Tetrapodophis

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Tetrapodophis
Temporal range: Early Cretaceous, Latest Aptian, ~115–113  Ma
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Tetrapodophis amplectus 3483.jpg
Fossil in Bürgermeister-Müller-Museum
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Clade: Toxicofera
Genus: Tetrapodophis
Martill et al., 2015
Type species
Tetrapodophis amplectus
Martill et al., 2015

Tetrapodophis (Greek meaning "four-footed snake") is an extinct genus of lizard from the Early Cretaceous (Aptian) aged Crato Formation of Brazil. It has an elongated snake-like body, with four disproportionately short limbs.

Contents

Tetrapodophis has been considered by some authors to be one of the oldest members of Ophidia; the taxonomic group which includes snakes and some of their closest extinct relatives. [1] [2] [3] However, this classification has been disputed by some other authors, [4] [5] [6] who identify Tetrapodophis as a dolichosaurid. The exact phylogenetic placement of Dolichosauridae is also disputed. Dolichosaurids could be related to Ophidia, [7] [8] which would mean that Tetrapodophis is indeed related to snakes, albeit more distantly than previously thought. Alternatively, Dolichosaurids could be more closely related to Mosasaurs. [9]

Description

Hindlimbs Tetrapodophis hindlimbs.jpg
Hindlimbs

Tetrapodophis possesses small yet well-developed fore- and hindlimbs like a lizard and a long body similar to a snake, around 19.5 cm (7.7 in) in length. [6] 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. 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]

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 David Martill [10] when he visited Germany in 2012, [11] and housed in a private collection in a private in a museum in Solnhofen. [11] The fossil had in the hands of the private collector for "several decades" prior to the publication. [12] While no locality information was provided for the specimen, [12] based on characteristics of the rock it is thought to come from the Early Cretaceous Crato Formation of Northeast Brazil. [12] Brazil's laws do not allow the removal of fossils from its territory since 1942, nor that studies on them be conducted without the participation of at least one Brazilian scientist. Due to a lack of information regarding the provenance of the fossil, it was possible that the fossil had been illegally exported from Brazil. [11] This caused controversy among Brazilian paleontologists, [13] and sparked a legal investigation by the Brazilian government. [11] According to lead author Martill, fossils from the Crato Formation are widely illegally collected and exported from Brazil due to corruption in the country, and are found in fossil shops and museums all over the world, and that if current regulations were followed many fossils would simply be destroyed rather than collected. [14]

When the fossil was collected is unknown. Dave Martill asserted in an interview to a Brazilian journalist that it was possible that the fossil was exported prior to 1942, but stated that ultimately he didn't "care a damn how [or when] the fossil came from Brazil", saying that it was irrelevant to its scientific significance. Martill stated that he was "critical of all laws that interfere with the science of paleontology; and blanket bans on fossil collecting are indiscriminatory and only hinder science ... They also lead to xenophobia -- Brazil fossils for Brazilians, British fossils for Brits. It should be fossils for all. No countries existed when the animals were fossilized." When asked why he did not include a Brazilian scientist on the study, Martill remarked that he was unaware of any Brazilian snake researchers when writing the study (though he later became aware of one following the controversy), but followed with "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." [13] Martill remarked several years later in 2020 that he felt his comments in the interview were poorly worded. [15] Nicholas Longrich, a co-author of the study, remarked that he would like to see the fossil returned to Brazil. [11]

Aside from the export issues, the fact that the specimen was in a private collection when described also caused controversy, and the owner of the fossil reportedly made it difficult for later researchers to study the specimen. [16] In 2024, the fossil of Tetrapodophis was donated to National Museum of Brazil. [17]

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

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 related to mosasaurs. [4] [18] A position supported by later analysis in 2018 [5] and in 2021. [6]

Cladogram after Caldwell et. al. 2021: [6]

Anguimorpha

However, a study in 2023 again supported its position as a stem-snake, finding it to be unrelated to mosasaurs. [3]

Related Research Articles

<span class="mw-page-title-main">Ophidia</span> Group of squamate reptiles

Ophidia is a group of squamate reptiles including modern snakes and reptiles more closely related to snakes than to other living groups of lizards.

<span class="mw-page-title-main">Mosasaur</span> Extinct marine lizards of the Late Cretaceous

Mosasaurs are an extinct group of large aquatic reptiles within the family Mosasauridae that lived during the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. They belong to the order Squamata, which includes lizards and snakes.

<span class="mw-page-title-main">Pythonomorpha</span> Clade of lizards

Pythonomorpha was originally proposed by paleontologist Edward Drinker Cope (1869) as a reptilian order comprising mosasaurs, which he believed to be close relatives of Ophidia (snakes). The etymology of the term Pythonomorpha comes from the Greek Python and morphe ("form"), and refers to the generally serpentine body plan of members of the group. Cope wrote, "In the mosasauroids, we almost realize the fictions of snake-like dragons and sea-serpents, in which men have been ever prone to indulge. On account of the ophidian part of their affinities, I have called this order Pythonomorpha." Cope incorporated two families, the Clidastidae and the Mosasauridae.

<i>Dinilysia</i> Extinct genus of snakes

Dinilysia is an extinct genus of snake from the Late Cretaceous (Coniacian) of South America. Dinilysia was a relatively large ambush predator, measuring approximately 2 m (6.6 ft) long. The skull morphology of Dinilysia is similar to boids, suggesting that it was able to consume large prey. Living in a desert-like environment, Dinilysia is likely a terrestrial or a semi-fossorial animal.

