Pleosporales » Tetraplosphaeriaceae

Byssolophis

Citation: Pem D et al. (2019) Mycosphere Notes 275-324: A morphotaxonomic revision and typification of obscure Dothideomycetes genera (incertae sedis). Mycosphere 10(1), 1115–1246

 

Byssolophis Clem., in Clements & Shear, Gen. fung., Edn 2 (Minneapolis): 83, 286 (1931)

Saprobic on decaying wood. Sexual morph: Ascomata hysterothecial, superficial or sunken in substrate, oval to elongate, or globose to subglobose, dark brown to black, carbonaceous, glabrous, straight or curved, with a subiculum, with brown hyphae. Ostiole slit-like, with a small to large, flat, crest-like apex. Peridium thick at the sides, broad at the apex and thinner at the base, dark brown, comprising a single stratum of dark brown cells of textura angularis in the inside and thin-walled cells of textura prismatica in the exterior part. Hamathecium comprising cylindrical to filiform pseudoparaphyses in a gelatinous matrix. Asci 8-spored, bitunicate, fissitunicate, elongate cylindric-clavate, straight or slightly curved, short-pedicellate, apically rounded, with an ocular chamber. Ascospores overlapping bi-seriate, narrowly fusiform to broadly cylindrical, straight or slightly curved, 1–3-septate, hyaline to pale brown, smooth, surrounded by a narrow appendage-like sheath. Asexual morph: Undetermined.

 

Type species Byssolophis byssiseda (Flageolet & Chenant.) Clem. 1931

 

NotesThe monotypic genus Byssolophis is based on B. byssiseda found on branches of Carpini rigny. Currently, two more species are accommodated in this genus namely, B. ampla (Berk. & Broome) L. Holm and B. sphaerioides (P. Karst.) E. Müll. (Holm 1986, Müller & von Arx 1962). The asexual morph of this genus is unknown. Due to its uncertain taxonomic placement, the genus was placed in Dothideomycetes genera incertae sedis (Wijayawardene et al. 2014). Zhang et al. (2012) examined the type species of B. byssiseda and suggested similar morphological characters to species in Lophiostoma, but could not resolve the taxonomic placement. We re-examined another species, B. sphaerioides (Nyl. ex P. Karst.) E. Müll. from K herbarium under the code K (M) 164030 in which the ascomata, asci and ascospores showed morphology similar to Tetraplosphaeriaceae. We also carried out phylogenetic analysis with the strains of Byssolophis sphaerioides (IFRDCC 2053) using LSU, SSU, TEF and RPB2 sequences from GenBank. Byssolophis sphaerioides clusters as an independent lineage close to Quadricura septentrionalis and other members of the Tetraplosphaeriaceae (Pleosporales) with weak bootstrap support (Fig. 13). Therefore, we transfer the genus Byssolophis in Tetraplosphaeriaceae as ascomata are scattered to gregarious, immersed to superficial, gabrous or with brown hyphae, asci are cylindrical to clavate with a short pedicel and ascospores are 1–3-septate, hyaline to pale brown surrounded by a narrow appendage-like sheath.

 

 

Figure 13 Phylogram generated from maximum likelihood analysis based on combined LSU, SSU, TEF and RPB2 sequence data retrieved from the GenBank. Related sequences were referred to Hashimoto al. 2017). Eighty-nine taxa are included in the gene sequence analyses which comprise 3457 characters after alignment. Lophiostoma crenatum (CBS 629. 86) and Sigarispora arundinis (CBS 621. 86) are used as the out-group taxa. Maximum likelihood (ML) analysis was conducted in the CIPRES Science Gateway V.3.3. The best sorting RAxML tree with a final likelihood value of -26435.927200 is presented. Estimated base frequencies were as follows: A = 0.247476, C = 0.248533, G = 0.272591, T = 0.231400; substitution rates AC = 1.176163, AG = 4.952466, AT= 1.237377, CG = 1.159438, CT = 9.445473, GT = 1.000000; gamma distribution shape parameter α = 0.457069; proportion of invariant 0.561533. ML bootstrap values ≥ 50% are given as the first set of numbers and approximate likelihood-ratio test (aLRT) ≥ 0.90 values as the second set of numbers above the nodes. Voucher/strain numbers are given after the taxon names, the one from type material are indicated in bold face. Sequence of interest is indicated in red. The bar length indicates the number of nucleotide substitutions per site.

 

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