Paleontologists have identified a new species within the extinct turtle genus Craspedochelys, based on some remarkable fossil shells and subsequent bones discovered in Colombia.
Artistic reconstruction of Craspedochelys Renzi and the shallow marine ecosystem it inhabited. The flip-like shape of the forelimbs is inspired by the most complete known specimen of Thalassemys bruntrutana. Image credit: Juan Guilard.
Craspedochelys Renzi thrived during the early Cretaceous Hauterivian period, approximately 132 to 125 million years ago.
This ancient species belonged to the Thalassocheridia, a group of marine-adapted turtles from the Jurassic and Cretaceous eras.
“Throughout their evolutionary journey, various unrelated turtle groups have developed adaptations for marine and coastal habitats,” says Dr. Edwin Alberto Cadena, a paleontologist at the Smithsonian Tropical Research Institute of Natural History.
“One such group is the Thalassocheridia, traditionally classified into three Jurassic families: Eurysternidae, Plesiochelyidae, and Thalassemydidae, which have complex and often debated phylogenetic relationships.”
“Among these families, the ‘Plesiochelyidae’ is particularly diverse, encompassing at least ten species across four different genera: Craspedochelys, Plesiochelys, Portlandomys, and Tropidemys.”
“The shells of ‘Plesiochelyids’ can be distinguished from other thalassocheridians by their large size (40-55 cm in shell length), with adults lacking the thyroid cortex of the hanging skin, typically displaying only a thick layer of fontanel in the center.”
Craspedochelys Renzi is characterized by a distinct shell featuring several occipital bones. Image credits: Cadena et al. , doi: 10.1186/s13358-025-00394-1.
The fossil specimen of Craspedochelys Renzi was first discovered by Swiss geologist Otto Lenz during a field expedition in the Cunja de Cuisa region of Guazila Province, Colombia, in the 1950s.
This specimen included partial shells measuring 25.5 cm long and 23.1 cm wide, along with hind limb bones and caudal vertebrae.
It was later stored in the paleontological collection of the Naturhistorisches Museum Basel in Switzerland, where it remained unnoticed for over 60 years among the fossil invertebrate collection.
“Geological evidence connects these specimens to shallow marine sediments from the Moina Formation, dating to the Hauterivian,” the paleontologist explained.
This fossil represents the youngest known occurrence of Thalassocheridians globally during the Hauterivian, and it is the second record from a non-European group.
“The discovery of Craspedochelys Renzi will greatly enhance our understanding of Thalassocheridians, particularly the ‘Plesiochelyidae’, expanding their geographical range to North Gondwana and temporal range to the Hauterivian,” the researchers stated.
“This find underlines the significance of reevaluating historical collections and the potential for future discoveries in less explored areas such as northern South America.”
“The existence of Craspedochelys Renzi in the Moina Formation further underscores the intricate paleobiogeographic history of early Cretaceous coastal habitats and marine turtles.”
“It also offers new perspectives on the evolutionary dynamics of Thalassocheridia and the still unresolved, unstable phylogenetic relationships within the group, which necessitates further detailed investigation in future research.”
The discovery of Craspedochelys Renzi is discussed in a paper published in the Swiss Journal of Palaeontology.
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ea. Cadena et al. 2025. The first occurrence of the “Plesiochelyidae” turtle in the early Cretaceous period of South America. Swiss J Palaeontol 144, 52; doi:10.1186/s13358-025-00394-1
Source: www.sci.news
