Protist classification


A protist is any eukaryotic organism that is not an animal, plant, or fungus. The protists do not form a natural group, or clade, since they exclude certain eukaryotes with whom they share a common ancestor; but, like algae or invertebrates, the grouping is used for convenience. In some systems of biological classification, such as the popular five-kingdom scheme proposed by Robert Whittaker in 1969, the protists make up a kingdom called Protista, composed of "organisms which are unicellular or unicellular-colonial and which form no tissues". In the 21st century, the classification shifted toward a two-kingdom system of protists: Chromista and Protozoa.
The following groups contain protists. The clade Opisthokonta also contains the animals and the fungi, and the kingdom Archaeplastida also contains algae and plants.
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Amorphea

The supergroup Amorphea contains very diverse heterotrophic organisms, from the macroscopic fungi and animals to the unicellular choanoflagellates and classical amoebae. They frequently exhibit the ability to produce multinucleated cells, a trait considered ancestral to Amorphea. They are also capable of producing pseudopodia, as does the closely related CRuMs clade, forming the clade Podiata.
Amorphea is divided into two clades: Amoebozoa, containing well-known amoebae and slime molds, and Obazoa, containing animals, fungi, and their closest relatives. The relationship between these two clades was initially called 'Unikonta', due to a hypothesis where their common ancestor was a unikont, i.e., a eukaryote with just one flagellum. However, this hypothesis was refuted, as there are bikont amorpheans and it likely is not an ancestral trait to have a single flagellum.

Obazoa

The clade Obazoa contains two small groups of flagellates, the breviates and the apusomonads, and
the large clade Opisthokonta, which contains animals, fungi, and their closest protist relatives. Under the Cavalier-Smith system, breviates and apusomonads were two classes that composed the phylum Apusozoa, but this taxon is paraphyletic, as apusomonads are more closely related to opisthokonts. The taxonomy of apusomonads was expanded in a 2022 phylogenetic study that introduced many new genera.
  • Class Breviatea, order Breviatida, family Breviatidae, genera Breviata, Lenisia, Pygsuia, Subulatomonas.
  • Class Thecomonadea, order Apusomonadida, family Apusomonadidae. Genera not assigned to any subfamily: Amastigomonas, Multimonas, Podomonas, Catacumbia, Cavaliersmithia.
  • *Subfamily Apusomonadinae, genera Apusomonas, Manchomonas.
  • *Subfamily Thecamonadinae, genera Chelonemonas, Karpovia, Singekia, Thecamonas.

