El esqueleto apendicular de la tortuga pleurodira Lapparentemys vilavilensis en el PALEO NE 2025/7th IMERP

Durante el pasado Paleo NE 2025 y 7th IMERP se presentó la comunicación titulada: “The appendicular skeleton of the pleurodiran turtle Lapparentemys vilavilensis (Paleocene of Bolivia).”, por parte de María Gutiérrez-Gálvez y Adán Pérez-García. En este trabajo se estudia el esqueleto apendicular de la tortuga pleurodira Lapparentemys vilavilensis. Este taxon procede del Paleoceno de Bolivia y no tenía ningún elemento del esqueleto apendicular figurado y descrito hasta ahora. Se ha comparado con el esqueleto apendicular de varios representantes actuales del grupo Podocnemididae dado que es el linaje actual más cercanamente emparentado. Se ha encontrado que la extremidad posterior de Lapparentemys vilavilensis es más similar a lo observado en los podocnemídidos, sin embargo, la extremidad anterior presenta más diferencias con estos.

Turtles represent a diverse lineage of reptiles, adapted to different habitats, including terrestrial, freshwater, and marine environments. Therefore, they have developed modifications in the appendicular skeleton relative to their primitive body plan. However, the appendicular skeleton of most described species of extinct turtles is unknown. In many cases, this is because it is not preserved, but in others this is a deliberate omission, because most anatomical and systematic studies consider the skull and shell of special relevance, often ignoring or barely mentioning the presence of other skeletal remains. This study bias particularly affects pleurodiran turtles, given they a priori show less morphological diversity in the appendicular skeleton than cryptodires, as almost all of them are freshwater forms, with no terrestrial representatives currently known. However, detailed analysis does reveal notable morphological variation, as shown by Lapparentemys vilavilensis (Testudines, Pleurodira), a peiropemydid turtle from the early Paleocene of Bolivia. The skull, cervical vertebrae, and shell of this taxon have been described in literature, but not its appendicular skeleton. We present here, for the first time, descriptions of appendicular bones attributed to Lapparentemys vilavilensis, including elements of the pelvic and pectoral girdles, as well as several bones of forelimbs and hindlimbs. We describe in detail the appendicular elements of this peiropemydid and compare them with extant and extinct representatives of its sister group Podocnemididae, with the aim of not only characterizing them, but also providing data on the lifestyle of this Paleogene species. As a result of these studies, we observed that the posterior limb of Lapparentemys vilavilensis is relatively similar in morphology to those of most of podocnemidids and taxa closely related to them. Meanwhile, the anterior limb displays relevant anatomical modifications, probably justified by a highly specialized ecological adaptation. For this reason, potential convergence with representatives of other pleurodiran lineages, but also with cryptodires, is evaluated.

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Más información:

• Referencia: Gutiérrez-Gálvez, M., Pérez-García, A. (2025). The appendicular skeleton of the pleurodiran turtle Lapparentemys vilavilensis (Paleocene of Bolivia). In Antonietto, L. S., Holgado, B., Conceiçao, D. M. Lima (Eds.). 7th International Meeting of Early-Stage Researchers in Paleontology, Paleo NE 2025. Livro de resumos. Santana do Cariri, CE, 21.