 Its full set of gill rakers in its branchial arches has never previously been found in an eel, but is common in bony fish.It is very different from all other living eels, and scientists estimate it must have diverged from the others around 200 million years ago, during the Mesozoic era.It thus has not only its own species, but also its own genus and family, as well, and has been referred to by scientists as a "living fossil".