The first fossil loggerhead sea turtle (Cheloniidae: Caretta) from the North Pacific and its nannofossil biostratigraphy
Abstract The Taiwan waters (western North Pacific) include five sea turtle species without an associated fossil record. Here, we describe the first fossil sea turtle from Taiwan. This fossil material is a partial hypoplastron from the uppermost Yuching Shale in Tainan. The preserved morphology of th...
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SpringerOpen
2025-07-01
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| Series: | Swiss Journal of Palaeontology |
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| Online Access: | https://doi.org/10.1186/s13358-025-00392-3 |
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| author | Yi-Lu Liaw Chih-Kai Chuang Cheng-Hsiu Tsai |
| author_facet | Yi-Lu Liaw Chih-Kai Chuang Cheng-Hsiu Tsai |
| author_sort | Yi-Lu Liaw |
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| description | Abstract The Taiwan waters (western North Pacific) include five sea turtle species without an associated fossil record. Here, we describe the first fossil sea turtle from Taiwan. This fossil material is a partial hypoplastron from the uppermost Yuching Shale in Tainan. The preserved morphology of this partial hypoplastron shows a slightly curved medial margin, a deep lateral notch, and a wide sutural anterior margin, indicating a taxonomic affinity to the genus Caretta. In comparison with extant Caretta, the preserved hypoplastral width at the sutural level (130.85 mm) suggests that this fossil belongs to an old subadult cf. Caretta. In addition, we also analyzed fossil foraminifera from the matrix of this hypoplastron, suggesting that the depositional environment was a continental shelf no more than 100 m deep. We further examined the nannofossils and found more than 200 calcareous nannofossils, including index fossils, such as Pseudoemiliania lacunosa, Helicosphaera sellii, and large Gephyrocapsa sp. (> 5.5 μm), corresponding to NN19a nannofossil biozone (Early Pleistocene in age). Given the first occurrence of the large Gephyrocapsa sp. and the last occurrence of Helicosphaera sellii, we narrowed down the age of this Pleistocene sea turtle from Taiwan to 1.57 to 1.28 million years ago. Our discovery of this Pleistocene sea turtle fossil represents not only the first cheloniid fossil in Taiwan but also the first well-dated fossil sea turtle from the global Pleistocene. The Taiwan waters during the Early Pleistocene may be a paleo-foraging ground for cf. Caretta, and future fieldwork and analysis should reveal a more detailed evolutionary history of sea turtles in the North Pacific. Our results also highlight the potential for more paleontological progress from Taiwan. |
| format | Article |
| id | doaj-art-bf1e2d78d23a4d29bc5fcbc0be5e3956 |
| institution | Kabale University |
| issn | 1664-2376 1664-2384 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | SpringerOpen |
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| series | Swiss Journal of Palaeontology |
| spelling | doaj-art-bf1e2d78d23a4d29bc5fcbc0be5e39562025-08-20T03:46:16ZengSpringerOpenSwiss Journal of Palaeontology1664-23761664-23842025-07-01144111110.1186/s13358-025-00392-3The first fossil loggerhead sea turtle (Cheloniidae: Caretta) from the North Pacific and its nannofossil biostratigraphyYi-Lu Liaw0Chih-Kai Chuang1Cheng-Hsiu Tsai2Department of Life Science, National Taiwan UniversityClimate Change Research Center, National Environmental Research AcademyDepartment of Life Science, National Taiwan UniversityAbstract The Taiwan waters (western North Pacific) include five sea turtle species without an associated fossil record. Here, we describe the first fossil sea turtle from Taiwan. This fossil material is a partial hypoplastron from the uppermost Yuching Shale in Tainan. The preserved morphology of this partial hypoplastron shows a slightly curved medial margin, a deep lateral notch, and a wide sutural anterior margin, indicating a taxonomic affinity to the genus Caretta. In comparison with extant Caretta, the preserved hypoplastral width at the sutural level (130.85 mm) suggests that this fossil belongs to an old subadult cf. Caretta. In addition, we also analyzed fossil foraminifera from the matrix of this hypoplastron, suggesting that the depositional environment was a continental shelf no more than 100 m deep. We further examined the nannofossils and found more than 200 calcareous nannofossils, including index fossils, such as Pseudoemiliania lacunosa, Helicosphaera sellii, and large Gephyrocapsa sp. (> 5.5 μm), corresponding to NN19a nannofossil biozone (Early Pleistocene in age). Given the first occurrence of the large Gephyrocapsa sp. and the last occurrence of Helicosphaera sellii, we narrowed down the age of this Pleistocene sea turtle from Taiwan to 1.57 to 1.28 million years ago. Our discovery of this Pleistocene sea turtle fossil represents not only the first cheloniid fossil in Taiwan but also the first well-dated fossil sea turtle from the global Pleistocene. The Taiwan waters during the Early Pleistocene may be a paleo-foraging ground for cf. Caretta, and future fieldwork and analysis should reveal a more detailed evolutionary history of sea turtles in the North Pacific. Our results also highlight the potential for more paleontological progress from Taiwan.https://doi.org/10.1186/s13358-025-00392-3Calcareous nannofossilEarly PleistoceneForaminiferaFossil recordTaiwan |
| spellingShingle | Yi-Lu Liaw Chih-Kai Chuang Cheng-Hsiu Tsai The first fossil loggerhead sea turtle (Cheloniidae: Caretta) from the North Pacific and its nannofossil biostratigraphy Swiss Journal of Palaeontology Calcareous nannofossil Early Pleistocene Foraminifera Fossil record Taiwan |
| title | The first fossil loggerhead sea turtle (Cheloniidae: Caretta) from the North Pacific and its nannofossil biostratigraphy |
| title_full | The first fossil loggerhead sea turtle (Cheloniidae: Caretta) from the North Pacific and its nannofossil biostratigraphy |
| title_fullStr | The first fossil loggerhead sea turtle (Cheloniidae: Caretta) from the North Pacific and its nannofossil biostratigraphy |
| title_full_unstemmed | The first fossil loggerhead sea turtle (Cheloniidae: Caretta) from the North Pacific and its nannofossil biostratigraphy |
| title_short | The first fossil loggerhead sea turtle (Cheloniidae: Caretta) from the North Pacific and its nannofossil biostratigraphy |
| title_sort | first fossil loggerhead sea turtle cheloniidae caretta from the north pacific and its nannofossil biostratigraphy |
| topic | Calcareous nannofossil Early Pleistocene Foraminifera Fossil record Taiwan |
| url | https://doi.org/10.1186/s13358-025-00392-3 |
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