Cladosterigma: an enigmatic fungus, previously considered a basidiomycete, now revealed as an ascomycete member of the Gomphillaceae

ABSTRACT

Cladosterigma clavariellum has been treated as a basidiomycete since its first description by Spegazzini in 1886 as Microcera clavariella. After further morphological studies, between 1919 and 2011, it remained among the basidiomycetes, most recently as incertae sedis in the order Cryptobasidiales. Our studies, based on light and scanning electron microscopy, supported by multilocus phylogenetic analyses—second-largest subunit of RNA polymerase II (RPB2), translation elongation factor 1-alpha (TEF1), small subunit (18S), large subunit (28S), and nuclear internal transcribed spacers (ITS1-5.8S-ITS2 = ITS) of the nuclear rDNA sequences, and mitochondrial rDNA small subunit (mtSSU)—finally determined the phylogenetic placement of Cladosterigma as the first nonlichenicolous mycoparasitic member of the Gomphillaceae within the Graphidales, an ascomycete order previously composed predominantly of lichen-forming fungi.

KEYWORDS:

• Brazil
• Cerrado fungi
• Graphidales
• hyperparasitism
• Lecanoromycetes
• mycoparasite
• Neotropical ascomycetes
• Ostropomycetidae

ACKNOWLEDGMENTS

We thank Dr. Keith Seifert for presubmission review of our manuscript, and Prof. Chris Fagg, Departamento de Botânica at the Universidade de Brasília, for a thorough revision of our English. We also thank Prof. Mariza Sanchez (in memoriam) for the excellence of her fungarium assistance. We acknowledge the important contribution of Dr. Robert Lücking through his positive criticism of the manuscript, and the technical assistance with the SEM work by Guilherme Tonelli Silveira.

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Funding

This work received financial support from the Fundação de Apoio à Pesquisa do Distrito Federal (FAP-DF) through project FAP-DF 00193-077/2019-41 (headed by Prof. Diceu Macagnan), CNPq/MCTI-Brazil-PPBIO-Cerrado 2012 to J.C.D., CNPq for doctorate fellowships to M.D.M.S. and D.C.G., and CAPES (Ministério da Educação-Brazil) for fellowships to W.R.S.O., R.A.F.S., and E.S.C.S.