Microthyriales G. Arnaud.

MycoBank number: MB 90485; Index Fungorum number: IF 90485; Facesoffungi number: FoF 07701.

Arnaud (1918) introduced this order, with type family Microthyriaceae. Microthyriales contained two families viz. Microthyriaceae and Micropeltidaceae based on their flattened ascomata with poorly developed base. However, members of Microthyriaceae have brown to black thyriothecia, comprising cuboid or angular cells arranged in parallel rows, with prominent central ostioles, and usually uniseptate ascospores (Doidge 1942; Müller and von Arx 1962; Luttrell 1973; Barr 1987b; Hofmann and Piepenbring 2006; Wu et al. 2011b; Hyde et al. 2013; Hongsanan et al. 2015b; Hongsanan and Hyde 2017), while Micropeltidaceae has black-blue or greenish thyriothecia, comprising interwoven hyphae, with a central ostiole, and multiple trans-septate ascospores (Clements and Shear 1931; Batista 1959; von Arx and Müller 1975; Barr 1987b; Wu et al. 2011b; Hyde et al. 2013; Hongsanan and Hyde 2017; Hongsanan et al. 2015a; Zeng et al. 2019). Hongsanan and Hyde (2017) excluded Micropeltidaceae from Microthyriales based on their phylogenetic analyses. This was supported by new collections of Micropeltidaceae in Zeng et al. (2019). Therefore, Microthyriales contains a single family, Microthyriaceae based on morphology and phylogeny. Species of Microthyriales cluster together as a distinct clade within Dothideomycetes with high support (Fig. 44). The divergence time for Microthyriales is estimated as 184 MYA (stem age, Hongsanan et al. 2020).

Accepted families: Microthyriaceae.