This 100 Million-Year-Old Snake Had Legs, but Cheekbone Provides Critical Insight Into Evolution

Ancient Snake Najash rionegrina

New research from a collaboration between Argentinian and University of Alberta paleontologists adds a new piece to the puzzle of snake evolution. Credit: Raúl Gómez

An ancient snake’s cheekbone sheds light on evolution of modern snake skull: 100-million-year old legged snake fossil provides critical insight into how the heads of modern snakes evolved.

New research from a collaboration between Argentinian and University of Alberta paleontologists adds a new piece to the puzzle of snake evolution.

The researchers examined a strikingly well-preserved fossil of the rear-limbed snake Najash rionegrina, found in Argentina. The study shows that nearly 100 million years ago, these legged snakes still had a cheekbone—also known as a jugal bone—that has all but disappeared in their modern descendants.

“Our findings support the idea that the ancestors of modern snakes were big-bodied and big-mouthed—instead of small burrowing forms as previously thought,” explained Fernando Garberoglio, from the Fundación Azara at Universidad Maimónides, in Buenos Aires, Argentina and lead author on the study. “The study also reveals that early snakes retained their hindlimbs for an extended period of time before the origin of modern snakes which are for the most part, completely limbless.”

For decades, paleontologists’ understanding of snake evolution was hampered by the limited fossil record. The new fossils presented in this study are crucial for reconstructing the early steps in the evolutionary history of modern snakes.

“This research revolutionizes our understanding of the jugal bone in snake and non-snake lizards,” said Michael Caldwell, professor in the Department of Biological Sciences and Earth and Atmospheric Sciences, and a co-author on the study. “After 160 years of getting it wrong, this paper corrects this very important feature based not on guesswork, but on empirical evidence.”

The nearly 100 million-year-old fossil snakes described in this study, found in Northern Patagonia, are closely related to an ancient lineage of snakes that populated the southern hemisphere continents of Gondwana, and appear to be related to only a small number of obscure, modern snakes. The researchers used micro-computed tomography (micro-CT) scanning to visualize the skull structures within the specimen, examining the pathways of nerves and blood vessels as well as the skeletal structure that would be otherwise impossible to see without damaging the fossil.

“This research is critical to understanding the evolution of the skulls of modern and ancient snakes,” added Caldwell.

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The paper, “New Skulls and Skeletons of the Cretaceous Legged Snake Najash, and the Evolution of the Modern Snake Body Plan,” will be published in Science Advances.
DOI: 10.1126/sciadv.aax5833

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5 Comments on "This 100 Million-Year-Old Snake Had Legs, but Cheekbone Provides Critical Insight Into Evolution"

  1. thabo rodney mosifane | November 21, 2019 at 3:59 am | Reply

    this kind of snake with legs are still existing today because we killed two of them in octobeber this year.but when we turn them over we realize that the four legs this legs were not prodruding like those of a lizard they were right on the belly of that reptile it was 15cm in lenth if you willing to contact for further deliberation on this my cell no 0665576301

  2. Snakes with legs hmm 🤔 makes perfect sense to me, so they can catch up to you and eat you. Imagine that.

  3. Snakes with legs are in the Bible. Science is slowly finding fossils and evidence for things and stories in this ancient tome.

  4. You guys are so dumb, you did up random stuff and slap a date on it. So dumb, and don’t give me that “it’s science” bs, because you dumb scientists ALWAYS change your mind about something significant every some amount of years. Evolution is the most popular lie ever! And yet so dumb. You say evolution is still happening all around us, yet most of the crap you claim that happens in evolution WE CAN’T SEE HAPPENING today. Like, why don’t we see half ape half humans? I know you guys have had years to come up with a lie to that, so give it.

  5. Wheres the pic of the fossil?
    At least have some evidence?
    Ah no I forgot this website sucks balls!

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