world of amoeboid organisms

Menu
Gocevia obscura
Gocevia obscura
Gocevia obscura, 52 and 43 µm, the same specimen

Gocevia obscura (Penard, 1902)

Diagnosis: amoeba more or less spherical in shape, with a central granular hump, partly or completely surrounded by a distinct hyaline margin; surface with a heavy covering of refractive mineral grains, which individually are clear or yellowish but give the cuticle a blackish appearance; cuticle is in rest spherical or ovoid; hyaline zone often irregular in outline with conical or digiform subpseudopodia and trailing filaments; cells uninucleate. Cysts observed.

Dimensions: Penard (1902): 25-30 µm, active up to 50 µm; Hoogenraad & De Groot (1940): 67-100 µm; my measurements 43-66 µm.

Ecology: fresh water, in sediments of clear water. Spiegelplas, Kootwijk, The Netherlands, Weser, Germany. Not common, but probably easily overlooked in its resting form. The species easily multiplies in wet mounts kept in a humidity chamber.

Remarks: the dense layer of mineral grains is supposed to be a flexible protection for the amoeba. The membrane resembles at first sight the shell of a Pseudodifflugia species.
This amoeba was described by Penard (1902) as Cochliopodium obscurum and placed in the genus Gocevia by Valkanov (1932). The name Gocevia obscurum is not correct and should be replaced by Gocevia obscura (Hoogenraad & De Groot, 1940).

Gocevia obscura
Gocevia obscura
Gocevia obscura
Gocevia obscura
Gocevia obscura, 67 µm, the same specimen changing within a minute
Gocevia obscura
Gocevia obscura
Gocevia obscura
The same specimen with different plasma shapes
Gocevia obscura
Gocevia obscura
Cell 35 µm in diameter and 23 µm high (bar = 10 µm)
Gocevia obscura
Drawing by Penard, in Faune Rhizopodique du Bassin de Léman, 1902
Gocevia obscura
Gocevia obscura, 58 µm
Gocevia obscura
Gocevia obscura, 66 µm
Recent posts

Polychaos spec.

Polychaos spec. Polychaos spec. Diagnosis: Large amoeba with an irregular more or less polypodial shape during slow locomotion; uroid finely papillated, usually very large fasciculate

Read More »

Spiculophrys

Genus Spiculophrys Zlatogursky, 2016 Diagnosis: Centrohelids lacking silica scales but with numerous thin, pointed organic (without any traces of silica) scales tapering towards acute apices. 18S

Read More »

Acanthocystis drakena

From Zlatogursky, 2016 Acanthocystis drakena Zlatogursky, 2016 Diagnosis: Cells are 21.1-30.5 µm (ca. 26.7) in diameter. Cell is covered with oval plate-scales having a margin

Read More »

Choanocystis symna

From Zlatogursky, 2014 Choanocystis symna Zlatogursky, 2014 Diagnosis: Cell body ca. 6.7 µm in diameter. Axopodia three–five times longer than a cell diameter. Plate-scales dumbbell-shaped

Read More »

Acanthocystis costata

From Zlatogursky, 2014 Acanthocystis costata Zlatogursky, 2014 Diagnosis: Cell body ca 9.5 µm in diameter. Axopodia 2–3 times longer than cell diameter. Length of spine-scales

Read More »

Kinetocyst

Left: ultra-structure of a kinetocyst of Raphidiophrys contractilis); right: two kinetocysts in an axopodium. Kinetocysts In centrohelid heliozoa, extrusomes are called kinetocysts, and are present

Read More »