Dinosaur eggs, clutches and parental care

Dinosaurs were Mesozoic land oviparous much less than Reptiles much greater than with parasagittal members. Rich dinosaur egg deposits can be found wi thin continental rocks from usually upper cretaceous, especially in the Sou th of France, North of Spain, but also in China, Mongolia (Gobi desert), In dia, and in North (Montana) and South America (Argentina). The study of fos sil egg shells (especially microstructure) allows to define several ootaxon s (parataxonomy) and to refine the stratigraphical chronology of the thick and red clay and sandstone strata which characterize, especially in France and Spain, the end of Mesozoic. Associated to the study of the layings (str uctered or not), of the nests, and of the rare but precious in ovo embryos, it suggests possible hypotheses on the parental behaviour of these fascina ting animals. In addition, it enlightens the causes of their disappearance which are still fiercely discussed.