Annulatascus K.D. Hyde, Aust. Syst. Bot. 5(1): 118 (1992)

MycoBank number: MB 25398; Index Fungorum number: IF 25398; Facesoffungi number: FoF 01213; 17 morphological species (Species Fungorum 2020), 7 species with sequence data.

Type speciesAnnulatascus velatispora K.D. Hyde

NotesAnnulatascus is the type genus of Annulatascaceae and was introduced by Hyde (1992b) based on two tropical freshwater taxa, A. velatispora as the type species and A. bipolaris. However, the holotype of A. velatisporus was in poor condition as herbarium material had only a few ascomata. Thus, Dayarathne et al. (2016a) designated an epitype, which was collected from submerged wood in a river, at Millaa Millaa Falls, north Queensland, Australia, based on morphological examination and DNA sequences. The genus presently contains 19 epithets (Index Fungorum 2020) and molecular data has demonstrated that this genus is polyphyletic (Abdel- Wahab et al. 2011, Luo et al. 2015) and confirmed that placement of species in this genus based solely on the relatively massive apical ascal ring is not very reliable (Abdel-Wahab et al. 2011, Luo et al. 2015). In our phylogenetic analyses, Annulatascus nilensis does not cluster within Annulatascus, but is basal to Ascitendus, Longicollum and Submersisphaeria with low bootstrap support (Fig. 3). Annulatascus nilensis also formed a weakly-supported clade with members of Annulatascus (Abdel-Wahab et al. 2011, Luo et al. 2019). Fresh collections and multigene phylogenies are needed to resolve the taxonomy of this group of fungi. We introduce a new species, Annulatascus thailandensis (Fig. 30) and redescribe the type species, A. velatisporus (Fig. 31).

Figure 3 – Phylogram generated from maximum likelihood analysis based on combined LSU, SSU, ITS and rpb2 sequence data of Diaporthomycetidae. One hundred and ninety-three strains are included in the combined analyses which comprised 3545 characters (859 characters for LSU, 972 characters for SSU, 659 characters for ITS) after alignment. Single gene analyses were carried out and the topology of each tree had clade stability. Tree topology of the maximum likelihood analysis is similar to the Bayesian analysis. The best RaxML tree with a final likelihood value of – 68207.368884 is presented. Estimated base frequencies were as follows: A = 0.248206, C = 0.241993, G = 0.285500, T = 0.224301; substitution rates AC = 1.369088, AG = 2.887040, AT = 1.413053, CG = 1.152137, CT = 6.303994, GT = 1.000000; gamma distribution shape parameter a = 0.315782. Bootstrap support values for ML greater than 75% and Bayesian posterior probabilities greater than 0.95 are given near the nodes. The tree is rooted with Diatrype disciformis (AFTOL-ID 927). Ex-type strains are in bold. The newly generated sequences are indicated in blue

Figure3 – Continued.

Figure3 – Continued.

Figure3 – Continued.

Figure 30 Annulatascus thailandensis (MFLU 18-1556, holotype). a-c Ascomata superficial on host surface. d Vertical section of ascoma. e Structure of peridium near the base. f Structure of peridium at upper part. g-j Unitunicate asci. k Paraphyses. l-o Ascospores. p Ascospore mounted in India ink. q Colony on PDA (from front). r Colony on PDA (from reverse). Scale bars: d, e, g-i = 50 μm, f = 30 μm, j-p = 20 μm.

Figure 31 Annulatascus velatisporus (Material examined – AUSTRALIA, North Queensland, on submerged wood in a small river, 14 April 2015, S. Fryar & B. Cawson MR102A, MFLU 16-2204, epitype) a Herbarium material. b, c Appearance of black ascomata on host. d Vertical section of ascoma. e Structure of peridium. f Paraphyses. g-i Unitunicate asci. j-l Ascospores. Scale bars: d = 100 μm, e = 50 μm, f, i-l = 10 μm, g, h = 20 μm.