The genus was circumscribed in 2021 by Vinodhini Thiyagaraja, Robert Lücking, Damien Ertz, and Kevin Hyde, with O. pruinosellus assigned as the type species.

In contrast, Ostropa has circular ascomata opening by a transverse slit, periphysoids in the above part, a prominent apical cap in the ascus, and eight-spored or polysporous asci.

The sexual morph of this genus includes perithecial ascomata that are typically solitary and either immersed or erumpent, with a distinct ostiole.

The asci are cylindrical and bitunicate, while the ascospores are overlapping and uniseriate, with a hyaline, transversely multi-septate structure.

[2] In its asexual morph, Ostropomyces develops erumpent, spherical pycnidia with a wall that shows two distinct layers in transverse section.