a specimen fossil of a sea turtle which had been collected in the 1950s by the Swiss geologist Otto Renz during an expedition in the Cuña de Cuiza region, department of La Guajira, Colombiait turned out to be a species that had not been discovered so far.
A study published by a group of Swiss paleontologists in the popular science magazine Swiss Journal of Palaeontology, explains the particularities of the specimen rediscovered and named as a new species, Craspedochelys renziwhich dates from the lower Cretaceousthat is, more than 125 million years.
The fossil was preserved in excellent condition over six decades, embedded in a biosparite limestone matrix. The experts clarified that it was labeled correctly, with information about the locality where it was found, but the advancement of technology and the new questions that scientists asked were key.
«It was kept in the paleontological collections of the Basel Natural History MuseumSwitzerland, where remained forgotten for more than 60 years in the cabinets of fossil invertebrate collections,» indicated the paleontologists who made the discovery in the introduction of the published paper.
Two of the co-authors, Jorge D. Carrillo-Briceño and Loïc Costeurcarried out an examination of the fossil collection from Latin America and thus found the holotype of the shell and other bone remains.
They analyzed part of the articulated carapace, bones of the hind limbs and several caudal vertebrae. through high-resolution photography and digital microscopy, which allowed them to identify decisive anatomical details.
They detailed the measures of the preserved shellof 25.5 centimeters long and 23.1 wide. He plastron -the flattened structure that makes up the ventral part of the turtle shell- preserved almost completely in the shape of a V in the posterior lobe.
All these particularities allowed the species to be located within the extinct family of turtles Plesiochelyidae.
Craspedochelys renzithe new species of sea turtles discovered
The new species of marine reptilescalled Craspedochelys renzibelongs to a lineage of sea turtles primitive species whose fossil record was until now concentrated in Europe in the late Jurassic.
But this discovery in northern South America implies reconsidering the dispersal patterns and survival of primitive sea turtles, since not only was the fossil classified, but the geological context and its position on the evolutionary tree.
The results suggest that these turtles also inhabited northern Gondwana during the Hauterivian, the floor of the Lower Cretaceous, therefore expanding the temporal and geographical map of the group.
«This context suggests a dynamic marine ecosystempossibly with high availability of nutrients, where these turtles adapted to coastal waters could develop,» said the paleontologists who led the research.
Throughout their evolution, different unrelated groups of turtles adapted again and again to live in marine environments and coastlines. In this case, the possible coexistence of different lineages of sea turtleswhich shared habitats during the early Cretaceous.
This implies changes in the conception of the evolutionary history of these marine reptiles, with a broader geographical and temporal range.
«Es the youngest record known so far of the thalassochelydians throughout the world, Hauteriviense -the stage of the Lower Cretaceous that is located between 132 and 125 million years ago-, and the second record of the group outside of Europe,» they stated in the article.
This displacement forces us to reconsider the dispersal and survival patterns of primitive sea turtles. Although it involves reanalyzing all the available information, the publication of the material generated enthusiasm in the scientific community.
The results demonstrated that correctly stored parts can provide essential information when analyzed with new methodologies and the constant updating of tools.
