Stigmella expressa Remeikis & Stonis

Stonis, Jonas R., Diškus, Arūnas, Remeikis, Andrius, Karsholt, Ole & Torres, Nixon Cumbicus, 2017, Illustrated review of the leaf-mining Nepticulidae of the central Andes (Peru and Bolivia), Zootaxa 4257 (1), pp. 1-70 : 21

6. Stigmella expressa Remeikis & Stonis , sp. nov.

( Figs 2 , 9 , 32 , 37 , 43–48 , 100, 101 )

Type material. Holotype: ♂, PERU, Dept. Ayacucho, 25 km W Puquio, Senal Cerro Palmaderas , 3370 m, 10– 12.iii.1987, O. Karsholt, genitalia slide no. RA 545♂ ( ZMUC) .

Other material (not type). 2 ♀, PERU, Dept. Ayacucho, 35 km W Puquio, elevation 3370 m, 10.iii.1987, O. Karsholt, genitalia slide nos RA 546♀, RA 547♀ ( ZMUC).

Diagnosis. Belongs to the Stigmella expressa group. The combination of very long vinculum, gnathos with two closely juxtaposed processes, large apical processes of valva, and narrow uncus distinguishes S. expressa sp. nov. from all other members of the group, except the most similar S. pseudorobusta Remeikis & Stonis. From the latter new species differs in very long vinculum in the male genitalia and in ductus spermathecae without coils in the female genitalia.

Male ( Fig. 32 ). Forewing length 3.0– 3.1 mm; wingspan 6.5–6.7 mm. Head: palpi white; frontal tuft white with some pale brown piliform scales; collor weakly developed, composed of some lamellar grey-white scales; scape cream, glossy; antenna longer than half the length of forewing; flagellum with 37 segments, gloosy grey, with some purple iridescence. Thorax, tegula and forewing concolorous, pale grey with some pale yellow tinge, gloosy; underside of forewing grey-brown, without spots or androconia. Hindwing pale grey with some pale yellow tinge on upper side and underside, without spots or androconia; its fringe pale grey cream. Legs grey cream, darkened with some dark grey-brown scales on upper side, particularly on forelegs. Abdomen dark grey, glossy on upper side, grey cream, shiny on underside; tufts short, pale grey; genital segments grey cream.

Female. Slightly smaller than males: forewing length about 2.5 mm; wingspan about 5.5 mm. Flagellum with 27 segments. Abdomen pale grey-brown to brownish cream on upper side, cream on underside.

Male genitalia ( Figs 43–48 ). Capsule much longer (360 µm) than wide (160 µm). Vinculum with small rounded lateral lobes and very long ventral plate. Uncus narrowing distally, with three small lobes. Gnathos with two slender, closely juxtaposed caudal processes and laterally widened plate. Valva 205–210 µm long, 60 µm wide, with two very large apical processes and slightly bulged and rounded (with no pointing corners) inner lobe; transtilla with long triangular sublateral processes. Juxta membranous. Phallus ( Fig. 47 ) 220 µm long, 75 µm wide; vesica with two large cornuti.

Female genitalia ( Figs 100, 101 ). Total length 705–715 µm. Anterior and posterior apophyses almost equal in lenght; anterior apophyses very broad proximally, strongly narrowing (pointed) distally; posterior apophyses very slender. Vestibulum broad, without sclerites. Corpus bursae with long, heavily folded distal part and oval-shaped, 315 µm long, 265 µm wide basal part; pectinations comb-like, distintive; signa absent. Accessory sac wide but very short; ductus spermathecae without convolutions. Abdominal apex broadly rounded.

Bionomics Adults fly in March. Otherwise biology unknown.

Distribution ( Fig. 9 ). This species occurs in the high Peruvian Andes ( Peru: Ayacucho Departamento) at altitudes about 3370 m.

Etymology. The species name is derived from Latin expressus (dictinct, prominent) in reference to the expressive male genitalia.

Figures

FIGURE 32. Adults of the central Andean Nepticulidae.

FIGURE 37. Diagnostics of the central Andean Stigmella.

FIGURES 1 – 8. Distribution of the central Andean Nepticulidae. 1, high-Andean species recorded at altitudes above 3700 m (after Stonis et al. 2016 d); 2, species recorded at altitudes below 3700 m; 3 – 8, some collecting areas in the Peruvian Andes.

FIGURES 9 – 11. Distribution of the central Andean Nepticulidae. 9, species recorded at altitudes below 3700 m; 10, 11, some collecting areas in Peru. * — Stigmella epicosma Meyrick is also known from Arica Province, northern Chile (Vargas 2011); ** – S. inca sp. nov. is also discovered in southern Ecuador.

FIGURES 43 – 48. Male genitalia of Stigmella expressa Remeikis & Stonis, sp. nov., holotype, genitalia slide no. RA 545 (ZMUC); 43, 45, 46, capsule with phallus removed; 44, uncus; 47, phallus; 48, gnathos and transtilla.

FIGURES 100 – 103. Female genitalia of new Stigmella species. 100, S. expressa Remeikis & Stonis, sp. nov., genitalia slide no. RA 546; 101, same, genitalia slide no. RA 547; 102, S. misera Diškus & Stonis, sp. nov., paratype, genitalia slide no. AD 678; 103, S. paracosma Remeikis & Stonis, sp. nov., paratype, genitalia slide no. Diškus 186 (ZMUC).