Faculty, Staff and Student Publications
Publication Date
1-1-2025
Journal
Swiss Journal of Palaeontology
DOI
10.1186/s13358-025-00415-z
PMID
41378096
PMCID
PMC12686080
PubMedCentral® Posted Date
12-8-2025
PubMedCentral® Full Text Version
Post-print
Abstract
Here, we present a new Cretaceous carettochelyid turtle, Byeoljubuchelys yeosuensis gen. et sp. nov., from the Lower Cretaceous Hasandong Formation of Yeosu, Korea. A nearly complete shell and select elements of the girdles and limbs provide crucial insight into the evolution and aquatic adaptation of this family. Phylogenetic analyses place Byeoljubuchelys yeosuensis at the most basal position within Carettochelyidae. The mid-sized plastron of Byeoljubuchelys yeosuensis appears to be plesiomorphic for the group. The expansion of the plastron during carettochelyid evolution, especially during the Paleogene, may be an evolutionary response to increasing body size or the threat of mammalian predators. Although the shell of Byeoljubuchelys yeosuensis lacks distinct scute sulci, traces are apparent that are reminiscent of juvenile scutes in the extant Carettochelys insculpta, suggesting that scute loss was facilitated in trionychian evolution through the thickening of the epidermis. Byeoljubuchelys yeosuensis possesses a plesiomorphic humerus with a proximally located lateral process and a sigmoidal shaft lacking torsion, implying rowing locomotion rather than the underwater flapping seen in more recent carettochelyids. The repeated acquisition of a softshell in two clades of trionychians during the mid-Cretaceous may be related to an environmental shift towards humid climates at that time, perhaps reflecting a remarkable adaptation to freshwater ecosystems.
Keywords
Byeoljubuchelys yeosuensis, Early Cretaceous, Hasandong formation, Korea, Carettochelyidae, Paleoecology, Micro-CT
Published Open-Access
yes
Recommended Citation
Kim, Minguk; Jung, Jongyun; Joyce, Walter G; et al., "A New, Early Cretaceous Carettochelyid Turtle From South Korea Provides Insights Into Softshell Evolution and Aquatic Ecology" (2025). Faculty, Staff and Student Publications. 6385.
https://digitalcommons.library.tmc.edu/uthgsbs_docs/6385
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