Magnetococcus marinus is a species of Alphaproteobacteria that has the peculiar ability to form a structure called a magnetosome, a membrane-encased, single-magnetic-domain mineral crystal formed by biomineralisation, which allows the cells to orient along the Earth’s geomagnetic field.
It is a basal group in the Alphaproteobacteria.
|Schematic ribosomal RNA phylogeny of Alphaproteobacteria|
|The cladogram of Rickettsidae has been inferred by Ferla et al.  from the comparison of 16S + 23S ribosomal RNA sequences.|