Análisis funcional del aparato alimentario de la tortuga pleurodira Lapparentemys vilavilensis en el PALEO NE 2025/7th IMERP

En el marco del congreso Paleo NE 2025, celebrado conjuntamente con el 7th IMERP, investigadores del Grupo de Biología Evolutiva y colaboradores presentaron un estudio centrado en el análisis funcional del aparato alimentario de la tortuga pleurodira extinta Lapparentemys vilavilensis (Paleoceno de Bolivia). La contribución se enmarca en una línea de investigación orientada a la aplicación de técnicas de modelado virtual y análisis biomecánico para inferir aspectos funcionales y ecológicos en vertebrados fósiles, aportando nuevos datos al conocimiento de la diversidad y especialización ecológica de las tortugas del pasado. A continuación, se presenta el resumen completo del trabajo:

Lapparentemys vilavilensis is an extinct pleurodiran turtle from the early Paleocene of Bolivia, belonging to an extinct clade of Pelomedusoides known from a very limited number of species (i.e., Peiropemydidae). Within this relatively poorly documented group, Lapparentemys is particularly notable due to the availability of several shells and well-preserved skulls, offering a good opportunity to investigate the functional morphology of a representative closely related to Podocnemididae. Despite the quality of the available cranial material, no studies have explored its paleoecology or feeding adaptations. Thus, the objective of this study is to provide a first assessment of the feeding ecology of Lapparentemys vilavilensis through biomechanical analysis of the skull. A micro-computed tomography (microCT) scan was conducted on a well-preserved adult specimen, preserving the articulated skull and lower jaw. As a comparative framework, two extant pleurodiran turtles with contrasting dietary strategies (i.e., Pelusios castaneus and Erymnochelys madagascariensis) were also analyzed. The digital fossil skull model was processed to correct taphonomic deformation and to reconstruct missing anatomical elements. Based on extant anatomical references and osteological correlates, three-dimensional reconstructions of the jaw adductor musculature were generated. The virtual meshes suitable for muscular modeling were created using Pixologic ZBrush v.2021.5 and Geomagic Studio v.2014. These models were subsequently used to perform Finite Element Analysis (FEA) under standardized loading conditions to evaluate and compare cranial biomechanics during biting. FEA simulations were carried out using Ansys software. The application of these virtual modeling techniques allowed us to investigate how cranial architecture relates to feeding function. Results indicate that Lapparentemys vilavilensis exhibits structural features associated with strong bite forces, consistent with a durophagous or resistant-prey feeding strategy. This study provides the first functional evidence related to the dietary ecology of Lapparentemys vilavilensis. By applying virtual modeling and biomechanical simulations to an extinct pleurodiran turtle, it offers novel insights into the feeding adaptations of fossil representatives closely related to Podocnemididae. Given the limited number of functional studies in extinct pleurodires, these results contribute significantly to our understanding of ecological diversity and specialization within this lineage, and more broadly, to the evolutionary pathways of trophic strategies in side-necked turtles.

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Más información:

• Referencia: Guerrero, A., López-Pachón, L., Pérez-García, A. (2025). Functional analysis of the feeding apparatus 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, 20.

Análisis de los canales sanguíneos y nerviosos de las tortugas pleurodiras del linaje Bothremydidae en el PALEO NE 2025/7th IMERP

Durante el Paleo NE 2025 y 7th IMERP celebrado entre los días 3 y 6 de diciembre en Santana do Cariri, los miembros del Grupo de Biología Evolutiva de la UNED Marcos Martín-Jiménez y Adán Pérez-García presentaron una comunicación oral sobre el sistema sanguíneo y nervioso craneal en el linaje Bothremydidae, conocido desde el Cretácico Inferior hasta al menos el Eoceno. Mediante el uso de escáneres de Tomografía Computarizada se reconstruyeron los canales de la arteria carótida y el nervio facial en diversos taxones de botremídidos. La mayoría de especies presentan un patrón en el que el nervio facial se bifurca en el proótico y se proyecta anteriormente a través del canal vidiano, como ocurre en otros grupos de pleurodiras como los podocnemídidos. En los miembros del linaje Nigeremydini sin embargo, la rama anterior del nervio facial se origina en el canal carotídeo que es compartido por la arteria carótida y el nervio vidiano. El resumen de la comunicación es el siguiente:

