¿Cómo se desplazaría un dinosaurio cojo? Entendiendo los límites de la locomoción de un ornitópodo de la Formación Arcillas de Morella en las X Jornadas Internacionales de Salas de los Infantes

Durante las X Jornadas Internacionales sobre Paleontología de Dinosaurios y su Entorno, miembros del Grupo de Biología Evolutiva de la UNED han presentado la comunicación titulada “How might a limping dinosaur move? Understanding the limits of the locomotion of an ornithopod from the Arcillas de Morella Formation (Castellón, Spain)”. En esta contribución, se han expuesto los resultados concernientes a la reconstrucción tridimensional de una cintura pélvica con anomalías anatómicas de un dinosaurio ornitópodo estiracosterno hallado de la Cantera de Mas de la Parreta, localizada en el municipio castellonense de Morella; siendo de especial interés la reconstrucción miológica en función de las marcas musculares, la descripción de las anomalías observadas y sus implicaciones en la locomoción del dinosaurio estudiado. A continuación, presentamos el resumen del trabajo:

Locomotion in non-avian dinosaurs is one of the most captivating aspects of the modern paleobiology of vertebrates. Despite the obvious constraints, the validation of biomechanical studies using fossils can be developed by a variety of methods: building of musculoskeletal models, analyzing fossilized footprints, comparing them with extant taxa, and studying the osseous elements. Among non-avian dinosaurs, a significant research on the reconstruction of inferred locomotion in styracosternan ornithopods has been conducted in recent years. Additionally, these dinosaurs are also known to have had a high number of palaeopathologies among the Mesozoic terrestrial vertebrates. Nevertheless, it is extremely rare to find pathologies or anomalous anatomical conditions affecting the mechanical processes of normal gait in any group of non-avian dinosaurs, considering the nature of the fossil record. Non-hadrosauroid styracosternan ornithopods are one of the best represented dinosaurs in the Lower Cretaceous European terrestrial vertebrate fossil record. In this context, the Arcillas de Morella Formation, in northeastern Spain, has provided a large amount of evidence for more than a decade. Among these, a nearly complete adult specimen from the Mas de la Parreta Quarry (CMP-5), characterized by several pathologies in its axial bones, exhibits an osteological anomaly in its left ilium. This anomaly consists of a markedly different morphology and proportions compared to its right counterpart. This results in a noticeable asymmetry of the pelvic girdle that affects the suprailiac crest and iliac plate muscle origins, mainly M. iliofemoralis, M. iliotibialis and possibly M. iliofibularis. Additionally, the morphology of the acetabulum would also be affected by this asymmetry. To analyze how this anomalous condition would affect the dinosaur, both 3D models of the pelvic girdle and the hindlimbs were created. Consequently, we have used photogrammetry to reconstruct the pelvis, right fibula and the first caudal vertebra of this individual. Additionally, photogrammetry was also implemented to finalize the reconstruction of the hindlimbs by utilizing bone elements from other individuals from the same fossiliferous area. These were scaled according to the proportions of the studied individual. Finally, the virtual skeleton was assembled using Blender software, establishing the areas of muscle origins and insertions. Therefore, the musculature reconstruction of this styracosternan provides a detailed examination of an unusual pelvic condition observed in a non-avian dinosaur. Regarding its lifestyle, this condition likely caused the styracosternan ornithopod to limp.

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