The first pan-trionychid turtle from the Upper Cretaceous of southern China, with a summary of the turtle succession in the Ganzhou Basin

YUZHENG KE, FENGLU HAN, and WALTER G. JOYCE

Ke, Y., Han, F., and Joyce, W.G. 2025. The first pan-trionychid turtle from the Upper Cretaceous of southern China, with a summary of the turtle succession in the Ganzhou Basin. Acta Palaeontologica Polonica 70 (3): 607–612.

Pan-trionychids are a group of aquatic turtles with a geological occurrence from the Early Cretaceous to the present. Here, we report a small pan-trionychid specimen from the Upper Cretaceous Zhoutian Formation of the Ganzhou Basin of Jiangxi Province, China, which consists of a nearly complete carapace and several associated fragments. The specimen is the first definitive pan-trionychid record from the Upper Cretaceous of southern China. Its general skeletal features are comparable with those of other pan-trionychids from the mid Cretaceous of Asia. However, because the specimen appears to be a juvenile and lacks sufficient anatomical details, we refrain from naming a new species or hypothesizing phylogenetic relationships. Upper Cretaceous sediments in the Ganzhou Basin document a succession of turtle faunas ranging from aquatic pan-trionychids to semi-aquatic lindholmemydids to possibly terrestrial nanhsiungchelyids, but the relationship between this succession and paleoclimate remains ambiguous.

Key words: Pan-Trionychidae, Ganzhou Basin, Cretaceous, Zhoutian Formation, China.

Yuzheng Ke [key1480@163.com; ORCID: 0000-0002-3728-898X ], School of Earth Sciences, China University of Geosciences (Wuhan), Wuhan 430074, China. Department of Geosciences, University of Fribourg, 1700 Fribourg, Switzerland.

Fenglu Han [hanfl@cug.edu.cn; ORCID: 0000-0003-3399-4008 ] (corresponding author), School of Earth Sciences, China University of Geosciences (Wuhan), Wuhan 430074, China.

Walter G. Joyce [walter.joyce@unifr.ch; ORCID: 0000-0003-4726-2449 ], Department of Geosciences, University of Fribourg, 1700 Fribourg, Switzerland.

Received 1 May 2025, accepted 9 July 2025, published online 18 September 2025.

Copyright © 2025 Y. Ke et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License (for details please see http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Introduction

Pan-Trionychidae is the total-clade of crown clade Trio­nychidae (Joyce et al. 2021). Its representatives are colloquially known as “soft-shell turtles”. This clade originated in Asia during the Early Cretaceous (Georgalis and Joyce 2017) and has an abundant, nearly world-wide fossil record consisting of at least 70 valid species in addition to countless fragmentary remains (Vitek and Joyce 2015; Georgalis and Joyce 2017). The 33 species of extant pan-trionychids (Turtle Taxonomy Working Group 2021) exhibit a number of unusual morphological ­­­­­characteristics: the nostrils are extended into a tube, the hard, keratinous scales (scutes) of the shell are replaced by leathery skin, and extensive webbing is developed between the digits (Zhou and Li 2013). In combination, these adaptations enable pan-trionychids to burrow themselves into the sediments at the bottom of freshwater ecosystems where they ambush their prey. Fossilized pan-trionychids can readily be distinguished from other turtles in the reduction of their carapace and plastron, as well as their unique shell surface texture (Vitek and Joyce 2015).

Even though soft-shelled turtles originated in Asia (Georgalis and Joyce 2017), their fossil record is scarce in the Cretaceous of China. Only five species are currently recognized as valid: Perochelys hengshanensis Brinkman et al., 2017, from the Lower Cretaceous of Zhejiang Province (Brinkman et al. 2017), Perochelys lamadongensis Li et al., 2015, from the Lower Cretaceous of Liaoning Province (Li et al. 2015a), “Trionyx” jixiensis Li et al., 2015, from the Early Cretaceous of Heilongjiang Province (Li et al. 2015b), as well as Kuhnemys maortuensis (Yeh, 1965) and Khunnuchelys erinhotensis Brinkman et al., 1993, from the Late Cretaceous of Inner Mongolia (Yeh 1965; Brinkman et al. 1993). Yeh (1965) also erected Aspideretes alashanensis Yeh, 1965, from the Upper Cretaceous of Inner Mongolia, but this species has been regarded as a junior synonym of Kuhnemys maortuensis (Georgalis and Joyce 2017). Another invalid species is Sinamyda fuchienensis (Yeh, 1974) from the Lower Cretaceous of Fujian Province (Yeh 1974), which has been regarded as a nomen dubium due to its uncertain provenience, unusual morphology, and doubtful authenticity (Georgalis and Joyce 2017). No other pan-trionychid remains, even fragments, have been reported from the Cretaceous of China, which stands in sharp contrast to the rich record of other pan-trionychians, such as the continental Nanhsiungchelyidae (e.g., Tong et al. 2024). This scarcity thus limits our understanding of the early diversification and evolution of pan-trionychids in this part of the world during the Cretaceous.