Bothremydidae was a successful lineage of pleurodiran turtles, identified from the Albian to at least the Eocene of most northern and the southern continents. Despite the high number of recognized bothremydid taxa, many preserving cranial remains, the neuroanatomical information is scarce. Recent works, based in the use of CT to generate three-dimensional models of neuroanatomical elements (e.g., endocranial cavity and endosseous labyrinth), have provided relevant data on the neuroanatomy of Bothremydidae. Previous studies of these structures in this extinct group are mostly restricted to the analysis of the models of the cranial cavities and canals. A detailed study of the carotid arteries and the facial nerves of bothremydids is carried out here for the first time, comparing them with those of several representatives of other lineages of pleurodires that are part of the current biodiversity (i.e., Chelidae, Pelomedusidae, and Podocnemididae), but also with members of extinct groups. Previous studies of Pleurodira, but also of Cryptodira, allowed the identification of different patterns related to the location of the geniculate ganglion and the distribution of the facial nerve canals. The carotid canals of most pleurodiran lineages are completely covered by bone from the foramina posterius canalis carotici interni to the posterior area of the pituitary fossa. These foramina are absent in all representatives of Podocnemididae, so the arteries enter the skull through the cavum pterygoidei, which is exclusive for this group. In the case of the facial nerve, the geniculate ganglion is in the prootic in most lineages of Bothremydidae (i.e., Cearachelyini, Bothremydini, and Taphrosphyini). The vidian nerve in these bothremydids is projected ante-roventrally through the canalis pro ramo nervi vidiani. The position of the ganglion and the presence of this canal were also observed in Podocnemidi-dae and in the extinct Euraxemydidae and Sahonachelyidae. However, the canalis pro ramo nervi vidiani is absent in the only representative of the bothremydid lineage Nigeremydini sensu Lapparent de Broin and Prasad (2020) in which this structure is known (i.e., Azzabaremys moragjonesi), with the ganglion located in the canalis cavernosus; and also in the extant Chelidae and Pelomedusidae, and the extinct Araripemydidae, all of them with the ganglion located close to the carotid canal. These features of the carotid-facial system for most bothremydids are shared with the members of its sister group Podocnemididae. The differences observed in Nigeremydini relative to all other bothremydids could be justified by the marine adaptation inferred for the representatives of this group.

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Más información:

• Referencia: Martín-Jiménez, M., Pérez-García, A. (2025). The carotid and facial nerve systems of the bothremydid turtles (Pleurodira, Bothremydidae): an update. 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, 24.

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.

Un resumen de la participación del GBE en el PALEO NE 2025/7th IMERP

Durante la pasada semana, del 3 al 6 de diciembre en Santana do Cairi, tuvo lugar la celebración del congreso Paleo NE 2025 junto con el 7º IMERP, siendo así la primera vez en su historia que este encuentro de jóvenes paleontólogos se celebra fuera de Europa. El encuentro tuvo modalidad hibrida, permitiendo la asistencia de forma presencial y telemática, así hubo participantes de doce países diferentes.

Además de las numerosas ponencias, se realizó una salida de campo el último día a los geossítios Pedra Cariri e Parque dos Pterossauros e Pontal da Cruz. Varios miembros del Grupo de Biología Evolutiva de la UNED han participado en este congreso con diferentes contribuciones:

• Guerrero, A., López-Pachón, M., Pérez-García, A. (2025). Functional analysis of the feeding apparatus 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, 20. 
• 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. 
• Martín-Jiménez, M., Pérez-García, A. (2025). The carotid and facial nerve systems of the bothremydid turtles (Pleurodira, Bothremydidae): an update. 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, 24. 
• Ricotti, V., Gascó-Lluna, F., Mocho, P., Torices, A., Pérez-García, A. (2025). Proposal of the first rigurous scientific illustrations of the main ecosystems in the Cenomanian paleontological area of Algora (Guadalajara, Spain). 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, 90.

