world of amoeboid organisms


Genus Dictyamoeba Berney, Bass & Geisen, 2015

Diagnosis: Multinucleate, highly branching and reticulate naked amoebae with slender, pointed, sometimes branched pseudopodia. Trophozoites moving too slowly to be seen in light microscopy. The main cell body is multiply branched and anastomosing even in its simplest form, and can grow into gigantic networks (up to several mm) with intersecting segments of varying width and numerous terminal branching areas. Abundant fine pseudopodia are concentrated mostly at the extremity of lateral and terminal branches, especially in complex networks, but can be formed anywhere around the cell body in simpler forms. Numerous contractile vacuoles observed everywhere in the network, but more commonly at intersections of the main branches. Movement of entire cells too slow to be directly observable. Cysts of varying sizes and shapes, the simplest ones rounded, the larger ones irregular inshape.

Type species: Dictyamoeba vorax

Dictyamoeba vorax Berney, Bass & Geisen, 2015

Diagnosis: Non-marine, with morphological characteristics of the genus. Size across between 30-300  µm in young trophozoites. Can survive on bacteria alone, but in that case retains a relatively simple form and medium size. Grows into a gigantic network in presence of yeasts, which are consumed very rapidly; in that case yeasts tend to be collected in clumps at nodes of the network before being consumed. When all food has been consumed, the whole network contracts simultaneously in different areas, leading to the formation the formation of very many cysts of all possible sizes and shapes, the position of which mirrors the original layout of the network.

Ecology: Garden soil sample with moss and lichens, Wales, UK.

Recent posts

Haplomyxa saranae

Haplomyxa saranae Dellinger, 2014 Diagnosis: cell body from small rounded (0.1 mm) to large elongated shape (up to 3.5 x 0.3 mm), usually flat but

Read More »

Haplomyxa spec.

Main cell body Haplomyxa spec. Description: The cell has a central body from which numerous granuloreticulopodia emerge. The cell body can be small or large,

Read More »

Haplomyxa spec.

Haplomyxa spec. These video’s show an undescribed Haplomyxa species which was collected from a mesotrophic freshwater pond in the Netherlands, January 2020, and kept in Petri

Read More »


Fritz Schaudinn (1871 – 1906) was a German zoologist. He was the co-discoverer of the causative agent of syphilis and did research on amoebas, particularly

Read More »

Alabasta longicollis

Alabasta longicollis, after Penard, 1890 Alabasta longicollis  (Penard, 1890) Diagnosis: Test pyriform, very elongated (3 times as long as wide), transparent, very little compressed, embedded

Read More »

Alabasta kivuense

Alabasta kivuense, after Gauthier-Lièvre and Thomas, 1961 Alabasta kivuense  Gauthier-Lièvre and Thomas, 1961 Diagnosis: In frontal view, the test is finger-shaped with subparallel sides, the

Read More »