An Inconvenient Hagfish

On the importance of intermediates.
















3 thoughts on “An Inconvenient Hagfish”

  1. Do you think the term “living fossil” is misleading? Even though sharks, coelacanths, etc. look very similar structurally to fossils hundreds of millions of years old, their genes must be substantially different due to genetic drift, right? The apparent physical consistency gives people the impression that some modern species are ancestors of other modern species.

    A similar effect occurs when discussing recent human evolution. Because humans’ common ancestor with chimps must have looked much more like a chimp than a modern human, the impression is that chimps and other apes have remained the same and we evolved.

    What do you think?


    1. Absolutely. Species referred to as living fossils have been found to have evolved genetically at the same average rate as non-“fossils”, and I’d say the hagfish gives a good example of why we need to be careful in our assumptions even when it comes to physical similarity of soft tissues that don’t fossilize well or may have very subtle differences. Here’s an article by well-known science writer Ed Yong that elaborates on that a bit more:

      I’ve heard people say more than once that the term should be retired. I would say it sometimes provides a useful shorthand, but you’re right to point out that there’s more to the story than apparent physical similarity, and it might be wise to clarify what we mean when we use it.


  2. Very nice article, the phylogeny of hagfish is a fascinating area of research. I think it is worth noting however that Mayomyzon is a fossil lamprey. I suspect you were referring to Myxinikela from the same Francis Creek shales? Both cyclostomes are referenced in the Gabbot et al. article you cited. Also, the Francis Creek shales are dated at just over 300 million years old so a fair amount of time earlier than 530 million years.


Comments are closed.

%d bloggers like this: