The Ascetosporea are a group of

eukaryote Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacte ...

s that are

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

s of animals, especially marine

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s. The two groups, the haplosporids and paramyxids, are not particularly similar morphologically, but consistently group together on molecular trees, which place them near the base of the

Cercozoa Cercozoa is a phylum of diverse single-celled eukaryotes. They lack shared morphological characteristics at the microscopic level, and are instead defined by molecular phylogenies of rRNA and actin or polyubiquitin. They were the first major eu ...

. Both produce

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

s without the complex structures found in similar groups (such as polar filaments or tubules). Haplosporid spores have a single

nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom *Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucle ...

and an opening at one end, covered with an internal diaphragm or a distinctive hinged lid. After emerging, it develops within the cells of its host, usually a marine

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

annelid The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecol ...

, although some infect other groups or freshwater species. The trophic cell is generally

multinucleate Multinucleate cells (also known as multinucleated or polynuclear cells) are eukaryotic cells that have more than one nucleus per cell, i.e., multiple nuclei share one common cytoplasm. Mitosis in multinucleate cells can occur either in a coordinat ...

d. Paramyxids develop within the digestive system of marine invertebrates, and undergo internal budding to produce multicellular spores. A 2009 study concluded that ''Haplosporidium'' species form a

paraphyletic group In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

and that the taxonomy of the haplosporidians needs a thorough revision.

Taxonomy

Class Ascetosporea Desportes & Ginsburger-Vogel, 1977 emend. Cavalier-Smith 2009 * Genus ?'' Marteilioides'' Comps, Park & Desportes 1986 * Genus ?'' Oryctospora'' Purrini & Weiser 1991 * Order

Claustrosporida The Ascetosporea are a group of eukaryotes that are parasites of animals, especially marine invertebrates. The two groups, the haplosporids and paramyxids, are not particularly similar morphologically, but consistently group together on molecula ...

Cavalier-Smith 2003 ** Family Claustrosporidiidae Larsson 1987 *** Genus '' Claustrosporidium'' Larsson 1987 * Order

Paradiniida The Ascetosporea are a group of eukaryotes that are parasites of animals, especially marine invertebrates. The two groups, the haplosporids and paramyxids, are not particularly similar morphologically, but consistently group together on molecula ...

Cavalier-Smith 2009 ** Family Paradiniidae Schiller 1935 *** Genus '' Paradinium'' Chatton, 1910 * Order

Mikrocytida The Ascetosporea are a group of eukaryotes that are parasites of animals, especially marine invertebrates. The two groups, the haplosporids and paramyxids, are not particularly similar morphologically, but consistently group together on molecula ...

Hartikainen et al. 2014 ** Family Mikrocytidae Hartikainen et al. 2014 *** Genus '' Paramikrocytos'' Hartikainen et al. 2014 *** Genus '' Microcytos'' Farley, Wolf & Elston 1988 * Order

Paramyxida The Ascetosporea are a group of eukaryotes that are parasites of animals, especially marine invertebrates. The two groups, the haplosporids and paramyxids, are not particularly similar morphologically, but consistently group together on molecula ...

Chatton 1911 aramyxea Chatton 1911; Paramyxidea Chatton 1911; Paramyxa** Family Marteiliidae Grizel et al. 1974 cclusosporida; Marteiliida Desportes & Ginsburger-Vogel, 1977; Marteiliidea Desportes & Ginsburger-Vogel, 1977*** Genus '' Paramarteilia'' Ginsburger-Vogel & Desportes 1979 *** Genus ''

Marteilia ''Marteilia'' is a protozoan genus of organisms that are parasites of bivalves. It causes QX disease in Sydney rock oysters and Aber disease in European flat oysters. After being infected by ''Marteilia'', bivalves lose pigmentation in their v ...

'' Grizel et al. 1974 ** Family Paramyxidae Chatton 1911 *** Genus '' Paramyxa'' Chatton 1911 * Order

Haplosporida The Ascetosporea are a group of eukaryotes that are parasites of animals, especially marine invertebrates. The two groups, the haplosporids and paramyxids, are not particularly similar morphologically, but consistently group together on molecula ...

Caullery & Mesnil 1899 [Balanosporida Sprague, 1979; Haplosporidia Hall, 1953; Haplosporea Caullery 1953; Haplospora Margulis & Schwartz, 1998; Haplosporidiidea Poche, 1913; Haplosporidies Caullery and Mesnil, 1905] ** Genus ?''Bertramia'' Mesnil & Caullery 1897 non Weiser & McCauley 1974 ** Genus ?''Coleospora'' Gibbs 1959 ** Family Nephridiophagidae Sprague 1970 ephridiophagea*** Genus '' Nephridiophaga'' Woolever 1966 'Coelosporidium''_Mesnil_&_Marchoux_1897.html" ;"title="Coelosporidium.html" ;"title="'Coelosporidium">'Coelosporidium'' Mesnil & Marchoux 1897">Coelosporidium.html" ;"title="'Coelosporidium">'Coelosporidium'' Mesnil & Marchoux 1897** Family Urosporidiidae Sprague 1979 [Anurosporidiidae] *** Genus ''Urosporidium'' Caullery & Mesnil 1905 [''Anurosporidium'' Caullery & Chappelier 1906] (8 species) ** Family Haplosporidiidae Sprague 1979 *** Genus '' Bonamia'' Pichot et al. 1980 *** Genus '' Haplosporidium'' Caullery & Mesnil 1899 (23 species) *** Genus '' Minchinia'' (Lankester 1895) Labbe 1896 (5 species)

References

Endomyxa Parasitic rhizaria Cercozoa classes {{Parasitic SAR-stub

Taxonomy

See also

References