Methanovore

The methanovore split from it's ancestor, the methanophagus. It arose after replication errors caused the effective quadrupling of their ancestral genome. This resulted in higher expressions of organelle makeup in in the progenitor methanovores, which have over the millennia allowed for these organelles to specialize to better assist in functionality and resulted in them growing to 10x the size of their ancestors, to an average of 40 μm in diameter. They have a mitochondria-analog, referred to as a "methanochondria" which shares its shape with that of their immediate ancestor, suggesting they are the result of an endosymbiosis event between two or more methanophagus. It lives in the blarg cold seep swimming freely while it's ancestor live in mats, allowing it to thrive without endangering methanophagus.