Understanding the evolution of phenotypical characters in the Micarea prasina group (Pilocarpaceae) and descriptions of six new species within the group.

Beata Guzow-Krzemińska,Martin Kukwa,Anna Łubek,Emmanuël Sérusiaux,Annina Launis,Pieter P G Van Den Boom,A Maarten Brand

doi:10.3897/mycokeys.57.33267

Abstract

Six new Micarea species are described from Europe. Phylogenetic analyses, based on three loci, i.e. mtSSU rDNA, Mcm7 and ITS rDNA and ancestral state reconstructions, were used to evaluate infra-group divisions and the role of secondary metabolites and selected morphological characters on the taxonomy in the M. prasina group. Two main lineages were found within the group. The Micarea micrococca clade consists of twelve species, including the long-known M. micrococca and the newly described M. microsorediata, M. nigra and M. pauli. Within this clade, most species produce methoxymicareic acid, with the exceptions of M. levicula and M. viridileprosa producing gyrophoric acid. The M. prasina clade includes the newly described M. azorica closely related to M. prasina s.str., M. aeruginoprasina sp. nov. and M. isidioprasina sp. nov. The species within this clade are characterised by the production of micareic acid, with the exception of M. herbarum which lacks any detectable substances and M. subviridescens that produces prasinic acid. Based on our reconstructions, it was concluded that the ancestor of the M. prasina group probably had a thallus consisting of goniocysts, which were lost several times during evolution, while isidia and soredia evolved independently at multiple times. Our research supported the view that the ancestor of M. prasina group did not produce any secondary substances, but they were gained independently in different lineages, such as methoxymicareic acid which is restricted to M. micrococca and allied species or micareic acid present in the M. prasina clade.

Highlights

Morpho-anatomical characters, together with secondary metabolites, have played an important role in the lichen classification (e.g. Brodo 1978, 1986; Lumbsch 1998)
In order to reduce the size of the tree, highly supported clades were collapsed for previously described taxa
The phylogenetic reconstruction (Fig. 1) shows that the M. prasina group is highly supported and monophyletic (100 bootstrap replicates (BS) and 1 Posterior probabilities (PP)) and it agrees with previous phylogenies based on a mtSSU marker (e.g. Czarnota and Guzow-Krzemińska 2010; GuzowKrzemińska et al 2016) or three loci (Launis et al 2019a)

Summary

Introduction

Morpho-anatomical characters, together with secondary metabolites, have played an important role in the lichen classification (e.g. Brodo 1978, 1986; Lumbsch 1998). Morpho-anatomical characters, together with secondary metabolites, have played an important role in the lichen classification Molecular phylogenies can serve as a backbone for tracing the evolution of morphological and chemical characters by reconstructing their ancestral states. Such interpretations of character evolution usually open new perspectives to the evolutionary history (Lumbsch et al 2006). Secondary metabolites have been traditionally used in the taxonomy of lichens at different taxonomic levels, their values have been questioned by many authors (Lumbsch et al 2006; Leavitt et al 2011; Lutsak et al 2017). The production of certain secondary metabolites might be triggered by the environment (e.g. climate, edaphic factors, associated symbionts) (Spribille et al 2016; Lutsak et al 2017)

Methods

Results

Conclusion