Development and release of a malacosporean (Myxozoa) from Plumatella repens (Bryozoa: Phylactolaemata)

Abstract

Abstract. During an experiment to transmit Tetracapsula bryosalmonae Canning, Curry, Feist, Longshaw et Okamura, 1999 to a laboratory-cultured bryozoan, Plumatella repens L. a previously undescribed malacosporean species was noted. This parasite produced sacs of spores in the host that reached 1.2 mm in length. The spores released from the sacs appeared similar in size to the two species of Tetracapsula previously described although slight differences in form were noted. Release of spores from the bryozoans was observed associated with the lophophore of the host. The use of experimental bryozoan cultures for the examination of malacosporeans is described and discussed.

Myxozoan genera: definition and notes on taxonomy, life-cycle terminology and pathogenic species

“…During capsulogenesis, external tube of the capsular primordium is not always observed but has been proven in some populations. In some malacosporean populations spores arise in the layer of mural cells (Morris et al 2002).…”

Transmission Biology of the Myxozoa

“…Only minimal morphological differences have been recorded between spores of different malacosporean species. Morris et al (2002) documented ornamented spores with a mean diameter of 19.0 µm in the bryozoan Plumatella repens infected with worm-like malacosporean stages. The spores observed by McGurk et al (2006a), also released by a worm-shaped malacosporean in P. repens, were spherical and 17.7 µm in diameter.…”

Evaluation of malacosporean life cycles through transmission studies

“…D. C. Morris et al (2002a) and D. J. Morris et al (2002) reported possible transmission of T. bryosalmonae and Buddenbrockia plumatellae from fish to bryozoans. However, these results may have reflected previous development of infection in bryozoans in the field, or PCR amplification of residual DNA that had adhered to bryozoans or of DNA from undetected, infected invertebrates.…”

“…Morris et al 2002). However, even if such transmission is eventually demonstrated, it may only be facultative since infected bryozoans occur in sites lacking salmonids in Ohio and Michigan .…”