Euglenozoa: taxonomy, diversity and ecology, symbioses and viruses

Abstract

Euglenozoa is a species-rich group of protists, which have extremely diverse lifestyles and a range of features that distinguish them from other eukaryotes. They are composed of free-living and parasitic kinetoplastids, mostly free-living diplonemids, heterotrophic and photosynthetic euglenids, as well as deep-sea symbiontids. Although they form a well-supported monophyletic group, these morphologically rather distinct groups are almost never treated together in a comparative manner, as attempted here. We present an updated taxonomy, complemented by photos of representative species, with notes on diversity, distribution and biology of euglenozoans. For kinetoplastids, we propose a significantly modified taxonomy that reflects the latest findings. Finally, we summarize what is known about viruses infecting euglenozoans, as well as their relationships with ecto- and endosymbiotic bacteria.

The distinctive flagellar proteome of Euglena gracilis illuminates the complexities of protistan flagella adaptation

“…or articulated surface structure or pellicle, which is itself underlain with a microtuble corset and endoplasmic reticulum membrane (Kostygov et al 2021;Leander et al 2017).…”

Single-cell genomics unveils a canonical origin of the diverse mitochondrial genomes of euglenozoans

“…Euglenozoans comprise four well-defined clades: kinetoplastids, diplonemids, euglenids, and symbiontids [ 10 – 12 ]. Most euglenozoans, including diplonemids [ 13 , 14 ], most kinetoplastids [ 15 ], and most euglenids are free-living HFs [ 16 , 17 ]. Symbiontids are anaerobic and covered in epibiotic bacteria [ 10 , 11 ].…”

A New Model Trypanosomatid, Novymonas esmeraldas : Genomic Perception of Its “ Candidatus Pandoraea novymonadis” Endosymbiont

“…The vast majority of trypanosomatids parasitize insects ( 3 ), using them as sole either hosts (monoxenous species) or vectors, transmitting the flagellates to vertebrates or plants (dixenous species) ( 4 ). Trypanosomatids and related lineages, represented mostly by free-living forms, constitute the class Kinetoplastea, which, together with marine diplonemids, freshwater euglenids, and anoxic environment-dwelling symbiontids, belong to the phylum Euglenozoa ( 5 , 6 ). Some members of this extremely diverse protist group harbor either extracellular or intracellular bacterial symbionts of varied provenience, as they include alphaproteobacteria, betaproteobacteria, gammaproteobacteria, and cyanobacteria, the latter confined to euglenids ( 6 ).…”