Thomas (Tom) Cavalier-Smith, FRS, FRSC, NERC Professorial Fellow, was a professor of evolutionary biology in the Department of Zoology, at the University of Oxford.
Amorphea is a taxonomic supergroup that includes the basal Amoebozoa and Obazoa. That latter contains the Opisthokonta, which includes the Fungi, Animals and the Choanomonada, or Choanoflagellates. The taxonomic affinities of the members of this clade were originally described and proposed by Thomas Cavalier-Smith in 2002.
The Apusozoa are a paraphyletic phylum of flagellate eukaryotes. They are usually around 5–20 μm in size, and occur in soils and aquatic habitats, where they feed on bacteria. They are grouped together based on the presence of an organic shell or theca under the dorsal surface of the cell.
Hemimastigophora is a group of single-celled eukaryotic organisms including the Spironemidae, first identified in 1988. Over the next 30 years, different authors proposed placing these organisms in various branches of the eukaryotes. In 2018 Lax et al. reported the first genetic information for Spironemidae, and suggest that they are from an ancient lineage of eukaryotes which constitute a separate clade from all other eukaryotic kingdoms. It is potentially related to the Telonemia.
Spironemidae is a family of heterotrophic flagellates, in the group Hemimastigophora. They vary in size and shape from the ellipsoid Hemimastix amphikineta to the vermiform Spironema terricola, and are united by the possession of two rows of cilia, called kineties.
Loukozoa is a proposed taxon used in some classifications of eukaryotes, consisting of the Metamonada and Malawimonadea. Ancyromonads are closely related to this group, as sister of the entire group, or as sister of the Metamonada. Amorphea may have emerged in this grouping, specifically as sister of the Malawimonads.
Holozoa is a clade of organisms that includes animals and their closest single-celled relatives, but excludes fungi and all other organisms. Together they amount to more than 1.5 million species of purely heterotrophic organisms, including around 300 unicellular species. It consists of various subgroups, namely Metazoa and the protists Choanoflagellata, Filasterea, Pluriformea and Ichthyosporea. Along with fungi and some other groups, Holozoa is part of the Opisthokonta, a supergroup of eukaryotes. Choanofila was previously used as the name for a group similar in composition to Holozoa, but its usage is discouraged now because it excludes animals and is therefore paraphyletic.
Ancyromonadida or Planomonadida is a small group of biflagellated protists found in the soil and in aquatic habitats, where they feed on bacteria. Includes freshwater or marine organisms, benthic, 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.
Diaphoretickes is a major group of eukaryotic organisms, with over 400,000 species. The majority of the earth's biomass that carries out photosynthesis belongs to Diaphoretickes.
Picozoa, Picobiliphyta, Picobiliphytes, or Biliphytes are protists of a phylum of marine unicellular heterotrophic eukaryotes with a size of less than about 3 micrometers. They were formerly treated as eukaryotic algae and the smallest member of photosynthetic picoplankton before it was discovered they do not perform photosynthesis. The first species identified therein is Picomonas judraskeda. They probably belong in the Archaeplastida as sister of the Rhodophyta.
Collodictyonidae is a group of aquatic, unicellular eukaryotic organisms with two to four terminal flagella. They feed by phagocytosis, ingesting other unicellular organisms like algae and bacteria. The most remarkable fact of this clade is its uncertain position in the tree of life.
The initial version of a classification system of life by British zoologist Thomas Cavalier-Smith appeared in 1978. This initial system continued to be modified in subsequent versions that were published until he died in 2021. As with classifications of others, such as Carl Linnaeus, Ernst Haeckel, Robert Whittaker, and Carl Woese, Cavalier-Smith's classification attempts to incorporate the latest developments in taxonomy., Cavalier-Smith used his classifications to convey his opinions about the evolutionary relationships among various organisms, principally microbial. His classifications complemented his ideas communicated in scientific publications, talks, and diagrams. Different iterations might have a wider or narrow scope, include different groupings, provide greater or lesser detail, and place groups in different arrangements as his thinking changed. His classifications has been a major influence in the modern taxonomy, particularly of protists.
Varisulca was a proposed basal Podiate taxon. It encompassed several lineages of heterotrophic protists, most notably the ancyromonads (planomonads), collodictyonids (diphylleids), rigifilids and mantamonadids. Recent evidence suggests that the latter three are closely related to each other, forming a clade called CRuMs, but that this is unlikely to be specifically related to ancyromonads
Cryptista is a clade of alga-like eukaryotes. It is most likely related to Archaeplastida which includes plants and many algae, within the larger group Diaphoretickes.
Obazoa is a proposed sister clade of Amoebozoa. The term Obazoa is based on the OBA acronym for Opisthokonta, Breviatea, and Apusomonadida, the group's three constituent clades.
The neokaryotes are a proposed eukaryote clade consisting of the unikonts and the bikonts as sister of for instance the Jakobea. It arises because the Euglenozoa, Percolozoa, Tsukubea, and Jakobea are seen in this view as more basal eukaryotes. These four groups, are traditionally grouped together in the Discoba. However, the Discoba may well be paraphyletic as the neokaryotes may have emerged in them.
The Scotokaryotes (Cavalier-Smith) is a proposed basal Neokaryote clade as sister of the Diaphoretickes. Basal Scotokaryote groupings are the Metamonads, the Malawimonas and the Podiata. In this phylogeny the Discoba are sometimes seen as paraphyletic and basal Eukaryotes.
CRuMs or Crumalia is a proposed clade of microbial eukaryotes, whose name is an acronym of the following constituent groups: i) collodictyonids also known as diphylleids, ii) rigifilids and iii) mantamonadids as sister of the Amorphea. It more or less supersedes Varisulca, as Ancyromonadida are inferred not to be specifically related to the orders Diphylleida/Collodictyonida, Rigifilida and Mantamonadida.
A supergroup, in evolutionary biology, is a large group of organisms that share one common ancestor and have important defining characteristics. It is an informal, mostly arbitrary rank in biological taxonomy that is often greater than phylum or kingdom, although some supergroups are also treated as phyla.
Eolouka is a paraphyletic phylum of protists localized in the clade Discoba. It contains two lineages: Jakobea and Tsukubea, the last containing only one genus, Tsukubamonas.
