Microworld

world of amoeboid organisms

Menu
Arcella arenaria
Arcella arenaria, after Bonnet, 1964

Arcella arenaria  Greeff, 1866

Diagnosis: Shell always circular in apical view, more or less dome-shaped in lateral view; dorsal surface usually with slight folds, but very often flattened. Shell yellowish brown to dark brown in color. Aperture small, circular in shape, its diameter barely reaching 1/5-1/6 that of the shell. Many small pores, 8-28 in number, around the aperture. Height of the shell not less than 1/2 diameter of the shell. Neither remarkable border nor bosses around the lateral margin. Many nuclei present: the large ones usually 3 in number and arranged in an equilateral triangle, the small ones not constant in number, varying 3-5, arranged irregularly. The pseudopodia very short, 6 at most, many vacuoles developing along the ectoplasm.

Dimensions: In literature shell 75-130 µm in diameter, 21-50 µm in height, aperture 12-28 µm in diameter, pores 8-18.

Ecology: Mostly in dryer mosses; on Hypnum and Polytrichum, also on lichens on trees and between Sphagnum.

Remarks: This species resembles Arcella catinus Penard; it can also be confused with Arcella artocrea. The folding of the dorsal surface is most distinct in lateral view.

Arcella arenaria
Arcella arenaria
Arcella arenaria
Arcella arenaria
Recent posts

Foraminifer drome

Unknown species, collected from the river Drôme, France, 2021 Unknown species September 2021, I found three specimens of an agglutinated foraminifer in a sample collected

Read More »

Cyclopyxis spec

Cyclopyxis spec., 168 µm Cyclopyxis spec. Diagnosis: Shell circular in ventral and dorsal view, more or less hemispherical in lateral view (height/diameter ≈ 0.5); lateral

Read More »

Difflugia fallax

Difflugia fallax, from Penard, 1902 Difflugia fallax Penard, 1890 Diagnosis: Shell hyaline or yellowish-greenish, black at low magnification, round in cross section, formed of a

Read More »

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 »