Corycidia (alternatively spelt Corycida) is a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

amoeboid An amoeba (; less commonly spelled ameba or amœba; : amoebas (less commonly, amebas) or amoebae (amebae) ), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and r ...

protists A protist ( ) or protoctist is any Eukaryote, eukaryotic organism that is not an animal, Embryophyte, land plant, or fungus. Protists do not form a Clade, natural group, or clade, but are a Paraphyly, paraphyletic grouping of all descendants o ...

within the

eukaryotic The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms ...

supergroup

Amoebozoa Amoebozoa is a major Taxonomy (biology), taxonomic group containing about 2,400 described species of Amoeba, amoeboid protists, often possessing blunt, fingerlike, Pseudopod#Morphology, lobose pseudopods and tubular mitochondrial cristae. In trad ...

. It contains all amoebae of the families

Microcoryciidae The Tubulinea are a major grouping of Amoebozoa, including most of the more familiar amoebae genera like ''Amoeba (genus), Amoeba'', ''Arcella'', ''Difflugia'' and ''Hartmannella''. Characteristics During locomotion most Tubulinea have a rough ...

, which was previously regarded as

Arcellinida Arcellinid testate amoebae or Arcellinida,http://www.microscopy-uk.org.uk/mag/artjun03/gsamoebae.html Testate amoebae, peat bogs and past climates. accessed 16 march 2007 Arcellacean or lobose testate amoebae are single-celled protists partially ...

(an order of

testate amoebae Testate amoebae (formerly thecamoebians, Testacea or Thecamoeba) are a polyphyletic group of unicellular amoeboid protists, which differ from naked amoebae in the presence of a test (biology), test that partially encloses the cell, with an apert ...

), and

Trichosphaeriidae ''Trichosphaerium'' is a genus of amoebozoan protists that present extraordinary morphological transformations, both in size and shape, during their life cycle. They can present a test that may or may not be covered in spicules. They are relate ...

, which contains the sole genus '' Trichosphaerium''.

Taxonomy

Corycidia is defined as the least inclusive

containing '' Amphizonella'', '' Diplochlamys'' and '' Trichosphaerium''. It was discovered in 2017 through a

phylogenomic Phylogenomics is the intersection of the fields of evolution and genomics. The term has been used in multiple ways to refer to analysis that involves genome data and evolutionary reconstructions. It is a group of techniques within the larger fields ...

study by Senghuo Kang and coauthors, published in the journal ''

Molecular Biology and Evolution ''Molecular Biology and Evolution'' (''MBE'') is a monthly peer-reviewed scientific journal published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. It publishes work in the intersection of molecular bi ...

''. It is supported by independent analyses. As of 2019, it is accepted by the International Society of Protistologists as part of the modern

cladistic Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...

classification of eukaryotes, although under the alternative spelling Corycida. The name Corycidia is derived , referring to the "leathery"

test Test(s), testing, or TEST may refer to: * Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities Arts and entertainment * ''Test'' (2013 film), an American film * ''Test'' (2014 film) ...

that members of the clade have.

Evolution

Corycidia is located in the

supergroup

, specifically inside the clade

Tubulinea The Tubulinea are a major grouping of Amoebozoa, including most of the more familiar amoebae genera like ''Amoeba'', '' Arcella'', '' Difflugia'' and '' Hartmannella''. Characteristics During locomotion most Tubulinea have a roughly cylindrica ...

which unites most lobose

amoebae An amoeba (; less commonly spelled ameba or amœba; : amoebas (less commonly, amebas) or amoebae (amebae) ), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and r ...

(i.e. amoebae with blunt, thick

pseudopodia A pseudopod or pseudopodium (: pseudopods or pseudopodia) is a temporary arm-like projection of a eukaryotic cell membrane that is emerged in the direction of movement. Filled with cytoplasm, pseudopodia primarily consist of actin filaments and ...

). It is the most basal tubulinean lineage. The following

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

depicts the

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

position of Corycidia among other amoebozoan clades.

Classification

A total of 7

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

are included within Corycidia, traditionally organized into two families:

(one genus '' Trichosphaerium''), under the monotypic order Trichosida, and

(six genera), previously assigned to the order

. Only three genera are firmly placed in Corycidia through phylogenetic analyses: '' Amphizonella'', '' Diplochlamys'' and '' Trichosphaerium''. The position of the genera '' Penardochlamys'', '' Microcorycia'', '' Zonomyxa'' and '' Parmulina'', listed as part of the family Microcoryciidae, is not clear. They have been tentatively placed in Corycidia due to a morphological resemblance, but it has not been demonstrated with molecular data. * Trichosida **

*** '' Trichosphaerium'' (=''Pontifex'', ''Atrichosa'') *

** '' Amphizonella'' ** '' Diplochlamys'' ** '' Microcorycia'' ** '' Penardochlamys'' ** '' Zonomyxa'' ** '' Parmulina''

References

{{taxonbar, from=Q109885287 Amoebozoa Taxa described in 2017