Paleontologists have described a new species of the extinct turtle genus Craspedochelys based on a remarkable fossil shell and some of its postcranial bones from Colombia.
Artistic reconstruction of Craspedochelys renzi and the shallow marine ecosystem where inhabited; the forelimbs with a flippler like shape is based on the most complete thalassochelydian known so far, Thalassemys bruntrutana. Image credit: Juan Giraldo.
Craspedochelys renzi lived during the Hauterivian age of the Early Cretaceous epoch, between 132 and 125 million years ago.
The ancient species was a type of thalassochelydian, a group of marine-adapted turtles from the Jurassic and Cretaceous periods.
“Throughout their evolution, various unrelated groups of turtles have developed adaptations to live in marine and littoral environments,” said Dr. Edwin-Alberto Cadena, a paleontologist at the Universidad del Rosario, Smithsonian Tropical Research Institute and Field Museum of Natural History, and his colleagues.
“One of these groups is called Thalassochelydia, formed traditionally by three Jurassic families: Eurysternidae, Plesiochelyidae, and Thalassemydidae, with unresolved and controversial phylogenetic relationships.”
“Of the three families that constitute the thalassochelydians, ‘Plesiochelyidae’ is one of the most diverse, including at least ten species in four different genera: Craspedochelys, Plesiochelys, Portlandemys, and Tropidemys.”
“Shells of ‘plesiochelyids’ can be distinguished from other thalassochelydians by exhibiting large sizes (carapace length of 40-55 cm), the absence of carapacial fontanelles in adults, an osseous bridge, and, at most, a central plastral fontanelle.”
Craspedochelys renzi represented by an articulated shell with some postcranial bones. Image credit: Cadena et al., doi: 10.1186/s13358-025-00394-1.
The fossil specimen of Craspedochelys renzi was initially discovered by the Swiss geologist Otto Renz during a fieldwork expedition to the Cuña de Cuiza region, Guajira Department of Colombia in the 1950s.
The specimen included a partial shell (25.5 cm in length and 23.1 cm in width), hindlimb bones, and caudal vertebrae.
Subsequently, it was housed at the paleontological collections of the Naturhistorisches Museum Basel, Switzerland, where it remained forgotten for more than 60 years in the cabinets of fossil invertebrate collections.
“Geological evidence links the specimen to the Moina Formation, a shallow marine deposit from the Hauterivian,” the paleontologists said.
The fossil represents the youngest record known so far for thalassochelydians worldwide, from the Hauterivian, and the second record of the group outside of Europe.
“The discovery of Craspedochelys renzi represents a significant contribution to the understanding of thalassochelydian, particularly of the ‘plesiochelyid’ turtles, extending their geographic range to northern Gondwana and their temporal range into the Hauterivian,” the researchers said.
“This finding underscores the importance of reevaluating historical collections and highlights the potential for future discoveries in underexplored regions like northern South America.”
“The presence of Craspedochelys renzi in the Moina Formation further emphasizes the complex paleobiogeographic history of costal and marine turtles during the Early Cretaceous.”
“It also offers new insights into the evolutionary dynamics of Thalassochelydia and the still-controversial and unstable phylogenetic relationships within the group, issues that warrant further, in-depth investigation in future studies.”
The discovery of Craspedochelys renzi is reported in a paper in the Swiss Journal of Palaeontology.
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EA. Cadena et al. 2025. The first occurrence of ‘Plesiochelyidae’ marine turtles in the Early Cretaceous of South America. Swiss J Palaeontol 144, 52; doi: 10.1186/s13358-025-00394-1