Here, we report a new pan-trionychid specimen (CUGW VH245) from the Upper Cretaceous Zhoutian Formation of Jiangxi Province, China. The specimen is too juvenile to allow diagnosing a new species, but shows intriguing similarities with other early pan-trionychids from across Asia and establishes the presence of pan-trionychids in south-eastern Asia as early as the early Late Cretaceous.

Institutional abbreviation.—CUGW, China University of Geosciences (Wuhan), Wuhan, China.

Geological setting

The Ganzhou Basin is a Mesozoic to Cenozoic fault basin situated in Jiangxi Province, China (Fig. 1A). The Upper Cretaceous, which forms the majority of the stratigraphic sequence (He et al. 2017), is comprised of five formations, namely the Maodian, Zhoutian, Hekou, Tangbian, and Lianhe formations (Bureau of Geology and Mineral Exploration and Development of Jiangxi Province 2017). The new pan-trionychid specimen, CUGW VH245, was collected from the Zhoutian Formation in Shang Wu Zhu Village (25°55′ N, 115°0′ E, Fig. 1B). The Zhoutian Formation is locally comprised of purple-red calcareous mudstone and calcareous siltstone intercalated with gypsum and rock salt, suggesting deposition in a lacustrine basin under arid conditions (Bureau of Geology and Mineral Exploration and Development of Jiangxi Province 2017). The age of the Zhoutian Formation is unclear, but is believed to be early Late Cretaceous (Cenomanian–Turonian) based on the fossil assemblage, especially spores and pollen (Bureau of Geology and Mineral Exploration and Development of Jiangxi Province 2017). Several vertebrate fossils have been found from the Zhoutian Formation, such as the titanosaur Gandititan cavocaudatus Han et al., 2024 (Han et al. 2024), but no turtle fossil has been reported to date.

Material and methods

The new specimen, CUGW VH245, consists of a nearly complete carapace and associated fragments (Fig. 2). The specimen was taphonomically crushed along its anteroposterior axis. It is currently housed in the palaeontological collection room of China University of Geosciences (Wuhan). The skeleton was prepared using an Engraving Pen AT-310 and photographed with a Canon EOS 6D camera.

A map was created to show the distribution of pan-trionychid turtles in the Cretaceous of Asia (Fig. 3). Most data come from Georgalis and Joyce (2017), and three new fossil sites are also added, including Ganzhou (Jiangxi, China), Duntou (Zhejiang, China), and Ibaraki (Japan) (Brinkman et al. 2017; Kato et al. 2019; this article). ArcGIS 10.8 software was used to plot the map.

Systematic palaeontology

Testudines Batsch, 1788

Cryptodira Cope, 1868

Pan-Trionychidae Joyce et al., 2004

Pan-Trionychidae indet.

Material.—CUGW VH245, a nearly complete carapace and associated fragments from Shang Wu Zhu Village, Ganzhou City, Jiangxi Province, China; Zhoutian Formation, Ceno­manian–Turonian (lower Upper Cretaceous).

Description.—General aspects: CUGW VH245 consists of a nearly complete carapace preserving eight neurals, eight pairs of costals, and associated postcranial fragments. As preserved, the midline length of the carapace is only 65 mm, but we estimate by comparison to Perochelys lamadongensis (Li et al. 2015a) that the total carapace length would have been about 72 mm. The other parts of the skeleton, such as the skull, the nuchal, and the plastron, have not been found. Due to poor preservation, it is unclear if a preneural or suprascapular fontanelles were­­­ present. The specimen was severely deformed taphonomically in the stratum, thus showing a pronounced inverted U-shape. The surface of the carapace is covered with the typical netlike pattern of most pan-trionychids (Joyce 2025) consisting of pits and ridges (“type A” of Danilov et al. 2014). There is no evidence of scute sulci.

