Análisis de caracteres dependientes de la ontogenia en el paladar de cocodrilos eusuquios en el 67th Annual Meeting of the Palaeontological Association

Durante la reciente 67ª edición del congreso anual de la Palaeontological Association, celebrado en Cambridge la pasada semana, varios integrantes del Grupo de Biología Evolutiva de la UNED presentaron la comunicación titulada "Ontogeny-dependent palatal characters in Eusuchia and implications for character-scoring". En este trabajo se ha analizado la variabilidad ontogenética del paladar utilizando morfometría geométrica bidimensional en una amplia muestra de crocorilos eusuquios. De esta forma, se han identificado ciertas estructuras palatinas cuya forma y posición relativa varían considerablemente a lo largo de la ontogenia, y cuya variabilidad podría afectar a la codificación de los ejemplares en función de su estadio ontogenético. Con estos resultados, se han evaluado diferentes matrices de caracteres publicadas recientemente para el clado Eusuchia como las de Turner (2015), Narváez et al. (2021) y Rio & Mannion (2021) con el fin de detectar estos estados de carácter que pueden variar en función del estadio ontogenético. Por tanto, y aunque el porcentaje de estos caracteres palatinos es bajo dentro de estas matrices, es aconsejable tener en cuenta la fase ontogenética del ejemplar a la hora de codificarlos para evitar errores de puntuación. El resumen es el siguiente:

Although assessing the approximate ontogenetic stage of fossil crocodyliforms is sometimes straightforward when dealing with complete skulls, this can become challenging when dealing with highly fragmentary specimens. In such cases, the specimen may be a juvenile or subadult individual rather than an adult and, if unrecognized, immature individuals could be included in phylogenetic analyses. Since scoring immature specimens in character matrices is discouraged, it is therefore relevant to identify the ontogenetic stage of the specimens. Previous studies of the ontogeny of extant eusuchians have focused primarily on the dorsal view of the skull, and current knowledge of the ontogenetic morphological transformations in the palatal region is limited. Therefore, the present study analyses the ontogenetic variability of the palate using twodimensional geometric morphometrics on a large sample of extant crocodilians, including 334 craniums from hatchling to adult individuals of 23 species. The analysis allowed the identification of certain palatal structures whose shape and relative position vary considerably throughout ontogeny, and whose variability could affect the scoring of specimens depending on their ontogenetic stage. Furthermore, several recently published character matrices for the Eusuchia clade have been evaluated in order to detect these character states, which may vary depending on the ontogenetic stage.

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Más información:

• Referencia: Narváez, I., de Celis, A., Ortega, F. 2023. Ontogeny-dependent palatal characters in Eusuchia and implications for character-scoring. Programme & Abstracts of the 67th Annual Meeting of the Palaeontological Association, 11th–15th September 2023, University of Cambridge, UK: 123-124.
• Bibliografía adicional:
• Narváez, I., de Celis, A., Escaso, F., De Jesús, S.M., Pérez-García, A., Rodríguez, A., Ortega, F. 2021. Redescription and phylogenetic placement of the Spanish middle Eocene eusuchian Duerosuchus piscator (Crocodylia, Planocraniidae). Journal of Vertebrate Paleontology 41: e1974868.
• Rio, J.P., Mannion, P.D. 2021. Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem. PeerJ 9: e12094.
• Turner, A.H. 2015. A review of Shamosuchus and Paralligator (Crocodyliformes, Neosuchia) from the Cretaceous of Asia. PLoS ONE 10: 1–39.