Lecythium granulatus
Lecythium granulatus, 82 µm

 

Lecythium granulatus (Schulze, 1875)

Diagnosis: test in lateral view broad elliptical or ovoid; in dorsal view circular; aperture flexible, with folds, often surrounded by a pliable collar; membane hyaline, colorless and flexible; cytoplasma usually with numerous fine granules; vesicular nucleus in the dorsal region; filopodia straight, branching and anastomising, sometimes extremely numerous; with veils between the base of some filopodia.

Dimensions: Literature 40-83 µm; my measurements 38-111 µm; nucleus c. 25 µm (hard to detect).

Ecology: I found this rather rare species in sediments of a ditch (Naardermeer) and the Spiegelplas, both in the Netherlands, and in the Weser river in Germany. This species is variable in size, and larger than other Lecythium-species which I have seen. Smaller species tend to have a nucleus with a more or less central nucleolar mass, while the nucleolar material in larger cells is scattered throughout the nucleus.

Lecythium granulatus
Lecythium granulatus
Cell with pseudostome (p) focused to the cover glass and surrounded by a pliable collar (c)the pseudostome is usually visible as a double ring
Lecythium granulatus
Two specimens from the same sample, 38 and 82 µm long.
Lecythium granulatus
Specimen with typical granules; each granule bears a smaller granule.
Lecythium granulatus
The same specimen as above, with a large nucleolar part?
Lecythium granulatus
The same specimen as above, with large pliable and flexible aperture, surrounded by a kind of vacuolated collar.
Lecythium granulatus
Filopodia which branch and anastomose; between filopodia veils can be formed.
Lecythium granulatus
Two cell after division, just connected by a small string of plasm. Each cell c. 40 µm.
Lecythium granulatus
Lecythium granulatus
Lecythium granulatus, arrows indicate the nuclear membrane. The nucleus resembles the one drawn by Penard, see his Fig. 9 below, with a more or less central nucleolar mass. In this species the nucleus is very hard to detect. The above cell was compressed between slide and cover slip.
Lecythium granulatus
Lecythium granulatus
In DIC this surface structure became visible, bacteria? It looks if the bacteria adhere to the outer surface of the membrane (arrows).
Lecythium granulatus - Ferry Siemensma
Lecythium granulatus
Detail of filopodia and aperture
Lecythium granulatus
Lecythium granulatus
Lecythium granulatus
After Penard, in: Faune Rhizopodique du Bassin de Léman (1902).
Lecythium granulatus
Empty membrane, 92 µm long; the living cell was 82 µm
Lecythium granulatusLecythium granulatus, 62 µm
Lecythium granulatusLecythium granulatus, 66 µm, with large funnel-shaped flexible collar.
Lecythium granulatusLecythium granulatus, 67 µm, with filopodia and large folds around the pseudostome.
Lecythium granulatusLecythium granulatus, with pseudostome and filopodia
Lecythium granulatusLecythium granulatus, 78 µm
Lecythium granulatusLecythium granulatus, Weser river, Germany – Phase contrast
Lecythium granulatusLecythium granulatus, Weser river, Germany – Phase contrast
Lecythium granulatusLecythium granulatus, Weser river, Germany – Phase contrast
Lecythium granulatusLecythium granulatus, Weser river, Germany – DIC
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