Neoplaca mirabilis, a new genus and a new epigaeic species containing naphthopyrans from the family Teloschistaceae

Abstract

The production of anthraquinones is a major characteristic of most species in the Teloschistaceae. Other secondary metabolites are quite rare in this family, but some species are known to produce depsides, depsidones, xanthones and usnic acid. A new monotypic genus, Neoplaca, with a new species N. mirabilis, is described from the subfamily Caloplacoideae of the family Teloschistaceae, lacking anthraquinones but containing the naphthopyrans simonyellin and consimonyellin. This is the first time this class of organic compounds has been found in the family Teloschistaceae and the second in the order Teloschistales, where simonyellin has been detected in Brigantiaeaceae. Simonyellin and consimonyellin have also previously been reported in the family Roccellaceae. Neoplaca mirabilis is currently known from the two nearby localities in Yakutia, Russia, where it is common and grows on base-rich soil on exposed south-facing siliceous outcrops. The thallus consists of scattered whitish to greyish, or rarely with pale yellow tinge, squamules 1–4.5 mm diam. and 0.3–1 mm thick with citrine to orange-yellow blastidia produced from their margin; apothecia and pycnidia are unknown. In addition to naphthopyrans, N. mirabilis contains an unidentified brown pigment similar in some features to melanin. The new species is also interesting in that the pigments are apparently located inside the cells of the cortex, not on their surface, where anthraquinones are found in Teloschistaceae.