Neurals: A total of eight neurals are developed in CUGW VH245. The anterior part of the first neural is damaged, but it is apparent that this element was hexagonal with short sides facing posteriorly. The second to the fourth neurals are hexagonal with short sides facing posteriorly, too. The neural reversal (i.e., the transition from hexagonal neurals with short sides oriented posteriorly versus hexagonal neurals with short sides facing anteriorly) is spread between the fifth and sixth neurals, a common anomaly found across pan-trionychids (Joyce 2025). The seventh neural is hexagonal with short sides facing anteriorly. Its posterior contact with the eighth neural is much narrower than all more anteriorly located interneural contacts. The eighth neural is developed asymmetrically, as it contacts the right eighth costal posteriorly, but not the left eighth costal. It is much smaller than all further anteriorly located neurals. As in Perochelys lamadongensis (Li et al. 2015a), the neurals are relatively broad, but not as broad as in many extant chitrines (Joyce 2025).

Costals: CUGW VH245 exhibits eight pairs of costals, most of which are damaged along their lateral margins. The first costal is incompletely preserved, which further hinders our understanding of its full shape and size, but its anteriorly convex margin is reminiscent of Perochelys lamadongensis (Li et al. 2015a) and somewhat suggestive of medially confluent suprascapular fontanelles. The second to the fifth costals are rectangular elements of similar size and with nearly parallel margins. The sixth costal is much shorter mediolaterally than the previous costals, expands distally, and is somewhat oriented posteriorly. The seventh costal is even shorter mediolaterally and further oriented towards the posterior. The eighth costal is greatly reduced in size but developed asymmetrically, the right element between twice as large as the left element. While the neural column medially separates all more anteriorly located costals, a short midline contact is present between the eighth costals. Most rib ends are poorly preserved, but their length relative to the costal callosities combined with the overall small size of CUGW VH245 suggests that it is a juvenile (Danilov and Vitek 2013; Brinkman et al. 2017; Joyce 2025). The eighth costal rib is only half as wide as of all more anteriorly located costal ribs.

Femur: The long bone located under the right seventh rib is identified as the femur, whose size relative to the shell is similar to that of extant juvenile Pelochelys cantorii Gray, 1864 (Xie et al. 2022). The ends of the femur are incompletely ossified, which is comparable with the juvenile Pelochelys cantorii as well (Xie et al. 2022). This also suggests that CUGW VH245 represents a juvenile.

Ilium: We interpret two recurved bones behind the eighth costals as the ilia. The dorsal ends are striated, as in extant trionychids.

Discussion

Alpha taxonomy and systematics.—CUGW VH245 can readily be attributed into Pan-Trionychidae based on the absence of carapacial scutes, presence of a netted surface texture, and the apparent absence of peripherals and suprapygals (Vitek and Joyce 2015). The general carapace morphology of CUGW VH245 is consistent with that of other Asian pan-trionychid turtles from the Cretaceous by exhibiting eight neurals (Yeh 1965; Danilov et al. 2014; Li et al. 2015a, b), but that characteristic does not have particularly strong taxonomic value as it occurs broadly across the tree (Joyce 2025). The position of the neural reversal and the distribution of the reversal across two neurals are highly variable among extant trionychids (Joyce 2025). The neural reversal in CUGW VH245 across the fifth and sixth neurals is thus highly consistent with other Cretaceous pan-trionychids, where the reversal typically occurs at the fifth or sixth neural (Yeh 1965; Danilov et al. 2014; Li et al. 2015a, b). Among Cretaceous Asian pan-trionychids, CUGW VH245 resembles Kuhnemys maortuensis, Perochelys lamadongensis, and Gobiapalone spp. (Yeh 1965; Danilov et al. 2014; Li et al. 2015a) by exhibiting notably reduced eighth costals. This character is of significance among these named taxa, as they are otherwise known from specimens suggesting skeletal maturity. CUGW VH245 is isolated from all other named Late Cretaceous pan-trionychids by being the only known specimen from the southern China, indeed all of southeastern Asia (Fig. 3). Pan-trionychids were also found in the Cretaceous of Japan (e.g., Kato et al. 2019), providing more evidence that the Japanese archipelago was still connected to Asian continent during the Cretaceous. Yet, as CUGW VH245 lacks sufficient anatomical details, we refrain from naming a new species.

