Anisonema

The name Anisonema means "unequal flagella", as it derives from Greek aniso-, meaning unequal, and -nema, meaning thread, in reference to the two flagella that are of unequal lengths. ==Description==

Anisonema is a genus of phagotrophic, single-celled flagellates found in fresh, marine and brackish waters. When moving, Anisonema cells glide on their posterior flagellum, and can reverse the direction of their movement quickly Unlike other flagellates, the flagellar apparatus of Anisonema replicates in the late stages of mitosis, as opposed to the early stages. They also contain a reservoir on the left side. The cell surface maintains a constant rigid shape most of the time, but is capable of some deformation. It is supported underneath by a non-thickened pellicle composed of more than 18 protein strips, as in other spirocute euglenids. Anisonema is similar in appearance to Dinema, but lacks its flexibility and thickened pellicle. ==Taxonomy==

The genus Anisonema was first named by French biologist Félix Dujardin in his 1841 work Histoire naturelle des zoophytes. He distinguished it from other genera of biflagellates with unequal flagella due to its more resistant, non-contractile surface that is also often perfectly transparent. He erected two species, A. acinus and A. sulcata. The latter was transferred to the genus Entosiphon, while A. acinus is considered the type species. Since its publication, around 20-36 Additional genetic sequences have been isolated from species that were previously assigned to Anisonema, but these are phylogenetically more related to ploeotiids and have been transferred to the new genera Hemiolia and Liburna. Later authors attribute this distinction to a common reaction in stressed cells, and do not accept it and other minor differences as justifying separation from A. acinus. • Anisonema bisulcatum . Observed in China. • Anisonema obliquum . The most similar to A. acinus, except for a larger size, a relatively shorter posterior flagellum, and no visible surface grooves. transferred to Hemiolia. ==References==