El esqueleto postcraneal de los alodaposúquidos de Lo Hueco en las X Jornadas Internacionales de Salas de los Infantes

Durante las últimas décadas, nuestro conocimiento de los crocodiliformes eusuquios tempranos en la Península Ibérica se ha visto aumentado por una serie de hallazgos, entre los que destacan los del yacimiento de Lo Hueco, Cuenca. Allí se han descrito dos especies de cocodrilos allodaposúquidos, Lohuecosuchus megadontos y Agaresuchus fontisensis. Sin embargo, el esqueleto postcraneal de Allodaposuchidae en general y de estos dos taxones en particular todavía es relativamente desconocido. En este trabajo, presentado en las X Jornadas Internacionales sobre Paleontología de Dinosaurios y su Entorno 2025, se analizan las claves para la identificación del material del esqueleto axial de Lo Hueco como perteneciente a uno u otro taxón, abriendo la puerta a una mayor comprensión de la anatomía de estos organismos y sus implicaciones evolutivas y filogenéticas. El resumen de esta contribución, cuyo título es "New insights into Allodaposuchidae vertebrae anatomy: taxonomic assignment of Lo Hueco morphotypes", es el siguiente:

Allodaposuchidae is an eusuchian clade endemic to the Late Cretaceous of Europe, which has become a keystone in our knowledge of early eusuchian evolution in recent decades. The first allodaposuchid species to be described, Allodaposuchus precedens Nopcsa, 1928, was based on fossil remains from the Maastrichtian of Romania. Since then, several new species have been described at various Campanian-Maastrichtian fossil sites in Spain and France. Most of the described allodaposuchids lack or only preserve scarce postcranial remains. Consequently, the abundant postcranial fossil remains of allodaposuchids from the Lo Hueco fossil site (Cuenca, Spain) are of particular importance in addressing the anatomy of these basal eusuchians. At the Lo Hueco site, two allodaposuchids have been described: Lohuecosuchus megadontos and Agaresuchus fontisensis. These two sympatric and synchronic species were first described using the cranial remains that were available at the time. In contrast, the postcranial anatomy of these species was only preliminarily explored in a number of studies.

Despite the recognition of two different postcranial morphotypes (appendicular and axial) among the remains of Lo Hueco, these could not be confidently assigned to either of the two allodaposuchid species from this site. In parallel, there has been a surge of interest in the postcranial skeleton of crocodylomorphs in general, and eusuchians in particular, with different aspects like their morphology, functional biology, and disparity being explored. Numerous studies have emphasized a previously underestimated disparity and locomotor complexity, with significant evolutionary implications. In this context, the importance of a deeper study of allodaposuchid postcranial anatomy is highlighted.

Following the association between a series of postcranial remains and the holotype of Agaresuchus fontisensis, along with previous work on morphotype identification, one of the vertebral morphotypes from Lo Hueco can now be confidently assigned to one of the two recognized allodaposuchid species. Consequently, the second morphotype can be reasonably attributed to the other species. This study formally establishes the taxonomic identity of the axial eusuchian morphotypes previously recognized at Lo Hueco, with the one formerly presented as “robust” being L. megadontos and the one presented as “slender” being A. fontisensis. In addition, the morphology of the vertebral elements belonging to both species is described and compared. As a consequence of these results, the axial record of the Lo Hueco allodaposuchids becomes a valuable dataset for future studies regarding the macroevolutionary transformations of the postcranial skeleton in early eusuchians.

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Más información:

Referencia: Villanueva, A., de Celis, A., Narváez, I., Ortega, F. New insights into Allodaposuchidae vertebrae anatomy: taxonomic assignment of Lo Hueco morphotypes. In P. Huerta, F. Torcida, J.I. Canudo and X. Pereda (eds.). Abstract Book/Libro de resúmenes X Jornadas Internacionales sobre Paleontología de Dinosaurios y su entorno, 225-226.

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