Xylariomycetidae O.E. Erikss & Winka, Myconet 1: 12 (1997)

Index Fungorum Number: IF501509

Different outlines of Xylariomycetidae have been published by Maharachchikumbura et al. (2016b), Samarakoon et al. (2016b) and Hongsanan et al. (2017). However, in the present study, we have revised the subclass. Concatenated LSU, ITS, rpb2 and tub2 based maximum likelihood phylogeny resulted in a well-supported backbone tree for 34 families in Xylariomycetidae. The divergence time for Xylariomycetidae is estimated as 278 MYA. There are three distinct clades in the tree representing the orders discussed in previous studies: Xylariales, Amphisphaeriales and Delonicicolales. The sister orders Xylariales (15 families) and Amphisphaeriales (17 families) have moderate statistical support (55% ML) and basal to these is the highly supported clade Delonicicolales (100% ML). Samarakoon et al. (2016b) and Hongsanan et al. (2017) provided divergence time estimations as additional information for Amphisphaeriales, which is estimated to have diverged from Xylariales around 152–187 Mya and provides evidence for these as distinct orders. Families accepted in Amphisphaeriales in this paper are similar to Hongsanan et al. (2017). In this study, we accept Cainiaceae as placed in Xylariales (Figs 1, 4), while Iodosphaeriaceae which was previously referred to as the Xylariomycetidae incertae sedis, (Hongsanan et al. 2017) is placed in Amphisphaeriales. Xyladictyochaetaceae (Crous et al. 2018b) is accepted in Amphisphaeriales and clusters with Phlogicylindriaceae with high statistical support (95% ML; Fig. 4). Hansfordiaceae (Crous et al. 2019b) is sister to Coniocessiaceae in Xylariales with strong statistical support (82% ML; Fig. 4). Cylindriaceae (Crous et al. 2018b) and Pseudotruncatellaceae (Crous et al. 2019b) are placed in Amphisphaeriales with poor statistical support (Fig. 4). Induratiaceae will be introduced by Samarakoon et al. (2020) and is placed in Xylariales (Fig. 4). Voglmayr et al. (2019a) introduced Leptosilliaceae as a new family which is sister to Delonicicolaceae, while rejecting Delonicicolales. However, with high statistical support (Fig. 4), we accept Delonicicolales in this study. Currently there are three orders and 35 families in this subclass.