Anaeromyces corallioides, sp. nov., a new anaerobic gut fungus from the faeces of cattle

We report on the isolation and characterization of three isolates of anaerobic gut fungi from a cattle faecal sample obtained in Stillwater, OK, USA. The isolates produced polycentric thalli with nucleated rhizomycelia, lobed appressorium-like structures, intercalary sporangia and constricted sausage-like hyphae. These morphological features are characteristic of members of the genus Anaeromyces. No zoospore production was observed during the isolation process or thereafter. The strains seemed to have propagated solely through their nucleated hyphae post initial enrichment. Phylogenetic analysis of the D1/D2 region of the large ribosomal subunit (D1/D2 LSU) rRNA, the ribosomal intergenic spacer region 1 (ITS1), RNA polymerase II large subunit (RPB1) and comparative average amino acid identity using transcriptomic datasets further confirmed the position of the type strain as a distinct member of the genus Anaeromyces, family Anaeromycetaceae and phylum Neocallimastigomycota. We propose to accommodate these isolates into a new species (Anaeromyces corallioides) within the genus Anaeromyces. The type strain is EE.1.