Microworld

world of amoeboid organisms

Menu

Thecamoeba aesculea Kudryavtsev and Hausmann, 2009

Diagnosis: Measured length of the locomotive form 70-119 µm (average 101.5 µm) (n = 60); breadth – 56-117.5 µm (average 80.4 µm); length : breadth ratio – 0.81-1.93 (average 1.29). Spatulate during locomotion, sometimes slightly posteriorly tapering and almost fanshaped. Dorsal surface with 2-5 longitudinal folds and numerous irregular wrinkles, especially in the uroidal part. Single vesicular nucleus 16-22 µm in diameter (average 18.5 µm); spherical central non-homogeneous nucleolus 7.5-14.4 µm in diameter (average 10.4 µm) (n = 35).
Ultrastructure: Glycocalyx up to 33 nm thick, consisting of a basal electron-dense layer 8-10 nm thick and a less dense outer layer about 10-15 nm thick, separated from the basal layer by an 8-10 nm thick electron-transparent space.

Observed habitat: Dry epiphytic mosses and bark surface of Aesculus hippocastanum in Saint-Petersburg, northwestern Russia.

Remarks: Almost identical to Th. sphaeronucleolus in the size, ultrastructure of nucleus and cytoplasm, but differs from the former type strain of this species (CCAP 1583/3) in having a broader locomotive form, spatulate or fan-shaped, rather than elongated drop-shaped; also differs in the structure of the glycocalyx. Slightly resembles Th. similis, but differs from this species in the structure of the nucleus and glycocalyx.

Literature: Kudryavtsev and Hausmann, 2009

Recent posts

Euglypha bryophila

Euglypha bryophila, after Brown, 1911 (L), from Ecuador (R) Euglypha bryophila  Brown, 1911 Diagnosis: (Original description) The test is very regular in form and subject

Read More »

Vernalophrys

(A) A Scenedesmus cell (arrow) is engulfed by a trophozoite. (B) Several Scenedesmus cells adhere to the surface of a plasmodium that has numerous vacuoles

Read More »

Actinosphaeridium spec.

Actinosphaeridium spec. Diagnosis: Cell surrounded by a membranous shell, with an outer mucous layer. Filopodia with granules, sometimes branching. Cell stalked. Ecology: I found this

Read More »

Euglyphidion

Euglyphidion enigmaticum – after Bonnet, 1960 Genus Euglyphidion Bonnet, 196 Diagnosis: Shell hyaline, ovoid, pseudostome circular or slightly elliptical. Shell loosely covered with two types of

Read More »

Leptomyxa spec.

Leptomyxa sp., slowly retracting in response to the light of the microscope Leptomyxa sp. Diagnose: This is a very large amoeba which I found in

Read More »

Zivkovicia spec.

Zivkovicia spec., 200 µm long; the right image is viewed through the aperture Zivkovicia spec.  Diagnosis: Shell pyriform, circular in oral view, with a clear

Read More »