Stigmella decora 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 : 8

Stigmella decora Diškus & Stonis , sp. nov.

( Figs 1 , 19–35 )

Type material. Holotype: ♀, ECUADOR: Chimborazo Province, about 30 km NE Pallatanga , 1°52'41"S, 78°54'11"W, elevation about 3325–3400 m, mining larvae on Rhynchotheca spinosa Ruiz & Pav. , 24.i.2005, field card no. 4828, Diškus & Stonis, genitalia slide no. AD 795♀ ( ZMUC) . Paratypes: 3 ♂, same label data as holotype, genitalia slides AD801♂, AD802♂ (see Remarks) (ZMUC).

Diagnosis. The combination of a gnathos with one slender caudal process, wide lobe-like uncus, valva with one apical process, and a unique shiny pattern of forewing ( Fig. 27 ) distinguishes S. decora sp. nov. from all other Stigmella , including the most similar S. unicaudata sp. nov.

Male. Forewing length about 2.1 mm; wingspan about 4.6 mm. Head: palpi pale brownish grey; frontal tuft pale beige; collar and scape cream; antenna longer than half the length of forewing; flagellum with 35–36 segments, brownish grey with some golden gloss on upper side and underside. Thorax and tegula grey-brown; forewing golden grey, apically with a large patch of fuscous brown scales surrounded by silvery shining scales; fringe grey; underside of forewing dark grey-brown, without spots. Hindwing grey on upper side and underside, without spots or androconia; its fringe grey. Legs pale brown, glossy. Abdomen grey-brown on upper side, brownish grey on underside; genital segments pale brow; anal tufts indistinctive.

Female ( Figs 26 , 27 ). Flagellum with 28 segments. Abdominal tip silvery shiny on underside. Otherwise as in male.

Male genitalia ( Figs 28–34 ). Capsule longer (270 µm) than wide (175 µm). Uncus with a single wide lobe slightly excavated distally. Gnathos with one pointed caudal process and small central plate. Valva 180 µm long, 65–70 µm wide, with one long apical process; transtilla without sublateral processes. Vinculum with lateral lobes and very short ventral plate. Phallus ( Figs 29 , 31, 32 ) 140–190 µm long, 85–90 µm wide; vesica with 6–8 spine-like cornuti.

Female genitalia ( Fig. 35 ). Total length about 840 µm. Anterior and posterior apophyses almost equal in length. Vestibulum narrow, without sclerites. Corpus bursae with short, weakly folded part and very large, 455 µm long, 315 µm wide basal part; pectinations distinctive; signa absent. Accessory sac short but wide; ductus spermathecae sinuous but without distinctive convolutions. Abdominal apex widely rounded.

Bionomics ( Figs 19–25 ). Host-plant: Rhynchotheca spinosa Ruiz & Pav (= Rhynchotheca spinosa var. lobata R. Knuth ) ( Geraniaceae / Vivianiaceae ) ( Figs 19, 21 ). Larva pale yellow with ochreous yellow intestine and dark brown head; mines in leaves in January. Leaf-mine ( Figs 20, 22 ) starts as a very slender sinuous gallery entirely filled with blackish brown frass; further in the gallery widens to a large elongated blotch with black-brown frass distributed irregularly and with very wide areas free of frass. Larval exit slit ( Figs 23, 24 ) on upper side of the leaf. Cocoon beige cream; length 2.6–3.5 mm, maximum width 1.3–1.4 mm. Adults fly in February.

Distribution ( Figs 1 ). This species occurs on the western slopes of the equatorial Andes ( Ecuador: Chimborazo Province) at altitudes around 3325–3400 m.

Etymology. The species name is derived from Latin decora (beautiful) in reference to the distinctive pattern of dark brown and silvery shiny scales of the forewing.

Remarks. Although one fully developed adult is available, all three paratype slides (AD784♂, AD801♂, AD802♂) are made from fully developed adults in pupal skin, not from pinned specimens.

Figures

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

FIGURES 19 – 26. Stigmella decora Diškus & Stonis, sp. nov. 19, 21, host plant Rhynchotheca spinosa Ruiz & Pav.; 20 – 24, leaf-mines; 25, cocoon; 26, adult, holotype.

FIGURES 27 – 30. Stigmella decora Diškus & Stonis, sp. nov. 27, adult, holotype; 28, male genitalia, capsule with phallus partially removed, paratype, mount in glycerol, slide no. 802; 29, phallus, genitalia slide no. AD 802; 30, same, capsule (ZMUC).

FIGURES 31 – 35. Stigmella decora Diškus & Stonis, sp. nov. 31, 32, male genitalia, paratype, genitalia slide no. AD 801; 33, dorsal processes, slide no. AD 784 (not type series); 34, paratype, slide no. AD 801; 35, female genitalia, holotype, slide no. AD 795 (ZMUC).