Ripella Smirnov, Nassonova, Chao et Cavalier-Smith, 2007

Patsyuk, M. K., 2016, New Finds Of Naked Amoebae (Protista) In Water Reservoirs Of Ukraine, Vestnik Zoologii 50 (4), pp. 291-300 : 293-294

Genus Ripella Smirnov, Nassonova, Chao et Cavalier-Smith, 2007

The amoebae belonging to the genus Ripella are of the fan-shaped morphotype, small, disc-like. The frontal area of the hyaloplasm is well-defined. They move relatively fast. The amoebae never form subpseudopodia and dorsal ridges. In this genus, no specific uroidal structures are seen. The cell’s posterior can be smooth, conical, or elongated. The nucleus is single.

Species of the genus were found in the water bodies of Europe, North America, India ( Page, Siemensma, 1991).

The amoebae we found belong to the fan-shaped morphotype ( fig. 3 ). They are small, the posterior of the cell is a half-circle. The hyaloplasm occupies about a half of the cell’s area. The posterior of the cell, where the granuloplasm is located, contains the contractile vacuole. There are no uroid structures.

The length of the cell is 8-16 µm, the width is 16–30 µ, the L/B ratio is 1.5–1.7.

The single nucleus is nearer to the frontal area of the hyaloplasm. Its diameter is 2.3–3 µm.

The floating form is of the radial type with short pseudopodia stemming from the central mass of the cytoplasm.

In the cultures, we did not observe cysts.

Previously we collected the species in the water bodies of Zhytomyr and Volyn Polissya ( Patcyuk, Dovgal, 2012). Here we report the new localities: Maryanivka village ( Vasilkiv District , Kyiv Region), the rivers Dnipro and Ingulets (Kherson Region) .

Figures

Fig. 3. Ripella sp.: 1–2 — locomotor forms, ×1240.