Population succession of turtles in Ganzhou Basin.—Turtle fossils are abundant in the Ganzhou Basin, but only nanhsiungchelyids have been formally published to date (Tong and Mo 2010; Ke et al. 2024a, b; Tong et al. 2024). He et al. (2017) reported many turtle skeletons from the Ganzhou Basin, but did not provide any photographs or taxonomic assessments. From 2021 to 2024, the corresponding author (FH) organized four field expeditions in Ganzhou Basin and collected a wealth of turtle fossils. Here, we briefly summarize these specimens and discuss the population succession of turtles among different strata.

With a lacustrine sedimentary face, the Zhoutian For­ma­tion only yielded Pan-Trionychidae indet. (CUGW VH245, this article) to date. Extant pan-trionychid turtles usually have a benthic lifestyle in rivers and lakes (Zhou and Li 2013), and given their broad correspondence in morphology, it is plausible to assert that Cretaceous pan-trionychids, including CUGW VH245, had a similar lifestyle. The Tangbian Forma­tion also represents a fluvial and lacustrine environment (Ling 1996), and Lindholmemydidae indet. (CUGW VH146 and CUGW VH171, yet unpublished) were found in this formation. Lind­holmemydids likely had a freshwater lifestyle (Danilov 2003), but their hard shells and scutes also allowed them to move across land, much as their living descendants, turtles of the clade Testudinoidea, do today. At the upper end of the Cretaceous succession, the upper member of the Tangbian Formation and the Lianhe Formation have yielded abundant nanhsiungchelyid materials, in particular Xian­yuechelys ying­liangi Ke et al., 2024, and Nanhsiungchelys sp. (Ke et al. 2024a, b). The lifestyle adaptation of nanhsiungchelyids has been debated for a long time, but most evidence supports a terrestrial lifestyle (see the summary in Mallon and Brinkman 2018). Although the sample is certainly limited, it is interesting to note that a gradation is apparent from fully aquatic pan-trionychids, to plausibly semiaquatic lindholmemydids, to terrestrial nanhsiungchelyids in the Late Cretaceous of the Ganzhou Basin (Fig. 4). Hutchison (1992) utilized a similar trend in the turtle fauna to support a climatological drying trend from the Eocene to the Oligocene of western North America, which is broadly supported by other data. Yet, while the turtles of the Ganzhou Basin perhaps suggests a trend towards increasing aridity over the course of the Late Cretaceous, the sedimentological record suggests a trend towards increasing humidity (Xiao et al. 2013). Although recent turtles are known to be more diverse in humid environments (Iverson 1992), numerous highly aquatic species are known to inhabit arid environments (e.g., the trionychid Trionyx triunguis Forskål, 1775, which inhabits the Nile river of northern Africa) while numerous terrestrial species occur in humid environments (e.g., the tortoise Manouria emys [Schlegel & Müller, 1840], which inhabits tropical rain forests) (Turtle Taxonomy Working Group 2021). There is thus no real conflict in the two opposing trends noted herein, as the single available trionychid retrieved from the arid Zhoutian Formation may have inhabited a rare desert lake, while the common nanhsiungchelyids of the Lianhe Formation may have walked upon the flood plains of a humid landscape. We thus conclude that turtle faunal successions may yield compel­ling trends, but that these should not be interpreted verbatim.

Conclusions

A small pan-trionychid specimen (CUGW VH245) is repor­ted from the Upper Cretaceous Zhoutian Formation of Ganzhou Basin, southern China. The specimen includes a nearly complete carapace and several postcranial fragments. It not only represents the first pan-trionychid record from the Upper Cretaceous of southern China, but of all of southeastern Asia. As the specimen appears to be a juvenile that lacks sufficient anatomical details, we here identify it as Pan-Trionychidae indet. only. The Late Cretaceous turtle faunas of the Ganzhou Basin show a succession from aquatic pan-trionychids to semi-terrestrial lindholmemydids to terrestrial nanhsiungchelyids, but this likely does not reflect a climatological drying trend.

Acknowledgements

We thank Yanxia Li (Nanjing Normal University, China) for the guidance in making map, Jiawei Tang (CUGW) for measuring the specimen, and Yangxuan Hu (Ganzhou Institute of Water Resources and Electric Power Investigation and Design, Ganzhou, China) for his help in field work. We also thank Daniel E. Barta (Oklahoma State University College of Osteopathic Medicine at the Cherokee Nation, USA), Georgios Georgalis (Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Kraków, Poland), and Don Brinkman (Royal Tyrrell Museum, Drumheller, Canada) for useful comments that helped improve the quality of the present manuscript. This project was supported by the National Natural Science Foundation of China (No. 42288201), China Scholarship Fund (No. 202406410086), and the Swiss National Science Foundation (No. SNF 200021_207377).

