Ventrifilosa
Euglypha
Scientific classification Edit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Clade: SAR
Phylum: Cercozoa
Subphylum: Monadofilosa
Superclass: Ventrifilosa
Cavalier-Smith, 2012 emend. 2018[1]
Classes

Ventrifilosa (from Latin venter 'belly', and filum 'thread')[2] is a highly diverse group of phagotrophic protists that glide through their flagella and emit filose pseudopods from their ventral side for feeding. Because of their mixture of amoeba and flagellate characteristics, they are amoeboflagellates. Members of this group are the Imbricatea, Sarcomonadea and Thecofilosea.[1]

Morphology

Protists in the group Ventrifilosa ancestrally have a rigid extracellular theca on the dorsal side, and emit non-granular filose pseudopods from a ventral aperture. This aperture is called "cleft" when belonging to an amoeboflagellate, or "astropyle" when belonging to a phaeodarian.[2]

The group includes descendants that have lost or modified some of these characteristics. For example, some have lost their pseudopods (such as the spongomonads and Ebria), some have lost their theca (such as Pseudopirsonia), and some have acquired axopodia (in Phaeodaria). The loss of flagella and scales has occurred in this group several times independently through evolution.[2][3]

Taxonomy

The superclass Ventrifilosa was first described in 2012 by Cavalier-Smith to unite Thecofilosea and Imbricatea.[2] However, the group proved to be polyphyletic because the sarcomonads were excluded. Later, in 2018, it was expanded to include Sarcomonadea, which belonged to the superclass Eoglissa before this change.[1]

The current classification of Ventrifilosa recognizes 3 classes, 20 orders and 60 families.[1]

References

  1. ^ a b c d Cavalier-Smith, Thomas; Chao, Ema E.; Lewis, Rhodri (April 2018). "Multigene phylogeny and cell evolution of chromist infrakingdom Rhizaria: contrasting cell organisation of sister phyla Cercozoa and Retaria". Protoplasma. 255 (5): 1517–1574. doi:10.1007/s00709-018-1241-1. PMC 6133090. PMID 29666938.
  2. ^ a b c d Cavalier-Smith T, Karpov SA (2012). "Paracercomonas Kinetid Ultrastructure, Origins of the Body Plan of Cercomonadida, and Cytoskeleton Evolution in Cercozoa". Protist. 163 (1): 47–75. doi:10.1016/j.protis.2011.06.004. ISSN 1434-4610. PMID 21839678.
  3. ^ Howe AT, Bass D, Scoble JM, Lewis R, Vickerman K, Arndt H, Cavalier-Smith T (2011). "Novel Cultured Protists Identify Deep-branching Environmental DNA Clades of Cercozoa: New Genera Tremula, Micrometopion, Minimassisteria, Nudifila, Peregrinia". Protist. 162 (2): 332–372. doi:10.1016/j.protis.2010.10.002. ISSN 1434-4610. PMID 21295519.
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