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The order Melanosporales comprises a large group of ascomycetes, most of them mycoparasites, characterized by the production of usually ostiolate, translucent ascomata, unitunicate asci, and unicellular, pigmented ascospores with germ pores or germ slits. The most studied taxa areMelanosporaandSphaerodes, but the boundaries with other morphologically closely related genera are not well resolved. In this study, the taxonomy ofMelanosporaand related taxa have been re-evaluated based on the analysis of nuclear rDNA, actin and elongation factor genes sequences of fresh isolates and numerous type and reference strains. The genusMelanosporahas been restricted to species with ostiolate ascoma whose neck is composed of intermixed hyphae, and with a phialidic asexual morph.Microtheciumhas been re-established for species ofMelanosporaandSphaerodeswithout a typical ascomatal neck or, if present, being short and composed of angular cells similar to those of the ascomatal wall, and usually producing bulbils. Three new genera have been proposed:Dactylidispora, possessing ascospores with a raised rim surrounding both terminal germ pores;Echinusitheca, with densely setose, dark ascomata; andPseudomicrothecium, characterized by ascospores with indistinct germ pores. Dichotomous keys to identify the accepted genera of the Melanosporales, and keys to discriminate among the species ofMelanosporaandMicrothecium, as well as a brief description of the accepted species of both genera, are also provided.

Phylogenetic analyses using internal transcribed spacer (ITS), large subunit rRNA (LSU), and small subunit (SSU) sequence data showed that Harzia, Chlamydomyces, and Olpitrichum are con-generic. Thus, Chlamydomyces, and Olpitrichum were reduced to synonymy of Harzia. The generic concept was amended and expanded accordingly. Eight new combinations were proposed. Melanospora and Sphaerodes are phylogenetically related to Harzia. However, several members of Melanospora and Sphaerodes are polyphyletic and belong to Hypocreales or Microascales in Sordariomycetes. The Proteophiala morph is not only a crucial morphological character, but also has a phylogenetical significance in defining Melanosporales. It is hypothesized that the taxa with synanamorphic or asexual Proteophiala all belong to Ceratostomataceae, Melanosporales.

Vittatispora coorgii gen. sp. nov., isolated from soil in India, is described and illustrated. The fungus has morphological characteristics of the genera Melanospora, Sphaerodes and Syspastospora. The most striking feature is the presence of a thick hyaline ridge along the vertical axis of the lemon- shaped ascospores wall. Perithecia also have a long neck composed of adhering hyphae, similar to that of Syspatospora. Phylogenetic studies on the 28S rDNA indicate it is closely related to Melanospora and Sphaerodes and belongs in the Ceratostomataceae. The new genus is based on the distinctive morphology and phylogenetic analyses. The fungus grew in culture only conjointly with a sterile fungus which a BLAST analysis suggested was close to Tetracladium marchalianum.