Spironemidae

Spironemidae is a family of heterotrophic flagellates, in the group Hemimastigophora. They vary in size and shape from the ellipsoid "Hemimastix amphikineta" (14 × 7 μm) to the vermiform "Spironema terricola" (43 × 3 μm), and are united by the possession of two rows of cilia, called kineties.
Phylogenomic analysis shows that Hemimastigophora are a distinct and ancient lineage of eukaryotic organisms, forming a possible sister clade to the supergroup Diaphoretickes.