Stigmella podanthae Diškus & Stonis, 2016

Stonis, Jonas R., Diškus, Arūnas, Remeikis, Andrius & Torres, Nixon Cumbicus, 2016, First description of leaf-mining Nepticulidae and Tischeriidae (Insecta, Lepidoptera) feeding on the Chilean endemic plant genus Podanthus Lag. (Asteraceae), Zootaxa 4061 (2), pp. 119-130 : 120-121

Stigmella podanthae Diškus & Stonis , sp.nov.

( Figs 1–6 , 14, 15 , 18 –29)

Type material. ♂, holotype, Region Metropolitana de Santiago, 18 km southeast of Pirque, Rio Clarillo (Nacional Reserve), 33°43'29''S, 70°28'57''W, elevation 910 m, larvae on Podanthus ovatifolius Lag. 15.iv.2014, ex pupa 12.v.2014, fieldwork card no. 5153, leg. A. Diškus, genitalia slide no. AD592; paratypes: 3♂, 2♀, same label data as holotype, ex pupae 10–20.v.2014, genitalia slide nos AD 591♂, AD 593♂, AD594♀; AD601♀ ( ZMUC).

Diagnosis. The new species belongs to the Stigmella salicis group (for the world catalogue of this group see Puplesis & Diškus, 2003). In male genitalia, it differs from all other species of the salicis group by the combination of very large cornuti aggregated in two lateral rows and the large medial plate of gnathos; the host-plant ( Podanthus ovatifolius ) also makes this species distinctive. Additionally, Stigmella podanthae differs from most similar but Rosaceae-feeding Ecuadorian S. montanotropica by the forewing fascia (in S. montanotropica the forewing is uniformly coloured, without fascia), and by 11 cornuti (instead 14 in S. montanotropica ); from the superficially similar Colombian S. johannis (Zeller) by the larger lateral lobes of vinculum, larger medial plate of gnathos, uncus divided in two large lobes (not into equally small four ones as in S. johannis ), and by the small transtilla with short sublateral processes (in S. johannis transtilla is rounded, without processes, and extending from the ventral plate of vinculum).

Male ( Fig. 14 ). Forewing length 2.2–2.6 mm; wingspan 4.3–5.5 mm. Head: palpi greyish cream; frontal tuft yellowish cream to beige cream or very pale orange; collar and scape very large, yellowish cream; antenna with 30 segments, distinctly longer than half of forewing; flagellum dark grey or fuscous on upper side, grey to cream grey on underside. Thorax, tegulae and forewing very densely irrorated with brown-black or black scales with purple iridescence. Forewing with distinctly postmedian, slightly oblique or straight, greyish cream or whitish fascia strongly narrowed or fully interrupted in the middle; cilia pale grey to dark grey, with overlapping apical spot of lamellar whitish cream scales; underside of forewing black-grey, without spots. Hindwing and its cilia grey to pale grey; underside of hindwing grey to fuscous grey. Legs pale grey to fuscous on upper side, yellowish cream or beige on underside. Abdomen fuscous on upper side, cream beige to grey yellow on underside; anal tufts short, beige; anal plates cream beige.

Female ( Fig. 15 ). Externally similar to male but forewing fascia 2–2.5 times broader, cream to yellowish cream, and not narrowed (constricted or interrupted) in the middle.

Male genitalia ( Figs 18–24 ). Capsule 290–300 Μm long. Vinculum with short triangular lateral lobes; ventral plate small (40 Μm long in the middle). Uncus gradually narrowed caudally, divided in two large lobes each bearing two papillae ( Figs 18, 21, 24 ). Gnathos with large central plate and two parallel and very slender caudal processes ( Fig. 21 ). Valva ( Figs 18, 23 ) 165 Μm long, small inner lobe, inwardly-bent apex with two pointed processes; transtilla with short, slightly variable sublateral processes ( Figs 18, 24 ). Juxta membranous, indistinct. Phallus ( Figs 19, 20, 22 ) 190–225 Μm long, 75–80 Μm broad; vesica with 11 various spine-like cornuti aggregated into two lateral clusters ( Fig. 22 ).

