Iodidimonas
Iodidimonas is a genus of bacteria that oxidizes elemental iodide to molecular iodine. It was isolated from iodide-rich brine associated with natural gas in Kujukuri, Japan.
Geiger et alii suggest that Iodidimonas may be the closest living relative of mitochondria. If true, this lineage and protomitochondria emerged from a common ancestor before the symbiogenetic event that gave rise to the eukaryotes.