Stigmella apicibrunella Diškus & Stonis, 2017

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 : 3-8

Stigmella apicibrunella Diškus & Stonis , sp. nov.

( Figs 1–18 )

Type material. Holotype: ♂, ECUADOR: Chimborazo Province, about 7 km NE Pallatanga , 1°58'19"S, 78°57'52"W, elevation 1800 m, mining larvae on Acalypha padifolia Kunth (Euphorbiaceae) 25.i.2005, field card no. 4830, A. Diškus & J. R. Stonis, genitalia slide no. AD 800♂ ( ZMUC) . Paratypes: 5 ♂, 2 ♀, same label data as holotype, genitalia slides AD772♂, AD813♀ (ZMUC).

Diagnosis. Belongs to the Stigmella nivea group. The combination of long sublateral processes of transtilla, very slender & closely juxtaposed caudal processes of gnathos, an unique band of cornuti, caudally narrowed uncus in the male genitalia, and a spined ductus spermathecae in the female genitalia distinguishes S. apicibrunella sp. nov. from all members of the S. nivea group, including the most similar S. olyritis (Meyrick, 1915) . Externally, S. apicibrunella sp. nov. may be easily distinguished from all species of the S. nivea group by the distinctly dark apex of the forewing.

Male. Forewing length 1.8–2.4 mm; wingspan 4.9–5.2 mm. Head: palpi cream; frontal tuft ferruginous; collar and scape golden cream; antenna as half the length of forewing; flagellum with about 30 segments, glossy with some purple iridescence, grey to dark grey on upper side, grey on underside. Thorax and tegula glossy, dark yellowish cream; forewing dark yellowish cream to pale yellowish beige, apically brown-black, with little purple and light blue or green iridescence; fringe grey, distally grey cream, with some purple and dark blue iridescence; underside of forewing very dark grey-brown, almost black-brown, except small elongated cream areas on forewing base, without spots. Hindwing grey with some golden gloss and purple iridescence, without spots or androconia; its fringe grey. Legs black-grey on upper side, golden cream on underside. Abdomen dark grey-brown to blackish grey with some purple and green iridescence on upper side, golden cream (very bright) with little purple and dark blue iridescence on underside; genital segments very distinctive, golden cream; anal tufts very short (indistinctive), black-grey.

Female ( Figs 5–7 ). Similar to male. Flagellum with 22 segments. Apex of abdomen narrowed to a slender ovipositor.

Male genitalia ( Figs 8–13 ). Capsule significantly longer (275 µm) than wide (155 µm). Uncus with a single lobe (not divided). Gnathos with two very slender and closely juxtaposed caudal processes and angular central plate. Valva 180–190 µm long, 50–55 µm wide, with two slender and sharp apical processes; transtilla with long sublateral processes. Juxta membranous. Vinculum with small pointed lateral lobes, and short ventral plate. Phallus ( Figs 12, 13 ) 260–300 µm long, 70–100 µm wide; vesica with a wide band of spine-like cornuti (it may not be continuous, i.e. can be interrupted).

Female genitalia ( Figs 14–18 ). Total length about 1060 µm. Anterior and posterior apophyses almost equal in length; anterior apophyses slender distally; posterior apophyses very slender. Vestibulum narrow, without sclerites. Corpus bursae with very large and wide folded part and large, 410 µm long, 280 µm wide basal part; pectinations distinctive, forming a band-like structure somehow resembling a weakly developed signum (see Fig. 18 ). Accessory sac small, folded; ductus spermathecae wide and spined proximally, with one sclerite. Abdominal apex tapered into slender ovipositor.

Bionomics ( Figs 2–4 ). Host-plant: Acalypha padifolia Kunth (Euphorbiaceae) ( Fig. 3 ). Larva yellow with brown head; mines in leaves in January and, judging by observed numerous old (empty) leaf-mines, also in December. Leaf-mine ( Fig. 4 ) starts as a very slender sinuous gallery with a very wide line of black or blackish brown frass. Larval exit slit on upper side of the leaf. Cocoon very pale, yellowish beige; length 2.1–2.3 mm, maximum width 1 mm. Adults fly in February.

Distribution ( Figs 1 , 2 ). This species occurs on the western slopes of the equatorial Andes ( Ecuador: Chimborazo Province) at altitudes about 1800 m ( Fig. 2 ).

Etymology. The species name is derived from Latin apice (apex) and brunus (brown) in reference to the color of the forewing with a distinctive brown apex.

Figures

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

FIGURES 2 – 7. Stigmella apicibrunella Diškus & Stonis, sp. nov. 2 — habitat, western slopes of the equatorial Andes (Ecuador: Chimborazo Province) at altitudes about 1800 m; 3 — host plant Acalypha padifolia Kunth (Euphorbiaceae); 4, leafmines; 5 – 7, female paratype adults.

FIGURES 8 – 13. Male genitalia of Stigmella apicibrunella Diškus & Stonis, sp. nov. 8 – 11, capsule with phallus removed, holotype, genitalia slide no. AD 800; 12, phallus, paratype, slide no. AD 772; 13, same, holotype, slide no. AD 800 (ZMUC).

FIGURES 14 – 18. Female genitalia of Stigmella apicibrunella Diškus & Stonis, sp. nov., genitalia slide no. AD 813 (ZMUC). 14, apophyses; 15, ductus spermathecae; 16, slerite of ductus spermathecae; 17, false signum; 18, corpus bursae.