Microworld

world of amoeboid organisms

Netzelia wailesi
Netzelia wailesi, Naardermeer, Netherlands, 2021

Netzelia wailesi (Ogden, 1980) Meisterfeld, 1984

Diagnosis: Shell transparent, ovoid, tapering slightly or more markedly to the aperture; circular in cross section, robust; outline regular, constructed of flat mineral grains, fragments of diatom frustules and idiosomes to give a smooth surface. Organic cement building-units as part of shell matrix. Aperture with four or five indentations, but can be roughly circular, surrounded by a thin necklace of mineral particles. Single ovular nucleus 24-28 µm in diameter with many nucleoli, it lies within a halo, in a region of dense endoplasmic reticulum. A single contractile vacuole lies just anterior to the nucleus.The cytoplasm is often seen centrally with epipodes attaching it to the fundus of the shell. Stored reserve siliceous nails often occupy a region anterior to the nucleus. Numerous lobose pseudopodia.

Dimensions: Ogden and Zivkovic (1983) length 73-112 µm. My measurements: length 113-124 µm, width 83 µm, nucleus 29 µm.

Remarks: Ogden (1980) creates a new name, Difflugia wailesi, for smaller specimens of N. tuberculata with a smooth outline and mainly composed of diatom frustules, earlier described as Difflugia tuberculata var. minor by Wailes (1919). In a later paper Ogden (1983), in contradiction to his earlier description and the main diagnostic character of the genus Netzelia, describes specimens of D. wailesi with shells mainly composed of flat pieces of quartz. He highlights the difficulty of differentiating the two species, based on the similarity of dimensions between specimens from several locations (e.g., 73-112 µm for D. wailesi and 96-152 µm for D. tuberculata).

Netzelia wailesi
Netzelia wailesi, preying on a filamental alga (the same specimen as above)
Netzelia wailesi
Netzelia wailesi
Nucleus (29 µm) and empty shell (113 µm)
Netzelia wailesi
Netzelia wailesi, with typical siliceous nail shaped idiosomes – From Ogden and Meisterfeld, 1989
Netzelia wailesi
Typical siliceous nail-shaped idiosomes – From Ogden and Meisterfeld, 1989
Netzelia wailesi
From Ogden and Zivkovic, 1983
Netzelia wailesi
From Ogden and Zivkovic, 1983
Netzelia wailesi
N. wailesi, smooth surface, image stacked from 21 images; 124 µm long.
Netzelia wailesi
Detail of the test above
Netzelia wailesi
Ferry Siemensma, created February 23, 2019; last modified July 08, 2021
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