The nature of the iodinophilous vacuole of myxosporidan spores, and a proposal to synonymize the genus Myxosoma Thélohan, 1892 with the genus Myxobolus Bütschli, 1882.

Abstract

SYNOPSIS. The myxosporidan genera Myxobolus and Myxosoma differ only by the presence or absence of a so‐called iodinophilous vacuole in their spores which has in the past been shown to contain glycogen. In the present study, spores of Myxobolus pseudodispar, M. cyprini, M. muelleri, Myxosoma heterospora and Agarella gracilis were tested for glycogen using Best's carmine, iodine, and the Bauer‐Feulgen technic. These tests showed that (a) Glycogen was present in variable amounts in spores of each species. In some spores this took the form of a vacuole, while in others the distribution was diffuse or particulate; (b) In no species of Myxobolus did the majority of spores contain a vacuole; (c) In Myxosoma heterospora vacuoles were present in a small proportion of spores. It is concluded that the iodinophilous vacuole cannot be used as a taxonomic criterion in the Myxosporida, and therefore that the genus Myxosoma should be synonymised with the genus Myxobolus.