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.
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.