Más iguanodontios en el Jurásico Superior del archipiélago europeo

Los iguanodontios son un grupo de dinosaurios ornitópodos con un gran enorme éxito evolutivo que se conocen desde la parte final del Jurásico y que poblaron las distintas tierras emergidas del planeta hasta el fin de la era Mesozoica. El registro ibérico del Jurásico Superior de ornitópodos iguanodontios juega un papel muy importante en la historia evolutiva del grupo y está conformado por cuatro especies: Eousdryosaurus nanohallucis, Draconyx loureiroi, Oblitosaurus bunnueli y Hesperonyx martinhotomasorum. Sin embargo, a este elenco de formas bípedas de dinosaurios herbívoros se le ha unido una nueva forma de iguanodontio de tamaño parecido a Oblitosaurus y la forma del registro de Norteamérica Campotosaurus, para complicar la cosa. Los restos fósiles de este nuevo ejemplar han sido publicados hace unas semanas en la revista científica Journal of Systematic Palaeontology. Además, se han descrito en este trabajo restos apendiculares de otros individuos de menor tamaño y edad que han podido relacionarse con esta nueva y desconocida forma del registro ibérico. Os dejamos aquí el resumen del trabajo:

The Upper Jurassic beds of the Lusitanian Basin in central Portugal yield diverse dinosaurian fauna, dated to the Kimmeridgian–Tithonian interval. Saurischian dinosaurs are, overall, more abundant than their ornithischian counterparts, in terms of both specimens collected and species recognized. Iguanodontians are so far represented by the styracosternan Draconyx loureiroi, the dryosaurid Eousdryosaurus nanohallucis and the enigmatic dryomorphan Hesperonyx martinhotomasorum. Here we aim to highlight the diversity of this clade in the Late Jurassic of Portugal, presenting evidence for yet another species of ankylopollexian iguanodontian dinosaur, represented by the specimen SHN.JJS.015, which is housed at the Sociedade de Historia Natural, Torres Vedras. Detailed comparisons rule out attribution to previously known taxa, and phylogenetic analyses that include SHN.JJS.015 indicate early-diverging ankylopollexian affinities for this specimen. As there is no robust diagnosis, we do not erect a new formal species for it at this stage. Nevertheless, this specimen represents a previously unreported taxon that highlights greater diversity than previously estimated among the iguanodontians of the Late Jurassic and highlights the importance of Europe in diversification and dispersal events of this clade. A series of smaller, isolated femora from the same sub-basin as SHN.JJS.015 may represent the same taxon, presenting evidence of thriving communities of ankylopollexians during the Kimmeridgian–Tithonian interval in Portugal.

Más información:

• Referencia: Rotatori, F. M., Escaso, F., Camilo, B., Bertozzo, F., Malafaia, E., Mateus, O., Mocho, P., Ortega, F., Moreno-Azanza, M. (2025). Evidence of large-sized ankylopollexian dinosaurs (Ornithischia: Iguanodontia) in the Upper Jurassic of Portugal. Journal of Systematic Palaeontology 23(1), 2470789. doi: 10.1080/14772019.2025.2470789
• Imágenes: Arriba, fémur derecho del ejemplar SHN.JJS.015 en vistas anterior (A), medial (B), posterior (C), lateral (D), proximal (E) y distal (F); abajo, húmero derecho del ejemplar SHN.JJS.015 en vistas posterior (A), anterior (B), proximal (C) y distal (D).

Explorando la biomecánica craneal de las tortugas Stereogenyini en el 5th Palaeontological Virtual Congress

Durante el pasado 5th Palaeontological Virtual Congress se presentó la comunicación titulada "Cranial biomechanics and feeding strategies in Stereogenyini turtles", realizada por Andrea Guerrero y Adán Pérez-García. Este trabajo fue reconocido con el Society of Vertebrate Paleontology award a la mejor presentación en diapositivas, lo cual nos llena de satisfacción. Este estudio investigó las adaptaciones biomecánicas del cráneo en tortugas Stereogenyini, analizando la relación entre su morfología y función. Se evaluó cómo las modificaciones palatinas reflejan estrategias de alimentación mediante reconstrucciones musculares y análisis de elementos finitos. El trabajo comparó distintos taxones para identificar trayectorias evolutivas dentro del grupo. Además, representa la primera reconstrucción de la musculatura craneal en este linaje, aportando nuevas perspectivas sobre su ecología trófica. A continuación, os dejamos el resumen perteneciente a este trabajo:

