THECAMOEBIDAE Schaeffer, 1926

Patsyuk, M. K., 2016, New Finds Of Naked Amoebae (Protista) In Water Reservoirs Of Ukraine, Vestnik Zoologii 50 (4), pp. 291-300 : 295-296

Family THECAMOEBIDAE Schaeffer, 1926

Genus Thecamoeba Fromentel, 1874

Species of the Thecamoeba do not form pseudopodia. The cell moves as a whole, it is capable to form dorsal ridges and hyaloplasm folds. These amoebae belong to the striate or rugose morphotypes. Most species of the genus lack uroidal structures; for some, bulbose or morulate uroids were described. Thecamoeba species have single nuclei.

Thecamoeba can live in fresh and sea water and in soil ( Alimov, 2000).

The genus is known from the water bodies of Asia, Europe, North America, India ( Page, Siemensma, 1991).

Flattened amoebae, oval in shape, of the striate morphotype ( fig. 5 ). The cell has smooth edges. When in motion, the hyaloplasm forms folds and parallel dorsal ridges, and the amoeba’s shape can change: an elongated, oval amoeba pulls itself to its frontal edge, the cell becomes a half-circle, the hyaloplasm edges almost the whole cell from both sides, and then the cell becomes slender again.

There are no differentiated uroidal structures. The single contractile vacuole is in the central region of the granuloplasm. The cell length is 25–40 µm, width is 12–18 µm, the L/B ratio is 1.5–2.5; the nucleus is vesicular, 1.5–2.5 µm in diameter.

The species is first reported from the Dnieper River in the vicinities of Kherson (Kherson Region) .

Figures

Fig. 5. Thecamoeba sp.: 5–6 — locomotor forms, ×1240.