Alveolate
Alveolate Temporal range:
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Ceratium furca | |
Scientific classification | |
Domain: | Eukaryota |
Clade: | Diaphoretickes |
Clade: | TSAR
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Clade: | SAR |
Clade: | Alveolata Cavalier-Smith, 1991 |
Phyla | |
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Synonyms | |
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The alveolates (meaning "pitted like a honeycomb")
Characteristics
The most notable shared characteristic is the presence of
Almost all sequenced mitochondrial genomes of ciliates and apicomplexa are linear.
History
The relationship of apicomplexa, dinoflagellates and ciliates had been suggested during the 1980s, and this was confirmed in the early 1990s by comparisons of ribosomal RNA sequences, most notably by Gajadhar et al.
Classification
Alveolata include around nine major and minor groups. They are diverse in form, and are known to be related by various ultrastructural and genetic similarities:[11]
- Ciliates – very common protozoa with many short cilia arranged in rows, and two nuclei
- Acavomonidia[11]
- Colponemidia[11]
- Dinoflagellates s.l. – mostly marine flagellates many of which have chloroplasts
- Perkinsozoa
- Chromerida– a marine phylum of photosynthetic protozoa
- Colpodellida
- Voromonadida
The Acavomonidia and Colponemidia were previously grouped together as colponemids, a taxon now split because each has a distinctive organization or ultrastructural identity. The Acavomonidia are closer to the dinoflagellate/perkinsid group than the Colponemidia are.[11] As such, the informal term "colponemids", as it stands currently, covers two non-sister groups within Alveolata: the Acavomonidia and the Colponemidia.[11]
The Apicomplexa and dinoflagellates may be more closely related to each other than to the ciliates. Both have
Some studies suggested the haplosporids, mostly parasites of marine invertebrates, might belong here, but they lack alveoli and are now placed among the Cercozoa.
The ellobiopsids are of uncertain relation within the alveolates. Silberman et al 2004 establish that the
Phylogeny
In 2017, Thomas Cavalier-Smith described the phylogeny of the Alveolata as follows:[17]
Alveolata
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Taxonomy
Alveolata Cavalier-Smith 1991 [Alveolatobiontes]
- Phylum CiliophoraDoflein 1901 stat. n. Copeland 1956 [Ciliata Perty 1852; Infusoria Bütschli 1887; Ciliae, Ciliozoa, Cytoidea, Eozoa, Heterocaryota, Heterokaryota]
- Subphylum Postciliodesmatophora Gerassimova & Seravin 1976
- Class HeterotricheaStein 1859
- Class Karyorelictea Corliss 1974
- Class
- Subphylum Intramacronucleata Lynn 1996
- Class ?Mesodiniea Chen et al. 2015
- Infraphylum Lamellicorticata
- Class Litostomatea Small & Lynn 1981
- Class Armophorea Lynn 2004
- Class CariacotricheaOrsi et al. 2011
- Class SpirotricheaBütschli 1889
- Infraphylum Ventrata Cavalier-Smith 2004 [Conthreep Lynn 2012]
- Order ?Discotrichida Chen et al. 2015
- Class Protocruziea Chen et al. 2015 [Protocruziidia de Puytorac, Grain & Mignot 1987]
- Class Colpodea Small & Lynn 1981
- Class Nassophorea Small & Lynn 1981
- Class Phyllopharyngea de Puytorac et al. 1974
- Class Prostomatea Schewiakoff 1896
- Class PlagiopyleaSmall & Lynn 1985 sensu Lynn 2008
- Class Oligohymenophorea de Puytorac et al. 1974
- Subphylum Postciliodesmatophora Gerassimova & Seravin 1976
- Phylum MiozoaCavalier-Smith 1987
- Subphylum Colponemidia Tikhonenkov, Mylnikov & Keeling 2013
- Class Colponemea Cavalier-Smith 1993
- Subphylum Acavomonadia Tikhonenkov et al. 2014
- Class Acavomonadea Tikhonenkov et al. 2014
- Subphylum Myzozoa Cavalier-Smith 2004
- Infraphylum Apicomplexa Levine 1970 emend. Adl et al. 2005
- Order ?Vitrellida Cavalier-Smith 2017
- Class ?Myzomonadea Cavalier-Smith & Chao 2004 sensu Ruggiero et al. 2015
- Class Chromerea
- Order ColpodellidaPatterson & Zölffel 1991 [Spiromonadida Krylov & Mylnikov 1986]
- Superclass SporozoaLeuckart 1879 stat. nov. Cavalier-Smith 2013 [Gamontozoa]
- Class BlastogregarinidaChatton & Villeneuve 1936 [Blastogregarinina; Blastogregarinorina Chatton & Villeneuve 1936]
- Class ParagregareaCavalier-Smith 2014
- Class GregarinomorpheaGrassé 1953
- Class CoccidiomorpheaDoflein 1901
- Class
- Infraphylum Dinozoa Cavalier-Smith 1981 emend. 2003
- Order ?Acrocoelida Cavalier-Smith & Chao 2004
- Order ?Rastromonadida Cavalier-Smith & Chao 2004
- Class Squirmidea Norén 1999 stat. nov. Cavalier-Smith 2014
- Superclass Perkinsozoa Norén et al. 1999 s.s.
