A 180-million-year-old fossil has revealed an odd creature, a crocodile with a tail like a dolphin, shedding light on the evolution of these ancient animals and how they became one of the greatest predators of the Jurassic period.
Researchers are hailing this new species as a “missing link” in the crocodile family tree. Their findings, published in PeerJ, are helping to explain how some ancient crocodiles evolved into dolphin-like creatures.
It all began in 1996, when an amateur collector found the fossil on a mountainside in the Gerecse Mountains of north-west Hungary. The specimen was stored at the Hungarian Natural History Museum in Budapest until in 2017, researchers examined it more thoroughly and noticed the odd-looking vertebra on its tail fin.
During the Lower Jurassic, there existed crocodiles that had bony armor on their backs and bellies and had adapted to walk on land. There were also ones that had evolved flippers and had tail fins, but no armor. This fossil, however, appeared to have been both heavily armored and have a tail fin, making it not only a new species, but, according to the researchers, the missing link between the two groups.
“This fossil provides a unique insight into how crocodiles began evolving into dolphin and killer whale-like forms more than 180 million years ago,” said Dr Mark Young of the University of Edinburgh's School of GeoSciences. “The presence of both bony armor and a tail fin highlights the remarkable diversity of Jurassic-era crocodiles.”
Based on the teeth, jaw, pelvis, and armor fragments found of Magyarosuchus fitosi – named after its founder, Attila Fitos – would have been around 5 meters (16 feet) long, and belonged to the Thalattosuchia group of crocodiles that first adapted to marine life. With large pointed teeth, perfect for snapping up fish and small reptiles, it would have been successful on both land and in the sea, making it a formidable predator.
“Because of this tail fin, it would have been better adapted to living in the ocean than any crocodile we have today but, based on what was preserved of its legs, would have been able to come back on land,” Dr Young told The Times. “This creature was long-jawed so it would have preyed on fish or small reptiles.”
The researchers were particularly excited by this fortuitous discovery that has expanded our knowledge of the evolutionary history of crocodiles, because the sedimentary layer of rock the fossil was discovered in comes from the Tethys Ocean, suggesting the slope it was found on was once deeply submerged by open ocean, which very rarely yields vertebrate fossils.
It looks like there is much we can learn from this strange hybrid creature then. Keep being weird, Jurassic crocodiles.