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Rhizaspis spinosa
Rhizaspis spinosa
The original description with original drawings, Penard, 1890.

Rhizaspis spinosa (Penard, 1890) Dumack et al., 2021
Basionym: Trinema spinosum Penard, 1890

Diagnosis: Theca 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.

Ecology: Freshwater.

Dimensions: Penard (1890): 35 µm long.

Remarks: This species has been described by Penard (1890) as Trinema spinosum. Later Penard (1902) accepted Lauterborns name Pamphagus armatus.

Pamphagus armatus
Rhizaspis spinosa
Left: Drawing of R. 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).
Rhizaspis spinosa
Drawing in Cash, Wailes and Hopkinson (1915)
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