Galeripora arenaria  (Greeff, 1866) González-Miguéns et al., 2021
Basionym: Arcella arenaria Greeff, 1866
Synonyms: Arcella aureola Maggi, 1888
Arcella microstoma Penard, 1890
Arcella arenaria form. compressa Chardez, 1957: 69
Arcella arenaria var. grandis Bunesco & Matic, 1982
Arcella arenaria var. irregularis Decloître, 1972: 167
Arcella arenaria var. sphagnicola Deflandre, 1928: 249
Arcella arenaria var. sphagnicola form. undulata Decloître, 1965: 33

Diagnosis: Shell always circular in apical view, more or less dome-shaped in lateral view; dorsal surface usually with slight folds, but very often flattened. Shell yellowish brown to dark brown in color. Aperture small, circular in shape, its diameter barely reaching 1/5-1/6 that of the shell. Small pores, 7—28 in number, around the aperture. Height of the shell not less than 1/2 diameter of the shell. Neither remarkable border nor bosses around the lateral margin. Many nuclei present: the large ones usually 3 in number and arranged in an equilateral triangle, the small ones not constant in number, varying 3—5, arranged irregularly. The pseudopodia very short, 6 at most, many vacuoles developing along the ectoplasm.

Dimensions: In literature, the shell is 75—130 µm in diameter, 21—50 µm in height, aperture 12—28 µm in diameter, with 7—18 pores.

Habitat: Mostly in dryer mosses; on Hypnum and Polytrichum, also on lichens on trees and between Sphagnum.

Remarks: This species resembles Galeripora catinus Penard; it can also be confused with Galeripora artocrea. The folding of the dorsal surface is most distinct in lateral view.

References: González-Miguéns, R., Soler-Zamora, C., Villar-dePablo, M., Todorov, M., Lara, E., 2021. Multiple convergences in the evolutionary history of the testate amoeba family Arcellidae (Amoebozoa: Arcellinida: Sphaerothecina): when the ecology rules the morphology. Zoological Journal of the Linnean Society zlab074. https://doi.org/10.1093/zoolinnean/zlab074