Monopis jussii, a new species (Lepidoptera, Tineidae) inhabiting nests of the Boreal owl (Aegolius funereus).

Monopis jussii Kaila, Mutanen, Huemer, Karsholt & Autto, sp. nov. (Lepidoptera, Tineidae) is described as a new species. It is closely related to the widespread and common M. laevigella ([Denis & Schiffermüller], 1775), but differs in its distinct COI DNA barcode sequences, four examined nuclear loci as well as details in forewing coloration and pattern. Most reared specimens of M. jussii have emerged from the nest remnants of the Boreal owl (Aegolius funereus (Linnaeus, 1758)), but also nests of the Ural owl (Strix uralensis Pallas, 1771) and the Great tit (Parus major Linnaeus, 1758) have been observed as suitable habitats. Based on the present knowledge, the new species has a boreo-montane distribution as it is recorded only from northern Europe and the Alps. Several extensive rearing experiments from Strix spp. nest remnants from southern Finland did not produce any M. jussii, but thousands of M. laevigella, suggesting that the species is lacking in the area or, more unlikely, that the nest of these owl species do not serve as good habitat for the new species. This unexpected species discovery highlights, once again, the usefulness of DNA barcoding in revealing the cryptic layers of biodiversity. To serve stability we select a neotype for Tinea laevigella [Denis & Schiffermüller], 1775, and discuss the complicated synonymy and nomenclature of this species.