Craspedochelys renzi, new marine turtle species from Cretaceous of Colombia + Jurassic pliosaurid(?) attack on nautilid
48 views
Skip to first unread message
Ben Creisler
Aug 26, 2025, 4:04:43 PM (12 days ago) Aug 26
to DinosaurMa...@googlegroups.com
Ben Creisler
Edwin-Alberto Cadena, Jorge D. Carrillo-Briceño, Dylan Bastiaans, Tandra Fairbanks-Freund, Loïc Costeur & 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: https://doi.org/10.1186/s13358-025-00394-1
https://link.springer.com/article/10.1186/s13358-025-00394-1
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.
Sreepat Jain, Mariusz A. Salamon, Christian Klug, Dean R. Lomax, Bartosz J. Płachno and Piotr Duda (2025)
An unusual predator-prey relationship inferred from a Bathonian (Middle Jurassic) nautilid from southern Poland
Lethaia 58(3):
doi: https://doi.org/10.18261/let.58.3.5
https://www.scup.com/doi/10.18261/let.58.3.5
The records of sub-lethally or lethally injured nautilids are rare, as are their Bathonian (Middle Jurassic) occurrences. Here, we report a large nautilid (88 mm shell diameter) from the Polish Jura (southern Poland), which was ventrally bitten at its phragmocone. It is a Cenoceras sp. from the middle Bathonian (Bremeri Zone) of the Gnaszyn brick-pit associated with the ammonite Prohecticoceras. Although coeval strata have yielded records of predatory shark teeth belonging to Palaeobrachaelurus, Protospinax, Sphenodus, and an orectolobiform, the bite traces on the nautilid are morphologically different and are at least 13 times larger, thus ruling out sharks as predators. Other plausible predators include marine reptiles such as pliosaurid plesiosaurs, thalattosuchian crocodylomorphs or ichthyosaurs, other cephalopods such as large squids, ammonites or even nautilids (including cannibalism). Based on the morphology and dimensions of the bite marks, the most likely candidate appears to be a pliosaurid whose remains have been well-recorded from the Middle and Upper Jurassic rocks of Poland. Regarding the predation attempt, it appears to have been lethal but possibly was a failed attack from the right side of the organism, as evidenced by the bite marks on its ventral surface. It is conceivable that the plesiosaur was unable to grasp the thick and presumably slippery nautiloid firmly after the first bite as reflected by the presence of only two 20 mm-wide bite marks, and then dropped the nautilid. Alternatively, it managed to rip the soft parts out of the conch and dropped the latter without further crushing it.
Marine reptile-related papers:
Free pdf:
Craspedochelys renzi sp. nov.
Edwin-Alberto Cadena, Jorge D. Carrillo-Briceño, Dylan Bastiaans, Tandra Fairbanks-Freund, Loïc Costeur & 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: https://doi.org/10.1186/s13358-025-00394-1
https://link.springer.com/article/10.1186/s13358-025-00394-1
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.
====
Free pdf:
Sreepat Jain, Mariusz A. Salamon, Christian Klug, Dean R. Lomax, Bartosz J. Płachno and Piotr Duda (2025)
An unusual predator-prey relationship inferred from a Bathonian (Middle Jurassic) nautilid from southern Poland
Lethaia 58(3):
doi: https://doi.org/10.18261/let.58.3.5
https://www.scup.com/doi/10.18261/let.58.3.5
The records of sub-lethally or lethally injured nautilids are rare, as are their Bathonian (Middle Jurassic) occurrences. Here, we report a large nautilid (88 mm shell diameter) from the Polish Jura (southern Poland), which was ventrally bitten at its phragmocone. It is a Cenoceras sp. from the middle Bathonian (Bremeri Zone) of the Gnaszyn brick-pit associated with the ammonite Prohecticoceras. Although coeval strata have yielded records of predatory shark teeth belonging to Palaeobrachaelurus, Protospinax, Sphenodus, and an orectolobiform, the bite traces on the nautilid are morphologically different and are at least 13 times larger, thus ruling out sharks as predators. Other plausible predators include marine reptiles such as pliosaurid plesiosaurs, thalattosuchian crocodylomorphs or ichthyosaurs, other cephalopods such as large squids, ammonites or even nautilids (including cannibalism). Based on the morphology and dimensions of the bite marks, the most likely candidate appears to be a pliosaurid whose remains have been well-recorded from the Middle and Upper Jurassic rocks of Poland. Regarding the predation attempt, it appears to have been lethal but possibly was a failed attack from the right side of the organism, as evidenced by the bite marks on its ventral surface. It is conceivable that the plesiosaur was unable to grasp the thick and presumably slippery nautiloid firmly after the first bite as reflected by the presence of only two 20 mm-wide bite marks, and then dropped the nautilid. Alternatively, it managed to rip the soft parts out of the conch and dropped the latter without further crushing it.
Reply all
Reply to author
Forward
0 new messages