Paleontologists Discover a 231 Million Year Old Fossil of a Tuatara-like Reptile | Paleontology

A three-dimensionally preserved skull of a previously unknown Argentine reptile from the Triassic period sheds light on the origin of lepidosauromorphs (lizards, snakes and tuataras).

Reconstruction of the life of Taytalura alcoberi. Image credit: Jorge Blanco.

Taytalura alcoberi lived in what is now Argentina during the Upper Triassic period, about 231 million years ago.

The ancient reptile was a member of Lepidosauromorpha, a large group that includes squamates (lizards and snakes) and sphenodontians (tuataras).

“Lepidosauromorphs and archosauromorphs represent the two main branches of the tree of life of reptiles that have survived to the present day,” said Dr. Ricardo Martínez of the Instituto y Museo de Ciencias Naturales of the Universidad Nacional de San Juan and his colleagues.

“Today, the former mainly include squamates (about 11,000 species of lizards, snakes and amphisbaenians) and the latter are mainly represented by birds (about 10,800 species).”

“However, unlike archosauromorphs, the early evolution of lepidosauromorphs remains one of the greatest gaps in knowledge of reptile evolution.”

Taytalura alcoberi holotype.  Image credit: Martínez et al., doi: 10.1038/s41586-021-03834-3.

Holotype of Taytalura alcoberi. Image credit: Martinez et al., doi: 10.1038/s41586-021-03834-3.

Taytalura alcoberi predates the split between squamates and sphenodontians, and is close to the origin of lepidosauromorphs.

The species is about 11 million years younger than the oldest known lepidosauromorphs from Europe and approximately the same age as the oldest known South American lepidosauromorphs.

The skull of Taytalura alcoberi shares features with modern tuataras, suggesting that several anatomical features, presumed exclusive to sphenodontians, must have originated early in the evolution of lepidosauromorphs.

Taytalura alcoberi suggests that the highly conserved skull architecture during sphenodontian evolution represents the plesiomorphic condition of all lepidosaurs, that stem and crown lepidosaurs were contemporaneous for at least 10 million years during the Triassic period, and that the first lepidosauromorphs had a much wider geographical distribution than before. thought,” the paleontologists said.

Their paper was published in the journal Nature.


RN Martinez et al. A Triassic stem lepidosaur sheds light on the origin of lizard-like reptiles. Nature, published online August 25, 2021; doi:10.1038/s41586-021-03834-3

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