Netzelia wailesi, with typical silicious nail shaped idiosomes - From Ogden and Meisterfeld, 1989

 

 

Netzelia wailesi (Ogden, 1980) Meisterfeld, 1984

 

Diagnosis: Shell transparant, 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) 73-112 µm.

 

Remarks: Questionable species. 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
Typical silicious nail shaped idiosomes - From Ogden and Meisterfeld, 1989
Netzelia wailesi
From Ogden and Zivkovic, 1983
Netzelia wailesi
From Ogden and Zivkovic, 1983
Netzelia oviformis
Netzelia oviformis
Two species, left: 113 µm, right: 66 µm, both from the Netherlands. The right one is embedded in glycerin, hence the hyaline structure; the dark objects are diatoms filled with water.
Netzelia wailesi
N. wailesi, smooth surface, image stacked from 21 images; 124 µm long.
Netzelia wailesi
Detail of the test above