According to this BBC News article it has.
What makes the story even more interesting is that the octopus in question is a currently existing species.
The above is Megaleledone setebos and according to recent DNA research (the article does not say whether it was mitochondrial or nuclear) it is the common ancestor of all deep sea octopi. From the article:
“She [Jan Strugnell – afarensis] was looking at the relationship between these different deep-sea octopuses and how they originated.
“She has been able to trace the timeline for their distribution back 30 million years to a common ancestor.”
The species could all be traced back to a shallow-water octopus called Megaleledone setebos, which is only found in the Southern Ocean.