Figs 38, 39). Forewing length 2.3 mm; wingspan 5.1–5.2 mm. Head: palpi pale grey; frontal tuft pale ochre-brown; collar and scape cream; antenna as half the length of forewing; flagellum with 27–28 segments, dark grey to fuscous grey on upper side, grey cream on underside. Thorax, tegula and forewing brownish grey with some golden gloss; apex of forewing with some longer brownish cream scales which could be invisible at certain angle of view; fringe pale grey to brown-grey; underside of forewing dark grey-brown, without spots or androconia. Hindwing grey to brown-grey on upper side and underside, without androconia or spots; fringe brownish grey. Legs grey on underside, dark brown-grey on upper side. Abdomen dark grey-brown on upper side and underside; anal tufts short, grey-brown; genital plates grey.

Female. Forewing length 2.4–2.4 mm; wingspan 5.3–5.5 mm. Forewing more glossy, apically with silvery shining scales. Otherwise as in male.

Male genitalia (Figs 4, 5, 17–20). Capsule longer (270 µm) than wide (170 µm). Uncus with two very wide lateral lobes (Figs 17, 19). Gnathos with two caudal processes. Valva (Figs 18, 19) 190 µm long, with bulged inner lobe and two large apical processes; transtilla with short transverse bar and long slender sublateral processes (Fig. 19); valvae with a basal connection. Ventral plate of vinculum short but wide, with rounded corners (almost without lateral lobes). Phallus (Fig. 20) 140 µm long, 70–80 µm wide; vesica with a specific set of cornuti, comprised of plate-like cornuti and one large horn-like cornutus (Fig. 20).

Female genitalia (Fig. 29–32). Total length about 770 µm. Posterior apophyses longer than anterior ones. Vestibulum without sclerites. Corpus bursae with slender folded distal part, and large (350 µm long), almost rounded basal part, without signa; comb-like pectinations numerous but indistinctive, weakly visible (Fig. 32). Accessory sac very large; ductus spermathecae with a rounded plate-like sclerite (Fig. 31). Abdominal tip rounded (Fig. 30).

Bionomics. Adults fly in February–March. Otherwise biology unknown.

Distribution. Known from two localities in the Andean Peru (Dept. Ayacucho and Ancash) at elevations about 3370–3870 m (Fig. 2).

Etymology. The species name is derived from Latin magnus (large, big) and spina (a spine, thorn, bone) in reference to the large cornuti in the male genitalia.

Remarks. Two females externally matching the holotype of Stigmella magnispinella sp. nov. have been collected in different locality than the male holotype. They are not included in the type-series.