Ancient crocodile had dolphin-like flippers and smooth skin

Once upon a time, around 135 million years ago, a unique crocodile roamed the seas during the age of dinosaurs. This marine predator, recently identified as Enalioetes schroederi, offers a fascinating glimpse into the diversity and lifestyle of ancient marine creatures.

The discovery of this species unveils a new chapter in our understanding of prehistoric crocodiles. The tale is set in the shallow seas of Germany during the Cretaceous Period, when Enalioetes schroederi thrived.

The crocodile belonged to the unique Metriorhynchidae family, distinguished by their dolphin-like bodies, smooth scaleless skin, flippers, and a tailfin.

Well-preserved, three-dimensional skull

Metriorhynchids, primarily known from the Jurassic Period, hunted various prey – squid, fish, and even other marine reptiles.

But as Earth moved into the Cretaceous Period, their fossils began to fade from the record. The well-preserved, three-dimensional skull of the Enalioetes schroederi stands as the most significant metriorhynchid discovery from this era.

Sven Sachs, the project leader from Naturkunde-Museum Bielefeld, expressed his fascination. “The specimen is remarkable as it is one very few metriorhynchids that is known by a three-dimensionally preserved skull.”

The exceptional condition of the specimen enabled CT scans, revealing hidden secrets of the internal anatomy of these marine crocodiles. The experts were able to reconstruct internal cavities and even the inner ears of the animal.

Evolution of ancient crocodiles

Enalioetes sheds light on the evolution of metriorhynchids during the Cretaceous Period. Dr. Mark Young from the University of Edinburgh’s School of GeoSciences gives us a deeper understanding of the significance of the discovery.

“During the Jurassic, metriorhynchids evolved a body-plan radically different from other crocodiles – flippers, tailfin, loss of bony armor and smooth scaleless skin,” explained Dr. Young. This transformation was driven by adaptations to an increasingly marine lifestyle.

Enalioetes had larger eyes and more compact bony inner ears than other metriorhynchids, which indicates it was a faster swimmer. These traits also suggest that the transformation of metriorhynchids continued into the Cretaceous.

The tale of the lost and found fossil

Interestingly, the perfectly preserved skull and first neck vertebrae were discovered more than a century ago by German government architect D. Hapke in a quarry near Hannover. The specimen was assumed lost during WWII, but was later rediscovered in the Minden Museum, Western Germany.

Initially studied by Henry Schroeder of the Prussian Geological Survey in Berlin, the species was eventually named in his honor.

The conclusions drawn from this discovery were possible only through a meticulous comparison of the newly found fossil with other museum collections.

This comparative study confirmed that the fossil belonged to a species new to science, reinforcing our curiosity and fascination with the world’s prehistoric times.

The ecological role of an ancient crocodile

Understanding the ecological role of Enalioetes schroederi provides valuable insight into the prehistoric marine ecosystems.

As a member of the Metriorhynchidae family, this ancient marine crocodile occupied a significant niche in the Cretaceous seas. With its streamlined body and adaptations for aquatic life, Enalioetes was likely an apex predator, preying on a variety of marine life, including fish and cephalopods.

Fossil evidence suggests that metriorhynchids, including Enalioetes, played a crucial role in maintaining the balance of prehistoric marine ecosystems. The hunting habits would have influenced the populations of their prey, helping to shape the biodiversity of their environment.

Furthermore, the presence of such predators indicates a thriving ecosystem with a range of prey species, underscoring the importance of these creatures in our understanding of ancient marine life.

Moreover, studying the dietary habits and ecological interactions of Enalioetes schroederi can shed light on how marine reptile predators adapted over time in response to environmental changes. As climate and sea levels fluctuated throughout the Cretaceous, these adaptations would have been critical for survival.

The fossil record not only provides a glimpse into the physical characteristics of these ancient creatures but also presents an opportunity to explore their behavior and ecological significance in the broader context of Earth’s history.

As researchers continue to analyze the find from Hannover, it opens up avenues for further studies into the evolutionary trends of marine reptiles and their ecosystems.

Image Credit: Joschua Knüppe

The study is published in the journal Journal of Systematic Palaeontology.

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