    Opisthokonta

Opisthokonts are divided into two branches: Holozoa, containing the ichthyosporeans, pluriformeans, filastereans and choanoflagellates; and Nucletmycea or Holomycota, containing the nucleariids and opisthosporidians. These groups, minus opisthosporidians, were classified as different classes within the paraphyletic phylum Choanozoa in the system of Cavalier-Smith, now obsolete. Instead, Choanozoa is the name used for the clade containing choanoflagellates and animals. opisthosporidians are often studied as protists, but are also considered fungi by protistologists and mycologists alike. Both Holozoa and Nucletmycea have been proposed once as superkingdoms by a group of mycologists who classified nucleariids and fungi as kingdoms, but without any mention of holozoan kingdoms.
  • Nucletmycea
  • *Order Rotosphaerida , family Nucleariidae , genera: Fonticula, Nuclearia, Parvularia, Pompholyxophrys, Lithocolla, Vampyrellidium, Elaeorhanis, Pinaciophora, Rabdiophrys, Rabdiaster, Thomseniophora.
  • *Kingdom Fungi
  • Holozoa. Genera incertae sedis: Tunicaraptor, Bicellum.
  • *Class Ichthyosporea
  • **Order Dermocystida, family Rhinosporidaceae, genera Amphibiocystidium, Amphibiothecum, Chromosphaera, Dermocystidium, Rhinosporidium, Sphaerothecum, Valentines.
  • **Order Ichthyophonida , family Amoebidiidae, genera Abeoforma, Amoebidium, Anurofeca, Astreptonema, Caullerya, Creolimax, Eccrinidus, Enterobryus, Enteropogon, Ichthyophonus, Palavascia, Pseudoperkinsus, Psorospermium, Sphaeroforma.
  • *Class Pluriformea, order Corallochytrida
  • **Family Corallochytriidae, genus Corallochytrium.
  • **Family Syssomonadidae, genus Syssomonas.
  • *Class Filasterea, order Ministeriida. Genus not assigned to any family: Pigoraptor.
  • **Family Ministeriidae, genus Ministeria.
  • **Family Capsasporidae, genus Capsaspora.
  • **Family Txikisporidae, genus Txikispora.
  • *Choanozoa
  • **Class Choanoflagellata
  • ***Order Craspedida, family Salpingoecidae , genera Astrosiga, Aulomonas, Barroeca, Choanoeca, Cladospongia, Codonocladium, Codonosigopsis, Codosiga, Desmarella, Dicraspedella, Diploeca, Diplosiga, Diplosigopsis, Hartaetosiga, Kentia, Lagenoeca, Microstomoeca, Monosiga, Mylnosiga, Pachysoeca, Proterospongia, Salpingoeca, Salpingorhiza, Sphaeroeca, Stagondoeca, Stelexomonas, Stylochromonas.
  • ***Order Acanthoecida
  • ****Family Acanthoecidae, genera Acanthoeca, Enibas, Helgoeca, Polyoeca, Savillea.
  • ****Family Stephanoecidae, genera Acanthocorbis, Amoenoscopa, Apheloecion, Bicosta, Calliacantha, Calotheca, Campanoeca, Campyloacantha, Conion, Cosmoeca, Crinolina, Crucispina, Diaphanoeca, Didymoeca, Kakoeca, Monocosta, Nannoeca, Parvicorbicula, Thomsenella, Pleurasiga, Polyfibula, Saepicula, Saroeca, Spinoeca, Spiraloecion, Stephanacantha, Stephanoeca, Syndetophyllum.
  • **Kingdom '''Metazoa'''

