Análisis funcional y paleoecológico de la anatomía sacral de Machimosaurus hugii en las XLI Jornadas de la SEP

Durante las XLI Jornadas de la Sociedad Española de Paleontología, que tuvieron lugar en Puertollano, durante los dias 30 al 3 de octubre, se ha presentado en poster "Functional and paleoecological implications of the sacral anatomy of Machimosaurus hugii (Thalattosuchia, Teleosauroidea) from the Late Jurassic of Portugal" en el que participan investigadores del Grupo de Biología Evolutiva de la UNED, en colaboración con el Museo de Alpuente y el Museo Geológico de Lisboa. En este trabajo se redescriben los elementos postcraneales del cocodrilo marino, Machimosaurus hugii, un cocodrilo marino de gran tamaño que habitó los mares del Jurásico Superior de europa. Los resultados preliminares de este nuevo estudio apuntan a un estilo de vida más terrestre que el resto del grupo de los Telesauridos, además de poner de manifiesto la importancia que tiene la región sacral, tanto a nivel sistemático, con caracteres muy diferentes entre especies del mismo grupo; como región que refleja la adaptación a la locomoción y estilo de vida de este grupo de animales. El resumen es el siguiente:

Throughout the Early and Middle Jurassic, thalattosuchians achieved a remarkable diversity, developing a wide range of adaptations within marine ecosystems via two distinct lineages: the pelagic, actively swimming Metriorhynchoidea, which evolved specialized paddle-like limbs and a hypocercal tail; and the Teleosauroidea, which retained more conservative adaptations tied to shallow, nearshore environments. This diversity gradually declined during the transition toward the Late Jurassic, leaving only a few surviving clades. Among the surviving teleosauroideans, machimosaurids exhibit a unique combination of adaptations, including a shorter and broader snout and blunt, conical teeth with pseudodenticles, which indicate a dietary shift toward durophagy. Within the genus Machimosaurus, M. hugii exhibits the most extreme expression of these characters, alongside a significantly larger body size. While recent research on this group has predominantly focused on cranial and mandibular anatomy, the postcranial skeleton has received little attention. However, postcranial elements are potentially highly informative. Among them, the sacrum can provide highly relevant information into locomotor mechanics, helping identify functional adaptations and thus contributing to a better understanding of the palaeoecology of machimosaurids. This study redescribes the preserved postcranial elements of Machimosaurus hugii, housed at the Museu Geológico in Lisbon (Portugal) including the first and second sacral vertebrae and a caudal vertebra. Based on this material, we analyze the morphological features of the sacral region, provide a comparative framework, and discuss the resulting palaeobiological implications for the locomotion and palaeoecology of these machimosaurids.

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Más información:

• Referencia: Gamonal, A., Narváez, I., Suñer, M. T., Ortega, F. (2026) Functional and palaeoecological implications of the sacral anatomy of Machimosaurus hugii (Thalattosuchia, Teleosauroidea) from the Late Jurassic of Portugal. In Narváez, I., Martínez-Pérez, C., Rodríguez-Tovar, F. J., Ortega, F. (Eds.), Libro de Resúmenes de las XLI Jornadas SEP. Palaeontological publications, 10, 191.