<span class="mw-page-title-main">Madtsoiidae</span> Extinct family of snakes

Madtsoiidae is an extinct family of mostly Gondwanan snakes with a fossil record extending from early Cenomanian to late Pleistocene strata located in South America, Africa, India, Australia and Southern Europe. Madtsoiidae include very primitive snakes, which like extant boas and pythons would likely dispatch their prey by constriction. Genera include some of the longest snakes known such as Vasuki, measuring at least 11–15 metres (36–49 ft) long, and the Australian Wonambi and Yurlunggur. As a grouping of basal forms the composition and even the validity of Madtsoiidae is in a state of flux as new pertinent finds are described, with more recent evidence suggesting that it is paraphyletic as previously defined.

<i>Adriosaurus</i> Extinct genus of lizards

Adriosaurus is an extinct genus of squamate which lived in what is now Slovenia and other parts of Europe during the Late Cretaceous. It was a small, snake-like reptile, with the type species Adriosaurus suessi measuring up to 30 cm (12 in) in length. Adriosaurus represents the first occurrence of vestigial limbs in fossil lizards, having lost its manus and forearm completely in order to elongate its axial skeleton. These unique anatomical features led to discussions of the evolutionary patterns of limb reduction in Squamata.

<i>Kaganaias</i> Extinct genus of lizards

Kaganaias is an extinct genus of basal and oldest dolichosaur that lived in what is now Japan during the Early Cretaceous. Kaganaias was semi-aquatic and is the only known aquatic squamate known from before the Cenomanian stage of the Cretaceous. It is also the first to be found in an inland area, instead of on the coast where aquatic squamates are commonly found. Its generic name is derived from Kaga Province, the old name for the Ishikawa Prefecture where the specimens were found, while the species name hakusanensis comes from the mountain that gives its name to Hakusan the city near its find site. The geological formation in which the specimens were found, the Kuwajima Formation, stands alongside the Tetori River and has been the site of numerous other finds including molluscs, dinosaurs, fish, and pterosaurs.

<i>Carsosaurus</i> Extinct genus of lizards

Carsosaurus is a genus of extinct amphibious reptiles, in the mosasaur superfamily, containing only the species Carsosaurus marchesetti. It is known from a single individual that lived during the Upper Cretaceous in what is now Slovenia. The specimen is well-preserved, containing many different bones as well as some skin impressions and sternal cartilage. While more remains are needed to be certain, it is generally thought to belong to the Aigialosauridae. In life, it was an amphibious creature that spent most of its time on land, although its later relatives would become fully aquatic.

Parviraptor is a genus of squamate containing one species, Parviraptor estesi, from the Late Jurassic (Tithonian) or Early Cretaceous (Berriasian) Purbeck Limestone Formation of Dorset, England. A second species, Parviraptor gilmorei, was described from the Late Jurassic Morrison Formation of Western North America; it was present in stratigraphic zone 4. However, the second species was subsequently transferred to a separate genus Diablophis. An indeterminate species is known from the Bathonian aged Kirtlington Mammal Bed.

<span class="mw-page-title-main">Timeline of mosasaur research</span>

This timeline of mosasaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, and taxonomic revisions of mosasaurs, a group of giant marine lizards that lived during the Late Cretaceous Epoch. Although mosasaurs went extinct millions of years before humans evolved, humans have coexisted with mosasaur fossils for millennia. Before the development of paleontology as a formal science, these remains would have been interpreted through a mythological lens. Myths about warfare between serpentine water monsters and aerial thunderbirds told by the Native Americans of the modern western United States may have been influenced by observations of mosasaur fossils and their co-occurrence with creatures like Pteranodon and Hesperornis.

Eophis is an early genus of stem-snake containing one species, Eophis underwoodi, from the Middle Jurassic (Bathonian) from the Forest Marble Formation of United Kingdom. It is known from a fragmentary dentary from Kirtlington Quarry. It was previously interpreted as an anguimorph lizard. The placement of Eophis as a stem snake was re-affirmed by subsequent analyses.

<span class="mw-page-title-main">Dolichosauridae</span> Extinct family of lizards

Dolichosauridae is a family of Cretaceous aquatic lizards. They are widely considered to be the earliest and most primitive members of Mosasauria, though some researchers have recovered them as more closely related to snakes.

<span class="mw-page-title-main">Ophidiomorpha</span> Clade of lizards

Ophidiomorpha is a proposed clade composed of snakes and a number of extinct squamate groups. The clade was defined by Placi and Caldwell in 2007 as a node-based clade containing the most recent common ancestor of dolichosaurs, adriosaurs, Aphanizocnemus, and fossil and extant Ophidia and all of its descendants.

<span class="mw-page-title-main">Mosasauria</span> Extinct squamates of the Cretaceous period

Mosasauria is a clade of aquatic and semiaquatic squamates that lived during the Cretaceous period. Fossils belonging to the group have been found in all continents around the world. Early mosasaurians like dolichosaurs were small long-bodied lizards that inhabited nearshore coastal and freshwater environments; the Late Cretaceous saw the rise of large marine forms, the mosasaurids, which are the clade's best-known members.

Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 2018.

This list of fossil reptiles described in 2019 is a list of new taxa of fossil reptiles that were described during the year 2019, as well as other significant discoveries and events related to reptile paleontology that occurred in 2019.

This list of fossil reptiles described in 2020 is a list of new taxa of fossil reptiles that were described during the year 2020, as well as other significant discoveries and events related to reptile paleontology that occurred in 2020.

This list of fossil reptiles described in 2015 is a list of new taxa of fossil reptiles that were described during the year 2015, as well as other significant discoveries and events related to reptile paleontology that occurred in 2015.

References

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