Bivalvulida

Bivalvulida is an order of myxosporean parasites which contains a number of species which cause economically significant losses to aquaculture and fisheries, such as Myxobolus cerebralis and Ceratomyxa shasta. The Myxosporean stages of members of the bivalvulida are characterised by their two spore valves (hence the name), which meet in a "suture line" which encircles the spore. They usually contain two polar capsules, but species have been reported which contain either one or four.

Taxonomy and systematics
The order Bivalvulida is composed of three suborders and thirteen families.
 * Suborder Platysporina Kudo, 1919
 * Myxobolidae Thélohan, 1892
 * Suborder Sphaeromyxina Lom & Noble, 1984
 * Sphaeromyxidae Lom & Noble, 1984
 * Suborder Variisporina Lom & Noble, 1984
 * Auerbachiidae
 * Alatasporidae Shulman, Kovaleva & Dubina, 1979
 * Ceratomyxidae Doflein, 1899
 * Chloromyxidae Thélohan, 1892
 * Coccomyxidae Léger & Hesse, 1907
 * Fabesporidae Naidenova & Zaika, 1969
 * Myxidiidae Thélohan, 1892
 * Myxobilatidae Shulman, 1953
 * Ortholineidae Lom & Noble, 1984
 * Parvicapsulidae Shulman, 1953
 * Sinuolineidae Shulman, 1959
 * Sphaerosporidae Davis, 1917

Gallery
Drawings and scanning electron microscopy of species of Chloromyxum