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Claparedellus lachmannii
Claparedellus lachmannii, common shape (Riedensee)

Claparedellus lachmannii  Khanipour Roshan and Clauß, 2020

Diagnosis: Multinucleate organic-walled monothalamous foraminifera. Test spherical to elongated pyriform or irregularly shaped, with a hyaline, flexible, membranous wall, varying in thickness. Aperture terminal, straight or oblique. Peduncle relatively narrow, asymmetrical and surrounded by a hyaline peduncular sheath. Nuclei spherical, ovular, with a hemispherical eccentric nucleolus. Cytoplasm without crystals.

Description: The tests are spherical to ovoid or irregularly shaped, in fast locomotion elongated pyriform, free of agglutinated materials, with a rounded or conical proximal end, with a flexible, hyaline wall, variable in thickness (0.5-8.0 µm). The length of the test is 72-320 µm, with one terminal oblique aperture. Cells are multinucleate, with about 100 nuclei, 6.5-12.7 µm in diameter, with a singular hemispherical eccentric nucleolus lying close to the nuclear membrane. The test is colorless, cells may appear yellowish or brown due to ingested food particles. Almost all tests show bilateral symmetry. The cytoplasm is granular without any crystals, but with several food and some contractile vacuoles. The peduncle is more or less circular in cross section and relatively narrow, and surrounded by a hyaline sheath. Locomotive cells move slowly along a long and relatively thick extended pseudopodium, with several trailing pseudopodia.

Remarks: This species is morphologically almost identical with L. wageneri and L. paludosa, but differs in its habitat (soil and dry mosses vs. freshwater). It differs from L. paludosa also in the structure of the nuclei (one large peripheral nucleolus vs. several small nucleoli scattered throughout the nucleus), their number (≥ 100 vs. 1-30) and size (6.5-12.7 µm vs. 20-82 µm; reference for L. paludosa). It differs from Edaphoallogromia australica mainly in the size of the nuclei (6.5-12.7 µm vs. 3.5-6.8 µm) and the structure (one large peripheral nucleolus vs. several small nucleoli scattered throughout the nucleus; see above and Meisterfeld et al. 2001).

Ecology: Feeds on filamentous Klebsormidium, coccale algae, cyanobacteria, diatoms, rotifers and yeast. The holotype was isolated from biocrust in sand dunes along the shore of the Baltic Sea; northern Germany (N 54°09’10.7″N 11°41’25.9″E), June 2017. A second strain of C. lachmannii was found in Jüterbog, Germany, and cultured from dry moss growing on a tree (51°59’43.45″N 13°4’21.17″E), April 2018.

References: Siemensma et al., (in press). Broad sampling of monothalamids (Rhizaria, Foraminifera) gives further insight into diversity of non-marine foraminifera. Europ. J. Protozool.

Claparedellus lachmannii
C. lachmannii, note the thick test wall (Riedensee)
Claparedellus lachmannii
C. lachmannii, in locomotion to the right (Jüterbog)
Claparedellus lachmannii
C. lachmannii, moving to the right (Jüterbog)
Claparedellus lachmannii
C. lachmannii  (Jüterbog)
Claparedellus lachmannii
C. lachmannii, note the nuclei (Jüterbog)
Claparedellus lachmannii
C. lachmannii (Riedensee)
Claparedellus lachmannii
C. lachmannii, scalebar 10 µm (Riedensee)
Claparedellus lachmannii
C. lachmannii (Riedensee)
Claparedellus lachmannii
C. lachmannii, with peduncle in optical cross-section (Riedensee)
Claparedellus lachmannii
C. lachmannii, with trumpet-shaped peduncle (Riedensee)
Claparedellus lachmannii
C. lachmannii, empty membrane after the cytoplasm was pressed out (Riedensee)
Claparedellus lachmannii
C. lachmannii, nucleus (Jüterbog)
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