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GLOBAL AND QUANTITATIVE ANALYSES INDICATE TITANOSAURIANS NESTING ON INLAND ENVIRONMENTS
BERNAT VILA; ALBERT G. SELLÉS; ASHU KHOSLA; FERNÁNDEZ, MARIELA S.
Simposio; VI Symposium of Eggs and babies; 2017
Eggs and clutches of the Megaloolithidae oofamily, profusely reported in Europe, India and South America, have been ascribed to titanosaurian sauropods. A key-point in the study of reproduction in titanosaurians is the selection of the nesting site which was most probably constrained by finding an environment with optimal incubation conditions that ensures the offspring success and avoid the pressure of predators. In order to test what, if any, habitat preferences existed among the titanosaurians during nesting season or if environmental versatility is statistically significant, we constructed a global database, based on literature and containing 132 sites with in situ megaloolithid eggs and clutches. The primary (inland and coastal) and the secondary (fluvial/palustrine-lacustrine/aeolic; barrier beach/lagoon/tidal flat) environments were specified for each site and the relationship between megaloolithid eggs and certain environments was tested by using statistical chi-square analyses. The results of the first chi-test found a global, statistically significant association of megaloolithid eggs with inland environments (87% of the sites). Splittered by regions, this association is positive in Europe and India (82% and 100% of the sites, respectively) whereas there is a random distribution in both inland and coastal habitats in South America. The tests made with the secondary environments call into question that the titanosaurians were versatil in the selection of nesting environments; global and regional analyses indicate that, as a rule, these sauropods show a clear and strong preference for nesting on inland habitats, in a variety of fluvial (Europe) and palustrine-lacustrine (India) settings, usually in mature paleosols developed in overbank deposits. This setting seems to fulfill the optimal conditions for incubation, irrespective of the varied lithologies of the nesting substrate.