lorica and cyst
Amphitrema (am-fee-tree-ma) a testate amoeba with an organic test with (unusually) two apertures at opposite poles of the test. This test with encysted cytoplasm found among moss at the margins of the lake. Differential interference contrast. This image taken by Michele Bahr and David Patterson of material collected from the water column and the margins of Lake Toolik (Alaska, USA) in August, 2001. Image copyright: Michele Bahr and D. J. Patterson, used under license to MBL (micro*scope).
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Amphitrema
From the collection
Lake Toolik, Arctic Alaska
| Description of Amphitrema: Test: elliptical, compressed, attached a mixture of siliceous particles, diatom frustules or flagellate cysts, a patterned cement network can be seen sometimes by scanning electron microscopy. Pseudostomes: 2, at opposite ends, elliptical, with or without short collar. Only A. wrightianum and A. stenostoma have been studied in more detail. In these species the protoplast nearly fills test, many filopods from protoplast at pseudostomes, often branched, to 150 µm long. Nucleus: spherical, with few small nucleolar globules. Symbionts: zoochlorellae. Habitat: wet sphagnum, peat bogs; indicator species in palaeolimnology (Tolonen, 1985). Four species, type: Amphitrema wrightianum Archer, 1869. |
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