Monotypic fungus genera

Geosiphon is a genus of fungus in the family Geosiphonaceae. The genus is monotypic, containing the single species Geosiphon pyriformis, first described by Kützing in 1849 as Botrydium pyriforme. In 1915, Von Wettstein characterized Geosiphon pyriforme as a multinucleate alga containing endosymbiotic cyanobacteria, although he also noted the presence of chitin, a component of fungal cell walls. In 1933, Knapp was the first to suggest the fungal origin of the species and described it as a lichen with endosymbiotic cyanobacteria. It is the only member of the Glomeromycota known to not form a sym

Lobosporangium is a fungal genus in the Mortierellaceae family of the Zygomycota. The genus is monotypic, containing the single species Lobosporangium transversale, found in the US and Mexico.

Utharomyces is a fungal genus in the family Pilobolaceae. The genus is monotypic, containing the single coprophilous (dung-loving) species Utharomyces epallocaulus, which is widely distributed in subtropical regions. Utharomyces was circumscribed by the Dutch botanist Karel Bernard Boedijn in 1958. U. epallocaulus has been collected in Bahamas, Ghana, India, Indonesia, Mexico, China, and the United States.

Aquamortierella is a fungal genus in the family Mortierellaceae. The genus is monotypic, containing the single species Aquamortierella elegans, found in New Zealand and Japan.

Cyllamyces is a fungal genus in the family Neocallimastigaceae. This is a monotypic genus, containing the single species Cyllamyces aberensis.

Bartheletia paradoxa is a species of dimorphic fungus and is the only member of the genus Bartheletia. Bartheletia is the only genus in the family Bartheletiaceae, which is the only family in Bartheletiales, which in turn is the only order in the class Bartheletiomycetes.

Abelspora is a genus of microsporidian parasites. The genus is monotypic, and contains the single species Abelspora portucalensis. The species parasitizes the shore crab, Carcinus maenas, within which it infects the hepatopancreas. The genus was first described by Carlos Azevedo in 1987 and is endemic to the Midwestern United States.