Microworld

world of amoeboid organisms

Menu
Amoeba proteus
Amoeba proteus

Amoeba proteus (Pallas, 1766) Leidy, 1878

Diagnosis: Locomotive cells, often 220 to 760 µm in length; usually polypodial with one dominant pseudopodium, usually with dorsal and lateral folds or ridges; resting or well fed, cells irregularly rounded; floating forms wit h long radiating pseudopodia; cytoplasm granular in appearance, often with truncated bipyramidal or plate-shaped crystals; posterior uroid morulate; nucleus discoid or ovoid, sometimes with peripheral granules; nucleolar material often scattered.

Dimensions: 220-760 µm (mean 425 µm); nucleus 22-62 µm (mean 38-47 µm), discoid, often biconcave.

Ecology: freshwater and wet Sphagnum, in different types of water. Not rare.

Remarks: Though this amoeba has been described as uninucleate, I have often seen multinucleate specimens. In one sample there were amoebae with one nucleus and specimens with several nuclei (see the graph below.)

Amoeba proteus
Amoeba proteus, polytactic form 400 µm – quaking bog, Bert Bospad
Amoeba proteus, monotactic form, with two nuclei
Amoeba proteus, c. 830 µm long
Amoeba proteus
Amoeba proteus
Nucleus c. 42 µm, and the same nucleus in lateral view
Amoeba proteus
Amoeba proteus
Nucleus, lateral view
Amoeba proteus
Amoeba proteus
Nucleus, lateral view
Amoeba proteus
Amoeba proteis
Nucleus, irregular outline
Amoeba proteus
Amoeba proteus
Nucleus, lateral view, 40 µm, nucleus, lateral view, 42 µm
Amoeba proteus

 

Amoeba proteusA-C polypodial locomotion; D monopodial locomotion; E amoeba in preparation for division; bipyramidal crystal; G plate-shaped crystal; clustered crystals.
Amoeba proteus
floating form; B amoeba changing from floating form to Cnumber of nuclei per amoeba; E-N different shapes of nuclei: G-N lateral view.
Recent posts

Apolimia

A. rotundistoma, from Korganova, 1987 Genus Apolimia Korganova, 1987 Diagnosis: Shell ovoid, quite large, opaque, round in cross section, densely covered with round or oval

Read More »

Erugomicula

E. bidens, 315 and 270 µm, Naardermeer, the Netherlands Genus Erugomicula Nasser, Gregory, Singer, Patterson and Roe, 2021 Typespecies: Erugomicula bidens (Penard, 1902) Diagnosis: laterally-compressed,

Read More »

Erugomicula bidens

Two shells from the same sample, 310 µm (Naardermeer, Netherlands) Erugomicula bidens (Penard, 1902) Basionym: Difflugia bidens Penard, 1902 Diagnosis: Test ovoid, compressed in cross-section,

Read More »

Cylindrothecina

Infraorder Cylindrothecina González-Miguéns et al., 2022   Diagnosis:  can be diagnosed by its specific sequences of the mitochondrial and nuclear DNA  markers (COI, NADH and

Read More »

Organic-walled species

Specimen with an optical cross-section of the peduncle (left) Organic-walled species Diagnosis: Multinucleated organic-walled monothalamous foraminifera. Test spherical to oval shaped, with a hyaline, flexible,

Read More »

Velamentofex tyrolensis

V. tyrolensis, two specimens Velamentofex tyrolensis Völcker and Clauß, 2020 April 2022, I found two specimens in a sample from the pond in Crailoo, Netherlands. I could

Read More »

Raphidiophrys spec. nov.

Raphidiophrys n. sp. Raphidiophrys n. sp. Diagnosis: Plate-scales canoe-shaped, elongated, with tapering, rounded poles, slightly curved upwardly. Light microscopically, these plate-scales show a clear rim;

Read More »

Lacogromia spec. Naardermeer

Lacogromia sp., Naardermeer, the Netherlands, 2022 (n=nucleus) Lacogromia sp. Six living specimens were found in an old sediment sample from a freshwater ditch in nature

Read More »

Sphenoderia rhombophora

S. rhombophora , after Bonnet, 1966 Sphenoderia rhombophora Bonnet, 1966 Diagnosis: Test hyaline, ellipsoidal, very slightly compressed. Fundus relatively narrow. Pseudostome largely truncated. Neck very

Read More »

Sphenoderia ovoidea

S. ovoidea , after Jung, 1942 Sphenoderia ovoidea Jung, 1942 Diagnosis: Shell with four layers of plate-scales. Distinguished from S. fissirostris by the ovoid tapering

Read More »