Breviata anathema is one of just afew described species of 'breviates',a recentlydiscoveredgroup of free-living protozoathatlive in oxygen-poor salinehabitats. Breviata anathema is a small single celled organism that can swim though fluids using its single flagellum (though some other 'breviates' have two flagella), but more often slowly creeps across surfacesinan amoeboid form.Creeping breviates usually extend fine pseudopodiafromthe anteriorportion of thecell at regular intervals.Theseextendlaterally andfix to surface, leading to a 'caterpillar track' effect as the cell moves forward past its own pseudopodia. The pseudopodia are also used to ingest bacterial prey.The mitochondrial organelles of breviates lack the ability to perform aerobic respiration, a feature they share with many protozoa from similar habitats.Moresurprisingly, in at least one breviate (Pygsuia biforma), thestandard mitochondrialiron-sulfur cluster assembly machinery (the ISC system) has been replaced bya 'SUFsystem' acquiredfrom Archaea.It has recently been demonstrated that breviates areamongst the closest relatives of Opisthokonta, the taxonomic group that includes both animals and true fungi.Researchers arenowexamining systemsinvolved in multicellularity in animals (e.g.cell adhesion andcommunication systems)todetermine whether there are recognizable antecedents of these systems in breviates (and other single-celled relatives of animals).
