INVESTIGADORES
FIORELLI Lucas Ernesto
congresos y reuniones científicas
Título:
DINOSAUR NESTING SITES AND EGGS FROM THE LATE CRETACEOUS OF URUGUAY: THE DEVELOPMENT OF THE PALAEO-OOLOGY IN THE LAST 10 YEARS
Autor/es:
ANDRÉS BATISTA; LUCAS ERNESTO FIORELLI; DANIEL PEREA
Lugar:
Caparica, Lisboa
Reunión:
Simposio; VI Symposium on dinosaur eggs and babies; 2017
Institución organizadora:
Universidade Nova de Lisboa
Resumen:
Dinosaur nesting sites, eggs and eggshells are well known in Cretaceous formationsworldwide, and Uruguay is not an exception. Since the 80´s dinosaur eggshells,eggs and egg clutches have been largely reported in the country from several sitesof Mercedes and Queguay formations. In the last 10 years, however, palaeo-oologyhas growth in relevance as a paleontological discipline in Uruguay, especially dueto new findings. Here we report a series of brand new dinosaur nesting sites, eggsand eggshells from the Late Cretaceous (Campanian-Maastrichtian for MercedesFormation ?based on palinomorphs?, and the age is still discussed for QueguayFormation) of Uruguay, displaying a wide diversity of dinosaurs not verified by boneremains. Classic and new outcrops were explored at central and western regionsof the country, allowing the discovered of several nesting sites in both units. Theseformations are characterized by conglomeratic sandstones with levels of ferricretes,silcretes, and calcretes. The morphologic and systematic analysis of these materialsprovide important evidences of its taxonomic assignment. We can describe with certainevidences that the most important fossil site, located in a private establishment closeto Algorta city, with many clutches containing dozens of in situ eggs and abundanteggshells belongs to neosauropods. Isolated eggs and eggshells represent a highbiodiversity (Sauropoda: Titanosauria; Theropoda: Avetheropoda, Averostra andAvialae), and are very common in other localities. In this abstract, we present anamended diagnosis of Sphaerovum erbeni and Tacuarembovum oblongum, howeverthe parataxonomic assignment of these specimens not represent a valid methodologyto fossil eggs classification as a biologic entity with evolutionary information. Dinosauregg remains from the Late Cretaceous units of Uruguay have particular diagenetichistory (high silicification), product of epigenetic processes that suffered both units.Palaeobiology and taphonomy, along with the geological characteristics, will shed lighton nesting behaviour and palaeoenvironmental aspects of egg-bearing units, whichwill reveal important aspect on dinosaur reproduction and the biological evolution ofamniotic egg. We suggest that the current western Uruguay had large and extensivenesting sites and reproductive colonies of titanosaurs. The study of these Uruguayandinosaur nesting sites and their eggs, as well as of its geo-paleoenvironment, willcontribute to the knowledge of amniote communities in South America during the LateCretaceous.