Epulonipiscium

While the bacteria have not been successfully grown in the lab, scientists have gained a better understanding of Epulonipiscium through microscopic, phylogenetic, and genomic analyses.

The epithet fishelsoni honors Lev Fishelson, a Polish-born Israeli ichthyologist[5][6] who was part of the group that made the discovery while studying the intestines of a brown surgeonfish from the Red Sea in 1985.

[7] Later, however, Epulopiscium fishelsoni was shown to comprise two phylogenetically distinct groups of bacteria by Angert and collaborators using rRNA gene sequence comparisons.

Although sporulation is widespread among other bacteria (such as Bacillus subtilis and Clostridium species) in the phylum Bacillota, spore formation is usually brought about by overcrowding, the accumulation of toxins in the environment, or starvation, rather than a standard form of reproduction.

The production of multiple endospores has been observed in other large gut symbionts such as Metabacterium polyspora, which are phylogenetically related to Epulonipiscium.