Indalia pygmaeola subsp. pygmaeola Macià & Ylla & Gastón & Huertas & Bau 2022, comb. nov.

Indalia pygmaeola pygmaeola (Doubleday, 1847) comb. nov.

Original combination: Lithosia pygmaeola Doubleday, 1847 Zoologist 5: 1914.

L. T.: East coast of Kent, England.

Material examined. BELGIUM: 2 ♂ y 1 ♀, Bredene Le Litoral, Flyes 30.vi.1987, F. Bolly leg.

ENGLAND: 3 ♂, East coast of Kent, Norfolk, 11.vii.2005, R. Macià col.; 1 ♀, East coast of Kent, 24.vi.1967, B. Goater leg.

Diagnosis. The specimens from British Isles, where Indalia pygmaeola was initially described, are readily distinguished from externally similar species such as Indalia marcida or Indalia lutarella. The forewings are a lighter straw-yellow colour and the hindwings are ivory coloured.

Re-description. Imago (Figs. 29–30). Wingspan of males between 26–32 mm, that of females 24–28 mm.

Genitalia (Fig. 63). Male genitalia: Uncus of medium size, thick, sclerotised, with a pointed tip; valvae ovoid, cucullus very pointed; saccular process clearly curved uniformly towards the cucullusx of the valva; sacculus well defined and sclerotised, with a widening in its central part; vinculum short. Aedeagus cylindrical and not very thick, with three cornuti, one of them smaller than the other two; apical fascia slightly sclerotised with a small, inconspicuous spur at the tip. Female genitalia: Anal papillae and 8th segment large compared to the rest of the genital structure, similar to Indalia marcida; lamella postvaginalis not very conspicuous; ostium bursae slightly sclerotised, cup-shaped; ductus bursae broad, trapezoidal, short and slightly sclerotised; corpus bursa with the shape of a pumpkin or a violin, with a membranous wart covered internally with micro-spines in the upper part and a circular signum in the inner wall of its lower part.

Immature stages. Not studied.

Molecular data. No samples for this subspecies have been analysed for DNA. A total of 25 records for Indalia pygmaeola from 7 countries, not including UK, (Austria, Italy, Germany, Netherlands, Finland, Croatia and Spain) are published in BOLD All these samples form a single BIN cluster. All these samples form a single BIN cluster (BOLD: AAE8202), so the available genetic data does not convey additional information on the subspecific differentiation of Indalia pygmaeola pygmaeola.

Biology. Univoltine, flying in a single generation through July, August and mid-September. Adults are active by day and at dusk, ans are attracted to bait and artificial light. The larvae feed on lichens.

Distribution (Fig. 109). East coast and Atlantic coast of England; Netherlands, coastal areas of the North Sea and its islands.

Observations. Nominotypical pygmaeola is locally common on the east coast; subsp. pallifrons is confined to Dungeness, round the corner on the south coast of Kent.