Piromyces mae and Piromyces dumbonica, two new species of uniflagellate anaerobic chytridiomycete fungi from the hindgut of the horse and elephant

Abstract

Vegetative thalli, developing sporangia, and zoospores of two new uniflagellate anaerobic chytridiomycete gut fungi, Piromyces mae sp. nov. and Piromyces dumbonica sp.nov., isolated from manure derived from the hindgut of the horse and elephant, respectively, were examined by light and electron microscopy. Piromyces mae differs from Piromyces communis by having papillae-like structures on the sporangium. Piromyces dumbonica differs from P. communis by its C-shaped elongated circumflagellar ring and characteristic organelle distribution in the zoospores. The circumflagellar rings in both new species are tilted at about 10° towards the spur in both prereleased and free zoospores. Three struts in both species connect the circumflagellar ring to the skirt and connective (a newly described perikinetosomal structure) surrounding the kinetosome opposite to the skirt. The connective interconnects the strut, skirt, scoop, kinetosome, and spur. A general model of the kinetosome and perikinetosomal apparatus is proposed for the gut fungi. This model attempts to unify and clarify previous descriptions of the apparatus in these fungi and shows the limited range of variations reported. Key words: gut fungi, Chytridiomycetes, kinetosomes, perikinetosomal apparatus.