Taxonomy of Cercozoa

Cercozoa (=Rhizopoda) is a phylum of protists. It was first described in 1998 by Thomas Cavalier-Smith. The phylum Cercozoa belongs to a group called Rhizaria. No specific morphological or behavioral characteristics are observed in its members. This phylum exhibits great diversity. Its members are biciliate and/or amoeboid and generally possess filopodia. Most contain tubular cristae, and cysts are common. Kinetosomes are attached to the nucleus via the cytoskeleton. Microbodies and extrusomes are generally present. This list shows the revisions made to Cavalier-Smith's Cercozoa classification and also shows Adl et al. classifications.

Taxonomy Before the phylum was described, a similar group was named as phylum Rhizopoda instead. In 1997, Rhizopoda was assigned to a superphylum named Neosarcodina that also included another phylum, the Amoebozoa. Here is a scheme from Cavalier-Smith, 1997:

Phylum Rhizopoda Subphylum Phytomyxa Class Phytomyxea Order Phagomyxida Order Plasmodiophorida Subphylum Reticulofilosa Class Chlorarachnea Order Chlorarachnida Class Proteomyxidea Order Pseudosporida Order Leucodictyida Subphylum Monadofilosa Class Sarcomonadea Order Cercomonadida Order Thaumatomonadida Class Filosea Subclass Cristidiscoidia Order Nucleariida Order Fonticulida Order Ministeriida Subclass Cristivesiculatia Order Vampyrellida Subclass Testaceafilosia Order Gromiida Order Euglyphida

In Cavalier-Smith, 1998, the phylum was proposed as a replacement for Rhizopoda. It was placed in infrakingdom Sarcomastigota along with the phyla Neomonada, Foraminifera and Amoebozoa. Order Spongomonadida was added to subphylum Monadofilosa and cristidiscoids were transferred to subphylum Choanozoa. The classification was this:

Phylum Cercozoa Subphylum Phytomyxa Class Phytomyxea Order Phagomyxida Order Plasmodiophorida Subphylum Reticulofilosa Class Chlorarachnea Order Chlorarachnida Class Proteomyxidea Order Pseudosporida Order Leucodictyida Subphylum Monadofilosa Order Spongomonadida Class Sarcomonadea Order Cercomonadida Order Thaumatomonadida Class Filosea Subclass Cristivesiculatia Order Vampyrellida Subclass Testaceafilosia Order Gromiida Order Euglyphida

In Cavalier-Smith, 2000, a new monotypic class Spongomonadea was named for the order Spongomonadida. Spongomonadea was placed in subphylum Reticulofilosa. Order Cryomonadida was added to class Sarcomonadea. Class Athalamea was used for the families Biomyxidae and Gymnophryidae in subphylum Reticulofilosa. Class Ramicristea was used in subphylum Monadofilosa and included the orders Heliomonadida and Commatiida:

Phylum Cercozoa Subphylum Phytomyxa Class Phytomyxea Order Phagomyxida Order Plasmodiophorida Subphylum Reticulofilosa Class Chlorarachnea Order Chlorarachnida Class Proteomyxidea Order Pseudosporida Order Leucodictyida Class Spongomonadea Order Spongomonadida Class Athalamea Subphylum Monadofilosa Class Sarcomonadea Order Cercomonadida Order Thaumatomonadida Order Cryomonadida Class Filosea Subclass Cristivesiculatia Order Vampyrellida Subclass Testaceafilosia Order Gromiida Order Euglyphida Class Ramicristea Order Heliomonadida Order Commatiida

In Cavalier-Smith, 2002, a new subphylum named Endomyxa was introduced to contain the new class Ascetosporea and the class Phytomyxea in the phylum Cercozoa. Ascetosporea contained the orders Haplosporida and Paramyxida. Subclass Testaceafilosia was ranked as a class Testaceafilosea. Phylum Cercozoa was placed in a new infrakingdom named Rhizaria along with the phyla Apusozoa, Retaria and Heliozoa:

Phylum Cercozoa Subphylum Reticulofilosa Class Chlorarachnea Order Chlorarachnida Class Proteomyxidea Order Pseudosporida Order Leucodictyida Class Spongomonadea Order Spongomonadida Class Athalamea Subphylum Monadofilosa Class Sarcomonadea Order Cercomonadida Order Thaumatomonadida Order Cryomonadida Class Filosea Order Vampyrellida Class Testaceafilosea Order Gromiida Order Euglyphida Class Ramicristea Order Heliomonadida Order Commatiida Subphylum Endomyxa Class Phytomyxea Order Phagomyxida Order Plasmodiophorida Class Ascetosporea Order Haplosporida Order Paramyxida

