Microworld

world of amoeboid organisms

Menu
Clathrella foreli
Clathrella foreli, with nucleus, cell body 36 µm, scales about 16 µm – Naardermeer

Genus Clathrella Penard, 1903

Diagnosis: Cell spherical, surrounded by a number of silicious, hyaline, colorless, bowl-shaped scales, with a minimum of six, loosely attached to each other. Filopodia extend through gaps between the scales. Pseudopodia filose, without granules, branching and when attached to the substrate also anastomosing. One vesicular nucleus.

Dimensions: 4-55 µm.

Ecology: Clathrella species are restricted to oligotrophic and mesotrophic water bodies. They occur not only in peat bogs, but also in streams and venns and lakes and ditches.
Penard found this amoeboid in Lake Geneva (Lac Léman), Switzerland, at a depth of 30-35µand at a single location along its shore. Hoogenraad found this species in 1914 in sediments of a Sphagnum bog, the Wisselsche Venn, in the Netherlands, where it was “very numerous”. His observations agreed well with those of Penard. I have found this species at several locations in the Netherlands and also in North- and South-America. Recently (2014) this species has also been observed in Germany by Eckhard Voelcker and Steffen Clauss (pers. comm.), in Lake Baikal by Cavalier-Smith and Chao (2012), probably in India (Anagha Datar, pers. comm.) and in Japan (see misidentification here). This species also seems to have been seen by Stepanek (1952).
One might think that Clathrella is very rare because in the century of its discovery and description it has only been recorded once (Hoogenraad & De Groot, 1940), but the past years I’ve found this species frequently in the Netherlands and in samples from Peru, Montana and Florida, which shows that this species isn’t very rare, but easily overlooked (Siemensma, 2014).

Remarks: I have found specimens with 6 scales each, building a cube or dice and specimens which are about 4 µm small. Just look at the composition below:

These three specimens were all in the same wet mount (all on scale, photomicrographs  were combined with Photoshop). According to Penard the small ones are young ones (see also his drawings below), but that is hard to accept (Meisterfeld, pers. comm.). I’ve cultured the large form without ever observing smaller forms. I’ve seen samples with only the dice-shaped specimens.
In 2013 Eckard Voelcker made some SEM-photomicrographs from dried shells and later he succeeded in preparing living cells for the SEM which you can see here!
Our conclusion is that there are at least three different species, which we want to describe when we have more information. For the moment I call the different species as follow:
Clathrella foreli: the large form, 25-50 µm;
Clathrella “quadratus”: the cubic form, about 10 µm;
Clathrella “vegrandis”: the smallest form, 4-10 µm.

Clathrella foreli
Drawing Penard in Les Sarcodinés des Grands Lacs, 1905.
Clathrella foreli
Original drawing for the book of Hoogenraadand De Groot (1940), collection Ferry Siemensma
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 »