![\"Life](\"https:\/\/cdn.sci.news\/images\/enlarge13\/image_14942_1e-Tametara-mirim.jpg\")
<\/a><\/p>\nLife reconstruction of Tametara mirim. Image credit: Gabriel Ugueto.<\/p>\n
\u201cSnakes are essentially highly modified lizards,\u201d said<\/a> co-author Dr. Roy Ebel, a researcher at the Museums Victoria Research Institute.<\/p>\n \u201cSometime in the age of dinosaurs, one lizard lineage lost its limbs and stretched out its body. The key question is why.\u201d<\/p>\n \u201cFor more than a century, several ideas have competed with each other.\u201d<\/p>\n \u201cOne says the first snakes colonized the water, with a long, limbless body suited for swimming, much like an eel.\u201d<\/p>\n \u201cA second says they lived on the surface of the land, among leaf litter and vegetation, where reduced limbs could have eased their movement through dense ground cover.\u201d<\/p>\n \u201cA third says they went underground, losing their limbs and elongating their bodies to pursue a head-first burrowing lifestyle, much like modern blind snakes.\u201d<\/p>\n \u201cThe trouble is that the evidence has rested on a tiny handful of fossils. Fewer than ten early snake skeletons are known from that era.\u201d<\/p>\n In their research, Dr. Ebel and colleagues examined an exceptionally preserved skull and postcranial material of a previously unknown species of stem snake.<\/p>\n Named Tametara mirim, the reptile lived in what is now Brazil during the Late Cretaceous epoch, roughly 85 to 75 million years ago.<\/p>\n The fossil was unearthed in 2020 at a quarry near Presidente Prudente in the Brazilian state of S\u00e3o Paulo.<\/p>\n The specimen is the first articulated snake fossil ever found in Brazil, and one of only a handful of three-dimensionally preserved snake fossils from the Mesozoic era anywhere in the world.<\/p>\n What sets Tametara mirim apart is the extraordinary detail preserved in its skull.<\/p>\n Using high-resolution CT scanning, the paleontologists reconstructed the animal\u2019s brain, cranial nerves and inner ear in unprecedented detail, producing what they describe as the most complete picture yet of brain anatomy in a stem snake.<\/p>\n Their reconstruction revealed a brain shape unlike that of any other early snake or any snake alive today, suggesting far more variation in brain structure \u2014 and likely sensory ability \u2014 during snake evolution than scientists had previously recognized.<\/p>\n Dr. Ebel and co-authors paired the brain data with an analysis of the fossil\u2019s bone microstructure, a technique that can reveal an animal\u2019s lifestyle from the density and thickness of its skeleton.<\/p>\n Both lines of evidence pointed independently to the same conclusion: Tametara mirim was a burrowing animal.<\/p>\n \u201cHead-first burrowers build denser, thicker bone in the skull roof,\u201d Dr. Ebel said.<\/p>\n \u201cThis trait has independently evolved across numerous burrowing lizard lineages.\u201d<\/p>\n \u201cWe presume this consolidates the skull against the strain exerted during its use as a digging tool.\u201d<\/p>\n \u201cTametara mirim shows exactly this trait combination,\u201d he said.<\/p>\n \u201cIn fact, our lifestyle reconstruction positions the fossil among the most specialised head-first burrowers living today, and well away from any lizards and snakes that pursue a more generalist lifestyle.\u201d<\/p>\n \u201cBut the skull roof was not our only line of evidence.\u201d<\/p>\n \u201cWe also digitally rebuilt its brain cavity, the most detailed such reconstruction yet for any early snake.\u201d<\/p>\n \u201cThis cavity would have closely matched the shape of the brain in the living animal.\u201d<\/p>\n \u201cThe reduced visual centres and simplified forebrain point the same way the bones do: underground.\u201d<\/p>\n The holotype of Tametara mirim. Image credit: Sim\u00f5es et al., doi: 10.1038\/s41586-026-10809-9.<\/p>\n<\/a><\/p>\n