Chytridiomycetes (/kᵻˌtrɪdioʊmaɪˈsiːtiːz, -ˈsiːts/) is a class of fungi. Members are found in soil, fresh water, and saline estuaries. They are primitive fungi, and are first known from the Rhynie chert. It has recently been redefined to exclude the taxa Neocallimastigomycota and Monoblepharidomycetes, which are now a phylum and a sister-class respectively. Chytridiomycetes is the major class of the phylum Chytridiomycota, which contains a number of parasitic species. At least two species in this class are known to infect a number of amphibian species.