Paleontologists Find Unique Dolphin-Like Marine Crocodile From the Age of Dinosaurs

A newly discovered species of marine crocodile from 135 million years ago has been described from Germany.

It’s new species of the ancient sea-mint, Enalioetes schroederidescribed by an international team of scientists, including researchers from Germany and the UK. This species lived about 135 million years ago in the shallow seas that once covered most of Germany during the Cretaceous Time.

This ancient crocodile was a member of the Metriorhynchidae family, a remarkable group that developed a dolphin-like body plan. Metriorhynchids had smooth skin, wings and a tailfin. They fed on a variety of prey, including fast-moving animals such as squid and fish, but some metriorhynchid species had large, sharp teeth indicating that they fed on other reptiles of the sea. Metriorhynchids are best known from Jurassic Time, with their fossils becoming rare in the Cretaceous. Enalioetes schroederi is known for its three-dimensional skull, making it the best-preserved metriorhynchid known from the Cretaceous.

Advanced Imaging Reveals Detailed Anatomy

Sven Sachs, from the Naturkunde-Museum Bielefeld and project leader, said: “This specimen is remarkable as it is one of the very few known metriorhynchids with a preserved three-dimensional skull. This allowed us to examine CT specimen and thus we were able to learn a lot about the internal structure of these marine crocodiles. That amazing preservation helped us to reconstruct the internal cavities and even the inner ears of that animal.”

Dr Mark Young, from the University of Edinburgh’s School of GeoScience, explains: “Analioetes gives us new insight into how metriorhynchids were evolving during the Cretaceous Period. During the Jurassic metriorhynchids developed a body plan that is very different from other crocodiles – fins, tailfins, loss of bone armor and smooth skin without scales. These changes were to adapt to the increasingly marine lifestyle. Analioetes shows us that this trend continued into the Cretaceous, as Analioetes it had larger eyes than other metriorhynchids (which were already large by crocodylian standards) and bony inner ears that were harder than other metriorhynchids , which is an indication that Analioetes maybe it was a fast swim.”

A perfectly preserved skull and the first vertebrae of the neck were discovered more than a century ago by the German government expert D. Hapke in a quarry in Sachsenhagen near Hannover. This model has an interesting history. It was given for preparation and study to Henry Schroeder of the Prussian Geological Survey in Berlin where it was supposed to be included in the collection. This led to speculation that the model was lost during WWII. The specimen was later rediscovered in the Minden Museum in West Germany. It turned out that the model had been returned to the person who found it which his family had brought to Minden where they found a new home after WW2, taking the model with them. The mint is therefore one of the most important specimens in the Minden collection.

Henry Schroeder of the Berlin Geological Survey gave the first description, and after him, the species is named.

By comparing the fossils with those from other museum collections, Sachs and his team discovered a new kind of science.

Reference: “A new species of metriorhynchid crocodylomorph from the Lower Cretaceous of Germany” by Sven Sachs, Mark T. Young, Jahn J. Hornung, Thomas Cowgill, Julia A. Schwab and Stephen L. Brusatte, 18 July 2024, Journal of Systematic Palaeontology.
DOI: 10.1080/14772019.2024.2359946