Its important features lie within the structure of its jaws and number of vertebrae. Such traits are only found in the most primitive of fossil eels. Such fossil are around 100 million years old, the proposed time for when eels broke off from the rest of the fish family. However Proteroanguilla's traits show that it evolved 200 million years ago. This can be deduced from two facts. The first is that its jaw structure is very similar to its common ancestor which lived 200 million years ago.
The second fact lies within its mitochondrial DNA. Mitochondrial DNA gathers mutations at a regular pace, and the number of mitochondrial mutations within its DNA shows, without a doubt, that its evolved 200 million years ago. A computer generated family tree of eels show that they actually evolved 100 million years earlier than previously thought. Proteroanguilla occupies the entire evolutionary branch between the 100 million year old eels and its common ancestor. At this time, dinosaurs had barely gained dominance over the planet. The key to its survival is its incredibly slow metabolism, which gives it a very long, but still undetermined lifespan.