The first occurrence of “Plesiochelyidae” marine turtles in the early cretaceous of South America

What is it about?

A new species of ancient costal-marine turtle, Craspedochelys renzi, from rocks in Colombia dating back about 130 million years (Early Cretaceous period). These turtles, called thalassochelydians, were among the first groups to adapt to life in coastal and marine environments. Until now, fossils of their family, the “plesiochelyids,” had only been found in Europe. This makes the Colombian find not only the youngest record of the group, but also the only one discovered outside Europe. The fossil, kept for over 60 years in the collections of the Naturhistorisches Museum in Basel, Switzerland, includes parts of the shell, hindlimbs, and tail bones. Careful study revealed features typical of “plesiochelyids,” such as a fully solid shell without openings and distinctive shapes in the plastron (the lower shell). Its broader shell and shorter lower shell confirm it belongs to the genus Craspedochelys. The specimen comes from the Moina Formation, a shallow sea deposit in Colombia, showing that these turtles once lived along South American coasts. This discovery broadens our knowledge of turtle evolution and how these animals dispersed across ancient oceans. It also demonstrates the hidden value of museum collections for revealing new insights into Earth’s past biodiversity.

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Photo by Aaron De Wit on Unsplash

Photo by Aaron De Wit on Unsplash

Why is it important?

This discovery is important because it changes what we know about the early history and distribution of marine turtles. Until now, fossils of the “plesiochelyid” turtles had only been found in Europe, suggesting they were restricted to that region. The Colombian specimen shows that these turtles also reached South America, expanding both their geographic range and survival into the Early Cretaceous. This makes Craspedochelys renzi the youngest and only record of the group outside Europe. It provides new evidence that ancient marine turtles were more widespread and adaptable than previously thought, helping us understand how they dispersed across prehistoric oceans. Beyond its scientific significance, the find highlights the value of museum collections: the fossil was stored for decades before its importance was recognized. Re-examining old specimens can therefore lead to groundbreaking discoveries, offering fresh perspectives on biodiversity and the evolutionary history of major animal groups.

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