Pensilisphaera antarcticaensis  Solbach, Siemensma & Holzmann, 2025

Diagnosis: Individuals more or less spherical with a hyaline, flexible, organic-walled test, often surrounded by a mucous layer. Peduncle relatively short. One or more nuclei present. Nuclei spherical, ovular, with several spherical nucleoli. Cytoplasm with many small vacuoles, containing one or up to five small granules. No crystals observed.

Dimensions: Test diameter approximately 75 μm (74.9 μm ± 14.4 μm, n = 24). Up to five nuclei per cell, varying in size between 17.7 and 20.8 μm (n = 7).

Habitat: Marine sediments, shoreline of Byers Peninsula (Livingston Island, South Shetland Islands, Antarctic.

Remarks: Solbach, M.D., Siemensma, F., Holzmann, M., 2025. A remarkable new monothalamid (Rhizaria, Foraminifera) from the shoreline of Livingston Island, Antarctica. European Journal of Protistology 99, 126148. https://doi.org/10.1016/j.ejop.2025.126148