Abstract
Trapelioid fungi constitute a widespread group of mostly crust-forming lichen mycobionts that are key to understanding the early evolutionary splits in the Ostropomycetidae, the second-most species-rich subclass of lichenized Ascomycota. The uncertain phylogenetic resolution of the approximately 170 species referred to this group contributes to a poorly resolved backbone for the entire subclass. Based on a data set including 657 newly generated sequences from four ribosomal and four protein-coding gene loci, we tested a series of a priori and new evolutionary hypotheses regarding the relationships of trapelioid clades within Ostropomycetidae. We found strong support for a monophyletic group of nine core trapelioid genera but no statistical support to reject the long-standing hypothesis that trapelioid genera are sister to Baeomycetaceae or Hymeneliaceae. However, we can reject a sister group relationship to Ostropales with high confidence. Our data also shed light on several long-standing questions, recovering Anamylopsoraceae nested within Baeomycetaceae, elucidating two major monophyletic groups within trapelioids (recognized here as Trapeliaceae and Xylographaceae), and rejecting the monophyly of the genus Rimularia. We transfer eleven species of the latter genus to Lambiella and describe the genus Parainoa to accommodate a previously misunderstood species of Trapeliopsis. Past phylogenetic studies in Ostropomycetidae have invoked “divergence order” for drawing taxonomic conclusions on higher level taxa. Our data show that if backbone support is lacking, contrasting solutions may be recovered with different or added data. We accordingly urge caution in concluding evolutionary relationships from unresolved phylogenies.Electronic supplementary materialThe online version of this article (doi:10.1007/s13225-015-0332-y) contains supplementary material, which is available to authorized users.
Highlights
Concepts of the phylogenetic relationships of lichenized fungi drew heavily on the shape and gross attributes of ascomata, ascospores and thallus and the photobionts with which they associate (Watson 1929)
The rump group can be considered to consist of 11 genera (Trapeliaceae sensu Lumbsch and Huhndorf 2010): Amylora, Coppinsia, Lambiella (Spribille et al 2014), Lithographa, Placopsis, Placynthiella, Ptychographa, Rimularia, Trapelia, Trapeliopsis and Xylographa (Sarea was recently excluded by Miadłikowska et al 2014)
Following removal of sites with missing data exceeding threshold values, the final alignment used for phylogenetic analyses consisted of 8978 positions including introns in the ITS and nuclear ribosomal large subunit (nuLSU) and nuclear ribosomal small subunit (nuSSU) region as well as in the RPB1 gene (Fig. 3)
Summary
Concepts of the phylogenetic relationships of lichenized fungi drew heavily on the shape and gross attributes of ascomata, ascospores and thallus and the photobionts with which they associate (Watson 1929). With the application of molecular phylogenetics to more members of this group it became apparent that ascus characters and ontogeny exhibit convergent evolution, and that several of these genera are only distantly related, including Anzina and Elixia (Wedin et al 2005), Miltidea (Widhelm and Lumbsch 2011) and not least the name-giving genus Agyrium (Lumbsch et al 2007a) This latter finding resulted in the taxonomic orphaning of the genera remaining and led to several new taxonomic proposals, partly reflecting renewed attention to relationships with Baeomycetaceae (e.g., Lumbsch et al 2007a; Lumbsch and Huhndorf 2010; Hodkinson and Lendemer 2011). For the purposes of the present discussion we will refer to this group as the trapelioid fungi (Fig. 1)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
