Researchers led by Tiago Simões of Princeton University have found that early snakes evolved across burrowing, land, and sea environments about 80 million years ago.
The origin of snakes has long been debated in evolutionary biology, with scarce fossil records making it difficult to determine what triggered their limbless body shape, according to Phys.org. Scientists debated for decades whether the elongated body adapted to burrowing or living in water, but a study in Nature refutes both single-path theories.
The study was led by Simões, an assistant professor at Princeton, alongside lead authors Nicolas Di-Poï of the University of Helsinki and Annie Hsiou of the University of São Paulo, working with an international team. Simões said the findings show early snakes achieved impressive ecological and morphological diversity in the Late Cretaceous period.
Brain anatomical analysis
The researchers described a new snake species, Tametara mirim, from Late Cretaceous deposits in southeastern Brazil dating back about 80 million years. The species ranks among the best-preserved fossil snake skeletons known worldwide. The team reconstructed the fossil using computed tomography and cinematic 3D visualization, revealing details of the skull, vertebrae, and brain endocast.
Simone Macrì, a research fellow, and Di-Poï, a research leader at the HiLIFE Institute of Life Science at the University of Helsinki, led the reconstruction and comparative analysis of brain anatomy. They linked early neuroanatomy to sensory ecology and habitat evolution by comparing Tametara with Dinilysia patagonica, a fossil specimen from Argentina.
Di-Poï explained that brain shape and bone microstructure showed Tametara was adapted to burrowing while Dinilysia lived on land. Brain shapes in both species differed strikingly from each other and most other studied snakes. Combined with marine deposit data, the findings indicate multiple transitions between burrowing, land, and sea habitats much earlier than previously thought.
Macrì said the brain provides a richer history than skeletons alone. Combining CT reconstructions with data from living snakes showed that early snakes experimented with diverse sensory and ecological strategies rather than moving toward a single modern state or following one evolutionary path.
Guam brown tree snake study
In other snake research, scientists have gained new insights into how brown tree snakes triggered a destructive wildlife invasion on Guam. The snakes, which are hunted by some mammals, expanded across the island.
A new study showed that hidden genetic diversity may have helped the brown tree snakes survive inbreeding conditions, adapt to their new environment, and reproduce throughout Guam.
