Here’s David Tyler on a“’living fossil’ eel – unknown in the fossil record”:
In a cave in a fringing reef, at a depth of 35m, off the Ngemelis Island, Republic of Palau, an amazing fish was discovered in March 2009. Not only was this fish new to science, but the more it was studied, the more unusual it appeared to be.
“Despite some early questions about its affinities, preliminary phylogenetic analysis based on whole mitogenome sequences and numerous osteological features confidently placed this fish within the true eels. Additional morphological and molecular analyses demonstrate that in some features it is more primitive than Recent eels, and in others, even more primitive than the oldest known fossil eels, suggesting that it represents a ‘living fossil’ without a known fossil record. [. . .] Here, we describe a new family, genus and species for this enigmatic eel. We demonstrate, based on convincing evidence from morphology and whole mitochondrial genomes, that this genus is the most primitive living member of the Anguilliformes, and we accordingly assign it to a new family.”
But Tyler asks,
I know of no other case where an animal is declared to be a “living fossil” when it is completely unknown as a fossil. Its evolutionary history has been deduced. In this sense, the find is quite different from the coelacanth, which has a significant fossil record.
If the suggestion to reclassify living fossils as “durable species” were followed, it might be harder to justify this decision.