El registro de terópodos dromeosáuridos del yacimiento de Lo Hueco en las XXXVIII Jornadas de la SEP

Siguiendo con las comunicaciones presentadas por integrantes del Grupo de Biología Evolutiva de la UNED en las recientes XXXVIII Jornadas de la Sociedad Española de Paleontología, continuamos con el trabajo sobre el registro de dinosaurios terópodos del Cretácico Superior (Campaniense-Maastrichtiense) del yacimiento de Lo Hueco (Cuenca). En el trabajo se presenta el estudio de un conjunto de fémures atribuidos a un grupo de eudromeosáuridos relacionado con otros registros conocidos, en particular del Cretácico Superior de Europa. Aunqué la interpretación filogenética de material aislado es compleja, la semejanza de los fémures de Lo Hueco con un ejemplar hallado en el Campaniense-Maastrichtiense de Cruzy (sur de Francia) parece indicar la presencia de formas de pequeños terópodos dromeosáuridos estrechamente relacionados en las faunas del contexto iberoarmoricano de finales del Cretácico. El estudio de más material en el futuro permitirá testar esta hipótesis y comprender mejor las posibles relaciones filogenéticas con las faunas de otras áreas de Europa. El resumen es el siguiente:

The paleontological fossil site of Lo Hueco (Cuenca, Spain) comprises a sequence of mudstone levels from the upper Campanian-lower Maastrichtian of Villalba de la Sierra Formation. These levels yielded a rich fossil record of theropods mainly represented by isolated materials attributed to abelisaurids and different maniraptoran clades. Here a collection of nine almost complete and well-preserved femora of small-sized theropods is described and their taxonomic affinities are discussed. The most complete femora range in length from 200 to 257 mm in length, have relatively slender diaphyses and are typically bowed in both posterior and lateral views. They show several features that are considered as synapomorphies for Coelurosauria, including the poorly developed or absent fourth trochanter and the dorsal margin of the lesser trochanter which is level with the greater trochanter. There is a rugose area on the posterolateral surface of the femora just below the dorsal margin of the greater trochanter that probably corresponds to the posterior trochanter, and this is a feature diagnostic for the Paraves clade. However, this trochanter is represented by a small rugose area as occurs in alvarezsaurids and Velociraptor, but distinct from the raised crest shared by most other coelurosaurians. The lesser trochanter forms a robust crest that is completely fused to the greater trochanter, which is a feature shared with some alvarezsaurids, dromaeosaurins, unenlagiins, and avialans. The popliteal fossa on distal femora is open as occurs in most coelurosaurians, except for some alvarezsaurids in which the fossa is closed distally by contact between the condyles. The combination of features of the specimens from Lo Hueco is compatible with the Dromaeosauridae clade and their morphology particularly resembles some unenlagiine taxa from the Late Cretaceous of South America and Africa as well as some isolated materials from the iberoarmorican region attributed to indeterminate dromaeosaurids. 

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Más información:

• Referencia: Malafaia, E., Escaso, F., Coria, R. A., Ortega, F. 2023. Dromaeosaurid theropods from Lo Hueco fossil site (Late Cretaceous. Cuenca, Central Spain). In Ros-Franch, S., Paredes-Aliaga, M. V., Martínez-Pérez, C. (Eds.), Libro de Resúmenes de las XXXVIII Jornadas SEP. Palaeontological Publications, 4, 165.