Stigmella lachemillae Diškus & Stonis, 2016

Stonis, Jonas R., Diškus, Arūnas, Remeikis, Andrius, Gerulaitis, Virginijus & Karsholt, Ole, 2016, Leaf-mining Nepticulidae (Lepidoptera) from record high altitudes: documenting an entire new fauna in the Andean páramo and puna, Zootaxa 4181 (1), pp. 1-94 : 27-28

Stigmella lachemillae Diškus & Stonis , sp. nov.

( Figs 1–5 , 17 , 27 , 55–66 )

Type material. Holotype: Ƌ, ECUADOR, Chimborazo Province, 25 km NW Riobamba , 1°31'20"S, 78°50'27"W, elevation 3980 m, mining larvae on Lachemilla orbiculata (Ruiz & Pav.) Rydb. 23.i.2005, ex pupae ii.2005, field card No. 4825, leg. A. Diškus & J. R. Stonis, genitalia slide no. AD637Ƌ ( ZMUC) . Paratypes (9 Ƌ, 5 ♀): 5 Ƌ, 5 ♀, same label data as holotype, genitalia slides nos AD661Ƌ, AD663♀, AD664♀, (ZMUC); 4 Ƌ, same locality, mining larvae on Lachemilla orbiculata (Ruiz & Pav.) Rydb. 22.ii.2007, ex pupae iii.2007, field card No. 4876, leg. A. Diškus & J.R. Stonis, genitalia slide nos AD636Ƌ, AD665Ƌ ( ZMUC) .

Diagnosis. The combination of a gnathos with closely juxta posed processes, short vinculum, distally fourpapillated uncus, grey forewing and golden cream facia distinguishes S. lachemillae sp. nov. from all other Stigmella species possessing two to three cornuti on the vesica (including the most resembling S. pangorica Diškus & Stonis, 2015 ); the host-plant Lachemilla orbiculata (Rosaceae) also makes this species distinctive.

Male ( Figs 55, 56 ). Forewing length 2.2–3.0 mm; wingspan 4.9–6.6 mm. Head: face unusually colored, golden cream; palpi pale grey to dark grey; frontal tuft ochre cream to pale ferruginous but brown to fuscous on vertex; scape golden cream; antenna distinctly longer than half the length of forewing; flagellum with 34 segments, dark grey-brown with golden gloss. Thorax, tegula and forewing ochre-grey to grey, with some (occasssionally without) sparsely distributed brown scales with purple and green iridescence. Forewing without fascia, sometimes with fuscous scales at base along costa; fringe cream to grey cream or grey; underside of forewing grey-brown to dark grey-brown with no spots or androconia. Hindwing pale greyish cream to pale grey-brown on upper side and underside; its fringe pale grey to grey. Legs greyish cream, darkened with grey to dark grey on upper side. Abdomen grey to dark grey or fuscous on upper side, pale grey, glossy on underside; tufts short, indistinctive; genital plates pale brown.

Female ( Fig. 57 ). Usually smaller than male; forewing length 2.1–2.2 mm; wingspan 4.7–5.0 mm. Palpi cream. Frontal tuft comprised of grey and ferruginous cream piliform scales (the latter are prevailing). Flagellum with 26 segments. Forewing ochre cream, apically fuscous with some gloss and purple iridescence; fringe cream to grey cream. Legs glossy cream, darkened with grey to dark grey on upper side. Abdomen golden cream to ochre cream on upper side and underside.

Male genitalia ( Figs 58–60 ). Capsule longer (250 µm) than wide (165 µm). Vinculum with short triangular lateral lobes and short ventral plate. Uncus with four papillae distally. Gnathos with two closely juxta-posed caudal processes and large central plate. Valva 140–150 µm long, 40–55 µm wide, with two distinctive apical processes; inner lobe slightly bulged; transtilla with very small sublateral processes. Juxta membranous, indistinctive. Phallus ( Fig. 58 ) 205–210 µm long, 60–80 µm wide; vesica with three large spine-like cornuti and a group of weakly chitinized, small and slender cornuti.

Female genitalia ( Fig. 66 ). Total length 820–825 µm. Posterior apophyses significantly longer than anterior ones. Vestibulum narrow, without sclerites. Corpus bursae with long, slightly folded (or wrinkled) distal part and oval-shaped, 330–335 µm long, 250–255 µm wide basal part without signa; pectinations comb-like. Accessory sac wide but short; ductus spermathecae wide, without convolutions but with sinuous chitinized part. Abdominal apex narrowed, distally truncated.

Bionomics. ( Figs 61–65 ). Larva mines in leaves. Host-plant: Lachemilla orbiculata (Ruiz & Pav.) Rydb. (Rosaceae) ( Figs 62–64 ). Larva pale yellow, with indistintive or ochre-brown intestine and dark brown head; mines in January-February. Leaf-mine starts as a slender sinuous gallery filled with dark brown to black-brown frass; later it developes to a blotch ( Figs 64, 65 ). Cocoon pale beige. Adults emerged in February and March.

Distribution ( Figs 17 , 27 ). This species occurs high in the equatorial Andes ( Ecuador) at altitudes about 3980 m in grass páramo habitats ( Figs 1–5 ) predominantly along streams in sheltered damp ravines ( Figs 61, 63 ).

Etymology. The species is named after the host-plant genus Lachemilla .

Figures

FIGURE 27. Distribution map of the high-Andean Nepticulidae with height records.

FIGURES 1 – 5. Habitats: grass páramo near volcano Chimborazo (Ecuador: Chimborazo Province) at altitudes about 3980 – 4000 m. 1, 2, habitat of Stigmella gynoxyphaga sp. n. and S. tripartita Diškus & Stonis, 1 ° 31 ' 20 " S, 78 ° 50 ' 27 " W; 3 – 5, habitat of S. lachemillae sp. n. and S. calceolariae sp. n., 1 ° 45 ' 41 " S, 78 ° 48 ' 51 " W.

FIGURES 16 – 17. Distribution of high altitude Stigmella species in the Ecuadorian Andes. 16, habitat of Stigmella paramica sp. nov. and S. confertae Diškus & Stonis, 3700 – 3800 m, 0 ° 21 ' 45 " S, 78 ° 11 ' 35 " W; 17, distribution map.

FIGURES 55 – 60. Stigmella lachemillae Diškus & Stonis, sp. nov. 55, adult, male holotype; 56, same, male paratype; 57, same, female paratype; 58, male genitalia, phallus, holotype, genitalia slide no. AD 637; 59, 60, same, capsule without phallus, holotype, genitalia slide no. AD 637 (ZMUC).

FIGURES 61 – 66. Bionomics and female genitalia of Stigmella lachemillae Diškus & Stonis, sp. nov. 61, habitat, grass páramo (predominantly along streams in sheltered damp ravines); 62, 63, host-plant Lachemilla orbiculata (Ruiz & Pav.) Rydb. (Rosaceae); 64, 65, leaf-mines; 66, female genitalia, slide no. AD 664 (ZMUC).