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Clade Elardia Kang et al. 2017

Diagnosis: Cells naked or covered with a hard test; tubular or produce tubular pseudopodia; if flattened or branched, capable of altering the locomotive form to monopodial or polypodial, with tubular pseudopodia. The least inclusive clade containing Amoeba proteus, Arcella intermedia and Rhizamoeba saxonica.

  1. Order Arcellinida Saville Kent, 1880
    Cell covered with hard or highly rigid organic or mineral extracellular test consisting of either self-secreted elements (calcareous, siliceous or chitinoid), a sheet-like chitinoid structure, or recycled organic or mineral particles bound together, with a single main opening.

      1. Sphaerothecina Kosakyan 2016
        Test rigid or more or less flexible, either completely chitinoid or comprising recycled organic or mineral particles held together by an organic cement, or composed of self-secreted chitinoid or siliceous elements; always rounded in radial symmetry but varying in height from flattened saucer-shaped, hemispheric or more elongated to egg-shaped; pseudostome circular or lobed, surrounded by a collar; produce thick, digitate pseudopodia.

      2. Difflugina Meisterfeld 2002, sensu Kosakyan et al. 2016
        Test either completely chitinoid or comprising organic or mineral particles, or recycled diatom frustules, scales or plates (often from Euglyphida), or composed of siliceous, calcite or chitinoid self-secreted plates (idiosomes) held together by an organic cement; may produce thick, digitate pseudopodia, or move using a flattened, disc-like hyaline projection.
        Heleopera sphagni Leidy 1874:  Test reinforced with mineral particles, slit-like aperture, numerous small digitate pseudopodia; with symbiotic Chlorella.

      3. Phryganellina Bovee 1985
        Test proteinaceous, with calcified inner layer, or completely chitinoid with recycled mineral or organic particles; pseudopodia conical, pointed, consist solely of the hyaloplasm, sometimes branched and may anastomose. Cryptodifflugia, Meisterfeldia, Phryganella, Wailesella.

  2. Order Euamoebida Lepşi, 1960, sensu Smirnov et al. 2011
    Naked amoebae with tubular, sub-cylindrical pseudopodia (or the entire cell is monopodial and sub-cylindrical); no alteration of the locomotive form; no adhesive uroidal structures; sorocarpic development in some species.

    Suborder 1. Amoebina Cavalier-Smith, 2016
    Suborder 2. Nolandina Cavalier-Smith, 2016

  3. Order Leptomyxida Pussard and Pons, 1976, sensu Smirnov et al. 2017
    Naked amoebae with locomotive form altering from a flattened expanded or reticulate one to a sub-cylindrical monopodial one when in rapid movement or under specific conditions; adhesive uroidal structures always present. Flabellula, Gephyramoeba, Leptomyxa, Rhizamoeba.
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