A four-legged fossil snake

A serpentine version of Archaeopteryx?


First published: 4 August 2015 (GMT+10)
Re-featured on homepage: 2 December 2021 (GMT+10)
Julius T. Cstonyisnake
An artist’s impression of Tetrapodophis putting its legs to work subduing its prey.

There are further updates to this article, from 2016 and November 2021.

CMI has received a number of enquiries about reports of a four-legged fossil snake, originally found in Brazil, Tetrapodophis amplectus. Having an interest in this subject (see my past articles on snake origins and the origin of snake carnivory), I read the original scientific paper on Tetrapodophis in the journal Science with interest.1 In what follows, please understand that CMI does not accept the ‘millions of years’ dates which are quoted from the secular literature. Actually, on their own terms, the dates place those snake researchers operating within an evolutionary worldview in something of a quandary.

Earlier in the year, there was media interest in alleged ‘leggy snakes’ after a scientific paper was published (27 January 20152) on the four ‘oldest’ fossil snake species yet discovered: Eophis underwoodi (167 million years old), Portugalophis lignites (157–152 million years old), Diablophis gilmorei (155 million years old), and Parviraptor estesi (145–140 million years old). You can find a report on the above snakes here and I encourage you to first read that in order to better appreciate the significance of the new paper. Tetrapodophis (according to Fig. 5 of the Science paper) is about 113 million years old.

Beautifully preserved

Dave Martill/University of Portsmouthsnake-fossil
Tetrapodophis amplectus—literally ‘four footed snake’ with an ‘embrace’. Note the scale bar; it is a small creature.

A complete skeleton of Tetrapodophis amplectus is preserved, in contrast to the much more fragmentary fossil remains for the four, much ‘older’ snakes:

  • Very few vertebrae were found in the ‘earliest’ four fossils, in contrast to 160 spinal and 112 tail vertebrae revealed in the Tetrapodophis fossil.
  • No trace of limbs or even limb girdles (pelvis or pectoral) were found in the four ‘oldest’ fossils. However, beautifully preserved hind and fore limbs are easily visible in the Tetrapodophis fossil.

Clarity or confusion regarding evolution?

Some evolutionists are being very cautious about whether Teptrapodophis is even a true snake (though opinion is currently divided) on account of its small size and certain skeletal features. Prof Michael Caldwell (who led the team who published on the four ‘oldest’ snake fossils in January this year) even suggests it may not be a reptile at all; rather a member of an extinct amphibian group.3 Others are keen to trumpet the new fossil, something the media willingly pick up on. For instance, evolutionary developmental biologist Prof Martin Cohn claims,

“ … this could be one of the most important fossils ever found. The combination of snake-like body with complete forelimbs and hindlimbs is like a snake version of Archaeopteryx.”4
Fig. 4 from the Science paper. (A) Forelimb. (B) Manus (‘hand’/front foot). (C) Hindlimbs and pelvis. (D) Pes (hind foot). (E) Pelvis. (See original paper for explanation of the abbreviations)

Since opinions are inevitably prejudiced by which fossils different experts favour as most significant in telling the snake evolution story, it’s likely that the debate will continue for some time into the future.

From an evolutionary viewpoint, Tetrapodophis helps to bridge the gap ‘in time’ between the four ‘earliest’ snakes and the next ‘oldest’ at approximately 100 million years ago. A few months ago, evolutionary scientists were highlighting a 40 million year gap between the ‘youngest’ Parviraptor fossil (at about 140 million years old) and the ‘sudden reappearance’ of ‘leggy’ fossil snakes (see here). That ‘time gap’ is now a bit shorter. However, Tetrapodophis is certainly not morphologically transitional between those ‘earliest’ (limbless) snakes and the later snake fossils with hind limbs; namely Pachyrhachis problematicus, Haasiophis terrasanctus and Eupodophis descouensi (the latter misspelled in Fig. 5 of the Science paper).

This is Fig. 5 of this latest Science paper. It depicts the ‘evolutionary position’ of Tetrapodophis amplectus in the context of many other fossil snakes—including the four recently-described ‘oldest’ species.

As stated, there is no doubt that the well-developed hind and forelimbs of Tetrapodophis were, according to Dr Nick Longrich, University of Bath, UK (one of the paper’s authors) “far from being ‘vestigial’ evolutionary leftovers, dangling uselessly.”5 Instead, the researchers believe Tetrapodophis used its long, clawed fingers and toes for grasping onto its prey, conveyed by the species name amplectus, meaning ‘embrace’—hence the various artists’ reconstructions used to illustrate media reports about the creature. The fossil even reveals the preserved remains of its last meal which seems to have been a small vertebrate of some sort. Since all known snakes are carnivores (eating other vertebrates in particular), this tends to support the identification of Tetrapodophis as a snake rather than an amphibian.

However the debate on this fascinating little creature pans out, two major points of my previous (March 2015) article are not altered by this new find:

  • The fact that, from an evolutionary perspective, mature, biologically diverse snakes already existed by 167 million years (the ‘age’ of the oldest fossil), leaves the evolutionary palaeontologists with no option but to argue for a much earlier origin for snakes.
  • Confounding things further, evolutionists now find themselves facing another serious problem; [these oldest] snake fossils do not provide a shred of hard evidence for a pelvis or hind limbs.

If this beautiful new fossil, Tetrapodophis, becomes accepted as a true snake it would be the first to show forelimbs—no other snake, fossil or living, has even the hint of a pectoral (shoulder) girdle, much less front legs or feet. This makes it even more imperative that evolutionary palaeontologists find much ‘older’ fossil snakes (at around 190 million years according to some experts) showing much more developed hind and forelegs (and associated pelvic and pectoral girdles respectively) than we see in Tetrapodophis amplectus. Since that ‘time’, evolutionists believe that snake bodies have been elongating while their limbs have been getting progressively smaller.

