Alveolate

The alveolates ("with cavities") are a major line of protists. There are three phyla, which are very divergent in form, but are now known to be close relatives based on various ultrastructural and genetic similarities: The most notable shared characteristic is the presence of cortical alveoli, flattened vesicles packed into a continuous layer supporting the membrane, typically forming a flexible pellicle. In dinoflagellates they often form armor ... more

The alveolates ("with cavities") are a major line of protists. There are three phyla, which are very divergent in form, but are now known to be close relatives based on various ultrastructural and genetic similarities: The most notable shared characteristic is the presence of cortical alveoli, flattened vesicles packed into a continuous layer supporting the membrane, typically forming a flexible pellicle. In dinoflagellates they often form armor plates. Alveolates have mitochondria with tubular cristae, and their flagella or cilia have a distinct structure. The Apicomplexa and dinoflagellates may be more closely related to each other than to the ciliates. Both have plastids, and most share a bundle or cone of microtubules at the top of the cell. In apicomplexans this forms part of a complex used to enter host cells, while in some colorless dinoflagellates it forms a peduncle used to ingest prey. Various other genera are closely related to these two groups, mostly flagellates with a... less