Plagiophrys arcuatus
Rhizaspis arcuatus

Rhizaspis arcuatus (Penard, 1902) (= Pamphagus arcuatus)

Diagnosis: test ovoid with a flexible, colorless, hyaline membrane; fundus tapering into a more or less sharp point; test in cross-section flattened; aperture usually between folds and flexible; plasma fills the test completely; nucleus vesicular or ovular; filopodia usually few, long and strait.

Dimensions: 86-90 µm

Ecology: Freshwater, sediments.

Remarks: I don’t think that this is a separate species, but identical to P. scutigera.

Plagiophrys arcuatus
Drawing Penard (1902
Rhizaspis scutigera, both specimens from the same sample. The left hand specimen has a pointed fundus. Maybe Penard thought this form to be a separate species.
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