Taxonomic revision of Chinemys pani (Testudines: Geoemydidae) from the Pleistocene of Taiwan and its implications of conservation paleobiology

Abstract

Proper taxonomic identification is critical to our understanding of biodiversity and the underlying evolutionary history. Here we re-examine the cast of the holotype of Chinemys pani, a geoemydid turtle from the Pleistocene of Taiwan; the actual specimen was not curated appropriately after the original publication and was most likely lost. Our results provide substantial evidence to show that Chinemys pani should be identified as Mauremys reevesii. The replica, though not ideal, preserves various morphological features that allow reliable taxonomic identification of Mauremys reevesii, including the presence of three longitudinal keels on the carapace, the second to sixth neural bones anteriorly short-sided, and the lack of a movable plastral hinge. In addition, we also confirm that the original diagnostic features that established the new taxon: Chinemys paniare polymorphic characters of Mauremys reevesii. Our taxonomic revision of a Pleistocene geoemydid turtle from Taiwan confirms the existence of the Pleistocene Mauremys reevesii. More importantly, this study offers new insights into the origin of modern biodiversity in Taiwan and gives a straightforward example of how fossils can be applied to conservation policies.

New findings on the evolution of turtles: A symposium in honor of Marcelo S. de la Fuente

“…Neuroanatomical studies were also conducted in Plesiobaena antiqua from the Campanian of the United States (Smith et al, 2023) providing details of its inner ear expanding the knowledge of the endocranial anatomy of baenid turtles. The taxonomic revision of Pleistocene geoemydids from Taiwan (Liaw & Tsai, 2023) confirms the synonymy of Chinemys pani with the extant Mauremys reevesii . This study also highlights the importance of fossils, especially those from the Quaternary, in conservation policies.…”

Crocodylian princess in Taiwan: Revising the taxonomic status of Tomistoma taiwanicus from the Pleistocene of Taiwan and its paleobiogeographic implications

“…For example, here we revised the taxonomy of historic crocodylian specimens—the first and the second fossil crocodylians in the history of Taiwan—which are properly curated in the NSMT and Waseda collections in Japan, making our study possible. On the contrary, some historic specimens from Taiwan should have been curated for future research, but the original fossils are lost, likely owing to the indifference to paleontological research (e.g., Liaw and Tsai, 2022; Tsai and Tseng, 2022). Our current efforts into the development of vertebrate paleontology in Taiwan aims to better understand the Pleistocene paleo-ecosystems and to further elucidate the driving factors of extinctions in the island.…”

The Australian gulf snapping turtle Elseya lavarackorum (Testudines: Chelidae) revisited—Is the late Pleistocene fossil species extant?

“…Characterization of morphological variation in the shells of extant Elseya can provide a baseline for interpretation of the character states of fossil specimens. However, other studies of this type serve to highlight the difficulties inherent in recognizing and accommodating intraspecific diversity in the fossil record (Vitek 2018;Guerrero and Pérez-García 2021;Joyce et al 2022;Liaw and Tsai 2022). This challenge becomes particularly acute when relatively few fossil specimens are available.…”

“…Differences between the sexes where the sexes are often unidentified in fossil material, and ontogenetic variation whereby large specimens in the fossil record represent an extension of the allometric trajectory present in available extant specimens, present particular difficulties for interpretation. Conspecificity of young fossils and extant populations is equally challenging to establish or refute, but it is not particularly uncommon to find reference to late Pleistocene fossils considered to be also represented by extant populations of the same species (Guilday et al 1978;Willis 1990;Archer et al 2019;Liaw and Tsai 2022). The question is one of whether the young fossil and the extant populations are on the same evolutionary trajectory, requiring phylogenetic judgement, and if they are, whether the fossil and extant forms show sufficient morphological divergence as to be considered separate chronospecies, which requires a subjective judgement (Dzik 1990;Futuyma 2005).…”