Acanthosphaera is a genus of green algae, in the family Chlorellaceae. It contains the sole species Acanthosphaera zachariasii, although some sources list a second species, Acanthosphaera tenuissima. It is widely distributed, in freshwater habitats and exists as phytoplankton.
Acanthosphaera is a genus of green algae, in the family Chlorellaceae. It contains the sole species Acanthosphaera zachariasii, although some sources list a second species, Acanthosphaera tenuissima. It is widely distributed, in freshwater habitats and exists as phytoplankton.
Acanthosphaera consists of solitary, free-living planktonic cells. The cell is spherical, about 8–15 μm in diameter and uniformly covered in 20–40 spines. The spines are distinctly thickened at the base, and very narrow at the tips. The spines are organized in four whorls of 4, 8, 8, and 4 respectively. Cells contain a single nucleus and one parietal, cup-shaped chloroplast, which has a single, prominent pyrenoid with a starch sheath.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).