Telonemia

Telonemia is a phylum of microscopic eukaryotes commonly known as telonemids. They are unicellular free-living flagellates with a unique combination of cell structures, including a highly complex cytoskeleton unseen in other eukaryotes.

Telonemia shares several distinctive features with its related group, the SAR supergroup. Among these features are cortical alveoli, small sacs beneath the cell's surface that act as cushions, providing support and helping to maintain the cell's shape. Additionally, they possess tripartite mastigonemes, complex three-part hair-like structures on their flagella, the whip-like tails used for movement. These structures enhance their swimming capabilities by increasing resistance against water. Furthermore, Telonemia is equipped with filopodia, very thin, thread-like projections extending from the cell body. These projections can serve various purposes, such as aiding in movement or capturing food particles by wrapping around them. Together, the two lineages compose the TSAR clade.

This phylum is monotypic, composed of a single class Telonemea, order Telonemida and family Telonemidae. It is classified in three genera and seven species, although numerous undescribed clades of environmental DNA are known. They are detected in all marine and freshwater environments, where they prey on bacteria and small phytoplankton by engulfing them in their plasma membrane (phagotrophy).