Filasterea is a proposed basal
Filozoan clade of single-celled ameboid eukaryotes that includes ''
Ministeria'' and ''
Capsaspora''.
It is a sister clade to the
Choanozoa
Choanozoa is a clade of opisthokont eukaryotes consisting of the choanoflagellates (Choanoflagellatea) and the animals (Animalia, Metazoa). The sister-group relationship between the choanoflagellates and animals has important implications for t ...
in which the
Choanoflagellate
Choanoflagellates are a group of free-living unicellular and colonial flagellate eukaryotes considered to be the closest living relatives of animals. The name refers to the characteristic funnel-shaped "collar" of interconnected microvilli and ...
a and
Animal
Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, ...
s appeared, originally proposed by Shalchian-Tabrizi et al. in 2008, based on a phylogenomic analysis with 78 genes. Filasterea was found to be the sister-group to the clade composed of Metazoa and Choanoflagellata within the Opisthokonta, a finding that has been further corroborated with additional, more taxon-rich, phylogenetic analyses.
Etymology
From Latin ''filum'' meaning "thread" and
Greek ''aster'' meaning "star", it indicates the main morphological features shared by all their integrants: small, rounded amoeboids with a mononucleated cellular body, covered in long and radiating cell protrusions known as filopodia. These filopodia may be involved in substrate adhesion and capture of prey.
Applications
There are currently cultures from two filasterean species: ''Capsaspora owczarzaki'' and ''Ministeria vibrans'', the first isolated from within a fresh-water snail, the second a marine, free-living bacteriovore. The complete genome sequences of ''C. owczarzaki'', ''M. vibrans'',
''Pigoraptor vietnamica'' and ''Pigoraptor chileana'' have been obtained. Comparative analyses have shown that Filasterea are key to unravel the genetic repertoire of the unicellular ancestor of animals and to provide insights into the origin of Metazoa.
Metabarcoding
Metabarcoding is the DNA barcoding, barcoding of DNA/RNA (or Environmental DNA, eDNA/Environmental DNA, eRNA) in a manner that allows for the simultaneous identification of many taxa within the same sample. The main difference between barcodin ...
analyses of
18S ribosomal RNA
18S ribosomal RNA (abbreviated 18S rRNA) is a part of the ribosomal RNA in eukaryotes. It is a component of the Eukaryotic small ribosomal subunit (40S) and the cytosolic homologue of both the 12S ribosomal RNA, 12S rRNA in mitochondria and the 1 ...
in marine environments have failed to recover other filasterean representatives, suggesting this clade may not be especially abundant in natural ecosystems.
Taxonomy
* Class Filasterea
Shalchian-Tabrizi et al. 2008
** Order
Ministeriida Cavalier-Smith 1997
*** Family
Ministeriidae Cavalier-Smith 2008
**** Genus ''
Ministeria''
Patterson et al. 1993
***** ''
Ministeria marisola''
Patterson et al. 1993
***** ''
Ministeria vibrans''
Tong 1997
*** Family
Txikisporidae Urrutia, Feist & Bass 2021
****Genus ''
Txikispora''
Urrutia, Feist & Bass 2021
*****''
Txikispora philomaios''
Urrutia, Feist & Bass 2021
*** Family
Capsasporidae Cavalier-Smith 2008
**** Genus ''
Capsaspora''
Hertel et al. 2002
***** ''
Capsaspora owczarzaki''
Hertel et al. 2002
**** Genus ''
Pigoraptor''
Tikhonenkov et al. 2017
***** ''
Pigoraptor chileana''
Tikhonenkov et al. 2017
***** ''
Pigoraptor vietnamica''
Tikhonenkov et al. 2017
In some research Capsaspora is found to be more closely related to Choanozoa than Ministeria.
References
{{Taxonbar, from=Q853084
Opisthokont classes
Monotypic eukaryote classes