Editor: Daniel Barta

References

Batsch, A.J.G.C. 1788. Versuch einer Anleitung, zur Kenntniß und Geschi­chte der Thiere und Mineralien. 528 pp. Akademische Buchhandlung, Jena. Crossref

Brinkman, D.B., Nessov, L.A., and Peng, J. 1993. Khunnuchelys gen. nov., a new trionychid (Testudines: Trionychidae) from the Late Cretaceous of Inner Mongolia and Uzbekistan. Canadian Journal of Earth Science 30: 2214–2223. Crossref

Brinkman, D.B., Rabi, M., and Zhao, L. 2017. Lower Cretaceous fossils from China shed light on the ancestral body plan of crown softshell turtles (Trionychidae, Cryptodira). Scientific Reports 7: 6719. Crossref

Bureau of Geology and Mineral Exploration and Development of Jiangxi Province 2017. Regional Geology of China, Jiangxi Province [in Chinese with English abstract]. 1069 pp. Geological Publishing House, Beijing.

Cope, E.D. 1868. On the origin of genera. Proceedings of the Academy of Natural Sciences of Philadelphia 20: 242–300.

Danilov, I. 2003. Gravemys Sukhanov and Narmandakh, 1983 (Testudinoi­dea: Lindholmemydidae) from the Late Cretaceous of Asia: new data. Paleobios 23: 9–19.

Danilov, I.G. and Vitek, N.S. 2013. Soft-shelled turtles (Trionychidae) from the Bissekty Formation (Late Cretaceous: late Turonian) of Uzbe­kistan: Shell-based taxa. Cretaceous Research 41: 55–64. Crossref

Danilov, I.G., Hirayama, R., Sukhanov, V.B., Suzuki, S., Watabe, M., and Vitek, N.S. 2014. Cretaceous soft-shelled turtles (Trionychidae) of Mongolia: new diversity, records and a revision. Journal of Systematic Palaeontology 12: 799–832. Crossref

Forskål, P. 1775. Descriptiones Animalium. Avium, Amphibiorum, Piscium, Insectorum, Vermium. Quae in Itinere Oriental Observavit. 12 pp. Mölleri, Haunia. Crossref

Georgalis, G.L. and Joyce, W.G. 2017. A review of the fossil record of Old World turtles of the clade Pan-Trionychidae. Bulletin of the Peabody Museum of Natural History 58: 115–208. Crossref

Gray, J.E. 1864. Revision of the species of Trionychidae found in Asia and Africa, with the descriptions of some new species. Proceedings of the Zoological Society of London 1864: 76–98.

Han, F., Yang, L., Lou, F., Sullivan, C., Xu, X., Qiu, W., Liu, H., Yu, J., Wu, R., Ke, Y., Xu, M., Hu, J., and Lu, P. 2024. A new titanosaurian sauropod, Gandititan cavocaudatus gen. et sp. nov., from the Late Cretaceous of southern China. Journal of Systematic Palaeontology 22: 2293038. Crossref

He, F., Huang, X., and Li, X. 2017. Occurrence rule and buried characteristics of dinosaur fossils in the Ganzhou Basin, Jiangxi Province [in Chinese with English abstract]. East China Geology 38: 250–254.

Hutchison, J.H. 1992. Western North American reptile and amphibian record across the Eocene/Oligocene boundary and its climatic implications. In: D.R. Prothero and W.A. Berggren (eds.), Eocene–Oligocene Climatic and Biotic Evolution, 451–463. Princeton University Press, Princeton. Crossref

Iverson, J.B. 1992. Global correlates of species richness in turtles. Herpetological Journal 2: 77–81.

Joyce, W.G. 2025. Overcoming polymorphism: a revised list of shell characters for the phylogenetic analysis of soft-shelled turtles (Pan-Trionychidae). Swiss Journal of Palaeontology 144: art. 25. Crossref

Joyce, W.G., Anquetin, J., Cadena, E., Claude, J., Danilov, I.G., Evers, S.W., Ferreira, G.S., Gentry, A.D., Georgalis, G.L., Lyson, T.R., Pérez-García, A., Rabi, M., Sterli, J., Vitek, N.S., and Parham, J.F. 2021. A nomenclature for fossil and living turtles using phylogenetically defined clade names. Swiss Journal of Palaeontology 140: art. 5. Crossref

Joyce, W.G., Parham, J.F., and Gauthier, J.A. 2004. Developing a protocol for the conversion of rank-based taxon names to phylogenetically defined clade names, as exemplified by turtles. Journal of Paleontology 78: 989–1013. Crossref

Kato, T., Sonoda, T., Miyata, S., Kawano, S., and Ando, H. 2019. Large soft-shelled turtle fossils from the Upper Cretaceous Nakaminato Group in Ibaraki Prefecture and their significance [in Japanese with English abstract]. Bulletin of Ibaraki Nature Museum 22: 31–36.

