Penard Labs

The Fascinating World of Amoebae
Difflugina Meisterfeld 2002
Test either completely chitinoid or comprising mineral particles, diatom frustules, or recycled scales or plates, or composed of siliceous, calcite, or chitinoid self-secreted plates (idiosomes) held together by an organic cement; granular, digitate pseudopodia.

1. Difflugiidae Wallich 1864
Aperture terminal; of variable shape.

1.1. Difflugia Leclerc 1815
Test composed of agglutinated mineral particles or diatom frustules in a structured or sheet-like organic cement.
Difflugia acuminata Ehrenberg 1832

Difflugia SEM Electron Microscope
Difflugia SEM Electron Microscope
Difflugia SEM Electron Microscope
Difflugia SEM Electron Microscope
Difflugia sp.

Difflugia Organic cement SEM Electron Microscope
Difflugia organic cement

2. Centropyxidae Jung 1942
Aperture eccentric; often invaginated.

2.1. Centropyxis Stein 1857
Centropyxis EM Electron Microsope
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Centropyxis aculeata Ehrenberg, 1838
A sharp xenosome is inserted into the tip of the horns.

3. Trigonopyxidae Loeblich and Tappan 1964
Aperture centric; often invaginated.

3.1. Trigonopyxis Penard 1912
Aperture irregular, frequently triangular, always surrounded by a ring of organic cement.
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Trigonopyxis arcula (Leidy 1879) Penard 1912

4. Hyalospheniidae Schulze 1877, emend. Kosakyan and Lara 2012
Test rigid, chitinoid, clear, oval- or flask-shaped, aperture terminal bordered with an organic collar. Test is either a completely self-secreted organic matrix or with additional self-secreted silicious plates or with recycled shell plates of small euglyphids or other similar material such as diatom frustules.

4.1. Hyalosphenia Stein 1859
Species with compressed, chitinoid transparent test with no foreign material; pseudostome often with a thickened lip.
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Hyalosphenia elegans Leidy 1874

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Hyalosphenia papilio Leidy 1874
Common in wet sphagnum; always with Chlorella symbionts.

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Hyalosphenia cuneata Stein 1857

4.2. Quadrulella (Wallich 1863) Cockerell 1909
Test composed of an organic matrix with silicious, quadrangular plates.
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Quadrulella sp.

5. Nebelidae Taranek 1882
Shell composed of shell plates of small euglyphids or plates of Quadrulella or diatom fragments.

5.1. Nebela Leidy 1874
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Nebela tubulosa Penard 1902

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Nebela galeata Penard 1890

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Nebela sp.

5.2. Padaungiella Lara and Todorov 2012
Test lageniform with a distinct elongated neck. Laterally compressed with the exception of two species (P. nebeloides and P. pulcherrima, which have a circular closs section). The pseudostome ranges from linear to strongly curved, with or without thickened organic lip. Test hyaline or slightly yellowish-brownish, composed of circular to elongated test plates predated from small euglyphids. One notable exception is N. nebeloides that can use mineral particles and produce a test somewhat similar to that of the genus Difflugia.
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Padaungiella lageniformis (Penard 1890) Lara and Todorov 2012

5.3. Argynnia Vucetich 1974 (incertae sedis)
Test compressed, aperture surrounded with siliceous plates. Shell greyish, composed of various euglyphid plates, mixed with diatom fragments and mineral particles porous cement. The structure of the test is intermediate between Nebela and Difflugia. Nucleus ovular.
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Argynnia dentistoma Penard, 1890

6. Lesquereusiidae Jung 1942
Test composed of endogenous siliceous rods, diatom frustules or collected mineral particles or a mixture of both. Idiosomes and xenosomes agglutinated by a mesh-like organic cement.

6.1. Lesquereusia Schlumberger 1845
Test with attached neck.
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Lesquereusia spiralis Ehrenberg 1840

6.2. Netzelia Ogden 1979
Aperture lobed.
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Netzelia tuberculata Wallich 1864

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Netzelia oviformis (Cash 1909) Ogden 1979

7. Heleoperidae Jung 1942

7.1. Heleopera Leidy 1879
Test composed of collected euglyphid body plates, mineral particles, or diatoms; laterally compressed. Aperture terminal, lenticular or slit-like.
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Heleopera sphagni Leidy 1874
Common in wet sphagnum; always with Chlorella symbionts.