A fast swimmer with a crocodile’s mouth: A Cretaceous fossil discovered almost 100 years ago near Hanover has turned out to be a very special find – a new representative of the scaleless saltwater crocodiles. The reptile, which lived 135 million years ago, has unusually large eyes and the characteristics of a fast swimmer. The species, named Enalioetes schroederi, is also one of the youngest representatives of these saltwater crocodiles, widespread in the Jurassic and early Cretaceous periods, as reported by paleontologists.
During the Jurassic and Cretaceous periods, Europe resembled an island world divided by warm, shallow sea areas. In addition to dinosaurs and early risers, prehistoric crocodiles also lived there. Unlike their modern descendants, some of these prehistoric crocodiles not only spent time in the water, but were also completely adapted to life in the ocean: they had fins instead of legs and their skin was scaleless and smooth like that of a dolphin.
Many fossils of these marine dinosaurs from the Metriorhynchidae group were discovered, among other places, around 200 years ago. in fine-grained limestone slabs Southern Germany, but it is also found further north.
Discovered 100 years ago, then lost
Now, paleontologists have taken a closer look at one of these German crocodile fossils and discovered something surprising. The fossil examined is a 135-million-year-old intact skull, including the first cervical vertebrae, discovered more than 100 years ago in a quarry in Sachsenhagen near Hanover. “This discovery is remarkable because it is one of the few metriorhynchid fossils for which there is a preserved three-dimensional skull,” says lead author Sven Sachs from the Bielefeld Natural History Museum.
However, it was previously unclear which marine dinosaur the find was. It was first assigned to the little-studied genus Enaliosuchus and then to Cricosaurus. Since the fossil was considered lost for decades, its identity remained unclear. The fossil was only recently rediscovered at the Minden Museum. “This allowed us to scan the skull using computed tomography and learn more about the internal anatomy of this saltwater crocodile,” says Sachs. “We were able to reconstruct the skull cavities and even the animal’s inner ear.”
A fast and big-eyed hunter
The analyses revealed: The long-enigmatic fossil belongs to a previously unknown genus and species of saltwater crocodiles. “The new species differs from all known metriorhynchids by a unique combination of characteristics,” the paleontologists report. Like all its relatives, this saltwater crocodile had neither scales nor fins in place of legs. In addition, the crocodile, named Enalioetes schroederi, was even more adapted to hunting prey in the open sea.
“Enalioetes had even larger eyes than other saltwater crocodiles, whose visual organs were already larger than those of other crocodiles,” says co-author Mark Young of the University of Edinburgh. “Their ossified inner ears were also more compact than those of other metriorhynchids – an indication that Enalioetes was an even faster swimmer than them.”
One of the last representatives of saltwater crocodiles
The fossil saltwater crocodile discovered near Hanover offers new insights into the marine life of Europe 135 million years ago. The discovery proves that saltwater crocodiles existed not only in Central Europe in the Jurassic, but also in the Cretaceous. At the same time, the fossil expands the spectrum of scaleless saltwater crocodiles to include another genus.
“Enalioetes schroederi contributes to the sparse population of Cretaceous metriorhynchids and represents one of the stratigraphically youngest occurrences of this group of marine dinosaurs,” Sachs and colleagues write. “This discovery may help expand our knowledge of Cretaceous marine dinosaur diversity.” (Journal of Systematic Palaeontology, 2024; is that i: 10.1080/14772019.2024.2359946)
Source: University of Edinburgh
August 13, 2024 – Nadja Podbregar