Catabotryales K.D. Hyde & Senan., ord. nov.

Index Fungorum number: IF 556718; MycoBank number: MB 556718Facesoffungi number: FoF 06864;

Saprobic on dead plant parts. Sexual morph: Stromata irregularly scattered, conspicuous, multi-loculate, superficial, with a base slightly penetrating the epidermis, discoid to pulvinate, reddish brown to black, scurfy surface, flat or slightly convex, composed of rather thin-walled, reddish yellow cells of textura angularis, textura globosa or textura epidermoidea. Ascomata perithecial, deeply imbedded in stromatic tissues, globose, with a long, periphysate, ostiolar neck. Peridium thick, composed of several layers of reddish-brown cells of textura angularis. Paraphyses hypha-like, numerous, tapering towards the apex, not embedded in a gelatinous matrix. Asci 8-spored, unitunicate, broad cylindrical, short pedicellate, apically rounded or truncate, with a J-, discoid, refractive, apical ring. Ascospores bi-seriate, hyaline, 1-celled, ellipsoidal to cylindrical, smooth-walled, lacking a mucilaginous sheath. Asexual morph: Undetermined.

Type family – Catabotryaceae Petr. ex M.E. Barr

Notes – Catabotryaceae was placed in Amplistromatales based on DNA sequence analyses (Maharachchikumbura et al. 2015, 2016b). However, this family was later placed in the Sordariomycetes families incertae sedis based on phylogeny and molecular clock evidence (Hongsanan et al. 2017). Catabotryaceae has only one strain representing its taxonomic placement, and more samples are needed to provide evidence for its ordinal status. Hyde et al. (2017a), however, suggested that a new order Catabotryales was needed to accommodate the monotypic family Catabotryaceae based on divergent time estimations. Catabotryales is formally introduced here for the single family Catabotryaceae. Catabotryales comprises saprobic species on the dead leaves and stems of tropical monocotyledons. This order is distinct from its sister orders in having astromatic ascomata, broad cylindrical asci and ellipsoidal to cylindrical ascospores without a mucilaginous sheath. The divergence time for Catabotryales has been estimated at 172 MYA (Fig. 2).

Figure 2 – The maximum clade credibility (MCC) tree, using the same dataset from Fig. 1. This analysis was performed in BEAST v1.10.2. The crown age of Sordariomycetes was set with Normal distribution, mean = 250, SD = 30, with 97.5% of CI = 308.8 MYA, and crown age of Dothideomycetes with Normal distribution mean = 360, SD = 20, with 97.5% of CI = 399 MYA. The substitution models were selected based on jModeltest2.1.1; GTR+I+G for LSU, rpb2 and SSU, and TrN+I+G for tef1 (the model TrN is not available in BEAUti 1.10.2, thus we used TN93). Lognormal distribution of rates was used during the analyses with uncorrelated relaxed clock model. The Yule process tree prior was used to model the speciation of nodes in the topology with a randomly generated starting tree. The analyses were performed for 100 million generations, with sampling parameters every 10000 generations. The effective sample sizes were checked in Tracer v.1.6 and the acceptable values are higher than 200. The first 20% representing the burn-in phase were discarded and the remaining trees were combined in LogCombiner 1.10.2., summarized data and estimated in TreeAnnotator 1.10.2. Bars correspond to the 95% highest posterior density (HPD) intervals. The scale axis shows divergence times as millions of years ago (MYA).

Figure 2 – Continued.

Figure 2 – Continued.