Korotnevella hortobotanici, Udalov & Völcker, 2022

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 : 21-23

Korotnevella hortobotanici sp. nov.

Locomotive cells have the shape of an irregular rectangle ( Fig. 2L, N ) or triangle ( Fig. 2M ). Cells form subpseudopodia ( Fig. 2L, N ) during locomotion. Length of locomotive form is 57–106 μm (average 81.5 μm), breadth is V). Arrows indicate a direction of cell movement. Abbreviations: CV, contractile vacuole; L, lacuna; LS, layer of scales; N, nucleus; Nu, nucleolus; SRB, spherical refractile body. Scale bars= 10 μm

Fig. 3 Scanning (A, B, D, H,

K) and transmission (C, E–G,

I, J, M) electron micrographs of scales of Korotnevella spp.

A region of cell coverings of critical point dried cell showing scales, SEM (A, B, D, H, K),

and whole mounts of air-dried cells, TEM (C, E–G, I, J, M).

Scales of Korotnevella sp. 1

(A–C). Scales of Korotnevella

sp. 2 (D–G). Scales of Korotnevella hortobotanici sp. nov.

(H–J). Scales of Korotnevella

sp. 3 (K, M). Abbreviations:

AC, apical column; DS, dishshaped scale; LB, latticework basket; BP, basal plate; Fi,

filaments; LC, lateral column;

PF, perforated flange; R, rim; S,

spike. Scale bars= 0.1 μm (A,

B, D, H, K, M), 0.2 μm (C, I),

0.5 μm (E–G, J)

20–61 μm (average 41.7 μm), L/B ratio is 1.2–3.8 (average 2.1). Single nucleus of ellipsoid shape ( Fig. 2M, O, P ) is 6.7–12.7 μm in length (average 8.0 μm) and 5.3–7.9 μm in breadth (average 6.4 μm). The nucleolus has either a spherical shape ( Fig. 2P ) or, in some cells, consists of several pieces of different sizes and contains transparent lacuna ( Fig. 2O ). The diameter of the nucleolus is 3.0–5.0 μm (average 4.0 μm), while the cytoplasm contains numerous spherical refractile bodies ( Fig. 2P ).

Cysts were never observed.

Cell surfaces are covered with two types of scales: large basket-shaped and small dish-shaped scales (Fig. 3H, J). The length of the basket-shaped scales is 528–773 nm (average 625.1 nm); breadth 235–344 nm (average 297.9 nm); and height 250–366 nm (average 308 nm). The length of the dish-shaped scales is 97–162 nm (average 132 nm); breadth 43–112 nm (average 75 nm); and height 16–30 nm (average 23 nm). Large scales include basal plate, perforated flange, and latticework basket in the shape of a closed hammock, which is supported by two apical and four lateral columns (Fig. 3H, I) and two spikes of equal size (Fig. 3I). The latticework basket has two rows of large meshes adjoining the upper part of the scale, and many meshes are located in its central part (Fig. 3H).

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,