A new study, published in Historical Biology, has revealed a stunning fossil discovery in Vienna, reshaping our understanding of prehistoric reptiles in Europe. Paleontologists have identified a 12.2-million-year-old fossilized skin plate that proves alligators survived in Europe a million years longer than previously believed.
A Forgotten Fossil Unlocks a Prehistoric Mystery
For over a hundred years, a fossil plate sat unloved in the Natural History Museum in Vienna, identified as a turtle shell. It was only after a more detailed investigation by vertebrate paleontologist Ursula Göhlich that it became apparent.
The fossil’s unusual rectangular shape and the presence of deep pits do not fit any known turtles. The shape was rather like bony skin plates of alligators. A further analysis revealed it belonged to a crocodilian species called Diplocynodon that lived in swampy Europe.
A district in northwest Vienna that was once a rich fossil find, Hernals was where the discovery was made. Clay pits in the region produced a wide variety of marine fossils in the 19th century, including those of seals, dolphins, and sea turtles. Finding a freshwater alligator fossil suggests the reptile’s body was washed out to the ocean, perhaps via rivers or floodwaters.
The Last Alligator in Europe?
The most astonishing detail of this discovery is its age. Previous research suggested that alligators disappeared from Europe around 13.6 million years ago, coinciding with a period of global cooling. However, the Vienna Diplocynodon is 12.2 million years old, meaning these prehistoric alligators survived far longer than previously thought.
This makes it the youngest alligator fossil ever found in Central Europe, rewriting the extinction timeline of European crocodilians. The implications are profound: if alligators persisted in Europe despite cooling temperatures, then something else—besides climate change—must have driven them to extinction.
Did Drought, Not Cold, Wipe Out Europe’s Alligators?
Until now, scientists believed that falling CO₂ levels and cooling temperatures during the Miocene epoch made Europe too cold for crocodilians. But the survival of Diplocynodon for an additional million years challenges this theory.
Modern alligators, such as the American alligator, can survive in near-freezing conditions. They enter a state of brumation, where they remain motionless underwater with only their nostrils exposed above the ice. If Diplocynodon had similar adaptations, it could have withstood cooling temperatures longer than expected.
Instead, researchers now believe that a period of extreme drought, rather than temperature shifts, may have been the real cause of their extinction. Around 12 million years ago, Europe experienced a drying phase, which drastically reduced wetlands and swamps—the primary habitat of Diplocynodon. With fewer rivers and marshes to sustain them, these reptiles gradually vanished.
A Glimpse Into Europe’s Lost Subtropical World
To understand why alligators once thrived in Europe, we have to go back 12 million years, when the continent looked vastly different. At that time, Central and Eastern Europe were part of a subtropical archipelago, surrounded by the Paratethys Sea—a vast, warm inland sea that stretched from present-day Austria to Kazakhstan.
These swampy islands were home to a variety of wildlife, including seals, dolphins, turtles, and early mammals. Diplocynodon was one of the top predators of this ecosystem, hunting fish, birds, and small mammals in slow-moving rivers and coastal wetlands.
However, as the Paratethys retreated and Europe’s landscapes shifted, many of these species—including alligators—faced extinction. The newly analyzed fossil from Vienna offers the last known evidence of these ancient reptiles in Europe, suggesting that they outlasted previous estimates before finally disappearing.
