Zoospore ultrastructure of members in the order Spizellomycetales:
Genera in the Spizellomycetales may be distinguished based on zoospore ultrastructure. However, molecular phylogenetic investigations have demonstrated that Spizellomyces is a polyphyletic genus (Wakefield et al. 2010). Differences in the form of the kinetosome-associated-structure (KAS) (Barr 1984) as illustrated below support that new genera will be necessary for some species currently classified in this genus.