Scientists have broken a missing bridge in the reptile’s tree of life.
This link is the small skull of a “profusely ornamented” lizard-like creature with features that suggest it gave rise to all the living lizards, snakes and the only survivor of another group of reptiles found only in New Zealand.
Called Taytalura alcoberi, the fossilized skull is set to be the most primitive-scale reptile discovered to date, the first fossil of its kind unearthed in South America and the earliest lepidosaur fossil ever found, according to the international team behind the discovery.
Lepidosaurs are scale reptiles such as lizards, snakes and the New Zealand Tuatara, which together represent the most diverse group of living vertebrates on earth today. However, little is known about its early origins compared to the other arms of reptile evolution that produced crocodiles, birds, and turtles.
“The almost perfectly preserved Taytalura skull shows us details of how a very successful group of animals originated, including more than 10,000 species of snakes, lizards and tuatara, ”says museum paleontologist and curator Ricardo N. Martínez of the National University of San Juan in Argentina.
The discovery of the one-inch-long skull also makes scientists reconsider what they knew about Mesozoic-era reptiles, which are often known for their huge reptiles and tall trees, and rethink where they should be. ‘go in search of ancient reptile fossils.
“There was a universe of wildlife sneaking between the larger legs, with claws or stones,” says paleontologist and co-author Sebastián Apesteguía at Maimónides University in Buenos Aires.
An illustration of Taytalura. (Jorge Blanco, 2021).
“Taytalura teaches us that we lacked important information looking not only for larger animals, but also thinking that the origin of lizards only occurred in the northern hemisphere, as evidence seemed to support it so far.”
The fossil, located in the Ischigualasto Provincial Park in northwestern Argentina, is about 11 million years younger than the oldest known lepidosaurs in Europe, but is one of the best preserved specimens of this type. , which means the team can have more confidence in their analysis.
“It looked more primitive than a real lizard and that’s something pretty special,” says Tiago R. Simões about his first impressions of the skull, which measures 32 mm (1.25 inches) long.
The fossilized Taytalura skull. (Ricardo Martinezl).
It is a fortunate finding, especially considering that the origins of lepidosaurs have been an open hole in evolutionary knowledge due to an “extremely irregular early fossil record comprising only a handful of fragmentary fossils,” which is found mainly in Europe. and which is often poorly preserved. .
“The rest of the known fossils are too incomplete, making it difficult to classify them with certainty, but the complete and articulate nature of Taytalura makes their relationships much more secure,” says team member and paleontologist Gabriela Sobral. , from the State Museum of Natural History. Stuttgart in Germany.
In a continental effort, the research team examined the structure of the skull using a high-resolution micro-CT scanner and analyzed the images. He Taytalura the skull had unique teeth and an unusual combination of features that the team did not expect to find in such an early specimen, preserved in three dimensions of striking detail.
“The extraordinary quality of fossil preservation at this site [in Argentina] it allowed us to preserve something as fragile and small as this specimen for 231 million years, ”says Martínez.
Tayta means Quechua father, the language of the Quechua people of the South American Andes, and back is the Kakán’s word for lizard, spoken by the people of Diaguita in northwestern Argentina, where the skull was found.
Restoration of the life of the Taytalura skull. (Jorge Blanco, Gabriela Sobral and Ricardo Martínez).
Some of its features were more like modern tuatara than live lizards and snakes, suggesting that the latter actually represents a major deviation in evolution, not so much the tuatara living in the wind-swept New Zealand islands.
Martinez and the team also deployed statistical tools to check the likelihood of possible evolutionary relationships Taytalura, and to estimate the timing of several evolutionary exits that branched out into other life forms.
These analyzes, based on a complete data set of reptile fossils, helped Taytalura it finds its place in the evolutionary tree, located between true lizards and tuatara, and in all other reptiles.
In addition, the discovery of Taytalura in Argentina suggests that the first lepidosaurs were able to migrate much further than previously thought, through thousands of miles to the ancient supercontinent Pangea that later split into the continents we see today: northern Europe and South America in the opposite hemisphere.
The whole journey of this little reptile.
The research was published in Nature.