A Blog by Brian Switek

Fossil Frog Still Looks Gooey After Over 34 Million Years

In a blog posted late last year, paleontologist Sarah Werning made an important point that has stuck with me ever since – we need to stop apologizing for the fossil record. There are gaps and discontinuities and an astonishing amount of as-yet-undiscovered history, but a great deal of what has been found so far is truly exceptional. Werning picked prehistoric frogs as a prime example – several specimens of Liaobatrachus preserved in such detail that researchers were able to examine how the skeletons of the frogs transformed from cartilage to bone. A new look at a specific fossil amphibian discovered 140 years ago reminded me of her point. In a PLoS One paper, Fabien Laloy examine an Eocene frog that still looks gooey after over 34 million years.

Views of the fossil frog Thaumastosaurus gezei. From Laloy et al. 2013.
Views of the fossil frog Thaumastosaurus gezei. From Laloy et al. 2013.

The point of the study by Laloy and coauthors was the resolve the identity of this amazing find. In 1873, the French naturalist Henri Filhol briefly mentioned a fossil frog discovered among the Quercy Phosphorites of southwestern France that included an external cast of the amphibian’s soft tissues. The specimen, a head and body with an associated leg, looks less like a fossil and more like the crispy remains of a modern frog left out in the sun too long.

In his later writings, Filhol named the frog Rana plicata. This left later paleontologists with a taxonomic knot as the name was preoccupied, and no one really knew exactly where the frog fossil came from and therefore how old it was. When they CT scanned the fossil to see if there was anything inside the lovely exterior, Laloy and coauthors found the clues to finally resolve the mystery. Filhol’s frog had a skeleton “almost identical to that of Thaumastosaurus gezei“, another frog found in the same deposits. That narrows down the age of the beautiful cast to between 40 and 34 million years ago, and also helps constrain ideas about which frogs Thaumastosaurus gezei was most closely related to.

Internal view of the bones inside the frog cast. From Laloy et al. 2013.
Internal view of the bones inside the frog cast. From Laloy et al. 2013.

But the new study immediately caught my attention because the frog Filhol first described is so beautiful. Paleontologists often deal with scraps and fragments of prehistoric life; broken clues such as bits of dinosaur bone eroding out of a hill or tatters of an ancient leaf. These natural curiosities are pretty in their own way, but to be able to see the face of a frog that died over 34 million years ago is a stunning opportunity that is about as close as we may get to actually traveling back to the Eocene. The fossil record is incomplete, just as modern ecosystems are not recording every single jot and tittle of life, but the fact that such tender remains exist at all is an unfathomable source of wonder.


Laloy, F., Rage, J-C., Evans, S., Boistel, R., Lenoir, N., et al. 2013. A re-interpretation of the Eocene anuran Thaumastosaurus based on microCT examination of a ‘mummified’ specimen. PLoS ONE 8, 9: e74874. doi:10.1371/journal.pone.0074874

15 thoughts on “Fossil Frog Still Looks Gooey After Over 34 Million Years

  1. We should turn the tables on creationists who point to gaps in the fossil record. Under separate creation, why should there be any fossil record at all, let alone one so clear that we can point to gaps in it?

  2. Oh, good grief. Chill out and enjoy the science, will you? Cut the belligerent crap and share the wonder. Divisiveness might make you feel special, but it ain’t gonna win you any “converts”.

  3. Why hasn’t Mr. Braterman’s question been asked over and over? Perhaps just too much common sense; creationists and their oppositionists tend to get theoretical and philosophical rather than just using good sense.

    This frog is just amazing, just absolutely amazing. Where has this fossil been all my life? Where is this frog? To see this fossil would be a fossil nut’s dream come true.

  4. The answer to the endless, mindless evolution-creation “debate” is education. The Theory of Evolution is not a belief. It is the reality we see when we look closely. Until the chain of generational ignorance is broken, these kinds of dialogues will continue to clog the blogs, diminishing the enjoyment and wonder we feel as we behold the image of a 34 million year old frog!

  5. Since you ask, most Young Earth creationists attribute the fossil record to Noah’s flood (some say conditions after the flood were responsible). Old Earth creationists view history pretty much according to the Establishment view, only with God creating different groups at different times. There are several variations on these views, and that’s leaving out Theistic evolutionists, who believe that “God created using evolution” but generally aren’t considered creationists.

    The fossil record doesn’t actually show a gradual development of life with a few gaps here and there; all the major phyla show up at about the same time in the Cambrian, then major divisions show up suddenly at different times, with a few possible transitional forms for most of them, often in about the same geological strata as more definitive forms. In the case of birds, almost all of the close “ancestral” forms fossilized appear in strata dated more recent than the first “descendant” forms. The three or four major divisions of fish appear at about the same level, there’s a few early examples of somewhat-more-amphibian-like fish and some early hints of amphibians, then suddenly a panoply of distinct, highly varied and specialized amphibians… etc. There is nothing that looks like a lizard or early dinosaur evolving toward being a pterosaur. Same with bats, although a number of different fossil gliding animals have been found. It’s not so much that the fossil record shows evolution, but evolutionary theory shapes the popular conception of the fossil record.

  6. Awesome! An animal so delicate that has lasted so long and offers so much! Nature is a never ending source of wonder and delight!

  7. Rather than shape the “conception of the fossil record, ” evolutionary theory arose from the fossil record as well as the study of living animals, genetics, etc. How many transitional fossils do you need exactly? Because it seems to me that so long as there are any gaps, the religious fundamentalists would continue to deny evolution. It’s remarkable the burden of proof the fundamentalists put on other schools of thought considering the only proof of their ideas they need is that their mother told them.

  8. @ David.
    I’ve actually looked at your source, The Bible, and it seems it is full of gaps. However, I won’t dismiss it based on that alone since some of the pages and sources could have been lost I mean it was 2000 years ago unlike evolution which took/takes millions and millions of years. That being said, it’s really the contradictions that bothers me. Did Joseph and Mary live in Bethlehem or did they travel there for the birth of Jesus? It seems an extremely important event yet we have two separate accounts. lets go a little further back, in one account Adam and Eve are said to have been created at the same time, in another Eve is created from Adams ribs. Again this is a major major event yet we have different written accounts. I’ve seen the word “myth” used in some instances, perhaps that is what they are… anyways is incest OK since Eve had two sons and somehow we are all here…ewwwww… . I think I could go on but I would like to state for the record, that your source, the bible, seems to be unreliable and therefore cannot be used in discussing evolution. Thank You
    Former Muslim
    Current and forever, and ever (till I die of course) and Atheist.

  9. Nice fossil!

    @David Bump:

    On the magic:

    That really doesn’t answer Braterman’s question, since the creationists obfuscate the record (eg no floods et cetera).

    Nitpick: Theistic evolutionists _are_ generally considered creationists, since their major domination, catholics, by way of their leader claims they are.

    And really, since they claim magic is involved in ‘creating’ humans, it is the only rational analysis.

    On the biology:

    Your claims lack reference, or are erroneous such as “show up suddenly”, and generally look like creationist obfuscation. A recent result shows that Cambrian lineages evolved about 5 times faster than today’s average, which is less than some species can do today. (And we have to remember the Cambrian evolution was experimenting with new tools, unlike today’s “been there, done that”.)

  10. Hello,
    I read once that frogs can hibernate by freezing and then thaw again in the spring. They are able to prevent that the ice crystals kill their cells.
    Could that be the explanation why the fossil is so well preserved, that it was buried frozen?
    Would be interested to know

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