Penard Labs

The Fascinating World of Amoebae
Amoebozoa Lühe 1913, emend. Cavalier-Smith 1998
Cells naked or testate, uni-, bi- and multinucleate, cysts common, sexual or asexual, pseudopodia of the lobopodia type. Details
  • Tubulinea[+]
    Tubular, sub cylindrical pseudopodia or capable of altering the locomotive form from a flattened, expanded one to a sub cylindrical one. Monoaxial flow of the cytoplasm in every pseudopodium or in the entire cell. Details
    Stacks Image 19043
    • Euamoebida[+]
      Naked with subcylindrical pseudopodia in locomotion (or the entire cell is monopodial and subcylindrical); without alteration of the locomotive form to a flattened expanded and branched one; without adhesive uroid; glycocalyx amorphous, filamentous or consisting of prismatic, cup-shaped structures.

      Including: Amoeba, Chaos, Hartmannella, Parachaos, Polychaos.

      Stacks Image 19147
    • Leptomyxida[+]
      Naked with locomotive form altering from a flattened expanded or reticulate one, when slowly moving, to a subcylindrical monopodial one when in rapid movement or under specific conditions; adhesive uroid.

      Including: Rhizamoeba, Leptomyxa

      Stacks Image 19201
    • Arcellinida[+]
      Testate, inside an organic or mineral extracellular test of either self-secreted elements (calcareous, siliceous, or chitinoid) or recycled mineral or diatom particles bound together, with a single main opening.

      Stacks Image 30450
  • Discosea[+]
    Flattened naked amoebae that never produce tubular, sub cylindrial pseudopodia and never alter their locomotive form. Cytoplasmic flow polyaxial or without a pronounced axis. Subpseudopodia short or absent. Details
    Stacks Image 19056
    • Flabellinia[+]
      Flattened generally fan-shaped, discoid or irregularly triangular, never with pointed subpseudopodia or centrosomes.

      Stacks Image 17447
    • Longamoebia[+]
      Flattened, elongated cell with pointed subpseudopodia; centrosomes in one lineage.

      Stacks Image 17549
    • Himatismenida[+]
      Dorsal surface covered with rigid coat without defined aperture; ventral surface naked.

      Stacks Image 17603
    • Pellitida[+]
      Cell coat envelops the entire cell and is integrated with the cell membrane. For locomotion and phagocytosis amoebae produce short subpseudopodia protruding through the cell coat and covered at the distal end solely by the cell membrane.

      Stacks Image 17657
  • Variosea[+]

    Aerobic ciliated amoebae with conical microtubular cytoskeleton and only temporary pointed pseudopodia or non-ciliate amoebae with long, tapering, usually pointed, often branched subspseudopodia.

    Stacks Image 19069
  • Archamoebae[+]
    Anaerobic or microaerobic mostly ciliated amoebae with reduced mitochondrial organelles and endosymbiotic bacteria. Amoeboid movement with eruptive lobopodia. Free-living or endobiotic.

    Stacks Image 19083
Nucletmycea Brown et al. 2009
This is a group that includes Fungi, Nuclearia Cienkowski 1865 and Fonticula Worley et al. 1979. Some nucleariid amoebae often show axopodia-like pseudopodia. Nucleariids have no axonemes and no kinetocysts.
  • Nuclearia[+]
    Amoeboid with rounded body, from which elongated filopodia extend. Often surrounded by a mucous layer with bacteria.

    Stacks Image 15660
Stramenopiles Patterson 1989, emend. Adl et al. 2005
Motile cells typically biciliate, typically with heterokont ciliation – anterior cilium with tripartite mastigonemes in two opposite rows and a posterior usually smooth cilium. Details
  • Actinophryidae[+]
    Ciliated cells absent. Axonemal pseudopodia with stiff microtubular core (axopodia). Axopodia originate from an amorphous centrosome near nuclei. Single large central nucleus or several peripheral nuclei.

    Including: Actinophrys, Actinosphaerium.

    Stacks Image 18878
  • Chrysophyceae[+]
    Predominantely ciliated cells, swimming cells biciliated. Cell coverings, when present, include organic scales, siliceous scales, organic lorica, and cellulose cell wall; eyespots present or absent. With statospores.

    Including: Dinobryon, Epipyxis, Cyclonexis, Chrysostephanosphaera, Chrysamoeba, Lagynion, Paraphysomonas.

    Stacks Image 18932
  • Dictyochophyceae[+]
    Single cells, colonial ciliated cells or amoebae; swimming cells usually with one cilium, anteriorly directed. Cells naked, with organic scales or with siliceous skeleton; eyespots absent.

    Including: Ciliophrys, Palatinella.

    Stacks Image 19012
  • Picophagophyceae[+]
    Naked plasmodium with finely branched filopodia and yellowish-green plastids and multiple vesicular nuclei.

    Including: Chlamydomyxa.

    Stacks Image 19134
  • Synurales[+]
    Predominantely ciliated cells, benthic palmelloid colonies known; swimming cells usually with two anteriorly directed cilia. Cells covered with bilaterally symmetrical silica scales; eyespots absent; statospores.

    Including: Synura, Mallomonas.

    Stacks Image 19212
  • Labyrinthulomycetes[+]
    Mainly osmotrophic cells capable of producing an ectoplasmic network of branched, anastomosing, wall-less filaments via a specialized organelle known as the bothrosome; Golgi-derived scales; biciliate zoospores with lateral insertion in many species.

    Including: Amphitrema, Diplophrys.

