Fossil of Brazilian burrowing snake reveals evolutionary pathways among reptiles – Jornal da USP

The newly described species was named Tametara mirim, meaning “small ornament”, in reference to the sagittal crest, a prominence along the midline of the skull. “This species has characteristics that help us understand the origin and evolution of snakes. It is considered a primitive snake from the Brazilian Cretaceous period”, the researcher emphasized.

Annie Hsiou noted that the species’ main characteristics include being small, with a preserved body length of about 42 centimeters and an estimated skull length of 3.3 cm. “The skull is highly specialized with primitive and unique characteristics such as a well-developed sagittal crest, strongly overlapping bones, and distinctive features in the occipital and mandibular regions”, she reported. “The absence of forelimbs is also notable, indicating that limb reduction had already occurred at this stage of snake evolution. The hind limbs could not be assessed, as the cloacal region was not preserved.”

“The brain was preserved indirectly, allowing us to reconstruct its shape and that of the inner ears, something unprecedented for such an ancient snake. Its lifestyle was fossorial; that is, it was a burrower. This conclusion is supported by various lines of evidence, such as brain shape, inner ear structure, and microstructure of the skull bones. These are combined with statistical analyses comparing its anatomy to that of modern snakes”, explained the paleontologist from USP’s Laboratory of Integrated Paleobiodiversity (LAPI).