I moved this over to the biology department, in the hopes of getting Steve's & Kat's perspective on what this means taxonomically, and on what this species' characteristics are that might tell us something about deep-sea octopuses in general. Bonus points for tying in vampytoteuthis, which clearly split from other octos much earlier.
I would really like to see what will be published. This is so vague as to not really mean much. Octopuses as is the superorder Octobrachia?, Order Octopoda?, Family Octopodidae? These all would have very different implications. Also octopuses dispersing 30 million years ago? That is VERY recently. That, as well as them implying that Megaleledone is basal, makes me think that they are implying Octopodidae family level (which would mean that the cirate octopods, like Grimpoteuthis or Cirrothauma and many other deep-sea pelagic octos, aren't included in this, and Vampyroteuthis would be very far outside the scope).
Anyhow, annoying evolution misconception of the day:
"The species could all be traced back to a shallow-water octopus called Megaleledone setebos, which is only found in the Southern Ocean."
I'm hoping we can reverse engineer what they actually mean... obviously, the antarctic species didn't stop evolving for 30 million years, so I assume they're saying that it has some traits that there is reason to believe are ancestral to some group of living octos, maybe because a lot of octos needed these traits to survive last ice age, and then radiated when things warmed up a bit.
I'm not sure if they're saying that Megaleledone is a separate clade from the rest of the Octopodidae that there is some reason to believe is closer to the last common ancestor than the radiated other members of Octopodidae, or something like that.
edit: OK, through sleeper agents, I have got my mitts on a copy of the paper. Further details after I read it, but it looks like this is only about a clade covering Pareledone, Thaumeledone, Megaleledone, Graneledone, and Velodona.
Fig. 2. Phylogenetic relationships of Southern Ocean endemic and deep-sea octopuses. Bayesian phylogenetic tree based on the results of the relaxed
phylogenetic analysis utilizing the seven genes: rhodopsin, pax-6, octopine dehydrogenase (ODH), 12S rDNA, 16S rDNA, cytochrome oxidase subunit
I (COI) and cytochrome oxidase subunit III (COIII) of 12 Antarctic octopus species, seven deep-sea octopus species and 15 outgroup taxa. The
topology is that from the posterior sample which has the maximum sum of posterior probabilities on its internal nodes. Each node in the tree is
labelled with its posterior probability, * indicates a posterior probability of 1.0. The divergence times correspond to the mean posterior estimate of
their age in millions of years. The genera Adelieledone (dark blue), Pareledone (blue), and Megaleledone (light blue) are endemic to Antarctic waters.
The deep-sea genera, Graneledone (red), Velodona (yellow), and Thaumeledone (orange) are a monophyletic group and are nested within the Antarctic
clade. The deep-sea clade was estimated to have originated around 33 millions years ago (Ma; 95% HPD interval 5–64 Ma). The three deep-sea
genera were estimated to have diverged from one another around 15 Ma (95% HPD interval 1–36 Ma). Depth ranges were taken from the literature
as follows except for P. turqueti and A. polymorpha (Allcock, unpublished data): A. piatkowski (Allcock et al., 2003a), Pareledone spp. except
P. turqueti (Allcock, 2005), M. setebos (Allcock et al., 2003b), G. antarctica (Voss, 1988; Vecchione et al., 2005), G. verrucosa (Allcock et al.,
2003c), G. boreopacifica and V. togata (Voss, 1988), T. peninsulae (Allcock et al., 2004; Strugnell et al., 2008), other Thaumeledone spp. (Allcock
et al., 2004).