    Amoebozoa

The phylum Amoebozoa contains around 2,400 species of primarily amoeboid protists. It includes a large portion of the traditional Sarcodina, the taxon uniting all amoebae. In particular, it groups naked and testate lobose amoebae, as well as the archamoebae and eumycetozoans, and a few flagellates. After the general 2019 revisions published by the International Society of Protistologists, there have been specific revisions to the classification of eumycetozoans and testate amoebae.
Phylum Amoebozoa. Genera incertae sedis: Belonocystis, Boveella, Biomyxa, Corallomyxa, Gibbodiscus, Hartmannia, Malamoeba, Malpighamoeba, Oscillosignum, Pseudothecamoeba, Rhabdamoeba, Schoutedamoeba, Stereomyxa, Subulamoeba, Triaenamoeba, Unda.
  • Class Tubulinea
  • *Corycidia
  • **Order Trichosida, family Trichosphaeriidae , genus Trichosphaerium.
  • **Family Microcoryciidae, genera Amphizonella, Diplochlamys, Microcorycia*, Parmulina*, Penardochlamys*, Zonomyxa*.
  • *Order Echinamoebida
  • **Family Echinamoebidae, genera Echinamoeba, Micriamoeba.
  • **Family Vermamoebidae, genus Vermamoeba.
  • *Elardia
  • **Order Leptomyxida
  • ***Family Leptomyxidae, genus Leptomyxa.
  • ***Family Rhizamoebidae, genus Rhizamoeba.
  • ***Family Flabellulidae, genus Flabellula.
  • ***Family Gephyramoebidae, genus Gephyramoeba.
  • **Superorder Eulobosia
  • ***Order Euamoebida
  • ****Family Amoebidae, genera: Amoeba, Chaos, Polychaos, Parachaos, Trichamoeba, Deuteramoeba, Hydramoeba.
  • ****Family Hartmannellidae, genera Cashia, Copromyxa, Copromyxella, Glaeseria, Hartmannella, Ptolemeba, Saccamoeba.
  • ****Family Nolandellidae, genus Nolandella.
  • ***Order Arcellinida. Genera incertae sedis: Acipyxis, Apolimia, Argynnia, Armipyxis, Conicocassis, Cornuapyxis, Ellipsopyxella, Ellipsopyxis, Erugomicula, Frenopyxis, Geamphorella, Geoplagiopyxis, Geopyxella, Hoogenraadia, Jungia, Lagenodifflugia, Lamptopyxis, Lamtoquadrula, Leptochlamys, Maghrebia, Meisterfeldia, Microquadrula, Nabranella, Oopyxis, Paracentropyxis, Paraquadrula, Pentagonia, Physochila, Planhoogenraadia, Pomoriella, Pontigulasia, Prantlitina, Proplagiopyxis, Protoplagiopyxis, Protocucurbitella, Pseudawerintzewia, Pseudonebela, Schoenbornia, Sexangularia, Suiadifflugia, Trigonopyxis, Wailesella, Cangwuella.
  • ****Suborder Phryganellina
  • *****Family Phryganellidae, genus Phryganella.
  • *****Family Cryptodifflugiidae, genus Cryptodifflugia.
  • ****Suborder Organoconcha, family Microchlamyiidae, genera Microchlamys, Spumochlamys, Pyxidicula.
  • ****Suborder Glutinoconcha
  • *****Infraorder Volnustoma, family Heleoperidae, genera Heleopera, Metaheleopera.
  • *****Infraorder Hyalospheniformes, family Hyalospheniidae , genera Alabasta, Alocodera, Apodera, Certesella, Cornutheca, Gibbocarina, Hyalosphenia, Longinebela, Mrabella, Nebela, Padaungiella, Planocarina, Porosia, Quadrulella.
  • *****Infraorder Excentrostoma, family Centropyxidae , genera Awerinzewia, Bullinularia, Centropyxis, Frenopyxis, Golemanskia, Plagiopyxis.
  • *****Infraorder Cylindrothecina, family Cylindrifflugiidae, genus Cylindrifflugia.
  • *****Infraorder Longithecina
  • ******Family Difflugiidae, genera Difflugia, Zivkovicia.
  • ******Family Lesquereusiidae, genus Lesquereusia.
  • *****Infraorder Sphaerothecina
  • ******Family Arcellidae, genera Arcella, Galeripora.
  • ******Family Netzeliidae, genera Cucurbitella, Cyclopyxis, Netzelia.
  • Class Discosea
  • *Subclass Flabellinia
  • **Superorder Dermelia
  • ***Order Mycamoebida, family Mycamoebidae, genera Mycamoeba, Janelia, Microglomus.
  • ***Order Dermamoebida
  • ****Family Dermamoebidae, genera Dermamoeba, Paradermamoeba, Coronamoeba.
  • ****Family Mayorellidae, genus Mayorella.
  • **Superorder Thecavania
  • ***Order Stygamoebida, family Stygamoebidae, genera Stygamoeba, Vermistella.
  • ***Order Thecamoebida, genera Sappinia, Stenamoeba, Stratorugosa, Thecamoeba, Thecochaos.
  • ***Order Dactylopodida, genera Cunea, Janickina, Korotnevella, Neoparamoeba, Paramoeba, Pseudoparamoeba, Vexillifera.
