Elachista marginata, Sruoga, 2022

Sruoga, Virginijus, 2022, New species and records of Elachistinae (Lepidoptera: Gelechioidea, Elachistidae) from Nepal, Zootaxa 5100 (4), pp. 573-584 : 576-577

Elachista marginata sp. nov.

( Figs 8–16 )

Type material. Holotype: ♂, Nepal, 70 km W Kathmandu, Baikunthapuri , 19.iv.1995, V. Sruoga leg. Gen. prep. VS504 (VU).

Diagnosis. The wing pattern of this species is hardly distinguishable from many others of the Elachista freyerella species group. It is one of five eastern Palaearctic or Oriental species of E. freyerella species group whose phallus contains elongate cornutus: Elachista spiculifera Meyrick, 1922 described from India, E. cornutifera Sruoga, 1995 described from the Russian Far East, E. nipponicella Sugisima, 2006 described from Japan, E. loeiensis Sruoga & Kaila, 2019 described from Thailand, and E. marginata . They can be separated from each other as follows: 1) the distal spine of the cucullus is very robust in E. spiculifera (cf. Sruoga & Diškus 2006), slender in the four other species; 2) the phallus is distally markedly bent in E. cornutifera (cf. Sruoga 1995) and E. nipponicella (cf. Sugisima 2006), evenly bent from middle to apex in E. loeiensis (cf. Sruoga et al. 2019), whereas it is almost straight in E. marginata ; 3) the ventral margin of digitate process is strongly reinforced in E. marginata , whereas it is not reinforced in other four species, which well separates this species.

Male ( Figs 8, 9 ). Forewing length 2.6 mm; wingspan 5.7 mm (n=1). Head: frons creamy white; vertex and neck tuft creamy white, some scales with whitish brown tips; labial palpus slightly longer than width of head, creamy white above, whitish brown below; scape creamy brown, flagellum light creamy brown, weakly annulated with paler rings; pecten present as a few short, creamy white seta-like scales at base of scape. Thorax, tegula and ground colour of forewing formed from basally shortly creamy white and distally dark greyish brown making mottled appearance. Forewing darker beyond middle; plical spot elongate, formed by blackish brown erect scales, at ½ wing length on dorsal side of fold; discal spot elongate, blackish brown, at ⅔ wing length in middle; fascia present as indistinct, creamy white, somewhat oblique band at ⅓ wing length; creamy white costal and tornal spots indistinctly delimited; fringe scales grey brown, fringe line blackish brown. Hindwing grey brown; fringe scales somewhat paler.

Female. Unknown.

Male genitalia ( Figs 10–16 ). Uncus lobes narrow and long, apically curved and tapered to pointed apex; ventral surface covered with mixture of short and thick, and long and slender setae. Basal arms of gnathos reinforced, spinose knob small, about 1.7 times as long as wide. Valva about 4.4 times as long as width at hump; sacculus weakly concave medially, distally with prominent, stout spine; cucullus neither expanded nor produced towards costa; basal fold of costa extended to ⅔ of valva, where it meets distal fold forming hump. Median plate of juxta 2.6 times as long as broad, proximal end formed as rounded sac; medial margin of juxta lobes strongly sclerotized; lobes small, elongate; ventral surface with few short setae. Digitate process nearly 2/5 length of valva, narrow, ventral margin reinforced ( Fig. 15 ), somewhat dilated beyond middle, distally obliquely tapered and setose. Vinculum produced into long wide blunt-tipped saccus. Phallus long and slender, as long as valva, almost straight, basally broadened, with prominent dorsal lobe of caecum; vesica with group of tiny spines ( Fig. 14 ) and one elongate cornutus.

Biology. Unknown.

Flight period. Based on the specimen available, adults fly in April.

Distribution. So far this species is known only from central Nepal.

Etymology. The species name is derived from the Latin margino (to provide with edges or borders) in reference to reinforced ventral margin of digitate process.

Figures

FIGURES 8–13. Elachista marginata sp. nov., holotype. 8, adult male. Scale bar 1 mm; 9, head, latero-frontal view; 10, right valva; 11, tegumen, uncus, vinculum and saccus; 12, left valvam, juxta and digitate process; 13, phallus. Gen. prep. VS504. Scale bar 0.1 mm.

FIGURES 14–16. Elachista marginata sp. nov., holotype. 14, distal part of phallus; 15, digitate process, in glycerol before permanent mounting in Euparal; 16, distal part of abdomen, dorsal view. Gen. prep. VS504.