Evolución de la diversidad taxonómica y disparidad morfológica de los cocodrilos eusuquios durante el Cretácico-Paleógeno en el XX Annual Meeting de la EAVP

Durante el XX congreso anual de la EAVP, celebrado en Sabadell, se presentó el trabajo titulado “Decoupling of diversity and disparity in eusuchians (Crocodyliformes, Eusuchia) across the Cretaceous-Paleogene”. Si bien lo esperable es que los procesos de diversificación taxonómica vayan acompañados de un aumento de la disparidad morfológica, no siempre ocurre así y este es el caso que se presenta en dicho trabajo. Los resultados muestran que, mientras los análisis de diversidad taxonómica señalan que existe un aumento considerable de paleodiversidad tras el límite Cretácico-Paleógeno, los análisis de disparidad morfológica muestran una disminución significativa de la disparidad. Estos nuevos análisis de disparidad morfológica se han realizado utilizando el paladar de cocodrilos eusuquios y técnicas de morfometría geométrica. A continuación, el resumen del trabajo:

Despite the widespread belief that eusuchian crocodiles possess a conserved cranial architecture, recent studies have shown that the morphological variability of the group is greater than previously thought. Our study of the taxonomic diversity of Eusuchia revealed that, during the Cretaceous, its fossil record was dominated by hylaeochampsids and allodaposuchids, endemic to Europe, whereas the first representatives of the crown group Crocodylia were scarce at this time. After the K-Pg boundary, these basal eusuchians had disappeared and a radiation of the crown group took place. However, this taxonomic turnover does not necessarily imply a significant increase in the morphological variability. Therefore, the evolution of morphological disparity has been studied using a geometric morphometric approach focused on the palate of eusuchians. This structure was chosen because of the importance of the secondary palate in the evolutionary history of Crocodyliformes. The disparity was calculated using three different metrics, each capturing different aspects such as total range, dispersion, and distance. The disparity was analysed in both extant and extinct eusuchians, and across time and space. The results indicate that morphological disparity is higher during the Cretaceous than during the Paleogene, in contrast to taxonomic diversity, which is lower during the Cretaceous than during the Paleogene. These findings suggest the presence of a decoupling event between taxonomic diversity and morphological disparity during the K-Pg transition in this crocodyliform group.

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Más información:

• Referencia: de Celis, A., Narváez, I., Ortega, F. 2023. Decoupling of diversity and disparity in eusuchians (Crocodyliformes, Eusuchia) across the Cretaceous–Paleogene. In: Alba, D.M., Marigó, J., Nacarino-Meneses, C., Villa, A. (Eds.), Book of Abstracts of the 20th Annual Conference of the European Association of Vertebrate Palaeontologists, 26th June– 1st July 2023. Palaeovertebrata, Special Volume 1-2023: 22. DOI: 10.18563/pv.eavp2023 (p. 66).