Cryptosphaeria halophila Dayarathne & K.D.Hyde, 2020

Dayarathne, Monika C., Wanasinghe, Dhanushka N., Devadatha, B., Abeywickrama, Pranami, G, E. B., Jones, areth, Chomnunti, Putarak, Sarma, V. V., Hyde, Kevin D., Lumyong, Saisamorn, C., Eric H. & Mckenzie, 2020, Modern taxonomic approaches to identifying diatrypaceous fungi from marine habitats, with a novel genus Halocryptovalsa Dayarathne & K. D. Hyde, gen. nov., Cryptogamie, Mycologie 20 (3), pp. 21-67 : 40-41

Cryptosphaeria halophila Dayarathne & K.D.Hyde , sp. nov.

( Fig. 8 )

MYCOBANK. — MB 824293.

FACESOFFUNGI NUMBER. — FoF 03945.

ETYMOLOGY. — Name referring to the saline environment from which the fungus was derived.

CULTURE CHARACTERS. — Reaching 2 cm within seven days on PDA, when incubated at 25°C, circular, flat, with diffuse margin, yellow, and becoming yellowish white, bright yellow to dull yellow with age.

MATERIAL EXAMINED. — Thailand, Krabi Province, Tha Pom Khlong Nam, 8°12’50.4”N, 98°46’42.7”E, on attached, intertidal decayed wood of Avicennia sp. at a mangrove stand, 16.XII.2015, M. Dayarathne, KLA006 (holo-, MFLU [MFLU- 16-1199 ]).

DISTRIBUTION. — Thailand.

DESCRIPTION

Saprobic on decaying stem of Avicennia sp.

Sexual morph

Undetermined.

Asexual morph

Pycnidia. 140-180 µm in diam., globose to subglobose, ostiolate, coriaceous, deeply immersed in a well-developed stroma.

Peridium. 12-20 µm thick around the pycnidial venter, onelayered, yellow-brown to brown, composed of polygonal, cells with thick walls forming textura angularis.

Conidiophores. 35-50 × 2-4 µm, 0-2-septate, cylindrical, hyaline, simple or branched, with one or more conidiogenous cells.

Conidiogenous cells. 20-25 × 2.5-3.5 µm, hyaline, unicellular, with wide base and tapering tip, producing one conidium, determinate, conidiogenesis holoblastic.

Conidia. 24-35 × 1-1.5 µm (ẍ = 36 × 2 µm, n = 30), onecelled, filiform, straight, curved or hook-like, hyaline to yellowish and apricot in mass.

NOTES

Cryptosphaeria halophila Dayarathne & K.D.Hyde , sp. nov., is the first record of an asexual morph in this genus, reported from a marine habitat. Libertella -like asexual morphs have been reported from host substrates and axenic cultures in previous studies by Trouillas et al. (2015) and Mehrabi et al. (2016). In our phylogenetic analyses (ML and BI) with combined SSU+LSU sequence data, this species grouped with Cr. ligniota and Cr. pullmanensis as a separate lineage, but with poor bootstrap support ( Fig. 3 ). MP results showed that this novel species nested with Cryptosphaeria avicenniae Devadatha & V.V.Sarma , sp. nov., with no support ( Fig. 4 ). The asexual morph of Cryptosphaeria avicenniae Devadatha & V.V.Sarma , sp. nov., is similar to Cryptosphaeria halophila Dayarathne & K.D.Hyde , sp. nov., and Halocryptovalsa avicenniae , comb. nov. (synonym of Cryptovalsa avicenniae ) in conidiomatal and conidial morphology. However, our phylogenetic analyses showed that they are phylogenetically distinct ( Figs 3-4 ). No cultures were obtained for this species since conidia did not germinate on any culture media used (WA, MEA/PDA, seawater MEA/PDA or CMA). We did not obtain ITS and Btub sequence data for this species by direct sequencing of fresh fruiting bodies, after several attempts with different temperature profiles. Hence, further taxon sampling, isolation and sequence data are required to further confirm phylogenetic placement of this taxon within this genus.

Figures

FIG. 8. — Cryptosphaeria halophila Dayarathne & K.D.Hyde, sp. nov.(MFLU 16-1199 – holotype):A, host (Avicennia sp.); B, horizontal section through conidioma; C-E, conidiophores and conidiogenous cells; F-I, conidia. Scale bars: A, 100 μm; B-E, 50 μm; F-I, 20 μm.

FIG. 3. — Phylogram generated from the best scoring RAxML tree based on combined LSU and SSU sequence data. Bootstrap support values for maximum likelihood (ML, blue) equal or greater than 60 % are given above the nodes. Bayesian posterior probabilities (PP, green) equal or greater than 0.90 are shown above the branches. The tree is rooted to Xylaria hypoxylon (OCS 100004) and Xylaria acuta (5089). All sequences from ex-type strains are in bold. Scale bar: 0.02 (expected number of nucleotide substitutions per site per branch).

FIG. 4. — Phylogram generated from the best scoring MP tree based on combined LSU and SSU sequence data. Bootstrap support values for maximum parsimony (MP) equal or greater than 60 % are given above the nodes. The tree is rooted to Xylaria hypoxylon (OCS 100004) and Xylaria acuta (5089). Scale bar: 50 (expected number of nucleotide substitutions per site per branch).