Elachista siamensis Sruoga & Kaila, 2019

Sruoga, Virginijus, Kaila, Lauri & Rocienė, Agnė, 2019, The Elachistinae (Lepidoptera: Gelechioidea, Elachistidae) of Thailand, with description of eight new species, European Journal of Taxonomy 574, pp. 1-34 : 28-31

Elachista siamensis Sruoga & Kaila sp. nov.

urn:lsid:zoobank.org:act:ADD7FEC2-3FB8-46AB-838E-FAD6824D7520

Figs 67–73

Diagnosis

In wing pattern and male genitalia, this species closely resembles Elachista loeiensis Sruoga & Kaila sp. nov., known from northeastern Thailand. See diagnosis of E. loeiensis Sruoga & Kaila sp. nov. for separation of the oriental and eastern palaearctic species of E. freyerella species group with a cornutus in the phallus.

Etymology

This species is named after Siam, the old name for Thailand, in reference to the type locality.

Type material

Holotype

THAILAND • ♂; Nakhon Nayok Prov., Khao Yai Nat. Park ; ca 700 m; 29 Sep.–6 Oct. 1984; Karsholt, Lomholdt and Nielsen leg.; ZMUC 2070 .

Paratypes

THAILAND • 2 ♂♂; same collection data as for holotype; ZMUC 1500 , 2071 • 1 ♂; same collection data as for holotype; VMU 1505 • 1 ♀; same collection data as for holotype; ZMUC 2075 • 1 ♂; Loei Province, Phu Luang Wildlife Sanctuary ; 700–900 m; 8–14 Oct. 1984; Karsholt, Lomholdt and Nielsen leg.; MZH 1504 .

Description

Male

EXTERNAL CHARACTERS ( Figs 67–68 ). Forewing length 2.6–2.8 mm; wingspan 5.8–6.3 mm (n = 5). Head: frons shiny, creamy white; vertex and neck tuft whitish brown, powdered with dark browntipped scales; labial palpus upwards curved, diverging, as long as width of head, creamy white above, whitish brown below; antenna greyish brown, weakly annulated with paler rings, somewhat serrate in distal ½; pecten present as a few short stiff 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; plical spot elongate, blackish brown, 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, its fringe scales somewhat paler.

MALE GENITALIA ( Fig. 69 ). 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 about 1.6 times as long as wide. Valva broadest in basal part; sacculus weakly concave medially, distally with stout spine; cucullus neither expanded nor produced towards costa, tip rounded; basal fold of costa extended to ⅔ of valva, where it meets distal fold forming broad distinct hump. Median plate of juxta two times as long as broad, proximal end formed as rounded sac; medial margin of juxta lobes strongly sclerotized; lobes short, broadest medially, tapered distally; ventral surface with few short setae. Digitate process ⅓ length of valva, narrow, distally somewhat dilated and setose. Vinculum produced into long and narrow saccus. Phallus about 0.9 length of valva, narrow, broadest basally, almost straight; caecum dorsally with cusp-like lobe whose anterior margin is concave; vesica with one short cornutus that consists of weakly sclerotized elongate plate with one acute tooth.

Female

EXTERNAL CHARACTERS ( Figs 70–71 ). Forewing length 2.8 mm; wingspan 6.3 mm (n = 1). Otherwise as male, but forewing more brightly coloured with ground colour dark blackish brown; fascia, costal and tornal spots white.

FEMALE GENITALIA ( Figs 72–73 ). Papilla analis setose, triangular. Apophysis posterioris slightly longer than apophysis anterioris. Ostium bursae in posterior margin of sternum 7, dorsal wall spinose. Ventral margin of ostium bursae deeply incised, narrow and V-shaped. Antrum rather short, approximately as long as apophysis posterioris and nearly three times as broad as colliculum. Inner side of antrum with minute spines. Anterior margin of sternum 7 reinforced. Colliculum as long as antrum, bent, more sclerotized on one side. Corpus bursae oval, covered by minute internal spines except caudally; signum oval sclerotized plate with pair of large apposite teeth and two small accessory teeth.

Biology

Unknown.

Flight period

Based upon specimens available, adults fly in September and October.

Distribution

So far this species is known only from northeastern and central Thailand.

Remarks

The putative association of male and female is based on similar appearance and on the occurrence at the same locality. Moths were caught at the same site and time.

The gnathos is slightly wider in two paratypes (slide numbers L. Kaila 1500 and 1504). In the absence of other reliable differences, we consider this as minor variation of the same species.

Figures

Figs 67–69. Elachista siamensis Sruoga & Kaila sp. nov., holotype, ♂ (ZMUC 2070). 67.Adult. 68. Head, latero-frontal view. 69. General view of male genitalia. Scale bars: 67–68 = 1 mm; 69 = 0.1 mm.

Figs 70–73. Elachista siamensis Sruoga & Kaila sp. nov., paratype, ♀ (ZMUC 2075). 70. Adult. 71. Head, latero-frontal view. 72. Female genitalia, caudal part. 73. Ductus and corpus bursae. Scale bars: 70–71 = 1 mm; 72–73 = 0.1 mm.