Ikaeria serusiauxii , a new Caloplaca -like lichen from Macaronesia and mainland Portugal, with a lichen checklist for Porto Santo

Abstract

The new species Ikaeria serusiauxii ( Teloschistaceae , lichenized Ascomycetes ) is described from the Madeira Archipelago, Canary Islands and continental Portugal. It is a crustose lichen on twigs and branches of trees and shrubs in xerophytic maritime vegetation. Superficially it is similar to Caloplaca cerina and C. haematites , from which it differs by the often black apothecium margin, very thick spore septa, black pycnidium ostioles, and the presence of the pigment Cinereorufa -green instead of Sedifolia -grey. ITS sequences suggest Ikaeria aurantiellina (syn. Caloplaca aegatica ) as the closest relative. Added is a preliminary lichen checklist for Porto Santo (Madeira Archipelago, Macaronesia).

Keywords

• taxonomy
• lichens
• diversity
• island biology