A comprehensive molecular phylogeny of Cephalotrichum and Microascus provides novel insights into their systematics and evolutionary history

Abstract

The genera Cephalotrichum and Microascus contain ecologically, morphologically and lifestyle diverse fungi in Microascaceae (Microascales, Sordariomycetes) with a world-wide distribution. Despite previous studies having elucidated that Cephalotrichum and Microascus are highly polyphyletic, the DNA phylogeny of many traditionally morphology-defined species is still poorly resolved, and a comprehensive taxonomic overview of the two genera is lacking. To resolve this issue, we integrate broad taxon sampling strategies and the most comprehensive multi-gene (ITS, LSU, tef1 and tub2) datasets to date, with fossil calibrations to address the phylogenetic relationships and divergence times among major lineages of Microascaceae. Two previously recognised main clades, Cephalotrichum (24 species)and Microascus (49 species), were re-affirmed based on our phylogenetic analyses, as well as the phylogenetic position of 15 genera within Microascaceae. In this study, we provide an up-to-date overview on the taxonomy and phylogeny of species belonging to Cephalotrichum and Microascus, as well as detailed descriptions and illustrations of 21 species of which eight are newly described. Furthermore, the divergence time estimates indicate that the crown age of Microascaceae was around 210.37 Mya (95% HPD: 177.18–246.96 Mya) in the Late Triassic, and that Cephalotrichum and Microascus began to diversify approximately 27.07 Mya (95% HPD:20.47–34.37 Mya) and 70.46 Mya (95% HPD:56.96–86.24 Mya), respectively. Our results also demonstrate that multigene sequence data coupled with broad taxon sampling can help elucidate previously unresolved clade relationships.