The evolution of the cranial morphology in extinct turtles relative to the functional performance remains poorly understood. Among side-necked turtles (Pleurodira), the extinct lineage Stereogenyini (Podocnemididae) stands out due to its unique modification of the palatine bones, forming a structure equivalent to a secondary palate. The acquisition of this feature, which varies in morphology and development among its representatives, probably reflect derived feeding strategies. This study investigates cranial biomechanical adaptations of Stereogenyini, focusing on the relationship between the cranial morphology and its function. This research aims to determine, through the analysis of several representatives which represent a spectrum of forms considering the development of the palatal modifications, how the observed morphological variations reflect adaptations to mechanical demands. The application of virtual techniques, including muscular reconstructions and finite element analysis, enables us to relate cranial differences to feeding behavior and the mechanical performance of the skull. Comparative analysis of different taxa within Stereogenyini will also shed light on the main cranial evolutionary trajectory or trajectories of the lineage. This study represents the first reconstruction of cranial musculature within this lineage, offering a new perspective on both the feeding strategies and the adaptive significance of their palatal structures.

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Más información:

• Referencia: Guerrero, A., Pérez-García, A. 2025. Cranial biomechanics and feeding strategies in Stereogenyini turtles. In Vlachos et al. (Eds.), Book of Abstracts of the 5th Palaeontological Virtual Congress, 348.

Tratamientos de conservación de los cráneos de ballena fósil del Museu Nacional de História Natural e da Ciência de Lisboa en el 5th Palaeontological Virtual Congress

El 5th Palaeontological Virtual Congress acogió la presentación de Fátima Marcos Fernández, miembro del equipo de conservación del Grupo de Biología Evolutiva (GBE). Su comunicación se tituló "Conservation of the fossil whale skulls of Vandelli from the collections Museu Nacional de História Natural e da Ciência, Universidade de Lisboa". En este trabajo se abordaron los desafíos y soluciones implementados en la conservación de tres cráneos fósiles de ballena descubiertos en los depósitos miocenos de Adiça (Sesimbra, Portugal) y documentados por Vandelli en 1831, afectados por casi dos siglos de deterioro. La presentación destacó el uso de técnicas avanzadas para la eliminación de contaminantes químicos, la estabilización de microfracturas y el desarrollo de soportes a medida, poniendo en valor la importancia de la sostenibilidad y reversibilidad en los tratamientos de conservación. El resumen es el siguiente:

This summary focuses on the conservation efforts of three fossilized whale skulls from the Museu Nacional de História Natural e da Ciência (Universidade de Lisboa). Discovered in the Miocene deposits of Adiça (Sesimbra, Portugal) during the first half of the 19th century and documented by Vandelli in 1831, these skulls hold significant scientific and historical value. Over their nearly 200-year history, the skulls suffered some damage, including a devastating fire in 1978. While they were not directly impacted by the flames, soot deposition and high temperatures introduced chemical contaminants that compromised their structural integrity and appearance. X-ray fluorescence was used to assess the effects of the fire, revealing heavy metal particles such as lead, zinc, and mercury on the fossil surface. Combined with soot embedded in microfractures, these factors further destabilized the fossils both chemically and physically. Moreover, soluble salts induced internal stress, causing fractures and skeletal disaggregation. Our intervention followed an interdisciplinary approach and guided by minimal intervention principles. Contaminants were removed through mechanical and chemical techniques, including gel-based solutions to dissolve deeply embedded deposits. Microfractures were consolidated using Paraloid B72, ensuring structural stability and reversibility of the treatments. Customized supports were also developed to safeguard the fossils during storage and handling. This case illustrates how the integration of advanced methods and modern conservation techniques can effectively mitigate the harmful effects of degradation agents. The outcomes not only preserve the physical and aesthetic integrity of the fossils but also ensure their long-term sustainability and the elimination of toxicity for future research.

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Más información:

• Referencia: Marcos-Fernández, F., Fernández-Martínez, J., Fernández-Fernández, E., Povoas, L., Judite Alves, M., Mocho, P. 2025. Conservation of the fossil whale skulls of Vandelli from the collections of Museu Nacional de História Natural e da Ciência, Universidade de Lisboa. In Vlachos et al. (Eds.), Book of Abstracts of the 5th Palaeontological Virtual Congress, 229.

Análisis neuroanatómico a partir de modelos tridimensionales de las tortugas del linaje Podocnemidoidea desde el Cretácico hasta el presente en el 5th Palaeontological Virtual Congress

Durante el 5th Palaeontological Virtual Congress celebrado el pasado mes de marzo se presentó una revisión de la neuroanatomía del clado Podocnemidoidea, incluido dentro del grupo de tortugas pleurodiras. Este clado incluye dos linajes principales: Bothremydidae reconocido desde el Cretácico Inferior hasta el Eoceno, y Podocnemidoidae, con algunos de sus representantes formando parte de la biodiversidad actual. En esta comunicación se analizaron los elementos neuroanatómicos en estos dos linajes, a partir de la metodología basada en el uso de Tomografía Computarizada. Los elementos fueron comparados además con otros grupos de tortugas pleurodiras, generando un marco neuroanatómico más amplio dentro de Pleurodira. A partir del análisis de las estructuras neuroanatómicas se observaron características comunes dentro de Podocnemidoidea, principalmente en la cavidad craneal y en los canales del nervio facial, que las diferencian del resto de linajes de pleurodiras. Además, se identificaron modificaciones en el laberinto óseo que responden a adaptaciones a medios acuáticos marinos, en contraste con la mayoría de tortugas pleurodiras de hábitos dulceacuícolas. El resumen de la comunicación es el siguiente:

Podocnemidoidea is a successful and diverse lineage of pleurodiran turtles, dating from the Early Cretaceous. It includes Podocnemididae, which is part of the current biodiversity, but also extinct clades, the most abundant and diverse being the Cretaceous to Paleogene Bothremydidae. Extant podocnemidids are restricted to freshwater environments of the Southern Hemisphere. By contrast, some extinct representatives of both Bothremydidae and Podocnemididae inhabited other regions, including Asia, Europe, and North America, some forms showing adaptations for life in transitional and even marine aquatic niches. Most adaptations to these habitats, especially to the marine ones, involved modifications in the skeletal morphology related to changes in their locomotion and the acquisition of more hydrodynamic body structures, mainly reflected in the carapace and appendicular skeleton. However, some modifications in the cranial anatomy and its neuroanatomy are also observed by the use of CT-scan and the reconstruction of internal cranial structures. Despite the neuroanatomical elements within Pleurodira are relatively conservative, some modifications exclusive to Podocnemidoidea were identified, as the shape of the endocranial cavity or the pattern of the facial nerve canals. Several neuroanatomical characters are exclusive to some of its lineages, as the presence of expanded cartilaginous rider in Bothremydidae, or short carotid canals in Podocnemidoidae. In addition, the shape and thickness of the semicircular canals of the labyrinth appear to correspond to adaptive responses. The differences observed through the comparative study of the neuroanatomical structures in several representatives of Podocnemidoidea are hereby discussed and included in a broader comparative framework within Pleurodira.

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Más información:

• Referencia: Martín-Jiménez, M., Pérez-García, A. 2025. The neuroanatomical structures in Podocnemidoidea (Testudines, Pleurodira) from the Cretaceous to the present: an update. In Vlachos et al. (Eds.), Book of Abstracts of the 5th Palaeontological Virtual Congress, 388.
• Figura: Escaneado de un cráneo de tortuga pleurodira (arriba izquierda), radiografía de uno de los cráneos analizados (arriba derecha), análisis de las estructuras craneales internas (abajo izquierda), y modelo tridimensional de los elementos neuroanatómicos (abajo derecha).

El registro fósil de simosáuridos en la región de Oriente Medio en el 5th Palaeontological Virtual Congress

Varios integrantes del Grupo de Biología Evolutiva de la UNED han presentado durante el 5th Palaeontological Virtual Congress el trabajo titulado “New perspectives on the simosaur fossil record of the Middle East: a preliminary review”. En esta comunicación, se han presentado resultados preliminares anatómicos y sistemáticos sobre nuevos restos de simosaurios de Israel, así como una puesta al día sobre el registro paleobiogeográfíco y estratigráfico de Simosauridae, con especial énfasis en la región de Oriente Medio. A continuación, os dejamos el resumen perteneciente a este trabajo:

Simosaurs (Simosauridae, Eosauropterygia) were marine reptiles whose fossil record is restricted so far to the Tethys west margin. They are mostly known from the lower Ladinian (Middle Triassic) to the Carnian (Upper Triassic) of Europe, where the only two defined species are known: Simosaurus gaillardoti, from the Ladinian of France and Germany; and Paludidraco multidentatus, from the Carnian of Spain. Conversely, Simosauridae is poorly represented by scarce fragmentary cranial and postcranial elements in the Middle East (i.e., Israel, Saudi Arabia, and Egypt). Those from Israel probably represent the oldest occurrence of Simosauridae, coming from uppermost Anisian or lowermost Ladinian levels. Most so far documented Middle East remains were studied more than two decades ago, when the only representative of the clade was S. gaillardoti. In this context, all the Middle East remains were referred to as Simosaurus sp. Recent anatomical and systematic studies have substantially increased knowledge about Simosauridae, allowing for a better identification of the diagnostic characters of both the clade and its representatives. In this sense, an exhaustive revision of the previously documented material from Israel, along with the study of relatively abundant unpublished material from the same country, and the recently published fossils from Egypt, is currently in process. Here, we provide anatomical and systematic analyses of all the remains attributable to Simosauridae from the Middle East, and paleobiogeographic implications for the clade. Postcranial elements not previously recorded for Simosauridae in the Middle East are recognized, along with the oldest unequivocal occurrence of this lineage.

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Más información:

• Referencia: Cabezuelo Hernández, A., de Miguel Chaves, C., Pérez-García, A. 2025. New perspectives on the simosaur fossil record of the Middle East: a preliminary review. In Vlachos et al. (Eds), Book of Abstracts of the 5th Palaeontological Virtual Congress, 26. 
• Imagen 1: Portada de la comunicación oral presentada en el congreso 5th Palaeontological Virtual Congress.

Una propuesta de etiquetado de microfósiles mediante un código de colores en el 5th Palaeontological Virtual Congress

Durante la quinta edición del Palaeontological Virtual Congress que ha tenido lugar durante el pasado mes de marzo, se presentó la comunicación titulada: "Proposal for managing microfossil labelling using colour codes". En este proyecto se propone reemplazar el siglado alfanumérico por un sistema basado en colores y su combinación, con el objetivo de facilitar una identificación visual rápida y eficiente. Esta metodología también permitirá reducir el espacio necesario para el siglado, lo que permite su aplicación en fósiles de pequeño tamaño, como dientes de cocodrilo y terópodo.

Además, se ha diseñado un sistema de organización asociado al código de color, que no solo optimiza la devolución de los ejemplares, sino que también reduce la posibilidad de disociación, mejorando al mismo tiempo el almacenamiento y la conservación de los mismos. El resumen es el siguiente:

Analyses of collections of small fossil vertebrate teeth, obtained by screen washing and hand picking of sediment samples, rank amongst the commoner techniques for determining the diversity of past ecosystems. However, the handling and management of these fossils present specific challenges due to their small size, particularly concerning the difficulty of applying legible and visible labelling, especially with alphanumeric characters. This increases the risk of dissociation between the fossils and their associated documentation.

A colour-coded labelling system is proposed here as an alternative to alphanumeric characters. This method links each specimen to its specific position within a storage box, where the necessary documentation for its identification is kept. Before applying the label, the most suitable area of the tooth is carefully assessed in order to avoid interfering with its future study.

The labelling system uses two coloured dots, each representing a row and column in the storage box, employing standardised colours based on the Pantone system. The dots are applied directly to the specimen's surface using an entomological needle, ensuring both precision and a minimal size. Corresponding positions in the box are marked with the same code, enabling specimens to be systematically returned to their original locations, thereby improving organisation and accessibility.

Each box incorporates a digital system with individual QR markers linking to associated information, such as photographs, photogrammetry models, and damage maps. This approach ensures the proper identification and preservation of specimens, minimises the risks of dissociation, facilitates handling, and optimises their consultation within scientific collections.

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Más información:

• Referencia: Nieto García, K., Marcos-Fernández, F., Ortega, F. 2025. Proposal for managing microfossil labelling using colour codes. In Vlachos et al. (Eds.), Book of Abstracts of the 5th Palaeontological Virtual Congress, 230.

Un nuevo crocodiliforme maquimosaurino del Jurásico Superior de Alpuente en el 5th Palaeontological Virtual Congress

Durante el mes de marzo tuvo lugar la quinta edición del Palaeontological Virtual Congress, donde se presentó la comunicación: "A machimosaurid crocodyliform from the Tithonian of the Villar del Arzobispo Formation at Alpuente (Valencia Spain)" realizada por Arturo Gamonal, Maite Suñer, Iván Narváez y Francisco Ortega. Este trabajo presenta los restos de un nuevo crocodiliforme maquimosaurino del Jurásico Superior de Alpuente. Estos nuevos restos son elementos poscraneales, con varios centros vertebrales, el sacro completo y un fémur, además de un fragmento de mandíbula. Se han comparado estos restos con los diversos talatosuquios del Jurásico Superior europeo, demostrando las similitudes de estos restos con la tribu Machimosaurinii, haciendo de estos restos los primeros elementos postcraneales de este taxón en España. El resumen es el siguiente:

Teleosauroidea were a diverse group of marine crocodyliforms that thrived during the Early and Middle Jurassic, having a decline in diversity towards the end of the Upper Jurassic. Few remains of this group have been recovered beyond the Jurassic-Cretaceous boundary. In this study, we present the remains of a large teleosauroid found in Alpuente (Valencia, Spain).

The material was recovered from the Corral de Marín fossil site, located at the base of the Villar del Arzobispo Formation, and dates from the lowermost Tithonian. It is therefore one of the few teleosauroids present during this age. The available remains include both cranial and postcranial elements: five dorsal vertebrae, a sacrum, four caudal vertebrae, a femur, a partial lower jaw, and osteoderms.

Comparative analysis with other teleosauroids from the Upper Jurassic of Europe reveals morphological features that enable its tentative classification within the Machimosaurini tribe. Key characters include the presence of three sacral vertebrae (two true sacrals and one caudosacral), the distinctive morphology of the Meckelian groove in the mandible, and the ornamentation of the teeth preserved in the alveoli of the lower jaw. The available characters allow for a preliminary assessment of the taxonomic status of the material, which exhibits unique features within the context of the Machimosaurini. This finding potentially represents the first record of skeletal remains for Machimosaurini in the Tithonian of Europe.

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Más información:

• Referencia: Gamonal, A., Suñer, M., Narváez, I., Ortega, F. 2025. A machimosaurid crocodyliform from the Tithonian of the Villar del Arzobispo Formation at Alpuente (Valencia, Spain). In Vlachos et al. (Eds.), Book of Abstracts of the 5th Palaeontological Virtual Congress, 242.
• Imagen: Reconstrucción en vida del cocodriliforme maquimosaurino del Jurásico Superior de Alpuente por Rafael Doñate.

Nuevos datos sobre la diversidad de tortugas de Ariño (Teruel) en el 5th Palaeontological Virtual Congress

Entre los trabajos presentados, por parte del Grupo de Biología Evolutiva de la UNED, en el recientemente celebrado 5th Palaeontological Virtual Congress se incluye uno que analiza la diversidad de tortugas del yacimiento del Albiense de Ariño, en Teruel. Dada el escaso registro de yacimientos con vertebrados esa edad a nivel europeo, la asociación faunística registrada en Ariño resulta peculiar. Así, allí fue definido el representante más antiguo de Pleurosternidae reconocido a nivel global, Toremys cassiopeia. Toremys no es la única tortuga primitiva allí representada, sino que, además de esa forma acuática, tortugas primitivas terrestres son reconocidas. Así, allí se ha definido un nuevo taxón, Aragochersis lignitesta, probablemente no siendo el único miembro de Helochelydridae registrado en esa mina de carbón.

En el nuevo trabajo presentado en este congreso científico se documenta, por primera vez, la presencia de una forma de tortuga derivada, que es atribuible al linaje de Pleurodira. Su atribución al grupo endémico de Europa Dortokidae no puede ser descartada. De ser correcta esta hipótesis, esta tortuga podría corresponder a la única de este linaje identificada en un largo lapso de tiempo en el que, hasta ahoras, no estaban representadas: a lo largo de los más de 35 millones de años que separan el Barremiense (en el Cretácico Inferior) del Santoniense (en el Cretácico Superior). El resumen de esta contribución es el siguiente:

The Spanish lower Albian Santa María coal mine (Ariño, Teruel Province) provides relevant information on European vertebrates that lived at the end of the Early Cretaceous. This is especially relevant considering that the pre-Albian and the uppermost Cretaceous faunas of Europe were remarkably different, but few sites provide data about this transition. One of the best-represented vertebrate lineage in this outcrop of the Escucha Formation is the turtles. Testudinata reported so far were limited to early representatives (i.e., taxa not attributable to the crown Testudines). Thus, a new aquatic turtle was defined, the pleurosternid Toremys cassiopeia; but also a new representative of the terrestrial lineage Helochelydridae, Aragochersis lignitesta. The coexistence of at least two helochelydrids was recently proposed. The analysis of new turtle remains, considering both isolated plates and a partial skeleton, allows us to identify a greater diversity, a representative of Testudines being recognized. It is attributable to Pan-Pleurodira and, most probably, to Dortokidae. Dortokids are exclusive to Europe, being relatively well-known at the Upper Cretaceous, from the Santonian to the Maastrichtian. They survived until the Paleocene. However, although they were identified from the Barremian, the Lower Cretaceous record is minimal: a gap is present from the Barremian to the Santonian. The Upper Cretaceous and Paleocene dortokids exhibit numerous derived traits relative to the Barremian representatives, including some unusual for Pan-Pleurodira (e.g., the loss of mesoplastra). The taxon from Ariño bridge the gap between them. Thus, analyzing it could provide new data on the diversity and evolution of this lineage.

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Más información:

• Referencia: Pérez-García, A., Espílez, E., Mampel, L., Cobos, A. 2025. On the potential youngest presence of dortokid turtes for the Lower Cretaceous record. In Vlachos et al. (Eds.), Book of Abstracts of the 5th Palaeontological Virtual Congress, 310. 
• Imagen: Holotipo de Aragochersis lignitesta, procedente del Albiense de Ariño (Teruel, España).

Tratamientos de consolidación adaptados a las características específicas de cada fósil en el 5th Palaeontological Virtual Congress

Durante el 5th Palaeontological Virtual Congress, celebrado online del 10 al 25 de marzo de 2025, el equipo de conservación del Grupo de Biología Evolutiva de la UNED presentó la comunicación titulada "The importance of adapting consolidation treatments to each fossil piece". Esta comunicación abordó la importancia de elegir tratamientos de consolidación adaptados a las características específicas de cada fósil y su contexto ambiental, garantizando intervenciones eficaces y respetuosas con la integridad de las piezas. 

Entre los temas destacados, se presentaron los criterios clave para la selección de consolidantes como Paraloid B72®, Acril ME y silicato de etilo, y los resultados de las pruebas realizadas en diferentes condiciones ambientales. Este trabajo subraya la relevancia de aplicar principios de intervención mínima y materiales reversibles para asegurar la sostenibilidad y conservación futura de los fósiles. Esta investigación no solo refuerza el valor científico y documental del patrimonio paleontológico, sino que establece una base metodológica esencial para futuras intervenciones en este campo. El resumen es el siguiente:

Consolidation is a key process in the conservation of fossils as it improves their internal cohesion, stabilizes damaged areas, and reinforces their structure. To ensure the effectiveness of the treatment, it is essential to select the appropriate consolidant, following rigorous criteria and adapting the intervention to the characteristics of each piece and its environmental context. The choice of consolidant should be based on factors such as the porosity of the fossil, its composition, and the active deterioration agents. Additionally, it is essential to apply principles of minimal intervention, prioritizing scientific and documentary value over aesthetic without compromising the integrity of the piece. Another crucial aspect is the discernibility of the consolidant material, both visually and in technical analyses, to avoid interference. Furthermore, the materials must be reversible and allow for future re-treatment. Based on these criteria, three consolidants that meet the established requirements and present different characteristics according to humidity and temperature have been selected: Paraloid B72® and Acril ME (acrylic resins) and ethyl silicate (inorganic). Tests were conducted on fossil fragments with various levels of porosity and alteration, in dry and humid conditions. The results showed that Paraloid B72® provides high cohesion and ease of application; ethyl silicate, while compatible with the fossil material, requires a prolonged curing time; and Acril ME is effective in humid environments. In conclusion, selecting the appropriate consolidant is fundamental to achieving an effective and durable treatment, which must be adapted to the specific characteristics of each fossil and each situation.

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Más información:

• Referencia: Fernández-Martínez, J., Fernández-Fernández, E., Marcos-Fernández, F. 2025. The importance of adapting consolidation treatments to each fossil piece. In Vlachos et al. (Eds.), Book of Abstracts of the 5th Palaeontological Virtual Congress, 225.

Análisis de las secuencias nucleotídicas de genes mitocondriales y nucleares de Crocodylia en el 5th Palaeontological Virtual Congress

Durante el 5th Palaeontological Virtual Congress, celebrado en formato online del 10 al 25 marzo, Ane de Celis presentó la comunicación titulada “Assessing the phylogenetic utility of molecular sequences in Crocodylia” en coautoría con Iván Narváez y Francisco Ortega. Esta comunicación se incluyó en la sesión temática “Unraveling crocodylomorph evolution: insights from fossils and new methodologies” y en ella se analizó la utilidad que tenían distintas secuencias nucleotídicas de genes mitocondriales y nucleares para reconstruir las relaciones filogenéticas entre las especies de Crocodylia existentes en la actualidad. 

Los resultados obtenidos del análisis individual de estos genes mediante inferencia bayesiana y máxima verosimilitud indicaron que las secuencias nucleotídicas de genes mitocondriales resultaron altamente útiles para discernir estas relaciones de parentesco entre cocodrilos, mientras que muchas de las secuencias parciales nucleares no fueron útiles con esta finalidad. El árbol filogenético final presentado, obtenido a partir de la concatenación y análisis conjunto de todas las secuencias nucleotídicas que resultaron tener una utilidad filogenética moderada-alta, muestra gran consistencia con hipótesis filogenéticas previas y valores de soporte muy altos en prácticamente todos los nodos. Los resultados obtenidos en este trabajo subrayan la importancia de seleccionar secuencias con utilidad filogenética para optimizar el análisis filogenético y serán de utilidad para posteriores estudios macroevolutivos en el clado Eusuchia. A continuación, el resumen del trabajo:

Palaeontologists traditionally rely on morphological characters and parsimony analyses to reconstruct phylogenetic relationships among organisms. In contrast, neontologists can use molecular sequences from extant species, a powerful tool for investigating evolutionary relationships. However, not all molecular sequences are equally valuable for elucidating phylogenetic affinity between taxa. While mitochondrial sequences like COX1 and CYTB are widely used and have a recognised phylogenetic utility, others are included in phylogenetic analyses without prior assessment. This is relevant for studies employing computationally demanding methodologies, such as Bayesian Inference, where increasing data size does not always improve phylogenetic resolution but significantly increases processing time. Therefore, 33 mitochondrial and nuclear nucleotide sequences from 23 extant crocodylian species were retrieved from NCBI GenBank to analyse their phylogenetic utility. Each sequence was aligned, tested for substitution saturation (protein-coding genes), and assigned its best nucleotide substitution model. Phylogenetic inference was performed using Bayesian Inference (BI) and Maximum Likelihood (ML), classifying the resulting trees in categories based on their ability to solve crocodylian relationships. Sequences producing trees with significant polytomies, mostly partial nuclear sequences, were discarded, reducing the dataset from approximately 26000 base pairs to 17500. The remaining sequences were concatenated and analysed with BI and ML, yielding a highly robust tree congruent with previous molecular phylogenetic hypotheses while optimising computational resources. These results underscore the importance of selecting molecular sequences with phylogenetic utility to improve both the robustness and efficiency of the analysis of crocodylian evolutionary relationships. Project funded by the Spanish Ministry of Science, Innovation and Universities (PID2023-148083NB-I00).

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Más información:

• Referencia: de Celis, A., Narváez, I., Ortega, F. 2025. Assessing the phylogenetic utility of molecular sequences in Crocodylia. In Vlachos et al. (Eds.), Book of Abstracts of the 5th Palaeontological Virtual Congress, 240.