Female genitalia (Figs 25–29). Total length 710 Μm. Abdominal apex distinctly truncate. Apophyses anteriores (125 m) almost equal to very narrow apophyses posteriores (130 Μm) (Figs 27, 28). Vestibulum relatively narrow, without sclerites. Accessory sac large and folded. Ductus spermathecae narrow and long, with one small but strongly chitinized convolution (Fig. 25); extending into oval utriculus (Fig. 26). Corpus bursae round (350 Μm long, 295 Μm broad), covered with numerous irregular granules but without signa (Figs 25, 26).

Bionomics. Mines in leaves ( Figs 4–6 ). Host-plant: Podanthus ovatifolius Lag. ( Asteraceae : subfamily Asteroideae : tribe Heliantheae ) ( Figs 3, 4 ). Egg on upper side of the leaf. Larvae mine in April (start feeding in early April). Sinuous or contorted gallery of mine with black frass; early mine (first third or half of mine) very slender and completely or almost completely filled with frass ( Fig. 6 ); the remaining two-thirds or half of mine almost abruptly become broad, with disperse or coiled frass deposited in an irregular, broad central line occupying one-third of the width of the gallery ( Figs 5, 6 ). Larva green (or yellowish green), with beige-brown intestine ( Fig. 5 ); in final instar predominantly yellowish, with beige-brown intestine ( Fig. 6 ). Larval exit slit on upper side of the leaf. Cocoon pale beige; length 2.1–2.2 mm, maximal width 1.2 mm. Adult emergence in May.

Using the ‘Formula of Evaluation of Abundance and Occurrence of Leaf-miners’ (see Diškus & Stonis 2012: 52– 54), it appears that S. podanthae sp. nov. is not rare at the type locality (18 km southeast of Pirque) (Rio Clarillo, figs 1, 2): It is limited in distribution but abundant (more than 20 leaf-mines recorded at a single site).

Distribution ( Figs 1, 2 ). Known only from central Mediterranean Chile at elevation about 910 m ( Fig. 2 ).

Etymology. The species is named after the host-plant genus ( Podanthus Lag. , Asteraceae ).

Figures

FIGURES 1 – 6. Geography and biology of the treated leaf-mining species. 1, distribution of Stigmella podanthae sp. nov. and Astrotischeria chilei Puplesis & Diškus; 2, central Mediterranean Chile at elevation about 910 m (18 km southeast of Pirque, Rio Clarillo); 3, Host-plant Podanthus ovatifolius Lag.; 4, same, with a leaf-mine of Stigmella podanthae sp. nov.; 5, 6, leafmines of Stigmella podanthae sp. nov. Podanthus ovatifolius Lag., 18 km southeast of Pirque, Rio Clarillo.

FIGURES 14 – 17. Adults. 14, 15, male (14) and female (15) of Stigmella podanthae sp. nov.; 16, 17, male (16) and female (17) of Astrotischeria chilei Puplesis & Diškus. Note: the forewing pattern is highly variable, the pattern (17, female) when ochreyellow scales predominate and black scales form irregular dots is equally characteristic for males.

FIGURES 18 – 24. Male genitalia of Stigmella podanthae sp. nov. (ZMUC). 18, capsule (without phallus), holotype, genitalia slide no. AD 592; 19, phallus, holotype, genitalia slide no. AD 592; 20, same, paratype, genitalia slide no. AD 591; 21, uncus and gnathos, paratype, genitalia slide no. AD 593; 22, cornuti, holotype, genitalia slide no. AD 592; 23, apical parts of valvae, holotype, genitalia slide no. AD 592; 24, dorsal view of genital capsule, paratype, genitalia slide no. AD 591.