  • ***Order Vannellida, family Vannellidae, genera Clydonella, Lingulamoeba, Paravannella, Pessonella, Ripella, Vannella.
  • *Subclass Centramoebia
  • **Order Acanthopodida , genera Acanthamoeba, Balamuthia, Luapeleamoeba, Protacanthamoeba, Dracoamoeba, Vacuolamoeba.
  • **Order Himatismenida, genera Cochliopodium, Ovalopodium, Parvamoeba.
  • **Order Pellitida, genera Endostelium, Gocevia, Paragocevia, Pellita.
  • Evosea
  • *Class Cutosea, order Squamocutida
  • **Family Squamamoebidae, genera Armaparvus, Squamamoeba.
  • **Family Sapocribridae, genus Sapocribrum.
  • **Family Idionectidae, genus Idionectes.
  • *Class Variosea. Genera not assigned to any lower clade: Angulamoeba, Arboramoeba, Darbyshirella, Dictyamoeba, Ischnamoeba, Heliamoeba, Filamoeba, Phalansterium.
  • **Family Flamellidae, genera Flamella, Telaepolella.
  • **Order Protosteliida , family Protosteliidae , genus Protostelium.
  • **Order Fractovitellida
  • ***Family Acramoebidae, genus Acramoeba.
  • ***Family Schizoplasmodiidae, genera Ceratiomyxella, Nematostelium, Schizoplasmodium.
  • ***Family Soliformoviidae. Genera: Soliformovum ; Grellamoeba.
  • **Order Cavosteliida , family Cavosteliidae , genera Cavostelium, Schizoplasmodiopsis, Tychosporium.
  • **Order Holomastigida , family Multiciliidae , genera Artodiscus, Multicilia.
  • *Class Archamoebea
  • **Family Tricholimacidae, genus Tricholimax.
  • **Order Entamoebida, family Entamoebidae, genera Entamoeba, Entamoebites.
  • **Order Pelobiontida
  • ***Suborder Pelomyxina, family Pelomyxidae, genera Mastigella, Pelomyxa.
  • ***Suborder Mastigamoebina
  • ****Family Rhizomastixidae, genus Rhizomastix.
  • ****Family Mastigamoebidae, genera Endamoeba*, Endolimax, Iodamoeba, Mastigamoeba, Mastigina*.
  • *Eumycetozoa
  • **Class Dictyostelea . Genus unassigned to any order: Synstelium. Genus incertae sedis: Coenonia.
  • ***Order Acytosteliales
  • ****Family Acytosteliaceae, genera Acytostelium, Rostrostelium, Heterostelium.
  • ****Family Cavenderiaceae, genus Cavenderia.
  • ***Order Dictyosteliales. Genus unassigned to any family: Coremiostelium.
  • ****Family Dictyosteliaceae, genera Dictyostelium, Polysphondylium.
  • ****Family Raperosteliaceae, genera Hagiwaraea, Raperostelium, Speleostelium, Tieghemostelium.
  • **Class Ceratiomyxomycetes , order Protosporangiida
  • ***Family Ceratiomyxaceae , genus Ceratiomyxa.
  • ***Family Protosporangiidae , genera Clastostelium, Protosporangium.
  • **Class Myxogastrea
  • ***Subclass Lucisporinia . Genera incertae sedis: Arcyriatella, Calonema, Minakatella, Trichioides.
  • ****Superorder Cribariidia, order Cribariales , family Cribariaceae , genera Cribaria, Lindbladia, Licaethalium.
  • ****Superorder Trichiidia
  • *****Order Reticulariales , family Reticulariaceae , genera: Alwisia, Lycogala, Reticularia, Tubifera.
  • *****Order Liceales, family Liceaceae , genera Licea, Listerella.
  • *****Order Trichiales
  • ******Family Dianemataceae , genera Calomyxa, Dianema, Dictydiaethalium, Prototrichia.
  • ******Family Trichiaceae , genera Hemitrichia, Arcyria ; Perichaena, Trichia.
  • ***Subclass Columellinia . Genera incertae sedis: Diachea, Echinosteliopsis, Leptoderma, Paradiachea, Protophysarum, Trabrooksia, Willkommlangea.
  • ****Superorder Echinosteliidia, order Echinosteliales , family Echinosteliaceae , genera: Barbeyella, Echinostelium.
  • ****Superorder Stemonitidia
  • *****Order Clastodermatales , family Clastodermataceae , genus Clastoderma.
  • *****Order Meridermatales , family Meridermataceae , genus Meriderma.
  • *****Order Stemonitales
  • ******Family Stemonitidaceae , genera Macbrideola, Stemonitis, Symphytocarpus.
  • ******Family Amaurochaetaceae , genera Comatricha, Stemonaria, Stemonitopsis, Amaurochaete, Brefeldia, Enerthenema, Paradiacheopsis.
  • *****Order Physarales . Genus not assigned to any family: Tasmaniomyxa.
  • ******Family Lamprodermataceae , genera Lamproderma, Collaria.
  • ******Family Didymiaceae , genera Diderma, Didymium, Lepidoderma, Mucilago.
  • ******Family Physaraceae , genera Craterium, Leocarpus, Fuligo, Physarum, Physarella, Physarina, Kelleromyxa.