world of amoeboid organisms

Centropyxis elongata
Centropyxis elongata
C. elongata, Croatia, Cave

Centropyxis elongata   (Penard, 1890) Thomas, 1959

Diagnosis: Test in ventral view elliptic, elongated with almost parallel or slightly tapering lateral sides towards the aperture; test covered with irregular, transparent, thin, often flat xenosomes; posterior region in lateral view slightly inflated; aperture circular or semicircular, strongly biased towards the anterior margin, occupying a third of the entire length of the shell, commonly encrusted with mineral particles along the outer contour.

Dimensions: Length of test: Penard (1890) 60-75 μm, Thomas (1959) 56-65 μm, Lüftenegger et al. (1988) 47-63 μm (n=30); width of test: Penard 25-40 μm, Thomas 29-33 μm, Lüftenegger et al. 29-36 μm; width of aperture: Thomas 18-20 μm, Lüftenegger et al. 15-20 μm.

Ecology: Sphagnum, soils, humus.

Centropyxis elongata
C. elongata, after Penard, 1890 (upper row) and Thomas, 1959 (lower row)
Centropyxis elongata
C. elongata, after Lüftenegger et al., 1988


Lueftenegger, G., Petz, W., Berger, H., Foissner, W. and Adam, H.: Morphologic and Biometric Characterization of Twenty-four Soil Testate Amoebae (Protozoa, Rhizopoda) – Arch. Protistenkd. 136 (1988): 153-189.

Thomas, R. (1959): Les Thécamoebiens muscicoles et terricoles: notions d’écologie générale et comparative. – P. Soc. Linn. Bordeaux 98: 27-53.

Recent posts


K. marinus, after Jepps, 1934 Kibisidytes marinus Jepps, 1934 Diagnosis: Small amoeboid organism occurring in the sea, attached to the surface film or to some

Read More »


P. aeris from Dumack et al., 2000 Phaeobola Dumack et al., 2000 Diagnosis: Cells roundish to oval shaped. Shell colorless to amber-colored, rough surface, few

Read More »

Rhizaspis armata

R. armata, 68 µm long, excl. spines – Laegieskamp Rhizaspis armata (Lauterborn, 1901) Dumack et al., 2021 Basionym: Pamphagus armatum Lauterborn, 1890 Diagnosis: Theca membranous,

Read More »

Rhizaspis spinosa

The original description with original drawings, Penard, 1890. Rhizaspis spinosa (Penard, 1890) Dumack et al., 2021 Basionym: Trinema spinosum Penard, 1890 Diagnosis: Theca membranous, ovoid

Read More »

Difflugia “pseudoclaviformis”

Difflugia “pseudoclaviformis”, front and side view, 424 µm Difflugia “pseudoclaviformis” Diagnosis: Shell pyriform, compressed, with a more or less pronounced aboral protuberance; shell composed of

Read More »

Difflugia from Lolo Pass

Shells 461-448 µm, stacked image. I found this large en remarkable shells in sediment of a small mountain lake near Lolo Pass, Montana USA. It differs

Read More »

Foraminifer drome

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

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 »