Paleontologists have identified four fossilized snake skeletons as belonging to a new species of ancient python. At roughly 47 million years old, the specimens are the oldest python fossils ever found, a discovery which has reconfigured the evolutionary tree of these serpents, reports Katherine Kornei for the New York Times. The new find pushes the origins of pythons back some 20 million years, according to a paper published earlier this month in the journal Biology Letters.
The fossils emerged from Germany’s Messel Pit, a former shale mine that is now a UNESCO World Heritage Site. The fossil bed is famous for providing a window into the evolution of early mammals during the Eocene (57 to 36 million years ago).
Discovering this early python, named Messelopython freyi, in Europe suggests the serpents may have first evolved in the Northern Hemisphere rather than in the Southern Hemisphere where most of their living relatives are found today, reports Laura Geggel for Live Science.
"So far, there have been no early fossils that would help decide between a Northern and Southern Hemisphere origin," Krister Smith, a paleontologist at the Senckenberg Research Institute in Frankfurt and co-author of the paper, tells Live Science via email. "Our new fossils are by far the oldest records of pythons, and (being in Europe) they support an origin in the Northern Hemisphere."
To discern the fossils’ status as a brand new species of python, the researchers compared the four specimens to others from museum collections around the world. The full menagerie included 90 different species of snakes and lizards, and the comparisons involved computerized tomography scans and microscopic examination, per the Times. These comparisons yielded 785 characteristics cataloging the number, arrangement and proportion of vertebrae, teeth and other bones.
Messelopython freyi was around 3.2 feet long and had some 275 vertebrae, according to the paper. Apart from highlighting the possibility that pythons first evolved in Europe, the find may also have interesting implications for when and why pythons and their slithering cousins boa constrictors may have diverged.
In the modern world, boas and pythons do not naturally occur together anywhere on Earth despite their similar appearances and shared predilection for squeezing the life out of their prey. But back in the Eocene it seems boas and pythons must have competed for the same prey, since the remains of both have been found in the Messel Pit.
“In Messel, both Messelopython freyi as well as primitive boas such as Eoconstrictor fischeri lived together in the same ecosystem—we therefore have to revisit the thesis that these two groups of snakes competed with each other, making them unable to share the same habitats,” says Smith in a statement.
The paper’s co-author, paleontologist Hussam Zaher of the University of São Paulo in Brazil, tells Live Science that we may be able to learn more about how these groups of snakes competed with one another by unearthing additional fossils of each in Europe, especially those with preserved stomach contents. Alternatively, Zaher says Florida, where introduced species of pythons and boas have each successfully established themselves, could offer a window into this ancient ecological matchup.