Litosoolithus poyosi, un nuevo ootaxón del Cretácico Superior de Guadalajara en el 85th Annual Meeting de la SVP

Tras la publicación del artículo en el que se describe y su presentación en sociedad (puedes verlo aquí), tocaba presentar a Litosoolithus poyosi ante la comunidad científica internacional. En el póster titulado “Litosoolithus poyosi, a new fusioolithid ootaxon from the Upper Cretaceous of Spain and its implications for titanosaur reproductive diversity” expuesto en el pasado 85th Annual Meeting de la Society of Vertebrate Paleontology, celebrado en Birmingham (Reino Unido), se recapitulan los avances realizados sobre este nuevo ootaxón. Estos incluyen, principalmente el estudio parataxonómico que ha permitido identificar los caracteres diagnósticos del ootaxón; el estudio tafonómico, que ha permitido interpretar aspectos de la paleobiología reproductiva de los productores como que estos huevos se depositaban enterrados en el sedimento; y de su paleoecología, pues las características de la cáscara apuntan a que se desarrollaban en microambientes más cálidos y secos que otros ootaxones. El resumen es el siguiente:

The Poyos fossil site (Villalba de la Sierra Fm., late Campanian–early Maastrichtian, Central Spain) has yielded an exceptional association of fusioolithid dinosaur eggs, possibly the oldest in Europe. This site has yielded numerous partial clutches of complete or near-complete eggs, associated eggshell fragments, and stratigraphically consistent horizons across more than 10 meters of section. Most eggs are preserved in three dimensions, laterally deformed post-burial but not compressed or collapsed, allowing detailed analysis of their morphology and taphonomy.

Two fusioolithid ootaxa have been identified at this locality: the widespread Fusioolithus baghensis and the newly erected Litosoolithus poyosi. The latter is based on very large, subspherical eggs (up to 250 mm in diameter) with extremely thin eggshells (0.8–1.1 mm), very low porosity (0,57 pores/mm2), and a dispersituberculated ornamentation, which contrasts with the compactituberculated pattern typical of other fusioolithids. The partial clutches (of up to 7 eggs so far) show an arrangement consistent with nesting patterns observed in other titanosaur oosites, such as those from Auca Mahuevo (Argentina) or Pinyes (Spain). Additionally, the eggshell microstructure reveals two sharply distinct spherolith morphologies: flat, heavily fused shell units that form internodal areas, and convex shell units that end in low, bell-shaped nodes. Statistical comparisons of spherolith height and width on over 400 thin-sectioned eggshell simples across 17 ootaxa, including multiple fusioolithid and megaloolithid species from Europe, South America, and India, demonstrate significant inter- and intraootaxonomic differences. These results support the parataxonomic validity of Litosoolithus poyosi and reinforce its distinction from Fusioolithus baghensis, with which it co-occurs on the same stratigraphic levels. Such fusioolithid co-occurrence is rare outside the Indian subcontinent and may reflect ecological differentiation among titanosaur species or reproductive partitioning within shared nesting areas. Litosoolithus poyosi represents the largest known titanosaur egg with the thinnest eggshell ever described, suggesting possible adaptations to incubation in hot, semi-arid conditions. This discovery significantly expands the known diversity of fusioolithid eggs in Europe and provides new insights into the reproductive strategies, environmental plasticity, and paleobiogeography of Late Cretaceous sauropods.

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Más información:

• Referencia: Sanguino, F., de Celis, A., de la Horra, R., Ortega, F. (2025). Litosoolithus poyosi, a new fusioolithid ootaxon from the Upper Cretaceous of Spain, and its implications for titanosaur reproductive diversity. In Hunter, J., Turner, N., Vlachos, E., Whatley, R. (Eds.) 85th Annual Meeting of SVP. Abstract book. Birmingham, 546-547.