Korotnevella sp. 2

Udalov, Ilya A. & Völcker, Eckhard, 2022, Is scale’s structure still a good character to delimitate species of Amoebozoa? case of the genus Korotnevella (Amoebozoa, Dactylopodida), Organisms Diversity & Evolution (New York, N. Y.) 22 (1), pp. 17-33 : 24

Korotnevella sp. 2

Cells in their cultures are almost always stationary or moving slightly with no certain direction. Very rarely, locomotive cells are wide and flattened and have the shape of an irregular oval ( Fig. 2G ) or rectangle ( Fig. 2H ). In some cells, the width exceeds the length ( Fig. 2G ). During locomotion, cells form short subpseudopodia ( Fig. 2G, H ). Length of the locomotive form is 74–113 μm (average 94.7 μm), breadth is 61–95 μm (average 77.4 μm), and L/B ratio is 0.8–1.6 (average 1.3). The single nucleus has the shape of an irregular sphere ( Fig. 2I, K ) or ellipsoid ( Fig. 2J ). It is 10.4–11.9 μm in length (average 11.2 μm) and 9.5–9.6 μm in breadth (average 9.6 μm). The nucleolus often has a simple spherical shape ( Fig. 2I ), but some cells have nucleoli with a rather remarkable structure ( Fig. 2J, K ). Some nucleoli have big transparent lacuna ( Fig. 2J ), while nucleoli in some other cells are small and numerous, and usually also with transparent lacuna ( Fig. 2K ). The diameter of the nucleolus is 5.3–6.6 μm (average 5.9 μm).

Cysts were never observed.

Cell surfaces are covered with two types of scales: large basket-shaped and small dish-shaped (Fig. 3D, G). The length of the basket-shaped scales is 461–661 nm (average 425.4 nm); breadth 247–339 nm (average 289 nm); and height 110–179 nm (average 142 nm). The length of the dish-shaped scales is 77–135 nm (average 112 nm); breadth 38–77 nm (average 57 nm); and height 12–26 nm (average 20 nm). Large scales include basal plate, perforated flange, and latticework basket in the shape of a closed hammock, supported by two apical and ten, rarely eight or twelve, lateral columns and two spikes (Fig. 3D–G). The length of the spikes varies within one cell: some scales have two elongated spikes (Fig. 3E), others have one short spike while the other is elongated (Fig. 3G), and, finally, the third category of scales has two equally short spikes (Fig. 3F). The elongated spikes are of approximately the same width along their entire length and are bluntly cut off at their ends (Fig. 3E, G).

Figures

Fig. 2 Light micrographs of Korotnevella sp. 1 (A–F), Korotnevella sp. 2 (G–K), K. hortobotanici sp. nov. (L–P), and Korotnevella sp. 3 (Q–V). Locomotive forms in a Petri dish, phase contrast (A–D, G, H, L–N, Q–S). Nucleus, DIC (E, I–K, O, P, T, U). Cyst, DIC (F,