 |
| Craspedochelys renzi Cadena, Carrillo-Briceño, Bastiaans, Fairbanks-Freund, Costeur & Scheyer, 2025 Illustration by Juan Giraldo |
Abstract
Thalassochelydians represent one of the earliest radiations of coastal to marine-adapted turtles, spanning from the Jurassic to Cretaceous periods. This study describes Craspedochelys renzi sp. nov., a new thalassochelydian, “plesiochelyid” turtle from the Hauterivian stage of the Early Cretaceous in Colombia. It is the youngest and the only known record of “Plesiochelyidae’ outside Europe. The holotype, housed at the Naturhistorisches Museum Basel, was rediscovered after over 60 years and includes a partial shell, hindlimb bones, and caudal vertebrae. C. renzi shares key traits with “Plesiochelyidae”, including a V-shaped posterior plastral lobe lacking an anal notch; an indentation at the hypoplastra-xiphiplastra contact; an “intermediate” bone between neural 8 and suprapygal 1; a fully ossified carapace and bridge; and absence of carapacial fontanelles. Within “Plesiochelyidae”, it is assigned to Craspedochelys by its broader carapace, with an estimated length/width ratio of 4.12 for left costal 4, similar to other species in the genus; a relatively shorter plastron; and wider hyoplastra. Geological evidence links the specimen to the Moina Formation, a shallow marine deposit from the Hauterivian. This discovery expands the genus’ spatial and temporal range, underscoring its evolutionary and paleobiogeographic significance. It highlights the importance of museum collections in re-evaluating long-overlooked specimens, enriching our understanding of past biodiversity and turtle dispersal patterns.
 |
| Craspedochelys renzi sp. nov. represented by an articulated shell with some postcranial bones. A, B Carapace in dorsal view and interpretative line drawing; C, D Plastron in ventral view, with some postcranial bones and their respective interpretative line drawing. Bones are indicated by dark grey, sutures by white lines, sulci by yellow lines, fractures and margins by black lines, and the rock matrix by light ochre shadows. Abbreviations: Abd, abdominal scute; Ana, anal scute; Co, costal bone; Fem, femoral scute; fem, femur; fib, fibula; Hum, humeral scute; hyo, hyoplastron; hyp, hypoplastron; Inf, inframarginal scute; Int, intermediate bone; isc, ischium; ne, neural bone; P, pleural scute; pe, peripheral bone; Pec, pectoral scute; py, pygal bone; sp, suprapygal bone; tib, tibia; V, vertebral scute; xip, xiphiplastron |
Craspedochelys renzi sp. nov.
 |
| Artistic reconstruction of Craspedochelys renzi sp. nov. 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 (Joyce et al., 2021). Illustration by Juan Giraldo |
Edwin-Alberto Cadena, Jorge D. Carrillo-Briceño, Dylan Bastiaans, Tandra Fairbanks-Freund, Loïc Costeur and Torsten M. Scheyer. 2025. The First Occurrence of “Plesiochelyidae” Marine Turtles in the early Cretaceous of South America. Swiss Journal of Palaeontology. 144; 52. DOI: doi.org/10.1186/s13358-025-00394-1 [25 August 2025]
