Genus Lesquereusia Schlumberger (1845)

Diagnosis: test with asymmetrical neck, more or less attached to the body, composed of endogenous siliceous rods or in other species with collected mineral particles, bound together with organic cement. Nucleus ovular.

Type species: Lesquereusia spiralis (Ehrenberg 1840).

Ecology: Freshwater. In sediment and mosses like Sphagnum. Feeding on diatoms and green algae.

Remarks: Species differ mainly in shape of the siliceous rods, the amount of mineral particles and the orientation of the neck.

This genus was erected by Schlumberger (1845) and obviously named after the swiss naturalist Lesquereux. By lapsus it was first published as Lecqereusia. The currently used spelling was introduced by Hopkinson (in Cash & Hopkinson, 1909)!

Lesquereusia, main parts of the test.

16 species have been described, the type species is Lesquereusia spiralis (Ehrenberg, 1840). Three well known species are L. spiralis, L. modesta and L. epistomium.  However, D. modesta and D. spiralis are sometimes hard to distinguish from each other, because they can have a mixture of endogenous rods and mineral particles. I am not sure if both species are  really different species.

Recent posts

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 »

Difflugia key spherical

Spherical tests Tests that are more or less spherical, some with a collar, but all without spines or other outgrowths. The aperture or pseudostome is

Read More »

Difflugia key compressed

Compressed tests Compressed tests are more or less oval or elliptical in cross-section. The aperture is round or oval or even lobed. This group has no

Read More »