Ascoglobospora marina Abdel-Wahab, sp. nov.

Index Fungorum number: IF 559819; Mycobank number: MB 559819; Facesoffungi number: FoF 12718; Fig. 1

Etymology – Named after the marine habitat of the fungus.

Holotype – CBS H-23855.

Saprobic on decaying driftwood. Sexual morph: Hyphae 2–3 μm in diam, light-brown, septate. Ascomata 110–180 μm in diam., globose to subglobose, erumpent to superficial, membranous, hyaline to light-brown, ostiolate, papillate, surrounded by septate hyphae. Neck 22–45 μm long, 18–21 μm wide hyaline to light-brown in color, cylindrical, periphysate. Peridium 15–24 μm thick, one-layered, hyaline, forming textura-angularis, consists of 9–12 cell layers of elongated, thick-walled, polygonal hyaline cells, the first outer layer is hyaline to light-brown in color. Catenophyses present. Asci 42–48×32–37 μm, eight-spored, subglobose, thin-walled, deliquesce early, without an apical apparatus. Ascospores 22–30×8–9 μm (x̅=26.3×8.2 μm, n=50), ellipsoidal, with rounded ends, multiseriate, one-septate, not constricted at the septum, hyaline, thick-walled (0.5–0.7 μm), with bipolar, hamate, apical appendages. Appendages 15–20 μm long extend beyond the median septa, uncoil in water to form long filaments. Asexual morph: unknown.

Culture characteristics – Single spore isolates of Ascoglobospora marina growing on PDA are light brown with tufts of aerial mycelium, reaching a 20–25 mm radius after one month at 25 ºC. No sporulation structure was observed.

Material examined – Japan, Yokohama, Umikaze Park, 35° 16′ 36″ N, 139° 41′ 02″ E, on decaying driftwood, 12 October 2007, M.A. Abdel-Wahab, CBS-H-23855 (holotype), ex-type living culture, NBRC 105278.

GenBank numbers – CBS-H-23855: ITS = OP150939, SSU=OP151088.

Notes – Ascoglobospora marina differs from Aniptosporopsis lignatilis by having globose, early deliquescing, thin-walled asci without apical apparatus, smaller ascospore dimensions that are ellipsoidal with rounded ends. The latter species has clavate, persistent asci, with a thickened plate, plasmalemma retraction, apical pore and active spore dispersal. Ascospores in A. lignatilis are fusiform with acute apices and larger than ascospores of A. marina (Hyde 1992; Jones et al. 2017).

Figure 1 – Ascoglobospora marina (CBS H-23855, holotype). a Vertical section of ascoma. b Magnified part of the peridium. c Catenophyses. d, e Asci at different stages of maturity. f–k Variously shaped ascospores with various stages of appendages uncoiling. Scale bars: a=25 µm, b–f=10 µm, g–k=5 µm

Figure 2 – Phylogenetic relationship of Ascoglobospora marina with related genera in Halosphaeriaceae based on the nucleotide sequences of the combined SSU and LSU rDNA. The maximum likelihood (ML) tree was constructed in RAxMLGUI v. 2.0.8 (Silvestro & Michalak 2012) using the GTR+GAMMA substitution model with 1000 bootstrap replicates. The best RAxML tree with a final likelihood value of−12,686.5456 is presented. The maximum parsimonious data set of the combined genes consisted of 51 taxa with 3 representatives of Xylariales used as outgroup. The combined dataset includes 1662 total characters, of which 1004 were constant, 280 parsimony-uninformative and 378 parsimony-informative. The parsimony analyses of the data matrix yielded 4 equally most parsimonious trees with a tree length of 2082 steps (CI=0.4539, RI=0.5734, RC=0.2602). Phylogenetic trees obtained from ML, maximum parsimony (MP) and Bayesian inference posterior probabilities (BYPP) were similar in topology. Bootstrap support on the nodes represents ML and MP≥70%. Branches with a BYPP of≥95% are in bold. The new taxon, Ascoglobospora marina in blue bold and type strains are in bold