- Class Perkinsea Levine 1978 [Perkinsasida Levine 1978]
- Superclass DinoflagellataButschli 1885 stat. nov. Cavalier-Smith 1999 sensu Cavalier-Smith 2013 [Dinozoa Cavalier-Smith 1981]
- Class Pronoctilucea
- Class Ellobiopsea Cavalier-Smith 1993 [Ellobiophyceae Loeblich III 1970; Ellobiopsida Whisler 1990]
- Class Myzodinea Cavalier-Smith 2017
- Class OxyrrheaCavalier-Smith 1987
- Class SyndineaChatton 1920 s.l. [Syndiniophyceae Loeblich III 1970 s.s.; Syndina Cavalier-Smith]
- Class Endodinea Cavalier-Smith 2017
- Class Noctiluciphyceae Fensome et al. 1993 [Noctilucae Haeckel 1866; Noctilucea Haeckel 1866 stat. nov.; Cystoflagellata Haeckel 1873 stat. nov. Butschli 1887]
- Class Dinophyceae Pascher 1914 [Peridinea Ehrenberg 1830 stat. nov. Wettstein]
- Infraphylum Apicomplexa Levine 1970 emend. Adl et al. 2005
- Subphylum Colponemidia Tikhonenkov, Mylnikov & Keeling 2013
Development
The development of plastids among the alveolates is intriguing. Cavalier-Smith proposed the alveolates developed from a chloroplast-containing ancestor, which also gave rise to the
Evolution
A Bayesian estimate places the evolution of the alveolate group at ~850 million years ago.
The ancestors of the alveolate group may have been photosynthetic.
In one school of thought the common ancestor of the
An ongoing debate concerns the number of membranes surrounding the plastid across apicomplexans and certain dinoflagellates, and the origin of these membranes. This ultrastructural character can be used to group organisms and if the character is in common, it can imply that phyla had a common photosynthetic ancestor. On the basis that apicomplexans possess a plastid surrounded by four membranes, and that peridinin dinoflagellates possess a plastid surrounded by three membranes, Petersen et al.
Ciliates are a model alveolate, having been genetically studied in great depth over the longest period of any alveolate lineage. They are unusual among eukaryotes in that reproduction involves a micronucleus and a macronucleus. Their reproduction is easily studied in the lab, and made them a model eukaryote historically. Being entirely predatory and lacking any remnant plastid, their development as a phylum illustrates how predation and autotrophy[20] are in dynamic balance and that the balance can swing one way or other at the point of origin of a new phylum from mixotrophic ancestors, causing one ability to be lost.
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Ciliophora)
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Ciliophora) (left)
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Plasmodium falciparum (Apicomplexa) in blood
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Dinoflagellata)
Epigenetics
Few
References
- ^
Li, C.-W.; et al. (2007). "Ciliated protozoans from the Precambrian Doushantuo Formation, Wengan, South China". Geological Society, London, Special Publications. 286 (1): 151–6. S2CID 129584945.
- ^ "alveolate". Memidex (WordNet) Dictionary/Thesaurus. Archived from the original on 2016-04-11. Retrieved 2011-01-26.
- PMID 23020233.
- PMID 25923521.
- PMID 21627782.
- PMID 26092225.
- PMID 22833609.
- ^
Gajadhar, A. A.; et al. (1991). "Ribosomal RNA sequences of Sarcocystis muris, Theilera annulata, and Crypthecodinium cohnii reveal evolutionary relationships among apicomplexans, dinoflagellates, and ciliates". Molecular and Biochemical Parasitology. 45 (1): 147–153. PMID 1904987..
- ISBN 978-0-19-857747-8.
- ^ Kumar, S. & Rzhetsky, A. 1996. Evolutionary relationships of eukaryotic kingdoms. Journal of Molecular Evolution, 42: 183–193
- ^ PMID 24740116.
- PMID 21629701.
- S2CID 11550698.
- S2CID 4362835.
- S2CID 42100119.
- S2CID 86797666.
- PMID 28875267.
- ^ PMID 20534454.
- PMID 16822745.
- ^ PMID 18595706.
- S2CID 28005870.
- S2CID 4283969.
- PMID 24572015.
- ^ ISBN 9781119821915.