Ostropomyces Thiyagaraja, Lücking, Ertz and K.D. Hyde, gen. nov.

Index Fungorum number: IF 556555; Faces of Fungi number: FoF 09511

Etymology: the name refers to characteristics similar to Ostropa.

Saprobic on bark, thallus whitish, pruinose.

Sexual morph: Ascomata perithecial, solitary, immersed to erumpent. Ostiole distinct. Exciple with clear border between outer and inner layer. Hamathecium comprising filamentous paraphyses. Paraphyses septate, branched, hyaline, filamentous. Asci cylindrical, bitunicate. Ascospores overlapping uniseriate, hyaline, transversely multi-septate, cells almost of equal size, deeply constricted at the septa of each cell, easily breaking into small septate part-spores.

Asexual morph: Pycnidia erumpent, globose. Pycnidial wall in transverse section shows two distinct layers. Outer layer hyaline, densely packed. Inner layer hyaline, loosely packed, cells elongate in pycnidial neck. Conidiophores lining inside and outside of pycnidia wall. Conidiogenous cells hyaline.  Conidia similar in shape to ascospore, filiform, aseptate, hyaline, and guttulate at maturity.

Notes: –  Ostropomyces is introduced to accommodate two newly discovered species, Ostropomyces pruinosellus and Ostropomyces thailandicus, which are collected from tropical forests in Northern Thailand. The new genus is related to Ostropa, but both emerge on long stem branches in our phylogenetic analyses (Figure 2). Ostropomyces differs from Ostropa in the presence of perithecial ascomata, presence of periphysoids, which are present in the inner face of the wall, in the lack of an apical cap in the ascus and four-spored asci. In contrast, Ostropa forms orbicular ascomata opening by a transverse slit, periphysoids in the above part, a prominent apical cap in the ascus, and eight-spored or polysporous asci [33]. The new genus formed a distinct clade with high bootstrap support in the multi-gene phylogenetic analyses, whereas its relationship to Ostropa was also strongly supported (84%).

Type species: Ostropomyces pruinosellus Thiyagaraja, Lücking, Ertz and K.D. Hyde