Pterosaur finger bone from Cretaceous of Denmark + Byeoljubuchelys, new turtle from Early Cretaceous from South Korea (free pdfs)

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

Recent papers:

Free pdf:

Jesper Milàn, Sten Lennart Jakobsen, and Bent Erik Kramer Lindow (2025)
A diminutive pterosaur from the uppermost Maastrichtian chalk of Denmark
Acta Palaeontologica Polonica 70(4): 723-730
doi:10.4202/app.01252.2025
https://www.app.pan.pl/article/item/app012522025.html

A fragment of pterosaur finger bone was found in the chalk in the uppermost Maastrichtian, Højerup Member of the Møns Klint Formation strata of Holtug quarry at the UNESCO World Heritage site Stevns Klint. This represents the first record of this group from the chalk of Denmark. The specimen is identified a fragment of a left proximal phalanx 1 of digit IV by comparison with similar elements showing the overall three-pronged expression of the posterior, ventral and olecranon processes. The dimensions of the specimen shows that small-bodied pterosaurs with a wingspan of less than 50 cm persisted through to the last 50 000–60 000 years of the Cretaceous. It overlaps in size with contemporaneous birds, rejecting previous hypotheses that Late Cretaceous pterosaurs and birds avoided competition through size-based niche partitioning.

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Free pdf:

Byeoljubuchelys yeosuensis gen. et sp. nov.

Minguk Kim, Jongyun Jung, Walter G. Joyce, Jae-Il Park, Hye-Yeon Jung, Hyemin Jo & Min Huh (2025)
A new, Early Cretaceous carettochelyid turtle from South Korea provides insights into softshell evolution and aquatic ecology
Swiss Journal of Palaeontology 144: 75
doi: https://doi.org/10.1186/s13358-025-00415-z
https://link.springer.com/article/10.1186/s13358-025-00415-z


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.

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