Rhizaspis spinosa – Microworld

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.

Habitat: 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.

Reference: Dumack, K., Siemensma, F., Clauß, S. 2021. Transfer of the thecate amoebae Lecythium spinosum and Pamphagus armatus to Rhizaspis (Thecofilosea, Cercozoa, Rhizaria), European Journal of Protistology, 125843, ISSN 0932-4739, https://doi.org/10.1016/j.ejop.2021.125843.

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).