<i>&gt;The complete absence of mitochondria is a secondary loss, not an ancestral feature</i><p>Basically the organism evolves to not need its mitochondria, replacing it with a different system.<p>The story goes that mitochondria used to be separate organisms (they have their own DNA) living in symbiosis with other cells, and eventually being subsumed.<p>So this would be an example of an organism similarly evolving to incorporate a bacterial symbiotic relationship (as opposed to what the mitochondria provide). Not surprising to me that this is possible, or that we eventually found something like this, given that this is how mitochondria came to exist in cells to begin with.<p>I was hoping that we would have found an organism that existed before mitochondria were subsumed into cells. That would be cool