renzelina reniformis
renzelina reniformis
Frenzelina reniformis, at two diffferent levels

Frenzelina reniformis Penard, 1902

Diagnosis: test membranous, semi-hemispherical or hemispherical, usually with an open ventral face; very small mineral grains, loosely attached to the membrane; test in dorsal view usually elliptical; test not always present; plasmabody broad-elliptical or kidney-shaped; aperture flexible, commonly a short small tube; numerous fine filopodia, often in a bundle; nucleus vesicular with one central nucleolus.

Dimensions: 26-30 µm (Penard); my measurements: shell 18-33 µm.

Ecology: fresh water, in ditches and lakes, between sphagnum and debris. Very common.

Remarks: Naked specimens closely resemble Lecythium-species, which also have a flexible aperture. Naked cells can have a thick layer of mucous to which small particles adhere.

Frenzelina reniformis - Ferry Siemensma
Empty shell, c. 33 µm
Frenzelina reniformis
Drawing: from Penard (1902)
renzelina reniformis
Filopodial network
renzelina reniformis
renzelina reniformis
Two cells from the same location
Frenzelina reniformis
renzelina reniformis
Frenzelina reniformis, just like Penards drawing above (l) and cell attached to the cover glass (r)
Frenzelina reniformis
Frenzelina reniformis
Dividing specimen, without test; kidney-shaped specimen without test
Frenzelina reniformis
Frenzelina reniformis
Small cylindrical aperture and bundle of filopodia
Frenzelina reniformis
Frenzelina reniformis
Pseudostomal view; lateral view
Frenzelina reniformis
Frenzelina reniformis
Cells about 24 µm, almost naked. Both cells from the same wet mount.
Frenzelina reniformis
Frenzelina reniformis, with filopodia, cell c. 28 µm.
Shell almost a complete sphere, with small pseudostome
Frenzelina reniformis
Frenzelina reniformis
The same specimen, changing its aperture within one minute.
Frenzelina reniformis
Frenzelina reniformis naked form
renzelina reniformis
Frenzelina reniformis
Frenzelina reniformis, nucleus visible
Frenzelina reniformis
Naked specimen
Frenzelina reniformis
Two naked specimens from the same wet-mount-culture. Notice the difference in size.
Frenzelina reniformis
Frenzelina reniformis, 26 µm
Frenzelina reniformis
Frenzelina reniformis, with small tubular pseudostome; body 22 µm
Recent posts

Difflugia ampla

Difflugia ampla, after Rampi, 1950 (l) and Gauthier-Lièvre et Thomas, 1958 (r) Difflugia ampla Rampi, 1950 Diagnosis: Test broadly pyriform, with a wide and rounded

Read More »

Difflugia parva

Difflugia parva, from Gauthier-Lièvre et Thomas, 1958 Difflugia parva  (Thomas, 1954) Ogden, 1983 = Difflugia oblonga var. parva Thomas, 1954 Diagnosis: Test pyriform, tapering evenly from

Read More »