Ancyromonadida or Planomonadida is a small group of
biflagellated eukaryotes
The eukaryotes ( ) constitute the domain of Eukaryota or Eukarya, organisms whose cells have a membrane-bound nucleus. All animals, plants, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of ...
found in the soil and in aquatic habitats, where they feed on bacteria.
[Cavalier-Smith, T. (2013)]
Early evolution of eukaryote feeding modes, cell structural diversity, and classification of the protozoan phyla Loukozoa, Sulcozoa, and Choanozoa
European journal of protistology, 49(2), 115-178. They are freshwater or marine organisms,
benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...
, dorsoventrally compressed and with two unequal flagellae, each emerging from a separate pocket. The apical anterior flagellum can be very thin or end in the cell membrane, while the posterior flagellum is long and is inserted ventrally or laterally. The cell membrane is supported by a thin single-layered theca and the mitochondrial crests are discoidal/flat.
The group's placement is doubtful, as it seems to fall outside the five
supergroups of
eukaryote
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 ...
s.
Cavalier-Smith
Thomas (Tom) Cavalier-Smith, Royal Society, FRS, Royal Society of Canada, FRSC, Natural Environment Research Council, NERC Professorial Fellow (21 October 1942 – 19 March 2021), was a professor of evolutionary biology in the Departme ...
considers that they constitute a basal group to
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 ...
and
Opisthokonta and places it together with other related groups in
Sulcozoa.
[Ruggiero, M. A., Gordon, D. P., Orrell, T. M., Bailly, N., Bourgoin, T., Brusca, R. C., Cavalier-Smith, T., Guiry, M.D. y Kirk, P. M. (2015)]
A Higher Level Classification of All Living Organisms.
/ref> However, they appear more basal than '' Malawimonas'', placing them in Loukozoa, possibly as stem podiates, and depending on the placement of the root position of the eukaryotes.
Phylogeny
Taxonomy
* Order Ancyromonadida Cavalier-Smith 1998 emend. Atkins 2000paraphyletic
Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...
References
External links
*
{{Taxonbar, from=Q9150820
Excavata
Scotokaryotes