Classification of anaerobic gut fungi from herbivores with emphasis on rumen fungi from Malaysia

Descriptive accounts and keys are given for 14 species in five genera of obligately anaerobic fungi found in the gut of herbivores. The descriptions are based entirely on thallus morphology as seen in the light microscope to permit the functional identification of genera and species. It is proposed to place Neocallimastix patriciarum and N. variabilis in synonymy with N. frontalis, and the status of N. hurleyensis as a distinct species is questioned. Two species of Orpinomyces are recognised: O. joyonii and O. intercalaris. Anaeromyces mucronatus and A. elegans are recognised, but the status of A. elegans is considered uncertain. The genus Ruminomyces is synonymous with Anaeromyces. Six species of Piromyces are included: P. communis, P. mae, P. dumbonica, P. rhizinflatus, P. minutus and P. spiralis. Caecomyces (syn. Sphaeromonas) comprises two species: C. equi and C. communis, but the status of C. equi is questioned. The present and future state of the taxonomy is discussed.