Arcella guadarramensis González-Miguéns & Lara, 2021
Diagnosis: Color ranges from transparent to yellow-orange. Sub hemispherical test shape, with flattened edges and dimples in the surface that gives the test a golf ball shape. No ribs or keels on the aboral side. Hexagonal building units are visible, which gives the test a rough appearance; little pores can be seen at the vertices. Building units can also be appreciated at the oral side of the test, with pores at the vertices and a central aperture. The aperture is invaginated outwards forming a short ring or lip.
Dimensions: Test diameter: clade L: 114–126 μm; aperture 19–30 μm; clade M 141–150 μm; aperture 31–35 μm.
Ecology: Wet Sphagnum moss, in a fen. Type locality: Spain, Madrid, Puerto de Canencia (40°52’N 3°45’W).
Intraspecific variability: The building units may vary slightly in shape. Some building units may be collapsed, giving a rough surface. There may be certain deformations in the test that prevent it from having a perfectly circular morphology.
Diagnosis with closely related species: Arcella guadarramensis can be diagnosed by its specific sequences of the mtDNA markers and by its phylogenetic placement. Arcella guadarramensis differs morphologically from similar-looking G. succelli by (1) its morphometric differences with G. succelli, both, clade N and O, are notably smaller than G. succelli and (2) the rough outlook of the test.
Literature: 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