The tectofilosids are a group of filose

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

e with shells. These are composed of organic materials and sometimes collected debris, in contrast to the euglyphids, which produce shells from siliceous scales. The shell usually has a single opening, but in '' Amphitrema'' and a few other genera it has two on opposite ends. The cell itself occupies most of the shell. They are most often found on marsh plants such as ''

Sphagnum ''Sphagnum'' is a genus of approximately 380 accepted species of mosses, commonly known as sphagnum moss, also bog moss and quacker moss (although that term is also sometimes used for peat). Accumulations of ''Sphagnum'' can store water, since ...

''. This group was previously classified as the Gromiida or Gromiina. However, molecular studies separate '' Gromia'' from the others, which must therefore be renamed. They are placed among the

Cercozoa Cercozoa (now synonymised with Filosa) is a phylum of diverse single-celled eukaryotes. They lack shared morphological characteristics at the microscopic level, and are instead united by phylogeny, molecular phylogenies of rRNA and actin or Ubiqu ...

, and presumably developed from

flagellate A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and the ...

s like '' Cryothecomonas'', which has a similar test. However, only a few have been studied in detail, so their relationships and

monophyly In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent comm ...

are not yet certain. In a recent classification, the group Tectofilosida was not used: Chlamydophryidae, Psammonobiotidae, Pseudodifflugiidae and Volutellidae were dispersally placed in Thecofilosea, while Amphitremidae was included in Labyrinthulomycetes. Lithocollidae was formerly placed in Tectofilosida, but 18S rRNA-based molecular phylogenetic analyses show it is actually part of

Nucleariida The nucleariids, or nucleariid amoebae, are a group of amoebae that compose the sister clade of the fungi. Together, they form the clade Holomycota. They are aquatic organisms found in freshwater and marine habitats, as well as in faeces. They a ...

Taxonomy

* Order Tectofilosida Cavalier-Smith & Chao 2003 (paraphyletic) ** Suborder Unitremina Cavalier-Smith 2012 *** Family Rhizaspididae Howe et al. 2011 hizaspidaceae Skuja 1948*** Family Fiscullidae Dumack et al. 2017 *** Family Pseudodifflugiidae De Saedeleer 1934 *** Family Psammonobiotidae Golemansky 1974 emend Meisterfeld 2002 *** Family Chlamydophryidae de Saedeleer 1934 emend. Meisterfeld 2002 *** Family Volutellidae Sudzuki 1979

References

{{Taxonbar, from=Q7692831 Filosa Amoeboids