Reassessment of Dyfrolomyces and Four New Species of Melomastia from Olive (Olea europaea) in Sichuan Province, China

Abstract

Pleurotremataceae species are saprobes on decaying wood in terrestrial, mangrove, and freshwater habitats. The generic boundary of the family has traditionally been based on morphology. All genera of Pleurotremataceae have a high degree of morphological overlap, of which the generic circumscription of Melomastia and Dyfrolomyces has not been well resolved. Thus, the delimitation of genera has always been challenging. Melomastia traditionally differs from Dyfrolomyces in having 2-septate, oblong, with obtuse-ends ascospores. These main characteristics have been used to distinguish Melomastia from Dyfrolomyces for a long time. However, the above characteristics sometimes overlap among Dyfrolomyces and Melomastia species. Based on the morphology and multigene phylogeny with newly obtained data, we synonymized Dyfrolomyces under Melomastia following up-to-date results. Four novel species (i.e., Melomastia fusispora, M. oleae, M. sichuanensis and M. winteri) collected from the dead branches of Olea europaea L. in Chengdu Olive Base, Sichuan Province in China are introduced based on detailed morphological characterization and phylogenetic analyses of sequences based on nuclear ribosomal (LSU and SSU) and protein-coding gene (tef1-α). The 11 new combinations proposed are Melomastia aquatica (= Dyfrolomyces aquaticus), M. chromolaenae (= D. chromolaenae), M. distoseptata (= D. distoseptatus), M. mangrovei (= D. mangrovei), M. marinospora (= D. marinosporus), M. neothailandica (= D. neothailandicus), M. phetchaburiensis (= D. phetchaburiensis), M. sinensis (= D. sinensis), M. thailandica (= D. thailandica), M. thamplaensis (= D. thamplaensis) and M. tiomanensis (= D. tiomanensis).

Four new species of Dothideomycetes (Ascomycota) from Pará Rubber (Hevea brasiliensis) in Yunnan Province, China

“…Melomastia has been recorded with 63 epithets in Index Fungorum (2024). Most Melomastia species have been found in terrestrial, freshwater and marine habitats and they have a wide geographical distribution in Africa, China, Germany, Italy, Japan, Poland and the United States of America (Norphanphoun et al 2017;Dayarathne et al 2020;Li et al 2022;. Melomastia was discovered to be closely related to Dyfrolomyces and their exact relationship is still unknown.…”

“…Melomastia was discovered to be closely related to Dyfrolomyces and their exact relationship is still unknown. Li et al (2022) reclassified Dyfrolomyces as Melomastia, based on morphology and phylogeny of four newly-introduced species from Olive in Sichuan Province, China. Melomastia tiomanensis and M. chromolaenae exhibit spindle-shape, 6-11-septate ascospores with acute ends.…”

“…Melomastia is characterised by immersed, ostiolate ascomata, multiple layered, dark brown peridium, filamentous pseudoparaphyses, unitunicate, cylindrical, 8-spored asci and ovoid, hyaline, 1-10-septate, fusiform to oblong ascospores with rounded or acute ends, with or without gelatinous sheath (Norphanphoun et al 2017;Dayarathne et al 2020;Kularathnage et al 2023). However, the asexual morph of Melomastia is still unknown (Norphanphoun et al 2017;Li et al 2022;Kularathnage et al 2023).…”