Alveolissa

Alveolissa is a genus of single-celled protists placed within the Alveolata, a major clade that includes ciliates, dinoflagellates, and apicomplexans. The taxonomic status of Alveolissa has varied among authorities, and it is not universally accepted as a valid genus. The name references the cortical alveoli—small cavities beneath the cell membrane characteristic of many alveolates.

Morphology and features: Members are typically 5–25 μm long and have a pellicle reinforced by cortical alveoli. Surface textures range from smooth to slightly sculptured. Locomotion and feeding structures vary by species, with some using flagella and others relying on general motility; most species feed by phagocytosis of bacteria or small algae.

Ecology and life cycle: Alveolissa species inhabit both freshwater and marine systems, often as free-living protists or as symbionts. They are primarily heterotrophic. Reproduction is mostly asexual via binary fission; some lineages can form dormant cysts under adverse conditions.

Taxonomy and status: Molecular and morphological data have not produced a stable placement for Alveolissa. Its status is disputed, and some researchers treat it as a provisional genus or synonym, pending additional sampling and sequencing to clarify its relationship to other alveolates.

Etymology and related groups: The name derives from the association with alveoli, the cortical sacs found in alveolates. Related topics include Alveolata and the major groups within it, such as ciliates, dinoflagellates, and apicomplexans.