Ke, Y., Niu, K., Rummy, P., Tong, H., Hu, J., and Han, F. 2024a. Xianyue­chelys yingliangi: a new nanhsiungchelyid turtle from the Late Cretaceous of Ganzhou Basin, China. Journal of Systematic Palaeontology 22: 2346838. Crossref

Ke, Y., Tong, H., Qiu, W., Shi, Z., and Han, F. 2024b. A partial plastron of Nan­hsiungchelys (Testudines: Cryptodira: Nanhsiungchelyidae) from the Upper Cretaceous of Ganzhou Basin, China. Historical Biology: 1–6. Crossref

Li, L., Joyce, W.G., and Liu, J. 2015a. The first soft-shelled turtle from the Jehol Biota of China. Journal of Vertebrate Paleontology 35: e909450. Crossref

Li, L., Tong, H., Gu, W., and Liu, J. 2015b. A new trionychid turtle from the Early Cretaceous of Heilongjiang Province, Northeastern China. Cretaceous Research 56: 155–160. Crossref

Ling, L. 1996. Establishment of the Maodian, Hekou and Tangbian formations in the Cretaceous of Jiangxi Province [in Chinese]. Geological Science and Technology of Jiangxi 23: 55–59.

Mallon, J.C. and Brinkman, D.B. 2018. Basilemys morrinensis, a new species of nanhsiungchelyid turtle from the Horseshoe Canyon Formation (Upper Cretaceous) of Alberta, Canada. Journal of Vertebrate Paleontology 38: e1431922. Crossref

Schlegel, H. and Müller, S. 1840. Over de Schildpadden van den Indischen Archipel, en beschrijving eener nieuwe soort van Sumatra. In: C.J. Temminck (ed.), Verhandelingen over de Natuurlijke Geschiedenis der Nederlandsche overzeesche bezittingen, 1839–44. Part 3. Zoo­logie, 29–36. Luchtmans and van der Hoek, Leiden.

Tong, H., Li, L., Ke, Y., Wang, Y., Jie, G., and Yi, L. 2024. Remarkable carapace morphology of Nanhsiungchelys (Testudines: Nanhsiungchelyi­dae) revealed by new material from Ganzhou Basin, Jiangxi Province, China. Geosciences 14: art. 184. Crossref

Tong, H. and Mo, J. 2010. Jiangxichelys, a new nanhsiungchelyid turtle from the Late Cretaceous of Ganzhou, Jiangxi Province, China. Geological Magazine 147: 981–986. Crossref

Turtle Taxonomy Working Group 2021. Turtles of the world: annotated checklist and atlas of taxonomy, synonymy, distribution, and conservation status (9th ed.). Chelonian Research Monographs 8: 1–472.

Vitek, N.S. and Joyce, W.G. 2015. A review of the fossil record of New World turtles of the clade Pan-Trionychidae. Bulletin of the Peabody Museum of Natural History 56: 185–244. Crossref

Xiao, G., Yao, Q., and Fan, A. 2013. Research on sequence stratigraphy of late Cretaceous in Jiangxi Province [in Chinese with English abstract]. Resources Survey & Environment 34: 141–149.

Xie, M., Hong, X., Li, W., Liu, X., Chen, C., and Zhu, X. 2022. Skeletal system analysis of Asian giant soft-shelled turtles and comparison with Chinese soft-shell turtle [in Chinese with English abstract]. Acta Hydrobiologica Sinica 46: 1–10.

Yeh, H. 1965. New materials of fossil turtles of Inner Mongolia. Vertebrata Palasiatica 9: 47–69.

Yeh, H. 1974. A new fossil Trionyx from Fuchien [in Chinese with English abstract]. Vertebrata Palasiatica 12: 190–191.

Zhou, T. and Li, P. 2013. Primary Color Illustrated Handbook of Classification of Chinese Turtles [in Chinese]. 285 pp. China Agriculture Press, Beijing.

Acta Palaeontol. Pol. 70 (3): 607–612, 2025

https://doi.org/10.4202/app.01263.2025