In Cavalier-Smith and Chao, 2003, the subphyla Reticulofilosa and Monadofilosa were ranked as superclasses in a new subphylum Filosa. Order Heliomonadida was transferred to class Proteomyxidea, a new order Reticulosida was created to include the only family Gymnophryidae, now also containing family Biomyxidae members. A new order Metopiida was assigned to class Sarcomonadea. A new class named Thecofilosea was created to contain the order Cryomonadida and the new order Tectofilosida. A new class named Imbricatea was created to contain the orders Thaumatomonadida and Euglyphida. A new order Claustrosporida was assigned to class Ascetosporea. A new class named Gromiidea contained the only order Gromiida. Order Commatiida was not listed, and order Vampyrellida was assigned kingdom Protozoa incertae sedis.

Phylum Cercozoa Subphylum Filosa Superclass Reticulofilosa Class Chlorarachnea Order Chlorarachnida Class Spongomonadea Order Spongomonadida Class Proteomyxidea Order Pseudosporida Order Leucodictyida Order Heliomonadida Order Reticulosida Superclass Monadofilosa Class Sarcomonadea Order Metopiida Order Cercomonadida Class Thecofilosea Order Tectofilosida Order Cryomonadida Class Imbricatea Order Thaumatomonadida Order Euglyphida Subphylum Endomyxa Class Phytomyxea Order Phagomyxida Order Plasmodiophorida Class Ascetosporea Order Haplosporida Order Paramyxida Order Claustrosporida Class Gromiidea Order Gromiida

In Bass and Cavalier-Smith, 2004, a new order Metromonadida was placed as superclass Monadofilosa incertae sedis. Order Metopiida was removed from class Sarcomonadea and placed subphylum Filosa incertae sedis instead. Class Spongomonadea was transferred to superclass Monadofilosa:

Phylum Cercozoa Subphylum Filosa Superclass Reticulofilosa Class Chlorarachnea Order Chlorarachnida Class Proteomyxidea Order Pseudosporida Order Leucodictyida Order Heliomonadida Order Reticulosida Superclass Monadofilosa Class Sarcomonadea Order Cercomonadida Class Thecofilosea Order Tectofilosida Order Cryomonadida Class Imbricatea Order Thaumatomonadida Order Euglyphida Class Spongomonadea Order Spongomonadida Class Incertae sedis Order Metromonadida Superclass Incertae sedis Order Metopiida Subphylum Endomyxa Class Phytomyxea Order Phagomyxida Order Plasmodiophorida Class Ascetosporea Order Haplosporida Order Paramyxida Order Claustrosporida Class Gromiidea Order Gromiida

In Bass et al., 2005, genus Sainouron was classified as superclass Monadofilosa incertae sedis, genera Helkesimastix and Cercobodo were also classified as subphylum Filosa incertae sedis:

Phylum Cercozoa Subphylum Filosa Superclass Reticulofilosa Class Chlorarachnea Order Chlorarachnida Class Proteomyxidea Order Pseudosporida Order Leucodictyida Order Heliomonadida Order Reticulosida Superclass Monadofilosa Class Sarcomonadea Order Cercomonadida Class Thecofilosea Order Tectofilosida Order Cryomonadida Class Imbricatea Order Thaumatomonadida Order Euglyphida Class Spongomonadea Order Spongomonadida Class Incertae sedis Genus Sainouron Order Metromonadida Superclass Incertae sedis Genus Helkesimastix Genus Cercobodo Order Metopiida Subphylum Endomyxa Class Phytomyxea Order Phagomyxida Order Plasmodiophorida Class Ascetosporea Order Haplosporida Order Paramyxida Order Claustrosporida Class Gromiidea Order Gromiida In 2005, Adl et al. proposed a rankless hierarchy:

Cercozoa Cercomonadida Cercomonadidae Heteromitidae Silicofilosea Thaumatomonadida Euglyphida Euglyphidae Trinematidae Cyphoderiidae Paulinellidae Incertae sedis Ampullataria Euglyphidion Heteroglypha Matsakision Chlorarachniophyta Phytomyxea Phaeodarea Phaeoconchia Phaeocystina Phaeogromia Phaeosphaeria Nucleohelea Clathrulinidae Gymnosphaerida Incertae sedis Cryothecomonas Gymnophrys Lecythium Massisteria Metopion Proleptomonas Pseudodifflugia

