Microworld

world of amoeboid organisms

Menu
Frenzelina
Frenzelina reniformis

Genus Frenzelina Penard, 1902

Diagnosis: Cell usually covered with a thin membranous test, which is hemispherical or nearly spherical, with a small or large aperture; very small mineral grains are loosely attached to the membrane; test in dorsal view usually elliptical; fine filopodia which pass the aperture in a stalk or bundle which can be relatively long; filopodia can be very numerous and branching; aperture flexible, circular to elliptical, sometimes rapidly changing; aperture somewhat tubular with a thickened rim; nucleus vesicular with central nucleolus.

Remarks: Two species have been described. The type-species is Frenzelina reniformis, described by Penard (1902) from some specimens collected from one single location. Some years later Hoogenraad (1910) described  Frenzelina minima. According to my observations, this species is identical with Frenzelina reniformis.
This species can be very variable. Within a sample one can observe naked specimens, specimens with a light covering and specimens with a heavy covered membrane. See Schönborn and Badewitz (2008).
Frenzelina can be very common in several types of fresh water.

Frenzelina - Ferry Siemensma
Frenzelina reniformis, 33 µm
Frenzelina
Frenzelina
Cell 30 µm
Frenzelina
Frenzelina
Naked cell, side view; pseudostome arrowed
Frenzelina
Frenzelina reniformis, with nucleus visible
Frenzelina
Frenzelina reniformis, two specimens, the upper one as cyst
Frenzelina
Frenzelina
Frenzelina reniformis, naked form
Recent posts

Zivkovicia compressoidea

Z. compressoidea, a-b after Chardez, 1958; c after Jung, 1942 Zivkovicia compressoidea  (Jung, 1942) new.comb. Basionym: Pontigulasia compressoidea Jung, 1942 Diagnosis: Shell ovoid and compressed,

Read More »

Zivkovicia flexa

Z. flexa, from Cash and Hopkinson, 1909 Zivkovicia flexa  (Cash and Hopkinson, 1909) Ogden, 1983 Basionym: Pontigulasia compressa var. flexa  Cash and Hopkinson, 1909 Diagnosis:

Read More »

Lagenodifflugia epiouxi

L. epiouxi, after Chardez, 1984 3 Lagenodifflugia epiouxi (Chardez, 1983) new comb. Basionym: Pontigulasia epiouxi Chardez, 1983 Diagnosis: Shell elongate, circular in cross-section or very

Read More »

Centropyxis lapponica

Centropyxis lapponica, after Grospietsch, 1954 Centropyxis lapponica  Grospietsch, 1954 Diagnosis: Shell nearly circular in circumference, without spines. Aperture clear square with rounded corners. Shell viewed

Read More »

Chaos spec. 6

Chaos spec., Crailoo, 2021 Chaos spec. This specimen was found in a samples from Crailoo, Netherlands. It was remarkable because of the absence of crystals.

Read More »

Bullinularia maxima

Bullinularia maxima – from Bobrov and Mazei, 2020 Bullinularia maxima Bobrov et Mazei, 2020 Diagnosis: Shell brown, opaque, elliptical in ventral view; ventral surface is

Read More »

Bullinularia macroporum

Bullinularia macroporum – from Bobrov and Mazei, 2020 Bullinularia macroporum Bobrov et Mazei, 2020 Diagnosis: Shell yellow-brownish, transparent, circular in ventral view; ventral surface is

Read More »

Nebela golemanskyi

N. golemanskyi, after Todorov, 2010 Nebela golemanskyi Todorov, 2010 Diagnosis: Shell large, colourless and pyriform, with a distinct short neck about one fourth of the

Read More »

Nebela nebeloides

N. nebeloides, after Gauthier-Lièvre and Thomas, 1958 Nebela nebeloides (Gauthier-Lièvre and Thomas, 1958) Todorov et al., 2010 Basionym: Difflugia nebeloides Gauthier-Lièvre and Thomas, 1958 Diagnosis:

Read More »