Interesting fossil reptiles provide clues to the origin of snakes and lizards

Twenty years after its discovery in Argentina, paleontologists have detailed a 231.4 million year old Lepidosaurus fossil. This animal has characteristics mentioned previously The division between lizards, snakes and sphenodonts (the branch of reptiles which today includes is just peculiar tuatara). The fossilized skull recently underwent a CT scan and a multidisciplinary team of researchers published Their analysis of the sample will be published this week in Nature.

Animal Taitura Alkoberi. To the untrained eye, it looks a lot like a lizard (a rusty gecko, to this writer). but the Animal anatomy is much older, something?The research team found out when they could examine the fossil in detail. Nothing survived of the animal’s body except for the skull – which is about an inch and a half long-He is Study co-author Gabriella Sobral, who oversaw the CT scan, told Harvard University: Press release. Seeing the skull in three dimensions gave new insight into how the skulls of snakes, chameleons, geckos, tuatara, and the like were derived.

“Almost perfectly preserved Taitura The skull shows us details of how a group of animals work, including: About 11,000 species have emerged, including snakes, lizards and tuatara ”, said Ricardo Martinez, lead author of the study and paleontologist at the National University of San Juan in Argentina.

“Taitura It shows some features that we thought were exclusive to the tuatara group, ”Martínez wrote in an email to Gizmodo. “Skull Taitura The early lepidoosaurs are shown to be more like a tuatara than a squat, and this species is therefore a significant departure from their ancestral model.NOT. ” Squamates are a group of reptiles made up of Snakes, lizards and lizards worms.

It was discovered in Argentina in 2001 (Martínez said: “I found it on the surface and picked it up”), T. koberic This is what researchers callspecies of stump,” a Term for animals that branch out earlier in the evolutionary tree Genealogy that still exists Until our days. In other words, they previously developed species that did not have living things. Grandsons. T. koberic It is an evolutionary branch that refers to the form of life before Lepidosaurs divided into two groups: squats and sphenodonts. In any event T. koberic They are smaller than some lizards – the oldest cartilage and sphenodont fossils are 242 million and 238 million years old, respectively – their shape is even older. The history of the reptile dates back to the Triassic Tyrannosaurus Rex over 150 million years ago.

T. koberic He had a number of traits that Tiago Simões, an evolutionary biologist at Harvard University and co-author of the research paper, said to be distinctive. It lacked a muzzle opening common in archosaurs, an evolutionary lineage that includes crocodiles and dinosaurs. Its square bone, which connected the skull to the lower jaw, had a peculiar shape. But the CT scan really brought it home: the animal had alternate bones for squats and sphenodonts.

The tuatara, a modern lizard species endemic to New Zealand, was the only sphenodont living on Earth For about 60 million years. Due to its relatively unchanged anatomy over the centuries, the tuatara is often referred to as a “living fossil”. And T. koberic This poster confirms, as the fossil animal looks much more like a tuatara than a chameleon, legless lizards and snakes.

Simões applied Bayesian analysis to place the fossil in the evolutionary tree. The modeling means that the research team can estimate when specific adaptations in lepidosaurs evolved and how quickly they changed. Bayes’ method confirmed to the team T. koberic It is the most primitive member of the reptile genus from which all lizards and snakes originate.

“In science, we never look for real answers or evidence, because the basic principles of science prohibit the existence of real answers… Basically, these trees are never true and change regularly over time. But if after future analyzes and perhaps new data, the placement Taitura Simões said in an email to Gizmodo:

The fossil is an important step towards understanding modern reptiles. In other words, those who did not fall with the dinosaurs. With the exception of crocodiles, many of these animals were small and lived in the shadow of giants for millions of years.

“We’re so used to accepting that the Mesozoic was the age of giant reptiles, giant proto-mammals, and giant trees, so we usually look for fossils that can be seen at human height, just by walking. Most of the components of the old ecosystem were small, as they are today. Co-author Sebastian Apisteguia, paleontologist at Maimonides University in Buenos Aires, said in Press release.

It’s always nice to see a few newly discovered twigs on the Tree of Life, but it’s probably even cooler to see clues about how whole branches initially look. T. koberic It’s just that; Small remnants of a large crack between the reptiles.

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