"Buddenbrockia plumatellae, an enigmatic worm-like myxozoan, was observed as continuously writhing free and attached ‘worms' and as free mature spores in the coelom of the freshwater bryozoans Plumatella fungosa, Hyalinella punctata, and Fredericella sp. ‘Worm’ numbers could double every three days. ‘Worms' and spores could be expelled from colonies by external pressure. Some mature ‘worms' exited actively, entraining release of free spores, and gradually ceased movement outside the host. Bryozoans sealed off infected regions of the colony. Infected colonies grew slowly, produced no statoblasts, and eventually regressed and died. Transmission was not achieved and prevalence was low." (Canning, Tops, Curry, Wood, Okamura 2002)
"The phylogenetic affinities of Buddenbrockia, a nematode-like parasite of freshwater bryozoans, have remained unknown since it was first reported in the nineteenth century. The discovery of Buddenbrockia parasitic in Hyalinella punctata in Ohio and Plumatella repens in France has provided material for the first ultrastructural study of this animal. This has revealed the presence of polar capsules, diagnostic myxozoan features, in the body wall. Other features, which place Buddenbrockia firmly among tetracapsulid myxozoans in the Class Malacosporea, are the unusual morphology of the polar capsules, the absence of the external tube in capsulogenesis, the body wall with its unusual cell junctions and utilization of freshwater bryozoans as hosts. The ultrastructural study has established the triploblastic organization of Buddenbrockia by confirmation of the presence of an inner layer of cells and 4 sets of longitudinal muscles. Our studies have, thus, simultaneously revealed that Buddenbrockia is a myxozoan and that the myxozoans are derived from bilaterians. The latter conclusion resolves the ongoing controversy over the triploblastic versus diploblastic nature of the Myxozoa. Our studies also provide evidence that bryozoans are ancestral hosts for the myxozoans and that loss of triploblast features has characterized the major radiation of the better known endoparasites of fish and worms in the Class Myxosporea." (Canning, Wood, Okamura, Curry 2002)
"Early cell complexes arise in the peritoneum after division and migration of isolated cells in the host body wall. The development of cell junctions linking the outer (mural) cells of the complex then produces a sac enclosing a mass of inner cells. Elongation to the vermiform stage (myxoworm) occurs during multiplication and reorganisation of the inner cells as a central core within the single-layered sac wall. The core cells develop into muscle and sporogonic cells separated from the mural cells by a basal lamina. Myogenesis occurs along the length of the myxoworm from cells that differentiate from the central core, and is independent of elongation. Four primary sporogonic cells maintain positions close to the basal lamina, between muscle cells, while giving rise to secondary sporogonic cells that eventually become free in the central cavity. At least some secondary sporogonic cells undergo meiosis." (Canning, Curry, Okamura 2008)
Buddenbrockia plumatella has no mouth, no clear nervous system, no brain, and no gut. It does not have a left or right side. Due to its complete difference in shape from its nearest relatives, it has been concluded that the body shape evolved from at least two completely different types of animal. The vermiform shape and four longitudinal muscle blocks suggests that Buddenbrockia would be placed in Bilateria. However, nematodes possess a nerve cord located beneath their gut, while Buddenbrockia have neither.
