Stigmella sexcornuta Rocienė & Stonis, 2014

Stonis, Jonas R. & Rocienė, Agnė, 2014, Additions to the Nepticulidae (Lepidoptera) of East Asia, with descriptions of three new species from Primorskiy Kray, Zootaxa 3846 (2), pp. 204-220 : 205-210

Stigmella sexcornuta Rocienė & Stonis , sp. nov.

( Figs 1–5 , 11–21 )

Type material. Holotype: ♂, Far East RUSSIA, Primorskiy Kray, 20 km E Ussuriysk, Gornotayezhnoe, Biological Station, 7.viii.2011, leg. A. Rocienė, genitalia slide no. AG429 ( ZIN). Paratypes: 2♂, same locality as holotype, 6–11.viii.2011, leg. A. Rocienė, genitalia slide nos AG430, AG431 ( ZIN).

Diagnosis. The new species belongs to the large and almost cosmopolitan Stigmella salicis species group (sensu lato, including the former Neartic S. fuscotibiella group), in which species diagnosis sometimes is difficult and most often (but not only) relies on shape and number of cornuti. In male genitalia, S. sexcornuta sp. nov. most closely resembles the Japanese S. azusa Hirano , a Salix serissaefolia feeding species recently described from Honshu, Japan ( Hirano 2010). However, from S. azusa and the remaining species of the S. salicis group, S. sexcornuta sp. nov. differs in the number and shape of cornuti: three cornuti are very broad and loose, three remaining are narrowed or very slender and form a cluster.

Male ( Figs 11, 12 ). Forewing length 1.9–2.0 mm; wingspan 4.2–4.4 mm (n=3). Head: palpi cream; frontal tuft yellowish orange to orange; collar and scape cream to yellowish cream; antenna with 28 segments, almost half as long as forewing; flagellum grey-brown on upper side and pale brownish to brown on underside. Thorax: dorsum and tegulae concolorous with base of forewing. Forewing: area proximal to fascia mottled grey brown, sometimes with coppery sheen; fascia postmedial, whitish to shining silvery, slightly broadened at tornus; distal to fascia coarsely scaled (mottled with blackish grey), with weak purplish iridescence; terminal cilia grey; underside of forewing uniformly dark grey-brown, with weak purplish sheen. Hindwing and its cilia grey, with no androconia. Legs ochre-grey to brown, glossy, with blackish or brown darkenings on tarsi (or foreleg tibia and tarsi).

Male genitalia ( Figs 13–21 ). Capsule 250 mm long. Vinculum with two short triangular lobes and broad trapezoidal anterior excavation ( Figs 13, 14 ). Uncus gradually narrowed caudally, with four small caudal lobes ( Figs 13, 14 ). Gnathos (65 mm) with large lateral arms and two parallel long and slender caudal processes ( Figs 13, 14 ). Valva ( Figs 15–17 ) 170 mm long, with broad angular inner lobe and short pointed, slightly inwardly-bent apical process; transtilla without sublateral processes ( Figs 13, 15 ). Phallus ( Figs 15 , 18–21 ) broad (80 mm wide, 215 mm long); vesica with six cornuti: three very broad and loose; remaining three narrowed or very slender and aggregated into a cluster ( Figs 20, 21 ).

Female. Unknown.

Bionomics. Host-plant unknown (possibly Salix sp.). Adults fly in August (collected at light).

Distribution. The type locality is in dense, deciduous mostly broad-leaf forests of Primorskiy Kray ( Figs 1–5 ).

Etymology. The species name is derived from Latin sex (six) and cornuti (horns/cornuti) in reference to the characteristic/diagnostic number of six cornuti on the vesica in the phallus of the male genitalia.

Figures

FIGURES 1 – 5. Collecting locality and habitats. 1, the Arboretum (“ Dendrarium ”) of Gornotayezhnoe Biological Station, a site of the light trap during the fieldwork of 2011; 2 – 4, a habitat—deciduous mostly braodleaf forest in Gornotayezhnoe; 5, map of the region (courtesy of T. Patterson, USA), showing the collecting locality in Gornotayezhnoe, 20 km E Ussuriysk (Primorskiy Kray, Far East Russia).

FIGURES 11 – 15. Stigmella sexcornuta Rocienė & Stonis, sp. nov. 11, adult, holotype; 12, same, paratype. Scale bar 1 mm; 13, male genitalia, capsule, holotype, genitalia slide no. AG 429 (ZIN); 14, same, with valvae removed, paratype, genitalia slide no. AG 431 (ZIN); valvae and phallus, paratype, genitalia slide no. AG 430 (ZIN). Scale bar 100 µm.

FIGURES 16 – 21. Details of male genitalia of Stigmella sexcornuta Rocienė & Stonis, sp. nov. 16, valva, paratype, genitalia slide no. AG 430 (ZIN); 17, same, flattened, genitalia slide no. AG 431 (ZIN); 18, phallus, holotype, genitalia slide no. AG 429 (ZIN); 19, same, paratype, genitalia slide no. AG 431 (ZIN); 20, same, reconstruction, paratype, genitalia slide no. AG 431; 21, same, reconstruction, holotype, genitalia slide no. AG 429 (ZIN). Scale bar 100 µm.