Tetrapodophis
Tetrapodophis Temporal range: Early Cretaceous
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Fossil in Bürgermeister-Müller-Museum | |
Scientific classification ![]() | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Family: | †Dolichosauridae |
Genus: | †Tetrapodophis Martill et al., 2015 |
Type species | |
†Tetrapodophis amplectus Martill et al., 2015
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Tetrapodophis (greek meaning "four-footed snake") is an extinct genus of squamate from the Early Cretaceous. Tetrapodophis was previously thought to be one of the oldest members of Ophidia (snakes and their extinct relatives).[1][2] However, this classification has been disputed by Caldwell et al. (2016),[3] Paparella et al. (2018)[4] and Caldwell et al. (2021),[5] who identify Tetrapodophis as a dolichosaurid (more closely related to the Ophidia than to mosasaurs, but lie in the greater clade, Ophidiomorpha). This species existed in the Cretaceous Period about 120 million years ago, located in modern day Brazil. This four legged animal is around 12 inches long, weighing around 15-17 ounces.
Description[]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/4/48/Tetrapodophis_hindlimbs.jpg/220px-Tetrapodophis_hindlimbs.jpg)
Tetrapodophis possesses small yet well-developed fore- and hindlimbs like a lizard and a long body similar to a snake. Nevertheless, it shares many characteristics with modern snakes, including an elongate body, short tail, broad belly scales, a skull with a short snout and long braincase, curved jaws, and sharp hooked teeth. BMMS BK 2-2 contains bones of another animal in its gut, indicating that Tetrapodophis was carnivorous like most snakes but it turns out to be a lizard. Other features such as short neural spines suggest that Tetrapodophis was adapted to burrowing, lending support to the hypothesis that snakes evolved in terrestrial environments (another hypothesis posits that they evolved in aquatic environments).[2] The high number of vertebrae (upwards of 150) in Tetrapodophis and snakes is not seen in other burrowing reptiles with elongate bodies and reduced or absent limbs, meaning that it is most likely not an adaptation for a serpentine form of movement.[1] Dolichosaurids are thought to be phylogenetically close to snakes as members of Ophidiomorpha, which explains some of the morphological similarities.
Discovery and controversy[]
The type species, Tetrapodophis amplectus, was named in 2015 on the basis of a complete skeleton (BMMS BK 2-2) preserved on a limestone slab in the Bürgermeister Müller Museum in Solnhofen, Germany, which was labeled as "unknown fossil" until its importance was recognized by paleontologist , and illegally exported from Brazil,[6] since the country's laws do not allow the removal of fossils from its territory, nor that studies on them be conducted without the participation of at least one Brazilian scientist. The specimen was later determined to come from the Early Cretaceous Crato Formation in Ceará, Brazil. When asked why he didn't have a Brazilian scientist in the describing team, as required by Brazilian law, Martill responded:[7]
But what difference would it make? I mean, do you want me also to have a black person on the team for ethnicity reasons, and a cripple and a woman, and maybe a homosexual too just for a bit of all round balance? … If you invite people because they are Brazilian then people will think that every Brazilian author on a scientific paper is there because he is Brazilian and not because he is a clever scientist.
Martill stated in 2020 that his comments were poorly worded.[8]
Classification[]
A phylogenetic analysis published alongside the original 2015 description of Tetrapodophis places it as a close relative of other lizards, but outside the crown group Serpentes, meaning that tetrapodophis branched off before the most recent common ancestor of all living snakes. Below is a cladogram from that analysis:[1]
Squamata |
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The interpretation of Tetrapodophis amplectus as an early fossorial snake was challenged by Caldwell et al. (2016), who considered it more likely to be a dolichosaurid squamate.[3][9] A position corroborated by later analysis in 2018[4] and in 2021.[5]
Related articles[]
- Ophidia
- Pythonomorpha, including dolichosaurs, snakes and mosasaurs
- Coniophis
- Paleontology
- Najash rionegrina
- Dinilysia patagonica
References[]
- ^ a b c David M. Martill; Helmut Tischlinger; Nicholas R. Longrich (2015). "A four-legged snake from the Early Cretaceous of Gondwana". Science. 349 (6246): 416–419. doi:10.1126/science.aaa9208. PMID 26206932. S2CID 25822461.
- ^ a b Lee, Michael S. Y.; Palci, Alessandro; Jones, Marc E. H.; Caldwell, Michael W.; Holmes, James D.; Reisz, Robert R. (2016-11-01). "Aquatic adaptations in the four limbs of the snake-like reptile Tetrapodophis from the Lower Cretaceous of Brazil". Cretaceous Research. 66: 194–199. doi:10.1016/j.cretres.2016.06.004. ISSN 0195-6671.
- ^ a b Michael W. Caldwell; Robert R. Reisz; Randall L. Nydam; Alessandro Palci; Tiago R. Simões (2016). "Tetrapodophis amplectus (Crato Formation, Lower Cretaceous, Brazil) is not a snake". Society of Vertebrate Paleontology 76th Annual Meeting Program & Abstracts: 108.
- ^ a b Paparella, Ilaria; Palci, Alessandro; Nicosia, Umberto; Caldwell, Michael W. (June 2018). "A new fossil marine lizard with soft tissues from the Late Cretaceous of southern Italy". Royal Society Open Science. 5 (6): 172411. doi:10.1098/rsos.172411. ISSN 2054-5703. PMC 6030324. PMID 30110414.
- ^ a b Michael W. Caldwell; Tiago R. Simões; Alessandro Palci; Fernando F. Garberoglio; Robert R. Reisz; Michael S. Y. Lee; Randall L. Nydam (2021). "Tetrapodophis amplectus is not a snake: re-assessment of the osteology, phylogeny and functional morphology of an Early Cretaceous dolichosaurid lizard". Society of Vertebrate Paleontology, latest articles.
- ^ Yong, Ed (23 July 2015). "A Fossil Snake With Four Legs". Phenomena: Not Exactly Rocket Science. National Geographic. Retrieved 24 July 2015.
- ^ "Author of 4-legged-snake paper defies Brazilian fossil laws". Herton Escobar (in Brazilian Portuguese). Retrieved 2020-12-16.
- ^ Elbein, Asher (2021-03-22). "Decolonizing the Hunt for Dinosaurs and Other Fossils". The New York Times. ISSN 0362-4331. Retrieved 2021-06-26.
- ^ Geggel, Laura (October 28, 2016). "Mistaken Identity? Debate Over Ancient 4-Legged Snake Heats Up". Live Science.
External links[]
Media related to Tetrapodophis at Wikimedia Commons
- Tetrapodophis as it may have been in life
- Scientists Discover Four-Legged Snake Fossil. On: SciTechDaily, Source: University of Portsmouth. August 2, 2015
- Susan Evans: “Four legs too many?,” In: Science Vol. 349 no. 6246 pp. 374–375. 24 July 2015; doi:10.1126/science.aac5672
- Cretaceous snakes
- Transitional fossils
- Early Cretaceous reptiles of South America
- Cretaceous Brazil
- Fossils of Brazil
- Crato Formation
- Fossil taxa described in 2015