A phylogenetic study of Micarea melaeniza and similar-looking species (Pilocarpaceae) unveils hidden diversity and clarifies species boundaries and reproduction modes

Abstract

Micarea (Ascomycota, Pilocarpaceae) is a large cosmopolitan genus of crustose lichens. We investigated molecular systematics and taxonomy of the poorly known Micarea melaeniza group focussing on M. melaeniza, M. nigella and M. osloensis. A total of 54 new sequences were generated and using Bayesian and maximum likelihood analysis of two markers (nuITS and mtSSU), we discovered two previously unrecognized phylogenetic lineages, one of which is described here as Micarea eurasiatica Kantelinen & G. Thor, sp. nov., morphologically characterized by pycnidia that are sessile to emergent, cylindrically shaped, with greenish-black K+ olive green, wall pigmentation and containing large mesoconidia up to 6 µm in length. The species is known from Japan and Finland. In addition, we show that the reproduction biology of M. osloensis has been poorly understood and that the species often occurs as an anamorph with stipitate pycnidia. We present a species synopsis and notes on pigments. Our research supports previous results of asexuality being an important reproductive strategy of species growing on dead wood.