In expeditions like the one that discovered the jellies, where Just dragged the ocean floor of Australia's southeastern continental slope, new species are par for the course. During that expedition alone, Just found nearly 300. But the two mushroom-like species proved to be a rare discovery.
The multicellular, mostly asymmetrical jellies, are called enigmatica and discoides. While they show some similarities to the phylums Cnidaria (jellyfish) and Ctenophora (comb jellies), the researchers were unable to classify them as part of either category. For now, they've declared them their own genus: Dendrogramma. Above that, they get a new family name: Dendrogrammatidae.
Dendrogramma are probably related closely related to Cnidaria and Ctenophora, but further genetic analysis is required to see just how much - and to show for certain that the new species really do get their own branch in the tree of life. If that's the case, the jellies probably represent a piece of the tree that branched off early, and could have more in common with animals that went extinct hundreds of millions of years ago than they do with modern relatives.