A fit with Biblical history?

From a biblical perspective, CMI’s friends at Creation Evolution Headlines hit the nail on the head in summarising the significance of this find as follows:

If you’re a creationist tempted to think that Tetrapodophis represents something out of Genesis 3, don’t go there. The fossil records an animal that was alive at the time of the Flood, possibly thousands of years later than Eden. We know that the present world is impoverished of many well-designed creatures that existed in the antediluvian world. Suffice it to say this is one of them. Some antediluvian birds had teeth and claws on their wings; the living hoatzin still has the claws, but not the teeth. It shouldn’t be surprising that some long, slithering reptiles, whether snakes [or] legless lizards, or amphibians also had limbs or the genetic information for them. In some, that information is present but not expressed (blind cave fish are an example). Limbs are designed. This creature had limbs and digits adapted for its needs. If anything, the limbs were ‘devolving’ not evolving; no new genetic information was emerging from scratch.6

A final thought. The Science paper reports that the laminated, ‘early Cretaceous’ limestone in which this Tetrapodophis fossil was entombed has fish coprolites (of the fish Dastilbe). The latter is an extinct genus of fish, likely adapted to saltwater.7 The skeletal features of Tetrapodophis are diagnostic of terrestrial, not marine, snakes. Therefore, the paleontological evidence (aquatic and terrestrial creatures buried together) is consistent with them having perished during the inundatory stage of Noah’s Flood.

Update, 5 December 2016

As discussed in this article, the identification of Tetrapodophis amplectus as a true snake has not been without controversy. For instance, some researchers suspect it was a marine lizard rather than a terrestrial snake. An article in the 4 November 2016 issue of Science gives an opposing view.8 Most frustratingly, for all concerned, it has come to light that this “missing link in the snake evolutionary tree” (Carolyn Gramling’s words in the new Science article) cannot be studied any more. When the slab containing the fossil was split open, one half showed the animal’s features much more clearly than the other (the ‘counterpart’). The better slab (upon which last year’s paper was based) reportedly is no longer available for study. This has greatly irritated the critics of the ‘Tetrapodophis is a snake’ advocates! The Bürgermeister-Müller Museum, which housed the fossil on behalf of a private owner, is no longer permitting access to the fossil, including the original researchers—there is speculation that this may be due to damage caused during the fossil’s analysis. Since, in principle, the original research findings cannot be checked by other experts, University of Cambridge palaeontologist Dr Jason Head says “Tetrapodophis is no longer science. … It’s not repeatable, it’s not testable.”

Update, 24 November 2021

As indicated in the last update five years ago, serious questions quickly arose among experts as to the claimed snake status for Tetrapodophis amplectus, published in Science the previous year. It is now even more likely that this interesting four-legged fossil was indeed misclassified as a snake, with the publication of a new paper in November 2021.1 Lead author Prof Michael Caldwell, long a sceptic of its snake status, now says, “Rather, all aspects of its anatomy are consistent with the anatomy observed in a group of extinct marine lizards from the Cretaceous period known as dolichosaurs.”2 For one thing, the teeth of Tetrapodophis lacked the hooked shape and orientation associated with those of true snakes, for helping swallow prey victims whole. In fact, there is some fossil evidence that it may have eaten fish. Furthermore, the fossil counter-slab had not been studied closely enough by the original team of scientists and it turns out that the skull was decidedly non-snake-like.

We can expect that the controversy over this unique fossil will continue, in spite of the conclusions reached by Prof Caldwell and his team. Strong opinions exist on both sides! Unfortunately, the fossil is still housed in a private collection in Brazil, so researchers cannot easily gain access to study it, whether they’re advocates of its snake or its dolichosaur identity.

References and notes

  1. Caldwell, M.W. and 6 others, Tetrapodophis amplectusis not a snake: re-assessment of the osteology, phylogeny and functional morphology of an Early Cretaceous dolichosaurid lizard, Journal of Systematic Palaeontology, 17 November 2021 | doi.org/10.1080/14772019.2021.1983044.
  2. Starr, M., Famous discovery of a four-legged snake fossil turns out to have a twist in the tale, sciencealert.com, 18 November 2021.

References and notes

  1. Marthill, D.M., Tischlinger, H., & Longrich, N.R., A four-legged snake from the Early Cretaceous of Gondwana, Science 349(6243):416–419, 24 July 2015. Return to text.
  2. Caldwell, M. W. et al., The oldest known snakes from the Middle Jurassic-Lower Cretaceous provide insights on snake evolution, Nature Communications 6, no. 5996, doi:10.1038/ncomms6996, 27 January 2015. Return to text.
  3. Perkins, S., Four-legged snake fossil stuns scientists—and ignites controversy, news.sciencemag.org, 23 July 2015. Return to text.
  4. Christakou, A., Four-legged fossil snake is a world first, www.nature.com/news, 23 July 2015. Return to text.
  5. Webb, J., Four-legged snake ancestor ‘dug burrows’, bbc.co.uk/news, 24 July 2015. Return to text.
  6. Four-footed snake? crev.info/2015/07/four-footed-snake, 25 July 2015. Return to text.
  7. See en.wikipedia.org/wiki/Dastilbe. Return to text.
  8. Gramling, C., ‘Four-legged snake’ may be ancient lizard instead, Science 354(6312):536–537, 2016. Return to text.

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