Lecythium spinosum – Microworld

Lecythium spinosum, 68 µm long, excl. spines – Laegieskamp

Lecythium spinosum (Penard, 1890)

Diagnosis: test membranous, ovoid or pyriform, in dorsal view circular or a little compressed, with numerous short curved spines, which are modifications of the membrane; aperture sub-terminal, oblique and pliable; nucleus granular, placed posteriorly; cytoplasm filling the test; filopodia numerous, simple or branched, sometimes anastomosing.

Habitat: aquatic vegetation (Hopkinson), sediments (Lauterborn). I have found one specimen in the sediments of a forest pond at Groeneveld, Baarn, the Netherlands, in 1981. I found some specimens again in the ooze of ditches in Den Treek (2012), Laegieskamp (2013) and Naardermeer (2015).

Dimensions: Lauterborn (1901), Penard (1902) and Cash et al. (1915): 45-70 µm long; my measurements: 49-75 µm long (n=11).

Remarks: This species has been described by Penard (1890) as Trinema spinosum and by Lauterborn (1901) as Pamphagus armatus. Later Penard (1902) accepted the name Pamphagus armatus. Penard (1902) described this species as follows: ‘Body pocket-shaped. Membranous test with curved spines all over its surface. 45-70 µm.

Lecythium spinosum, 51 µm – Den Treek

L. spinosum, 68 µm long, excl. spines; some filopodia are visible to the left; note the large granules.

L. spinosum, apertural view; the cell hangs on the cover glass.

L. spinosum, from the Naardermeer, 57 µm

Lecythium spinosum, with detail showing that spines are modifications of the membrane

L. spinosum, mouth (arrow) – both specimens from Den Treek, Amersfoort

L. spinosum with large food vacuole, body 58 µm long; in the fundus region the nucleus is visible, but without distinct visible structure. It looks if the nucleolar material is fragmented and sausage shaped – Den Treek, Amersfoort

Specimen from the Naardermeer (70 µm)

Specimen from the Naardermeer (75 µm)

L. spinosum, filopodia – Phase Contrast

L. spinosum, filopodia – DIC

The original description with original drawings, Penard, 1890.

Left: Drawing of L. spinosum by Penard (1902). He considered this specimen as a Trinema-species (Penard, 1890), but corrected his identification later in Pamphagus armatus, giving the credit to Lauterborn.

Right: Drawing of Pamphagus armatus by Lauterborn (1901).

Drawing in Cash, Wailes and Hopkinson (1915)

Lecythium spinosum – Photo: Eckhard Voelcker, Berlin, and L. spinosum, apical view

Lecythium spinosum – Photomicrograph: Eckhard Voelcker, Berlin

Lecythium spinosum (Length 49 µm, width 37 µm) – drawing Ferry Siemensma

The photomicrographs below were made by Francisco Pujante, Spain, and might represent L. spinosum or a closely related species:

According to Francisco, his sample comes from Parque La Albufera in Valencia in Spain, freshwater with moderate pollution. Water temperature approx. 18 º Celsius. The lake is fed by the river Turia and is in contact with the Mediterranean Sea through various channels. All around the lake are rice fields flooded with water for several months a year. He “found a lot of them”.