In Cavalier-Smith 2007, the order Metromonadida was assigned to its own class Metromonadea directly under subphylum Filosa and class Phaeodarea and order Metopiida were added to superclass Monadofilosa:

Phylum Cercozoa Subphylum Filosa Class Metromonadea Order Metromonadida Superclass Reticulofilosa Class Chlorarachnea Order Chlorarachnida Class Proteomyxidea Order Pseudosporida Order Leucodictyida Order Heliomonadida Order Reticulosida Superclass Monadofilosa Order Metopiida Class Sarcomonadea Order Cercomonadida Class Thecofilosea Order Tectofilosida Order Cryomonadida Class Imbricatea Order Thaumatomonadida Order Euglyphida Class Spongomonadea Order Spongomonadida Class Phaeodarea Class Incertae sedis Genus Sainouron Superclass Incertae sedis Genus Helkesimastix Genus Cercobodo Subphylum Endomyxa Class Phytomyxea Order Phagomyxida Order Plasmodiophorida Class Ascetosporea Order Haplosporida Order Paramyxida Order Claustrosporida Class Gromiidea Order Gromiida

In Cavalier-Smith et al., 2008, the orders Pansomonadida and Metopiida and new family Sainouridae was added to class Sarcomonadea and order Desmothoracida was added to class Proteomyxidea:

Phylum Cercozoa Subphylum Filosa Class Metromonadea Order Metromonadida Superclass Reticulofilosa Class Chlorarachnea Order Chlorarachnida Class Proteomyxidea Order Pseudosporida Order Leucodictyida Order Heliomonadida Order Reticulosida Order Desmothoracida Superclass Monadofilosa Class Sarcomonadea Family Sainouridae Order Cercomonadida Order Pansomonadida Order Metopiida Class Thecofilosea Order Tectofilosida Order Cryomonadida Class Imbricatea Order Thaumatomonadida Order Euglyphida Class Spongomonadea Order Spongomonadida Class Phaeodarea Superclass Incertae sedis Genus Helkesimastix Genus Cercobodo Subphylum Endomyxa Class Phytomyxea Order Phagomyxida Order Plasmodiophorida Class Ascetosporea Order Haplosporida Order Paramyxida Order Claustrosporida Class Gromiidea Order Gromiida

In Bass et al., 2009, a new class named Granofilosea was added to subphylum Filosa and contained five orders: Leucodictyida, Limnofilida, Cryptofilida, Desmothoracida and Heliomonadida. A new order Paradinida was added to class Ascetosporea. Order Aconchulinida was added to class Proteomyxidea, a new family named Rhizoplasmidae was also added to the class as incertae sedis. Class Proteomyxidea was transferred to subphylum Endomyxa:

Phylum Cercozoa Subphylum Filosa Class Metromonadea Order Metromonadida Class Granofilosea Order Leucodictyida Order Limnofilida Order Cryptofilida Order Desmothoracida Order Heliomonadida Superclass Reticulofilosa Class Chlorarachnea Order Chlorarachnida Superclass Monadofilosa Class Sarcomonadea Family Sainouridae Order Cercomonadida Order Pansomonadida Order Metopiida Class Thecofilosea Order Tectofilosida Order Cryomonadida Class Imbricatea Order Thaumatomonadida Order Euglyphida Class Spongomonadea Order Spongomonadida Class Phaeodarea Superclass Incertae sedis Genus Helkesimastix Genus Cercobodo Subphylum Endomyxa Class Proteomyxidea Order Reticulosida Order Aconchulinida Order Pseudosporida Order Incertae sedis Family Rhizoplasmidae Class Phytomyxea Order Phagomyxida Order Plasmodiophorida Class Gromiidea Order Gromiida Class Ascetosporea Order Haplosporida Order Paramyxida Order Claustrosporida Order Paradinida In Howe et al., 2009, a new order Glissomonadida was also assigned to class Sarcomonadea and genus Pseudopirsonia was added as superclass Monadofilosa incertae sedis:

Phylum Cercozoa Subphylum Filosa Class Metromonadea Order Metromonadida Class Granofilosea Order Leucodictyida Order Limnofilida