135-million-year-old crocodile unveils secrets of dinosaur-dominated seas

In the shallow waters that once covered Germany, a crocodile with a dolphin-like body thrived 135 million years ago.

During the Cretaceous Period, this ancient marine crocodile lived alongside some of the most terrifying dinosaurs.

This period saw the peak diversity of dinosaurs, with famous species such as Tyrannosaurus rex, Triceratops, and Velociraptor roaming the land. In the skies, giant pterosaurs soared, while some big marine reptiles ruled the oceans.

An international team of researchers recently described this new crocodile species using its fossilized remains found some time ago. The new-to-science species has been scientifically named Enalioetes Schroeder.

Three-dimensional fossil preservation

Thanks to a remarkably well-preserved skull, the researchers were able to reconstruct the lifestyle and behavior of this extinct crocodile.

This ancient reptile belonged to a group called Metriorhynchidae, known for its dolphin-like adaptations. With smooth scaleless skin, flippers, and a powerful tailfin, it was perfectly suited to life in the water.

Enalioetes, with their “serrated teeth” and streamlined bodies, were likely top-notch hunters. These predators feasted on fish and squid, but some even hunted other marine reptiles.

Although Metriorhynchids flourished in the Jurassic, their fossil record thins considerably in the Cretaceous.

The researchers highlight that exceptional three-dimensional preservation of the ancient creature’s skull offers a rare glimpse into this later period.

“Enalioetes gives us fresh insight into how metriorhynchids were evolving during the Cretaceous Period. During the Jurassic metriorhynchids evolved a body-plan radically different from other crocodiles—flippers, tailfin, loss of bony armor and smooth scaleless skin,” said Mark Young from the University of Edinburgh.

Young further explained: “These changes were adaptations to an increasingly marine lifestyle. Enalioetes shows us that this trend continued into the Cretaceous, as Enalioetes even larger eyes than other metriorhynchids (which were already big by crocodylian standards) and the bony inner ears were even more compact than other metriorhynchids, a sign that Enalioetes was probably a faster swimmer.”

Fossil found several years ago

The fossilized skull, which comprises the skull and the first neck, was found over a century ago in a quarry near Hannover, Germany.

To identify the new crocodile species , the researchers matched the fossil to other known examples.

“The specimen is remarkable as it is one very few metriorhynchids that is known by a three-dimensionally preserved skull. This allowed us to CT scan the specimen and so we were able to learn a lot about the internal anatomy of these marine crocodiles. The remarkable preservation allowed us to reconstruct the internal cavities and even the inner ears of the animal,” said Sven Sachs, the project leader from the Naturkunde-Museum Bielefeld.

This fossil has an interesting past; it was lost and rediscovered.

Initially, the fossil underwent preparation under the care of Henry Schroeder of the Prussian Geological Survey in Berlin. ​​However, the fossil was thought to have been lost during World War II. Years later, it resurfaced in the Minden Museum in western Germany. As per the press release , the finder’s family relocated to Minden post-war, bringing the fossil and ending up in the museum.

And it’s now helping researchers in piecing together the Cretaceous crocodile diversity puzzle.

The findings were published in the Journal of Systematic Palaeontology.