Netzelia corona
Netzelia corona with some spines and a number of teeth

Netzelia corona (Wallich, 1864) Gooma et al., 2017
Syn.: Protocucurbitella coroniformis Gauthier-Lièvre & Thomas, 1960

Diagnosis: Shell spherical to sub-spherical. The shell wall is composed of mineral grains, quartz and diatom  frustules, which are agglutinated together by an organic cement. The shell is ornamented by conical hollow spines at the posterior third. The aperture is circular, surrounded by a variable number of inward-oriented angular crenulations (tooth-like structures). Shells ornated with tuberculate structures similar to Netzelia tuberculata have been observed by Vucetich (1973) and Siemensma (2013).

Dimensions: 140-320 µm (Leidy); 200-250 µm (Penard); 180-310 µm (Awerinzew); 180-230 µm (Cash); 155-200 µm(Hoogenraad & De Groot); 80-380 µm (Lahr & Lopes); my measurements 105-193 µm, mean 156 µm.

Ecology: Freshwater, in different water types; in sediments, in sphagnum, on waterplants, often very common. This species has been found in icefield lakes high in the mountains (Monti 1906).

Remarks: Sometimes the shell has a tuberculate structure as in D. tuberculata. The number of conical spines I counted in Dutch specimen is commonly 4-6.

Netzelia corona
Netzelia corona
Shell, dorsal and apertural view
Netzelia corona Difflugia corona
Netzelia corona Difflugia corona
Small spine, 33 µm long and spine with a mineral grain in the opening
Netzelia corona
Drawing: Penard, in Faune Rhizopodique du Bassin du Léman, 1902
Netzelia corona
Aperture with 12 denticulate lobes.
Netzelia corona
Each lobe is a hollow structure at the outer most part.
Netzelia corona
Shell with tubercular structure
Netzelia corona
Shell with tubercular structure – stacked image
Netzelia corona
Shell with crenulate structure, drawing Vucetich, 1973.
Netzelia corona
Netzelia corona; collection of individuals to show the variation in size and form; in number, length and shape of the spines, and the like. All drawn to the same scale. In: Jennings, 1916.
Recent posts

Difflugia key bag-shaped

Tests that are bag or thumb-shaped Tests that are bag, finger or thumb-shaped.This group has no taxonomic significance. D. polliciformis D. lemani D. pecac D.

Read More »

Difflugia polliciformis

Difflugia polliciformis, after Van Oye, 1952 Difflugia polliciformis  Van Oye, 1958 Diagnosis: Test more or less thumb-shaped, without clear neck, chitinoid, mainly covered with very

Read More »

Difflugia australis

D. australis after Playfair, 1917 Difflugia australis (Playfair, 1917) Gauthier-Lièvre et Thomas, 1958 Syn.: Difflugia bacillariarum var. australis Playfair 1917 Diagnosis: Test broadly ovate, with

Read More »

Difflugia baradlana

D. baradlana after Varga, 1963 Difflugia baradlana Varga, 1963 Diagnosis: Test ovoid with a very small neck which is about 1/4 of the test length.

Read More »

Difflugia angelica

D. angelica after Gauthier-Lièvre et Thomas, 1960 Difflugia angelica Gauthier-Lièvre et Thomas, 1960 Diagnosis: Test spherical, slightly mammillated. Pseudostome regularly lobed like a star with

Read More »

Difflugia algaephila

D. algaephila after Decloitre, 1977 (l) and Chardez (1980) Difflugia algaephila Decloitre, 1977 Diagnosis: Test ovoid, neatly pointed, with oblique round pseudostome. Dimensions: Length 73-75

Read More »