Bivalvulida is an order of
myxosporea
Myxosporea is a class of microscopic parasites, belonging to the Myxozoa clade within Cnidaria. They have a complex life cycle which comprises vegetative forms in two hosts, an aquatic invertebrate (generally an annelid but sometimes a bryozoan) ...
n parasites which contains a number of species which cause economically significant losses to aquaculture and fisheries, such as ''
Myxobolus cerebralis
''Myxobolus cerebralis'' is a myxosporean parasite of salmonids (salmon and trout species) that causes whirling disease in farmed salmon and trout and also in wild fish populations. It was first described in rainbow trout in Germany in 1893, ...
'' and ''
Ceratomyxa shasta
''Ceratonova shasta'' (syn. ''Ceratomyxa shasta'') is a myxosporean parasite that infects salmonid fish on the Pacific coast of North America. It was first observed at the Crystal Lake Hatchery, Shasta County, California, and has now been report ...
''. 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 capsule
Polar capsules are structures found in the valves of Myxosporean parasites, which contain the polar filament. The polar capsule is constructed of a proteinaceous and a polysaccharide layer, both layers of which continue into the polar filament.
...
s, 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[Kudo, R. (1919). Studies on Myxosporidia. A synopsis of genera and species of Myxosporidia. ''Illinois Biological Monographs'', 5.]
**
Myxobolidae
Myxobolidae is a Family (biology), family of myxosporean parasites which typically infect freshwater fishes, and includes the economically significant species, ''Myxobolus cerebralis''. They have been shown to have a complex life cycle, involving ...
Thélohan, 1892[Thélohan, P. (1892). Observation sur les myxosporidies et essai de classification de ces organismes. ''Bulletin de la Société Philomatique de Paris'', 4, 165–178.]
*Suborder Sphaeromyxina
Lom & Noble, 1984[Lom, J. & Noble, E. R. (1984). Revised classification of the class Myxosporea Bütschli, 1881. ''Folia Parasitologica'', 31, 193–205.]
**
Sphaeromyxidae Lom & Noble, 1984[
*Suborder Variisporina Lom & Noble, 1984][
** Auerbachiidae
** Alatasporidae Shulman, Kovaleva & Dubina, 1979][Shulman, S. S., Kovaleva, A. A. & Dubina, V. R. (1979). New myxosporidians from fishes of the Atlantic coast of Africa. ''Parazitologiya'', 13, 71–79.]
** Ceratomyxidae Doflein, 1899[Doflein, F. (1899). Amerikanische Dekapoden der k. bayerischen Staatssammlungen. ''Sitzungberichte der mathematisch-physische Klasse der bayerischen Akademie der Wissenschaften'', 29, 177–195.]
**Chloromyxidae
''Chloromyxum'' is a genus of parasitic, myxosporean cnidarians belonging to the family Chloromyxidae.
The species of this genus are found in Northern America and Australia.
Species:
*''Chloromyxum argusi''
*''Chloromyxum atlantoraji''
*''Ch ...
Thélohan, 1892[
** Coccomyxidae Léger & Hesse, 1907][Léger, L. & Hesse, E. (1907). Sur une nouvelle Myxosporidie parasite de la sardine. ''Compte Rendus de l'Académie des Sciences, Paris'', 145, 85–87.]
** Fabesporidae Naidenova & Zaika, 1969[Naidenova, N. N. & Zaika, W. E. (1969). Two new species of Protozoa from the fishes of the Black Sea. ''Parazitologiya'', 3, 97–101.]
** Myxidiidae Thélohan, 1892[
** Myxobilatidae Shulman, 1953][Shulman, S. S. (1953). New and little-studied myxosporids. ''Zoologicheskii Zhurnal'', 32(3), 384–393.]
** Ortholineidae Lom & Noble, 1984[
** Parvicapsulidae Shulman, 1953][
** Sinuolineidae Shulman, 1959][Shulman, S. S. (1959). New classification of Myxosporidia. ''Trudy Karel'skogo Filiala Akademii Nauk SSSR, Parazitologiya'', 33–47.]
** Sphaerosporidae Davis, 1917[Davis, H. S. (1917). The Myxosporidia of the Beaufort Region. A systematic and biologic study. ''Bulletin of the United States Bureau of Fisheries'', 35, 201–243.]
Gallery
Drawings and scanning electron microscopy of species of '' Chloromyxum''
Parasite180057-fig1 Chloromyxum atlantoraji SEM.png, '' Chloromyxum atlantoraji''
Parasite180057-fig2 Chloromyxum atlantoraji drawing.png, '' Chloromyxum atlantoraji''
Parasite180057-fig4 Chloromyxum zearaji drawing.png, '' Chloromyxum zearaji ''
References
Myxosporea
Cnidarian orders
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