5 species have been described in the genus Osedax:
To understand the evolutionary origin of O. mucofloris, scientists have been comparing the DNA sequences of Osedax species with those of other related annelid worms and invertebrates.
The results suggest that O. mucofloris is indeed a type of highly unusual polychaete worm in the family Siboglinidae. This family includes the giant hydrothermal vent tubeworm, Riftia pachyptila.
O. mucofloris shares a recent common ancestor with R. pachyptila, raising the interesting possibility that at some point the ancestors of these species were able to switch from hydrothermal vents to whale bones.
However, we are a long way from understanding this process fully. The main problem is that we know there are probably hundreds, if not more, species of Siboglinidae that have yet to be discovered. Without these missing branches of the evolutionary tree, it is difficult to understand how exactly O. mucofloris evolved, or when.