Durante el XX EJIP, celebrado del 19-22 de abril en Cañaveral de León (Huelva), Fernando Sanguino y colaboradores han presentado el póster del trabajo titulado “Eggshell structure provides a first insight into the nesting ecology of the dinosaur egg clutches from Poyos (Upper Cretaceous, Guadalajara, Spain)”.
Recientes trabajos indican que la morfología del huevo y la estructura de sus cáscaras, en especial el grosor y porosidad de las cáscaras, está significativamente correlacionada con varios factores abióticos y bióticos como la temperatura y precipitación, el tamaño del adulto o el tipo de nido. A partir de los datos obtenidos en esos estudios en base a análisis de cáscaras de huevo de aves y reptiles no avianos actuales, se ha procedido a comparar dichos resultados con los huevos y cáscaras de huevos de dinosaurio procedentes del yacimiento de Poyos (Cretácico Superior de Guadalajara). Los huevos recuperados en las campañas de excavación parecen pertenecer a titanosaurios y son subesféricos, de gran tamaño, con cáscaras notablemente delgadas (~1mm) y muy poco porosas, especialmente cuando se les compara con huevos similares también atribuidos a titanosaurios. Dado que en reptiles no avianos actuales estas características se han encontrado en huevos adaptados a desarrollarse en condiciones secas y de alta temperatura, se interpreta, por un lado, que los huevos de dinosaurio de Poyos tendrían unas condiciones óptimas de desarrollo similares y, por otro lado, que probabablemente serían más secas y cálidas que las inferidas para otros huevos de titanosaurio.
A continuación, os dejamos el resumen del trabajo:
Egg morphology and eggshell functional properties are critical to the survival of the embryo, and therefore, its design is an excellent example of adaptative response to the environment. In extant birds and reptiles, egg size and shape, and eggshell thickness and porosity have been found to be significantly related with abiotic and biotic selective pressures. Thus, these relationships can be used to infer the nesting ecology of extinct species. The Poyos locality (Campanian-Maastrichtian, Villalba de la Sierra Formation) from Sacedón (Guadalajara, Spain) represents a recurrent dinosaur nesting area that has provided abundant oological remains, including clutches with complete eggs, believed to have been produced by titanosaurian sauropods. Current available information indicates that clutches from this locality are compatible with the pattern described in sites with reported in ovo titanosaurian embryos: a relatively high number of large eggs laid in a comma-shaped groove that may be completely covered by sediments. This is akin to most extant non-avian reptiles, which do not incubate their eggs and instead bury them in soil or mounds, thus remaining more exposed to the external environmental conditions. So far, all identified clutches from Poyos are comprised by large, subspherical eggs with thin (~1 mm) eggshells and low porosity. In extant non-avian reptiles, eggshell thickness has been found to have a positive relationship with humidity and precipitation, while porosity has a negative relationship with ground temperature, even when buried. Additionally, rounder eggs have a higher heat capacity compared to elongated eggs and, among extant species, have been found to be more common in hot and dry environments. Therefore, the egg morphology and eggshell structure features allow to infer that the studied eggs from Poyos were developed under high temperature and low humidity conditions.-----
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