    Stacks Image 19266
Centrohelea Kühn 1926, stat. n. Cavalier-Smith 1993
Non-flagellate heliozoa with axopodial axonemes; nucleus eccentric; centrosome central; two types of siliceous scales present ancestrally (flat inner tangential plate scales and elongated, usually pointed, outer radial spine scales), but outer scales or both scale layers secondarily lost in several derived lineages. Details
  • Pterocystida[+]
    Silicified species always with both plate and spine scales; plate scales oval without an inrolled margin; spine scales (spicules) radially asymmetric, ranging from a shape like a pointed moss leaf with axial rib, through reduced forms with the blade restricted to the base, to a vertical stalk emanating from a notched asymmetric basal disc.
    Stacks Image 20000
    • Pterocystidae[+]
      Periplast ancestrally with two contrasting types of siliceous scales: tangential basal plate scales; outer bipartite radial spine scales, usually extended apically as a projecting needle-like point.

      Including: Pterocystis, Raineriophrys, Chlamydaster, Echinocystis.

      Stacks Image 20566
    • Choanocystidae[+]
      Periplast with two contrasting types of siliceous scales, oval or bilobed tangential basal plate scales; outer bipartite radial spine scales consisting of a vertical stalk, sometimes curved or branched but lacking lateral wings. Funnel-shaped scales absent.

      Including: Choanocystis.

      Stacks Image 20620
    • Heterophryidae[+]
      Centrohelids lacking silica scales but with numerous thin pointed organic scales tapering towards acute apices.

      Including: Heterophrys, Sphaerastrum, Parasphaerastrum.

      Stacks Image 20674
  • Acanthocystida[+]
    Silicified species with both plate and spine scales or only plate scales lacking a hollow inrolled margin; outer radial spine scales radially symmetric, present in one or both of two forms: funnel-shaped with apical flared and toothed funnel on a stalk and a discoid base, or needle-like with a radially symmetric peltate base and/or apical branches.
    Stacks Image 20013
    • Chalarothoracina[+]
      Always with silica scales.
      Stacks Image 20880
      • Acanthocystidae[+]
        Periplast with two or three types of siliceous scales, a basal layer of typically oval plate scales and an outer layer of radial funnel-shaped siliceous spine scales and/or radial needle-like spine scales sometimes apically branched and/or with a peltate radially symmetrical basal disc lacking a lateral indentation.

        Including: Acanthocystis, Raphidocystis, Pseudoraphidocystis.

        Stacks Image 21408
      • Raphidiophryidae[+]
        Periplast typically containing tangential siliceous plates surrounded by a hollow marginal rim but never goblet-shaped or other radial spine scales.

        Including: Raphidiophrys, Pseudoraphidiophrys, Polyplacocystis, Heteroraphidiophrys.

        Stacks Image 21462
    • Marophryina[+]
      Periplast lacking silica scales but with numerous thin, pointed organic spicules tapering towards acute apices.
      Stacks Image 20893
      • Marophryidae[+]
        Spicules radially oriented, numerous, length approximately half the cell diameter, tapering abruptly from base to acute tips.

        Including: Marophrys.

        Stacks Image 21328
Cercozoa Cavalier-Smith 1998, emend. Adl et al. 2005
This is a group of flagellates and amoebae defined by molecular phylogenies. The amoeboid genera have either filose pseudopodia (filopodia) or networks of anastomosing reticulopodia. Very often with cysts. Details
  • Granofilosea[+]
    With very delicate reticulopodia bearing frequent regular extrusomes.

    Including: Clathrulina, Microgromia, Apogromia, Microcometes, Paralieberkuehnia.

    Stacks Image 19602
  • Vampyrellida[+]
    Naked, phagotrophic amoeboid organisms; amoeboid, free-moving trophozoites alternating with an obligatory digestive cyst.

    Including: Vampyrella, Leptophrys, Hyalodiscus.

    Stacks Image 19615
  • Glissomonadida[+]
    Small (<15 µm), naked biflagellate cells, bacterivorous or algaevorous.

    Including: Viridiraptor.

    Stacks Image 19628
  • Thecofilosea[+]
    Ancestrally with robust organic extracellular theca; theca with perforations for cilia and for pseudopodia; ventral filose pseudopodia emerge from ventral groove.

    Including: Diaphoropodon, Lecythium, Lithocolla.

    Stacks Image 19642
  • Imbricatea[+]
    Cells with secreted surface silica scales.

    Including: Euglypha, Trinema, Cyphoderia, Paulinella, Pinaciophora, Pompholyxophrys.

    Stacks Image 19657
Foraminifera d’Orbigny 1826
Filopodia with granular cytoplasm, forming branching and anastomosing network (reticulopodia); bidirectional rapid (10 mm/s) transport of intracellular granules. With some exceptions this is a large taxon of marine species.
  • Monothalamids[+]
    Single chamber test with an organic or agglutinated wall or no test at all.
    • Allogromiidae[+]
      Test globular to ovate with single, terminal aperture. Cell wall proteinaceous, sometimes incorporating agglutinated particles.

      Stacks Image 22162
    • Recticulomyxidae[+]
      Large plasmodia with hundreds or thousands of small nuclei involved in bidirectional streaming. Obligatory alternation of sessile and motile stages. Locomotion by migration via one or several giant pseudopodia with predominantly unidirectional centrifugal streaming of protoplasm. Cyst formation. Tectum as (protective) covering. Occasional formation of protoplasmic propagules (blisters, blebs) from pseudopodia and central areas. Omnivorous or predatory. Occurring in freshwater habitats.

      Stacks Image 22224
Twilight Zone
Unidentified amoebae and amoebae where the phylogenetic placement is unknown.